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1147
Effect of Adenosine on Histamine Release and
Atrioventricular Conduction During Guinea Pig
Cardiac Anaphylaxis
Lois J. Heller and Jean F. Regal
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Anaphylactic events occurring in cardiac tissue can result in severe metabolic imbalances. The present
study addresses the question of whether adenosine, produced in response to this stress, influences
either the antigen-antibody-induced alterations in cardiac function or the release of histamine, which
is known to be one of the important mediators of the anaphylactic reaction. Isolated hearts of passively
sensitized guinea pigs were perfused at constant flow in a Langendorff preparation with physiological
salt solution. Under control conditions, antigen challenge evoked a rapid transient release of histamine, an increase in coronary vascular resistance and beating rate, and an increase followed by a
decrease in left ventricular systolic pressure. The antigen-induced transient increase in adenosine
release from 0.26±0.07 to 4.66±0.48 nmol/min/g was associated with a 75 ±9% increase in the PR
interval in all hearts and atrioventricular blocks in six of 17 hearts. Antigen challenge was also
conducted in the presence of theophylline, 8-(4-sulfophenyl) theophylline (SP-T), erythro-9-(2hydroxy-3-nonyl) adenosine hydrochloride (EHNA), or exogenous adenosine. The major findings
were that 1) the antigen-induced prolongation of the PR interval was attenuated by the adenosine
receptor blockers theophylline (to 23 ± 6%) and SP-T (to 15 ±4%); 2) the incidence of antigen-induced
atrioventricular blocks tended to be decreased by theophylline (to three of 10 hearts) and SP-T (to zero
of seven hearts) and to be increased by the adenosine deaminase inhibitor, EHNA (to six of 10 hearts);
3) none of the interventions had major influences upon antigen-induced alterations in vascular
resistance, atrial automaticity, or systolic pressure; and 4) EHNA and adenosine both significantly
increased adenosine levels before anaphylaxis and also enhanced the total histamine release induced
by antigen challenge from a control value of 2,321 ± 244 ng/g to 3,424 ± 307 ng/g and 4,298 ± 616 ng/g,
respectively. We conclude from our data that increases in levels of endogenous adenosine during
cardiac anaphylaxis may contribute to the development of atrioventricular conduction delays and
blocks and that increases in levels of adenosine before antigen challenge may increase the amount of
histamine released during cardiac anaphylactic reactions. (Circulation Research 1988;62:1147-1158)
A cute interaction of antigen with specific anti/ \
bodies present in tissue results in the release
X \ - of various mediators and produces the rapid,
dramatic, and often life-threatening alterations in pulmonary and cardiovascular function referred to as anaphylaxis or an immediate hypersensitivity reaction.1 It
has been shown in several studies that when such interactions occur in heart tissue, there are increases
in heart rate, changes in atrioventricular action potential conduction, alterations in inotropic state, and increases in coronary vascular resistance.2"9 These alterations may produce a substantial imbalance in the
relation between oxygen supply and demand that is
likely to provoke an increase in adenosine formation
by the heart. 10 " Indeed, our recent studies indicate that
adenosine (and inosine) release into the venous effluent of isolated perfused guinea pig hearts is greatly
enhanced during an anaphylactic reaction.l2"14 This obFrom the Departments of Physiology and Pharmacology, University of Minnesota, Duluth, School of Medicine, Duluth, Minnesota.
Supported in part by National Institutes of Health grants HL34351 and HL-35869 and by grants from the American Heart Association, Minnesota Affiliate.
Address for correspondence: Lois Jane Heller, PhD, Department
of Physiology, University of Minnesota, Duluth, School of Medicine, Duluth MN 55812.
Received July 27, 1987; accepted January 6, 1988.
servation has been confirmed by a recent study of
Genovese et al.15
Since adenosine is known to dilate the coronary
vasculature,16 blunt the inotropic effects of histamine, 1718 decrease automaticity,1920 and delay atrioventricular nodal conduction,21 it is possible that the
endogenous adenosine may alter some of the effects
of the mediators released during cardiac anaphylaxis.
In addition, however, there are several reports that
suggest adenosine may affect the amount of mediators, such as histamine, released from various tissues
by antigen challenge.22"2* Thus, the role of adenosine
in modulating cardiac anaphylaxis may be quite
complex.
The studies reported here are designed to address
two specific questions: 1) does the adenosine produced
during anaphylactic reactions of isolated perfused
guinea pig hearts influence any of the observed
changes in beating rate, atrioventrieular conduction,
coronary vascular resistance, or left ventricular systolic pressure that result from the antigen challenge? and
2) does adenosine (either present at the time of antigen
challenge or produced during the anaphylactic reaction) influence the antigen-induced release of histamine from the isolated perfused guinea pig hearts?
Four separate interventions, designed to alter either
the effects or the tissue levels of adenosine, were used
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Vol 62, No 6, June 1988
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to answer these questions. These interventions included addition to the perfusion media of theophylline, an
adenosine receptor antagonist,27 8-(4-sulfophenyl)
theophylline (SP-T), a theophylline analogue confined
to the extracellular space20 and possessing potent adenosine-receptor antagonistic action,20-27 erythro-9-(2hydroxy-3-nonyl)-adenosine hydrochloride (EHNA),
an adenosine deaminase inhibitor28 that has been
shown to significantly increase estimates of interstitial
levels of adenosine in isolated rat hearts,29 or exogenous adenosine. The latter intervention was designed
to examine the effect of significant elevation of tissue
adenosine before antigen challenge upon the antigeninduced histamine release. Anaphylactic reactions produced in the presence of these interventions were compared with those produced under control conditions.
The major findings of this study were that endogenous adenosine produced during anaphylactic reactions 1) contributes significantly to PR interval prolongation and atrioventricular conduction blocks, 2) has
minimal influence upon antigen-induced alterations in
coronary vascular resistance, atrial automaticity, and
left ventricular systolic pressure, and 3) has little influence upon the amount of histamine released by the
antigen challenge. However, if adenosine levels are
elevated before antigen challenge, especially by perfusion with exogenous adenosine, histamine release is
significantly enhanced.
Materials and Methods
Production of Antibody and Passive Sensitization of
Guinea Pigs
Male guinea pigs (300-500 g, Dunkin-Hartley descendants from Bio-Lab, St. Paul, Minnesota) were
immunized with ovalbumin according to a regimen
that produced both IgG and IgE antibodies. The serum
from 12 animals was pooled and passed over a protein
A-Sepharose affinity column to separate IgG from other serum constituents. The ovalbumin-specific content
of this IgG preparation, assessed by a passive cutaneous anaphylactic reaction of anesthetized nonsensitized guinea pigs, was such that 245 ng IgG gave a 5mm bluing reaction in three of five guinea pigs.
Aliquots of this preparation were stored at — 20° C for
later use. Details of these procedures are included in a
previous study.30 For the experiments described in this
report, untreated ether-anesthetized guinea pigs were
passively sensitized to ovalbumin by intracardiac injections of 0.34 mg of the IgG preparation, 12-24
hours before removing hearts for perfusion. The few
hearts (<5%) that showed visible evidence of damage
from the intracardiac injection were not included in the
study.
Isolated Perfused Heart Preparation
Hearts removed from passively sensitized guinea
pigs that had been injected with heparin (2.5 mg i.p.)
and anesthetized with sodium pentobarbital (35 mg/kg
i.p.) were placed in ice-cold modified Krebs-Henseleit
solution. This solution contained (mM) NaCl 118.0,
KC1 4.7, NaHCO3 25.0, CaCl2 3.0, MgSO< 1.2,
KH2PO4 1.2, glucose 10.0, and Na2-EDTA, 0.5; and
insulin, 10 units/131 and heparin 1,000 units/1. After
trimming extraneous tissue from the heart, the aorta
was attached to the perfusion apparatus, and the coronary bed was perfused in a Langendorff preparation
with modified Krebs-Henseleit solution bubbled with
95% O2-5% CO2, pH 7.4. A probe placed in the right
ventricle through the atrioventricular valve was used to
record the intraventricular temperature, and by feedbackregulationof the temperature of the water jackets
surrounding the perfusion lines, the intracardiac temperature was maintained at 32° C. A peristaltic pump
was used to hold coronary flow constant at approximately 10 ml/min, a rate that produced an initial perfusion pressure of about 50 mm Hg. Perfusion pressure
was measured from a side arm in the perfusion line
located at heart level. Coronary vascular resistance
was calculated by dividing the perfusion pressure by
the flow rate per gram of wet heart weight. The wet
weight of the heart was determined at the end of each
experiment. A partially inflated fluid-filled balloon attached to a pressure transducer was placed in the left
ventricle through the mitral valve to record ventricular
pressure. Balloon volume was adjusted to obtain a
diastolic pressure (5-10 mm Hg) that produced maximum systolic pressure. A drain was placed in a puncture hole at the apex of the left ventricle toremoveany
fluid that might accumulate in the chamber. Bipolar
surface electrocardiograms were continuously recorded from electrodes placed on the right atrium and left
ventricle. Atrial and ventricular rates were determined
from the frequency of P waves and QRS complexes on
the ECG records. PR intervals were determined at
timed intervals from ECG records obtained at paper
speeds of 125 mm/sec. Hearts were perfused for 45
minutes before antigen challenge to allow stabilization
of the measured variables. The procedures described
above were used for previous studies of cardiac anaphylaxis.12-14
Protocol for Antigen Challenge
After equilibration in control preparations (n= 17),
1.34 mg ovalbumin in 0.2 ml normal saline was injected into the aortic cannula. Changes in perfusion pressure, left ventricular pressure, atrial and ventricular
beating rates, and PR intervals were monitored for 10
minutes after antigen challenge. Preliminary experiments indicated that challenge with these levels of
antigen and antibody resulted in consistent anaphylactic responses with maximal increases in heart rate,
coronary vascular resistance, and left ventricular systolic pressure. Because of tachyphylaxis to ovalbumin,
hearts were challenged only once. Previous experiments had shown that guinea pig hearts passively sensitized to ovalbumin reacted to challenge with bovine
serum albumin with less than a 5% change in heart
rate, perfusion pressure, PR interval, and left ventricular systolic pressure.
Samples of venous effluent were collected on ice
before and at timed intervals after antigen challenge.
One-milliliter aliquots were acidified with 0.1 ml 2N
Heller and Regal
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perchloric acid to prevent enzymatic degradation of
histamine, adenosine, and inosine. Samples were then
stored at - 2 0 ° C until assayed. Results were expressed as either the concentration in the venous effluent or the release into the venous effluent. Release was
calculated as the concentration in the venous effluent
multiplied by the coronary flow rate per gram wet
weight of heart. The total amount of histamine, adenosine, or inosine released during anaphylaxis was estimated by summation of the average content of the
substance in the effluent within each collection interval. In the case of adenosine and inosine, basal release
determined from preantigen levels was subtracted
from the total release to obtain an estimate of the total
change in release of adenosine and inosine induced by
antigen challenge.
To determine to what extent the antigen-induced
alterations in coronary vascular resistance and left ventricular systolic pressure were influenced by antigeninduced alterations in heart rate, atrial tissue was removed from five passively sensitized hearts, and
ventricular rate was held constant by external pacing at
4.0 Hz. This pacing rate was chosen because it was
above the maximum spontaneous ventricular rate
achieved during cardiac anaphylaxis. Pacing was initiated 10 minutes before antigen challenge and continued for the remainder of the experiment.
Four different approaches were used to assess the
effects of adenosine on cardiac anaphylaxis. In each
case, hearts were perfused with a substance that might
influence either the effects or levels of adenosine in the
hearts. Perfusion with these substances began 10 minutes before the antigen challenge and was continued
for the remainder of the experiment. These substances
included 1) 100 /JM theophylline (n= 10), an adenosine receptor antagonist,27 which at this concentration
has been shown to significantly attenuate adenosineinduced effects upon isolated perfused rat20-32 and guinea pig32 hearts; 2) 10 /x.M SP-T (n = 7), an adenosine
receptor antagonist,27 which at this concentration was
found in five preliminary experiments to attenuate the
decrease in coronary vascular resistance induced by
perfusion of guinea pig hearts with 10 (iM exogenous
adenosine (from - 1 7 ± 2 % to - 2 ± 5 % , p < 0 . 0 3 ) a n d
to eliminate the adenosine-induced development of
atrioventricular nodal conduction blocks (from 100%
to 0%, /?<0.00); 3) 10 fiM EHNA (n = 10), an adenosine deaminase inhibitor, which at this concentration
has been shown to significantly increase estimates of
interstitial levels of adenosine in isolated perfused rat
h e a r t s ; and 4) 10 FIM exogenous adenosine (n = 8).
Histamine Analysis
Histamine content of the samples of coronary effluent was determined by a manual fluorometric method.33'34 Histamine standards were included in each assay and carried through the extraction procedure.
Addition of 10 fiM adenosine did not alter the histamine standard curve. The total histamine content of
eight individual guinea pig hearts (which were neither
sensitized with antibody nor challenged with antigen),
Adenosine's Role in Cardiac Anaphylaxis
1149
perfused as described above for 45 minutes, was determined in the following manner, individual hearts were
homogenized in 2-3 ml 0.4N perchloric acid. The
homogenate was then centrifuged at 30,000g at 4° C
for 15 minutes, and the supernatant was diluted with an
equal volume of water and was assayed according to
the methods identified above.
Adenosine and Inosine Analysis
Adenosine and inosine content of the acidified samples of venous effluent was determined by high-performance liquid chromatography (HPLC) techniques
previously described.12 Briefly, 250-/A1 samples of
acid-treated venous effluent were injected directly
onto a reverse-phase, 5-^im C-18 HPLC column. The
mobile solvent was programmed as a linear gradient
changing from 95% 5 raM KH2PO4 and 5% of 100%
methanol to 75% 5 mM KH2PO4 and 25% of 100%
methanol during 25 minutes at a flow rate of 0.5
ml/min. Absorbance of the column eluate was continuously monitored at 254 nM. Absorbance peaks were
identified by comparison with retention times and peak
magnitudes of acidified known samples of adenosine
and inosine.
Data Analysis
Results are expressd as mean±SEM. Baseline values of the variables determined before interventions
were made are designated as pre values. Values of the
variables determined 10 minutes after addition of theophylline, SP-T, EHNA, or exogenous adenosine (just
before antigen challenge) are designated as initial values. The maximum value of the variable achieved during the anaphylactic reaction is designated as the peak
value. Paired t tests were used to compare pre values
with initial values with determine whether any of the
four interventions altered baseline levels of the variables being monitored. Paired t tests were also used to
compare initial values with peak values to determine
whether antigen challenge caused a significant change
in the variable. Determination of differences in peak
values between control and treated groups was assessed in two ways: 1) conservatively by analysis of
variance (ANOVA) with Scheffe's test for multiple
comparisons between groups or 2) less conservatively
with an unpaired t test with Bonferroni's correction for
multiple comparisons. Since statistical analysis may
be controversial in some cases, levels of significance
from both assessments are reported. In all cases, significant differences were unequivocally declared for p
values less than 0.05 obtained with the conservative
ANOVA test. Fisher's exact test was used to determine
whether the difference in incidence of arrhythmias was
significant.
Results
Antigen-Induced Alterations in Control Experiments
Addition of antigen to the perfusate of isolated, passively sensitized, guinea pig hearts resulted in release
of histamine, significant alterations in various functional characteristics, and substantial changes in aden-
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osine and inosine levels in the venous effluent. The
time course of these events as they occurred in the
control experiments is indicated in Figure 1. Histamine
release from one of the preparations and coronary vascular resistance determinations from three of the preparations were not reliably obtained and therefore not
included in the data analyses. All data were included in
the analyses of the other variables.
Note that the release of histamine was very rapid and
was completed within 4 minutes of the antigen challenge (Figure 1A). The maximum concentration of
histamine achieved in the venous effluent after antigen
challenge was 246 ±38 ng/ml. Increases in coronary
vascular resistance (Figure IB) and atrial rate (Figure
1C) reached their maximum values at approximately 2
minutes after the antigen challenge, and although there
was a tendency to decline somewhat, both coronary
vascular resistance and atrial rate remained elevated
above initial values throughout the 10-minute observation period. Left ventricular systolic pressure increased initially and then decreased below initial values to a minimum at 7 minutes (Figure ID).
There was a significant increase in the PR interval
that was transient, reaching a peak at about 3 minutes
after antigen challenge and returning toward initial
levels near the end of the 10 minutes (Figure IE).
Second- and third-degree atrioventricular nodal blocks
were evident in a total of six of the 17 preparations
(Figure IF) and appeared between 1.5 arid 7.0 minutes
after antigen challenge. PR intervals were not determined in these preparations when conduction blocks
occurred, and therefore, the sample number in each
PR-interval data point of Figure IE between 1.5 and
7.0 minutes is reduced from the total of 17 by the
number of preparations with conduction blocks at
this time.
Adenosine and inosine release also increased transiently after antigen challenge and had returned to
initial levels by about 8 minutes after antigen challenge
(Figures 1G and 1H). The concentrations of adenosine
and inosine in the venous effluent before antigen
challenge were 33 ± 8 nM and 275 ±38 nM, respectively, and reached maximums of 578 ± 56 nM and
3,105 ± 394 nM, respectively, during the anaphylactic
reaction.
The peak venous adenosine and inosine concentrations achieved during cardiac anaphylaxis of the six
preparations that did develop conduction blocks were
566 ± 74 nM and 3,904 ± 777 nM, respectively, while
those of the 11 preparations that did not develop con-
E. Pfl Interval
B. Coronary Vascular Resistance
a
o
s
'
e
F. Incidence o« Conduction Blocks
•
halengeUlnutes After Antigen Challenge
o
2
t
e
a
Ulnutes After Antigen Challenge
FIGURE 1. Time course of antigen-induced alterations in various characteristics of isolated, passively sensitized, perfused guinea pig •
hearts obtained under control conditions. (See text for details.)
Heller and Regal
Adenosine's Role in Cardiac Anaphylaxis
1151
TABLE 1. Coronary Vascular Resistance and Left Ventricular Systolic Pressure Before and After Antigen
Challenge of Paced (4.0 Hz) and Unpaced Isolated, Passively Sensitized, Guinea Pig Hearts
Paced preparations
Unpaced preparations
Peak
Peak
Initial
Pre
Initial
Variables
Heart rate (beats/min)
CVR (mm Hg/
ml/min/g)
LVSP (mm Hg)
135±14
240
240
4.31+0.33
109 + 8
4.41 ±0.34
78 ±3*
5.28±0.26t
101±llt
(83 ±5)
181 ± 6
269 ± 6 t
5.60±0.22
104±3
8.65±0.41t
13O±3t
(87±2)t
Data are mean ± SEM. Paced preparations, n = 5; unpaced preparations, n = 17 for heart rate and LVSP, n = 14 for
CVR. Values in parenthesesrepresentminimum LVSP obtained during the 10 minutes after antigen challenge. Pre values
obtained just before pacing and 10 minutes before antigen challenge; Initial values obtained just before antigen challenge;
Peak values obtained in response to antigen challenge.
CVR, coronary vascular resistance; LVSP, left ventricular systolic pressure.
*p<0.05 as compared with Pre value. tp<0.05 as compared with Initial value.
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duction blocks were 585 ± 7 9 nM and 2,660 ±407
nM, respectively. Although the mean value of venous
inosine achieved in hearts developing conduction
blocks was somewhat higher than that of hearts without conduction block, the difference was not signifi-
cant (p = 0A4).
The effect of pacing upon coronary vascular resistance and left ventricular systolic pressure and upon
the changes that occur during anaphylaxis is indicated
in Table 1. Changes in these variables that occurred
during anaphylaxis of the spontaneously beating preparations are included in Table 1 for comparison. Note
first that the initial coronary vascular resistance of the
preparations to be paced was slightly lower than that of
the spontaneously beating preparations, perhaps reflecting the fact that the atria were removed at the
beginning of the equilibration period. Note also that
initiation of pacing had no significant effect upon the
coronary vascular resistance but did result in a significant decrease in systolic pressure. Finally, note that the
antigen-induced responses of the paced preparations
were similar to those of the unpaced preparations in
that in both groups, significant increases in vascular
resistance and systolic pressure occurred, although the
magnitude of the vascular resistance change in the
paced preparations was somewhat less than in the unpaced preparations. The increase in systolic pressure in
the paced preparations was transient and returned to
the preantigen challenge levels within 3—4 minutes
but, unlike the spontaneously beating preparations, did
not fall below these initial values. These data indicate
that antigen-induced increases in coronary vascular resistance and systolic pressure in the spontaneously
beating hearts are not the results of an increase in
beating rate but rather the results of the direct effects of
the various mediators of the anaphylactic reaction.
The delayed depression in systolic pressure, however,
may reflect the effect of the sustained antigen-induced
tachycardia.
Effects of Adenosine-Modulating Interventions Upon
Antigen-Induced Alterations
Adenosine and inosine release. The effects of the
various interventions upon initial concentrations of
adenosine and inosine in the venous effluent are indicated in Table 2. Note that addition of theophylline and
the theophylline analogue, SP-T, did not significantly
alter the initial concentrations of adenosine, but for
unknown reasons, SP-T did decrease the initial concentration of inosine. Addition of EHNA increased the
adenosine concentration and decreased inosine concentration, which is consistent with its action as an
adenosine deaminase inhibitor. Addition of 10 /tM
exogenous adenosine increased venous levels of adenosine to 5.56 (JM before antigen challenge. Since venous levels of inosine also increased substantially, we
conclude that the infused adenosine was exposed to an
endogenous adenosine deaminase.
TABLE 2. Effect of Various Adenosine-Modulating Interventions on the Concentration of Adenosine and Inosine
in Venous Effluent of Isolated Perfused Guinea Pig Hearts
[Adenosine], nM
[Inosine], nM
Initial
Pre
Intervention
Initial
Pre
274 ±38
33 ± 8
Control (n=17)
43+14
332 ±72
252 ±28
36±17
+ THEO, 1 0 0 M M ( / I = 1 0 )
25±4
255 ±65
164±33*
tSP-T, 10/xM (n = 7)
28±4
306±45
184±23*
71 ±17*
37±7
+ EHNA, 1 0 M M ( / I = 1 0 )
5,559 ±266*
3,787 ±375*
292 ±29
27±5
+ ADO, 10 ^M (n = 8)
Adenosine and inosine levels were determined in the venous effluent before addition of the adenosine-modulating
substances (Pre) and 10 minutes later just before antigen challenge (Initial).
THEO, theophylline; SP-T, 8-{4-sulfophenyl) theophylline; EHNA, erythro-9-(2-hydioxy-3-nony\)adenosine hydrochloride; and ADO, adenosine.
*p<0.05, as compared with Pre value (paired I test).
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Antigen challenge evoked a significant increase
in release of adenosine and inosine in all groups
(p <0.05, paired t test). The antigen-induced release of
adenosine and inosine followed approximately the
same time course in all experimental groups as in the
control group (Figures 2A and 2B). The data in Figure
2C represent the total change in adenosine and inosine
release from the hearts induced by antigen challenge.
Note that neither theophylline nor its analogue affected
the total change in antigen-induced release of adenosine or inosine. Addition of EHNA, however, increased the total change in antigen-induced adenosine
release (Scheffe p<0.03, Bonferrroni p<0.001) and
tended to decrease the total change in antigen-induced
inosine release (Scheffep<0.20, Bonferronip<0.04).
These results are consistent with an EHNA-induced
inhibition of adenosine deaminase. The sum of the
total change in antigen-induced adenosine and inosine
release in the presence of EHNA was not different
from the control experiments. Addition of exogenous
adenosine resulted in an increase in the total change in
antigen-induced release of both adenosine (Scheffe
p<0.03, Bonferroni p<0.05) and inosine (Scheffe
/?<0.03, Bonferroni p<0.02).
Histamine release. The time course of release of
histamine after antigen challenge in the treated groups
2
i
I
Minutes After Antigen Challenge
1
was similar to that of the control group as shown in
Figure 3A. The average total histamine released by
antigen challenge in any of the groups represented a
range from 30% to 63% of the average total histamine
content of guinea pig hearts (Figure 3B). The total
amount of histaminereleasedby antigen challenge was
increased significantly above that of the control group
by addition of exogenous adenosine (Scheffe p<0.05,
Bonferroni p<0.01) and tended to be increased by
addition of EHNA (Scheffe p<0.20, Bonferroni
p<0.04). The reason for the high variability in the SPT group was not apparent.
Atrial rate. The time course of changes in atrial rate
induced by antigen challenge in all groups was similar
to that of the control group as shown in Figure 4A.
None of the interventions had a significant effect upon
the initial atrial rate or upon the maximum antigeninduced increase in atrial rate (Figure 4B). Except for
the preparations perfused with exogenous adenosine
or those that developed atrioventricular conduction
blocks during anaphylaxis, ventricular rate was the
same as the atrial rate shown in Figure 4A. Addition of
exogenous adenosine produced second- and third-degree blocks in all preparations before antigen challenge
so that the ventricular rate often became irregular and,
at an average rate of 74 ±4 beats/min, was significant-
FIGURE 2. Effects of antigen challenge on adenosine and inosine release from isolated, passively
sensitized, perfused guinea pig hearts obtained
under control conditions (CTL) and in the presence of 100 fjM theophylline (THEO), 10 yM 8(4-sulfophenyl) theophylline (SP-T), 10 fiM
eTyihro-9-(2-hydroxy-3-nonyl)adenosine hydrochloride (EHNA), or 10 fiM adenosine (ADO).
Panel A: Time course of adenosine release after
antigen challenge. Panel B: Time course of inosine release after antigen challenge. Panel C: Total change in release of adenosine (ADOr), inosine (INOr), and adenosine i+ inosine (ADOr +
INOr) obtained over the 10-minute interval after
antigen challenge. * and ** p<0.05 as compared
with value obtained under control conditions (t
test with Bonferroni correction and ANOVA followed by Scheffe test, respectively).
Heller and Regal
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a
£
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•
SPT (H-7)
EKHA(n-llJ)
o- —
2
Minutes After Antigen Challenge
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IMlnutM After Antigen Challenge
ft
^
I WE
• HTIAL
B KM
1
CTL
(O.17)
THEO
(iwiO)
8P-T
(n-7)
EHNA
ADO
(n.10)
(n-«)
FIGURE 4. Effect of antigen challenge on atrial rate of isolated, passively sensitized, perfused guinea pig hearts obtained
under control conditions (CTL) and during perfusion with 100
\iM theophylline (THEO), 10 \iM 8-(4-sulfophenyl) theophylline (SP-T), 10 fiM eryihm-9-(2-hydroxy-3-nonyl)adenosine
hydrochloride (EHNA), or 10 pM adenosine (ADO). Panel A:
Time course of changes in atrial rate after antigen challenge.
Panel B: Atrial rate before addition of the substance (PRE),
atrial rate 10 minutes after addition of the substance and just
before antigen challenge (INITIAL), peak atrial rate achieved
in response to antigen challenge (PEAK). §p<0.05 as compared with INITIAL value within that group (paired t test).
Adenosine's Role in Cardiac Anaphylaxis
1153
FIGURE 3. Effect ofantigen challenge on histamine release from isolated, passively sensitized, perfused guinea pig hearts obtained under control conditions (CTL) and during
perfusion with 100 fiM theophylline (THEO),
10 fiM 8-(4-sulfophenyl) theophylline (SP-T),
10 IJM erythro-9-(2-hydroxy-3-nonyl)adenosine hydrochloride (EHNA), or 10 yM adenosine (ADO). Panel A: Time course of changes
in histamine release after antigen challenge.
Panel B: Total histamine release obtained over
the 10-minute interval after antigen challenge
(solid bars) in the various groups and total
histamine content ofperfused unsensitized and
unchallenged guinea pig hearts (hatched bar).
* and ** p<0.05 as compared with value obtained under control conditions ft test with
Bonferroni correction and AN OVA followed by
Scheffe test, respectively). Percent designations above each solid bar represent comparison of mean value to average total histamine
content of unchallenged hearts.
ly slower than the atrial rate. In these preparations
treated with exogenous adenosine, the conduction
blocks remained throughout the anaphylactic reaction
during which time the ventricular rate increased to a
maximum of 226 ± 6 beats/min.
PR intervals and atrioventricular conduction
blocks. The time course of antigen-induced changes in
the PR interval in preparations treated with theophylline, SP-T, and EHNA was generally similar to that of
the control group, as shown in Figure 5A. Because of
the development of conduction blocks after antigen
challenge in some preparations, the actual sample
number in the data points from 1.5 to 7.0 minutes after
antigen challenge will be less than the total in that
group as indicated in Table 3. Addition of theophylline, theophylline analogue, or EHNA had no significant effects upon initial PR intervals as indicated in
Figure 5B and did not evoke any arrhythmias before
antigen challenge. As noted above, addition of exogenous adenosine resulted in second- or third-degree
conduction blocks in all eight preparations before antigen challenge. The maximum antigen-induced prolongation in the PR interval of the preparations (which, in
preparations with conduction blocks, occurred either
just before the block began or just after it ended) was
significantly attenuated in the presence of theophylline
(Scheffe p<0.05, Bonferroni p<0.Qil) or SP-T
(Scheffe p<0.03, Bonferroni p<0.01) but was not
influenced by EHNA. The antigen-induced incidence
and average duration of second- and/or third-degree
conduction blocks is given in Table 2. (All experiments were included for determination of the average
duration of the block.) There was no statistically significant difference in incidence or average duration of
these arrhythmias between groups. However, the com-
1154
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MlnutM Attar Antigen Challenge
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CTL.
the control group (Figure 6A). As can be seen in Figure
6B, addition of the theophylline and SP-T increased
the initial coronary vascular resistance, whereas addition of exogenous adenosine decreased this variable.
EHNA had no significant effect upon initial values
(paired t tests). The antigen-induced increase in coronary vascular resistance was attenuated in the presence
of theophylline (Scheffe /?<0.04, Bonferronip<0.03)
but was not significantly altered by additions of SP-T,
EHNA, or exogenous adenosine.
Left ventricular systolic pressure. The time course
of changes in left ventricular systolic pressure after
antigen challenge in all but one of the experimental
groups was similar to that of the control group (Figure
7A). As can be seen from Figure 7B, the only intervention that influenced the initial value of systolic pressure
was addition of theophylline, which resulted in a slight
but significant increase in pressure development
(paired t test). The antigen-induced increase in systolic
pressure was attenuated in the presence of the SP-T
(Scheffe /><0.01, Bonferroni p<0.01) but was not
(n-17)
FIGURE 5. Effect of antigen challenge on PR intervals obtained from ECG records of isolated, passively sensitized, perfused guinea pig hearts under control conditions (CTL) and
during perfusion with 100 (JLM theophylline (THEO), 10 /XM 8(4-sulfophenyl) theopbylline (SP-T), 10 txM erythro-9-(2-/i;ydroxy-3-nonyl)adenosine hydrochloride (EHNA), or 10 yM
adenosine (ADO). Panel A: Time course of changes in PR
intervals after antigen challenge. Sample numbers for data
points between 1.5 and 7.0 minutes after antigen challenge may
differ from the total depending upon presence or absence of
atrioventricular nodal conduction block (see Table 3). Panel B:
PR intervals just before addition of the substance (PRE), PR
intervals 10 minutes after addition of the substance and just
before antigen challenge (INITIAL), peak PR interval achieved
in response to antigen challenge (PEAK). §p<0.05 as compared with INITIAL value' within that group (paired t test),
**p<0.05 as compared with CTL values (ANOVA followed by
Scheffe test).
plete absence of atrioventricular conduction blocks in
the presence of SP-T, the tendency for a shortened
duration of these arrhythmias in the presence of theophylline, and the 60% incidence of these arrhythmias
occurring in the presence of EHNA deserves note.
Coronary vascular resistance. The time course of
changes in coronary vascular resistance after antigen
challenge in all treatment groups was similar to that of
TABLE 3. Incidence and Duration of Atrioventricular Conduction Blocks Induced by Antigen Challenge of Isolated, Passively Sensitized, Guinea Pig Hearts
Control
+THEO +SP-T +EHNA
Incidence (n/total n)
6/17
3/10
0/7
6/10
1.2±0.4
Duration* (minutes) 1.1 ±0.5
0.5±0.3
0
•Duration of block is calculated from the total n in each group.
THEO, theophylline; SP-T, 8-(4-sulfophenyl) theophylline; and
EHNA, <ry''Iro-9-(2-hydroxy-3-nonyl)a(ienosine hydrochloride.
(
e r - •
•
T>CO(n-10)
aP-TH-7)
E
MlnutM After Antigen Challenge
FIGURE 6. Effect of antigen challenge on coronary vascular
resistance (CVR) of isolated, passively sensitized, perfused
guinea pig hearts under control conditions (CTL) and during
perfusion with 100 nM theophylline (THEO), 10 fxM 8-(4sulfophenyl) theophylline (SP-T), 10 pM eryihro-9-(2-hydroxy3-nonyl)-adenosine hydrochloride (EHNA), or 10 (JLM adenosine (ADO). Panel A: Time course of changes in CVR following
antigen challenge. Panel B: CVR before addition of the substance (PRE), CVR 10 minutes after addition of the substance
and just before antigen challenge (INITIAL), peak CVR
achieved in response to antigen challenge (PEAK). §p<0.05 as
compared with PRE value within that group (paired t test),
§§p<0.05 as compared with INITIAL value within that group
(paired t test), **p<0.05 as compared with CTL value (ANOVA
followed by Scheffe test).
Heller and Regal
1155
ing the anaphylactic reaction does not influence antigen-induced histamine release. However, antigen-induced histamine release from sensitized guinea pig
hearts is enhanced when adenosine levels before antigen challenge are increased. The bases for these conclusions and their implications are presented below.
E
ft
0)
Adenosine's Role in Cardiac Anaphylaxis
100
Mlmitas Aftar Antlgan Ch«ll«ng»
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FIGURE 7. Effect of antigen challenge on left ventricular systolic pressure (LVSP) of isolated, passively sensitized, perfused
guinea pig hearts under control conditions (CTL) and during
perfusion with 100 pM theophylline (THEO), 10 fiM 8-(4sulfophenyl) theophylline (SP-T), 10 yM eryihw-9-(2-hydroxy3-nonyl)-adenosine hydrochloride (EHNA), or 10 \xM adenosine (ADO). Panel A: Time course of changes in LVSP after
antigen challenge. Panel B: LVSP before addition of the substance (PRE), LVSP after addition of the substance and just
before antigen challenge (INITIAL), peak LVSP achieved in
response to antigen challenge (PEAK). §p<0.05 as compared
with PRE value within that group (paired t test), §§p<0.05 as
compared with INITIAL value within that group (paired t test),
**p<0.05 as compared with CTL values (ANOVA followed by
Scheffe test).
altered by the other interventions. The magnitude of
the delayed decrease in systolic pressure was not altered by any of the interventions.
Discussion
Responses of the isolated, sensitized guinea pig
hearts to antigen challenge under control conditions
(shown in Figure 1) are similar to those reported in a
previous study from this laboratory12 and by others.2"9
The present study comparing these control responses
to anaphylactic reactions obtained in the presence of
various substances that modify adenosine effects or
levels leads to several new conclusions. First, the very
high level of adenosine produced by the heart after
antigen challenge may contribute significantly to the
prolongation of the PR interval and to the development
of atrioventricular conduction blocks that occur during
cardiac anaphylaxis. Second, it does not appear as if
the adenosine produced during anaphylaxis has a major influence upon the antigen-induced changes in
coronary vascular resistance, left ventricular systolic
pressure, or atrial rate. Third, adenosine produced dur-
Endogenous Adenosine Promotes Development of
Atrioventricular Conduction Delays and Blocks
During Cardiac Anaphylaxis
This conclusion is based upon the previous observations that exogenous adenosine produces atrioventricular nodal conduction delays and blocks in guinea pig
hearts32 and the present observations that 1) substantial
amounts of adenosine are released during anaphylaxis
with a time course that is similar to the PR-interval
prolongation and incidence of atrioventricular blocks
(Figure 1); 2) theophylline and SP-T, which significantly attenuate the effect of exogenous adenosine on
development of conduction block in this preparation,
also attenuate the antigen-induced increase in PR intervals (Figures 5A and 5B); 3) SP-T eliminated the development of atrioventricular conduction blocks (Table 3); and 4) EHNA tended to increase the incidence
of conduction blocks (Table 3). These findings are
consistent with previous studies suggesting that endogenous adenosine may be an important modulator of
atrioventricular nodal function under hypoxic conditions2133 and confirm preliminary reports that adenosine may also contribute to atrioventricular conduction
blocks during cardiac anaphylaxis.
The effectiveness of SP-T in blocking the antigeninduced alterations in PR intervals confirms a previous
suggestion32 that the effects of adenosine upon atrioventricular conduction are most likely exerted through
interaction with an extracellular receptor. This conclusion is based upon studies that suggest SP-T does not
enter cells,20 and its effects are therefore not complicated by inhibition of intracellular phosphodiesterases.27
Wolff and Levi36 have suggested that the antigeninduced alterations in impulse conduction in the heart
may be primarily due to released histamine. They
based this conclusion upon three lines of evidence:
1) arrhythmias produced by exogenous histamine are
qualitatively similar to those produced by immunological challenge, 2) the alterations are directly proportional to the amount of histamine released from the
isolated heart during anaphylaxis, and 3) antihistamines can prevent the development of the arrhythmias.
Studies by Wiedmeier and Spell37 indicate that exogenous histamine results in significant increases in adenosine released from isolated perfused hearts. This information, combined with the present observation that
theophylline and SP-T attenuated the atrioventricular
conduction delays and/or blocks during cardiac anaphylaxis without altering the histamine release, suggests that it is not the histamine that is actually producing the atrioventricular conduction defects, but rather
it is the endogenous adenosine produced in response to
the other effects of histamine (and probably other mediators as well).
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Endogenous Adenosine Has Little or No Effect on
Changes That Occur in Atrial Automaticity, Left
Ventricular Systolic Pressure, or Coronary Vascular
Resistance During Cardiac Anaphylaxis
We originally hypothesized that the high adenosine
levels that were achieved during the anaphylactic reaction might have some modulating influence upon the
antigen-induced alterations in other cardiac functional
variables. Specifically, since adenosine is a vasodilator,16 attenuates the inotropic effects of histamine,1718
and has negative chronotropic effects,19 we expected
that the antigen-induced increase in coronary vascular
resistance, systolic pressure, and atrial rate would be
enhanced by the presence of the adenosine receptor
antagonists theophylline and SP-T. We also expected
that the increased adenosine levels achieved in the
presence of EHNA and exogenous adenosine during
anaphylaxis (Figure 2) might have attenuated the antigen-evoked increase in coronary vascular resistance,
systolic pressure, and sinus rate.
In the present studies, the predicted effects of the
adenosine receptor antagonists on antigen-induced alterations in beating rate, coronary vascular resistance,
and left ventricular systolic pressure clearly were not
obtained. The antigen-induced increases in atrial rate,
vascular resistance, and systolic pressure were not enhanced by theophylline or SP-T (Figures 4B, 6B, and
7B). In fact, in the presence of theophylline, the antigen-induced increase in coronary vascular resistance
was significantly attenuated (Figure 6B), and in the
presence of SP-T, the antigen-induced increases in left
ventricular systolic pressure were actually eliminated
(Figure 7B). Since antigen-induced changes in coronary vascular resistance and systolic pressure in the
spontaneously beating preparations are similar to those
achieved in paced preparations (comparing data from
Figure 1 and Table 1), it is unlikely that the slight
differences in the ventricular beating rate between the
control preparations and those treated with theophylline and SP-T that were due to the variable appearance
of conduction blocks during anaphylaxis could account for the unexpected effects of theophylline and
SP-T. These attenuating effects of theophylline and
SP-T upon antigen-induced alterations in coronary
vascular resistance and systolic pressure, respectively,
are interesting, but they are unexplainable findings that
may well be related to other effects of these agents
(e.g., an increase in cyclic AMP by theophylline) that
are not directly related to their antagonistic influence
upon adenosine receptors.
The enhanced adenosine levels observed during
anaphylaxis in the presence of EHNA and exogenous
adenosine also did not produce the expected effects.
Neither of the interventions produced the expected attenuations of the antigen-induced increases in atrial
rate, coronary vascular resistance, or left ventricular
systolic pressure (Figures 4B, 6B, and IB). It should
be noted, however, that some (or all) of these proposed
adenosine-induced attenuations might have been cancelled out by the adenosine-induced augmentation of
histamine release that occurred with EHNA and exogenous adenosine perfusion as discussed below.
These results might suggest that under anaphylactic
conditions, theophylline and SP-T do not block the
effects of endogenous adenosine and that EHNA does
not increase interstitial adenosine concentration in the
vicinity of the effector cells. However, we think it
more likely that the powerful vasoconstrictive, positive chronotropic and initial positive inotropic effects
of various mediators of cardiac anaphylaxis (e.g., histamine, thromboxane, prostaglandins, and leukotrienes2"9) simply overwhelm the vasodilatory, negative chronotropic and indirect negative inotropic
effects of the increased adenosine levels. The only
significant observable effect of the elevated adenosine
levels during anaphylaxis is the pronounced negative
dromotropic action.
Adenosine Production During Anaphylaxis Does Not
Influence Histamine Release, but Elevation of
Adenosine Levels Before Antigen Challenge
Enhances Histamine Release
The first part of this conclusion is based upon the
observations that maximum histamine release after
antigen challenge always preceded maximum adenosine release and that the time course of histamine release after antigen challenge was not altered by any of
the interventions. The second part of the conclusion is
based upon the observations that treatment with EHNA
and exogenous adenosine that increased initial prechallenge concentrations of adenosine in the venous
effluent (Table 2) also was associated with enhanced
histamine release upon antigen challenge (Figures 3A
and 3B). These findings are consistent with previous
studies indicating that exogenous adenosine enhanced
antigen-induced release of histamine from rat mast
cells,22 from guinea pig lung tissue,23 and when added
at the time of antigen challenge, from human basophil
cells and human lung mast cells. It should be noted,
however, that the presence of adenosine before antigen
challenge has also been found to inhibit histamine release from the human cells.
The total histamine content of guinea pig hearts was
similar to that reported by others.36 The proportional
amount of histamine released under control conditions
in these preparations (34% of the total) is similar to that
reported by Capurro and Levi4 to be released from
guinea pig hearts during in vivo fatal systemic anaphylaxis (31% of the total). The adenosine-induced enhancement of histamine release with EHNA and exogenous adenosine to 51% and 63% of the total,
respectively, suggest that there may be substantial
modulation of this variable.
Our study also suggests that adenosine's potentiation of histamine release in this model is probably not
mediated through A, or A2 receptor mechanisms. If
such receptors were involved, we might have expected
the nonspecific adenosine receptor antagonists theophylline and SP-T to decrease the antigen-induced histamine release. Such a decrease was not evident from
our data (Figure 3B). However, because of the wide
variability in the antigen-induced histamine release of
the SP-T-treated preparations, we are hesitant to draw
specific conclusions from these data. It may also be
Heller and Regal
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that it was only in the presence of EHNA or exogenous
adenosine that the tissue levels of adenosine before
antigen challenge were high enough to influence histaraine release. Studies of theophylline antagonism of
adenosine's effects on histamine release in other models are not consistent. Results of earlier studies indicated that theophylline attenuated adenosine modulation
of histamine release from isolated rat mast cells,22 human basophils,24 and human mast cells.23 However,
Church et al26 recently reported that 8-phenyl-theophylline did not influence adenosine potentiation of
immunologically induced mediator release from rat
mast cells. In addition, Lohse et al38 recently found that
methylxanthines did not block the adenosine potentiation of calcium ionophore- or concanavalin A-induced histamine release from rat mast cells. Our data
support the conclusions of these most recent studies
that adenosine's effect on histamine release is not mediated through A, or A2 receptors but rather may be
dependent upon action at an intracellular site.
Assumptions
The conclusions of our study are based upon the
assumption that adenosine levels in the coronary effluent reflect, by some constant factor, the interstitial
levels of adenosine in the vicinity of the various effector cells (e.g., vascular smooth muscle, atrioventricular nodal tissue, pacemaker cells, myocardial cells,
and mast cells). We concede that this assumption may
not be valid. The vascular endothelium under control
conditions represents a considerable metabolic barrier
for adenosine.3940 It is likely that, under steady-state
conditions, venous adenosine concentration significantly underestimates the interstitial adenosine concentration produced by endogenous processes and
overestimates that concentration produced by adenosine infusion.2941 The fact that in the present study we
found perfusate adenosine concentration to decrease
from 10 (J.M to 5.5 (i.M as it passed through the coronary bed indicates that significant uptake and/or degradation processes are present in this preparation. It
should also be pointed out that during an anaphylactic
reaction, significant changes in the metabolic and
physical characteristics of the vascular endothelial barrier may occur. If so, variations in adenosine release
may be misleading. However, in the absence of any
specific information about anaphylaxis-induced alteration in the endothelial barrier for adenosine, we have
assumed that changes in adenosine release are proportional to changes in tissue levels of adenosine.
Adenosine release from these hearts under control
conditions before antigen challenge was somewhat
higher than that reported for guinea pig hearts perfused
at constant pressure.l0'42'43 This discrepancy may result
from several differences in experimental conditions
(e.g., 32° versus 37° C, perfusate contents, and ventricular loading conditions) as well as from the lack of
ability of the hearts in the present study to autoregulate
flow to meet metabolic needs. The observations that
both theophylline and SP-T additions increased the
coronary vascular resistance before antigen challenge
(Figure 4) suggests that under initial conditions, en-
Adenosine's Role in Cardiac Anaphylaxis
1157
dogenous adenosine levels were high enough to have
vasodilatory effects.
Release of adenosine after antigen challenge under
control conditions is substantial and most likely reflects the severity of the mismatch between oxygen
supply and demand. 10 " Although the absolute peak
magnitude of adenosine release after antigen challenge
(4.50 ±0.48 nmol/min/g) is significantly greater than
that reported to occur with challenges such as norepinephrine,10 severe hypoxia,42 or isoproterenol43 (1.5,
1.6, and 1.9 nmol/min/g, respectively), the relative
increase in adenosine release (15-fold) was similar to
those reported in these studies (18-fold, 30-fold, and
14-fold, respectively). The enhancement of the antigen-induced increase in release of adenosine in the
presence of exogenous adenosine (Figure 2C) is not
clearly understood. It is not likely that this enhancement reflects saturation of an adenosine deaminase^
system since our data also show that the antigeninduced change in inosine release in the presence
of exogenous adenosine is also greatly enhanced
(Figure 2C).
A second assumption that we have used is that the
effects we are noting are primarily due to adenosine.
However, it has been reported that, at high concentrations, exogenous inosine may act as a coronary vasodilator44 and, furthermore, may influence histamine release from rat mast cells.22 The source of the inosine in
the venous effluent of the hearts in the present study is
not fully understood. The decrease in inosine concentration in the presence of EHNA is consistent with the
suggestion that at least part of the inosine is a result of
deamination of adenosine. However, inosine may also
arise from.activity of a cytoplasmic 5' nucleotidase
acting preferentially upon inosine monophosphate.45
Given the high levels of inosine in the coronary effluent under initial conditions and especially after antigen
challenge, it is indeed possible that this substance may
also have significant effects.
Acknowledgments
We appreciate the expert advice of Dr. Ronald R.
Regal of the Statistical Center of the University of
Minnesota, Duluth. We also thank Richard A. Nelson
for his excellent technical assistance with this study
and Carol Peterman and Nancy LaVoy for their careful
attention to the preparation of the manuscript.
References
1. Bleecker ER, Lichtenstein LM: Systemic anaphylaxis, in Lichtenstein A, Fauci S (eds): Current Therapy in Allergy and
Immunology. Philadelphia, Decker, 1983, pp 78-83
2. Feigen GA, Prager DJ: Experimental cardiac anaphylaxis:
Physiologic, pharmacologic and biochemical aspects of immune reactions in the isolated heart. Am J Cardiol 1969;
24:474-491
3. Levi R: Effects of exogenous and immunologically released
histamine on the isolated heart: A quantitative comparison. J
Pharmacol Exp Ther 1972;182:227-238
4. Capurro N, Levi R: Anaphylaxis in the guinea-pig isolated
heart: Selective inhibition by buriamide of the positive inotropic and chronotropic effects of released histamine. Br J Pharmacol 1973;48:620-628
1158
Circulation Research
Vol 62, No 6, June 1988
Downloaded from http://circres.ahajournals.org/ by guest on June 18, 2017
5. Capurro N, Levi R: The heart as a target organ in systemic
allergic reactions. Comparison of cardiac anaphylaxis in vivo
and in vitro. Circ Res 1975;36:52O-528
6. Liebig R, Bemauer W, Peskar BA: Prostaglandin, slow reacting substance, and histamine release from anaphylactic guinea
pig hearts and its pharmacological modification. Naunyn
Schmiedebergs Arch Pharmacol 1975;289:65-76
7. Zavecz JH, Levi R: Separation of primary and secondary cardiovascular events in systemic anaphylaxis. Circ Res 1977;
40:15-19
8. Levi R, Burke JA, Corey EA: SRS-A, leukotrienes and immediate hypersensitivity reactions of the heart. Adv Prostaglandin
Thromboxane Uukotriene Res 1982;9:215-222
9. Aehringhaus U, Peskar BA, Wittenberg HR, Wolbling RH:
Effect of inhibition of synthesis and receptor antagonism of
SRS-A in cardiac anaphylaxis. BrJPharmacol 19S3;$0:73-80
10. Bardenheuer H, Schrader J: Supply-to-demand ratio for oxygen determines formation of adenosine by the heart. Am J
Physiol l986;25O(Heart Circ Physiol 19):H173-H180
11. Sparks HV Jr, Bardenheuer H: Regulation of adenosine formation by the heart. Circ Res 1986;58:193-201
12. Regal JF, Heller LJ: Cardiac anaphylaxis in isolated guinea pig
hearts perfused at constant flow or constant pressure. Proc Soc
Exp Biol Med 1987;185:193-200
13. Heller LJ, Nelson RA, Regal JF: Adenosine increases antigeninduced histamine release from isolated guinea pig hearts (abstract). Circulation 1986;74:II-176
14. Heller LJ, Nelson RA, Regal JF: Role of adenosine in arrhythmia generation during cardiac anaphylaxis (abstract). Fed Proc
1987;46:1202
15. Genovese A, Sakuma I, Boykin MT, Levi R, Belardinelli L:
Cardiac anaphylaxis: Adenosine release and negative dromotropic effect (abstract). Fed Proc 1987;46:932
16. Berne RM: The role of adenosine in the regulation of coronary
blood flpw. Circ Res 1980;47:807-813
17. Bauman G, Schrader J, Gerlach E: Inhibitory action of adenosine on histamine- and dopamine-stimulated cardiac contractility and adenylate cyclase in guinea pigs. Circ Res 1981;48:
259-266
18. Hattori Y, Levi R: Adenosine selectively attenuates H2 and
beta-mediated cardiac responses to histamine and norepinephrine: An unmasking of H| and alpha-mediated responses. J
Pharmacol Exp Ther 1984;231:215-223
19. Szentmiklosi AJ, Nemeth M, Szegi J, Papp JGy, Szekeres L:
Effect of adenosine on sinoatrial and ventricular automaticity
of the guinea pig. Naunyn Schmiedebergs Arch Pharmacol
1980;311:147-149
20. Heller LJ, Olsson RA: Inhibition of rat ventricular automaticity
by adenosine. Am J Physiol 1985;248(//ear( Circ Physiol
17):H907-H913
21. Belardinelli L, West GA, Clemo SHF: Regulation of atrioventricular node function by adenosine, in Gerlach E, Becker BF
(eds): Topics and Perspectives in Adenosine Research. Berlin,
Springer-Verlag, 1987, pp 344-355
22. Marquardt DL, Parker CW, Sullivan TJ: Potentiation of mast
cell mediator release by adenosine. J Immunol 1978;120:871878
23. Welton AF, Simko BA: Regulatory role of adenosine in antigen-induced histamine release from the lung tissue of actively
sensitized guinea pigs. Biochem Pharmacol 1980;29:10851092
24. Church MK, Holgate ST, Hughes PJ: Adenosine inhibits and
potentiates IgE-dependent histamine release from human basophils by an Arreceptor mediated mechanism. Br J Pharmacol
1983;80:719-726
25. Hughes PJ, Holgate ST, Church MK: Adenosine inhibits and
potentiates IgE-dependent histamine release from human lung
mast cells by an A2-purinoceptor mediated mechanism. Biochem Pharmacol 1984;33:3847-3852
26. Church MK, Hughes PJ, Vardey CJ: Studies on the receptor
mediating cyclic AMP-independent enhancement by adenosine
of IgE-dependent mediator release from rat mast cells. Br J
Pharmacol 1986;87:233-242
27. Daly JW, Ukena D, Jacobson KA: Analogues of adenosine
theophylline and caffeine: Selective interactions with Ai and
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
A2 adenosine receptors, in Gerlach E, Becker BF (eds): Topics
and Perspectives in Adenosine Research. Berlin, SpringerVerlag, 1987, pp 23-36
Baker DC, Hanvey JC, Hawkins LK, Murphy J: Identification
of the bioactive enantiomer of erythro-3-(adenine 9-yl)-2-nonanol (EHNA), a semi-tight binding inhibitor of adenosine
deaminase. Biochem Pharmacol 1981;3O:l 159-1160
Heller LJ, Mohrman DE: Estimates of interstitial adenosine in
isolated rat hearts from surface exudates during rapid pacing
and EHNA infusion, in Gerlach E, Becker BF (eds): Topics
and Perspectives in Adenosine Research. Berlin, SpringerVerlag, 1987, pp 425-434
Regal JF: Immunoglobulin G- and immunoglobulin E-mediated airway smooth muscle contraction in the guinea pig. J
Pharmacol Exp Ther 1984;228:116-120
Weissler AM, Altschuld RA, Gibb LE, Pollack ME, Kruger
FA: Effect of insulin on the performance and metabolism of the
anoxic isolated perfused rat heart. Circ Res 1973;32:108-l 16
Belardinelli L, Fenton RA, West A, Linden J, Althaus JS,
Berne RM: Extracellular action of adenosine and the antagonism by aminophylline on the atrioventricular conduction of
isolated perfused guinea pig and rat hearts. Circ Res 1982;
51:569-579
Shore PA, Burkhalter A, Conn VH: A method for the fluorometric assay of histamine in tissues. J Pharmacol Exp Ther
1959;137:182-186
Anton AH, Sayre DF: A modified fluorometric procedure for
tissue histamine and its distribution in various animals. J Pharmacol Exp Ther 1969; 166:285-291
Belardinelli L, Belloni FL, Rubio R, Berne RM: Atrioventricular conduction disturbances during hypoxia: Possible role of
adenosine in rabbit and guinea pig heart. Circ Res 1980;
47:684-691
Wolff AA, Levi R: Histamine and cardiac arrhythmias. Circ
Res 1986;58:1-16
Wiedmeier VT, Spell LH: Effects of catecholamines, histamine, and nitroglycerin on flow, oxygen utilization, and adenosine production in the perfused guinea pig heart. Circ Res
1977;41:503-508
Lohse MJ, Maurer K, Gensheimer HP, Schwabe U: Dual actions of adenosine on rat peritoneal mast cells. Naunyn Schmiedebergs Arch Pharmacol 1987;335:555-560
Nees S, Gerlach E: Adenosine nucleotide and adenosine metabolism in cultured coronary endothelial cells: Formation and
release of adenine compounds and possible functional implications, in Beme RM, Rail TW, Rubio R (eds): Regulatory
Function of Adenosine. Boston, Martinus Nijhoff Publishing,
1983, pp 347-360
Sparks HV Jr, DeWitt DF, Wangler RD, Gorman MW, Bassingthwaite JB: Capillary transport of adenosine. Fed Proc
1985;44:2620-2622
Heller LJ, Mohrman DE: Estimates of interstitial adenosine
from surface exudates of isolated rat hearts. J Mol Cell Cardiol
(in press)
Schrader J, Haddy FJ, Gerlach E: Release of adenosine, inosine and hypoxanthine from the isolated guinea pig heart during hypoxia, flow-autoregulation and reactive hyperemia.
PftugersArch 1977;369:l-6
Bardenheuer H, Schrader J: Relationship between myocardial
oxygen consumption, coronary flow and adenosine release in
an improved isolated working heart preparation of guinea pigs.
Circ Res 1983^1:263-271
Jones CE, Mayer LR: Nonmetabolically coupled coronary
vasodilation during inosine infusion in dogs. Am J Physiol
l98Q;23S(Heart Circ Physiol 7):H569-H574
Newby AC, Worku Y, Meghji P: Critical evaluation of the role
of ecto- and cytosolic 5' nucleotidase in adenosine formation,
in Gerlach E, Becker BF (eds): Topics and Perspectives in
Adenosine Research. Berlin, Springer-Verlag, 1987, pp 155169
KEY WORDS • adenosine • arrhythmia • atrioventricular
conduction • histamine • anaphylaxis • immediate
hypersensitivity • theophylline • coronary vascular resistance
• cardiac muscle
Effect of adenosine on histamine release and atrioventricular conduction during guinea pig
cardiac anaphylaxis.
L J Heller and J F Regal
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Circ Res. 1988;62:1147-1158
doi: 10.1161/01.RES.62.6.1147
Circulation Research is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 1988 American Heart Association, Inc. All rights reserved.
Print ISSN: 0009-7330. Online ISSN: 1524-4571
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