Download Japan-Canada Joint Health Research Program – U

1
1st day
February 20, 2009
PROGRAM
2
学術フロンティア研究報告会
13:00
はじめに
越川憲明（薬理学教室）
13:00
特別講演
座長：越川憲明（薬理学教室）
NEW INSIGHTS INTO OROFACIAL PAIN MECHANISMS:GLIAL AND NEURONAL
INTERACTIONS
BARRY J. SESSLE (Faculty of Dentistry, University of Toronto)
Session I
14:00
室）
14:45
室）
15:45
室）
16:15
顎顔面口腔領域における感覚機能の基礎的研究
“痛みの基礎研究”
座長：岩田幸一（生理学教
鈴木郁子
（生理学教室）
本田訓也
（口腔外科学教室第 2 講座）
坪井美行
（生理学教室）
“味覚・口腔感覚の基礎研究”
座長：小林真之（薬理学教
小林真之
（薬理学教室)
藤田智史
（薬理学教室）
脇坂聡
（大阪大学大学院歯学研究科）
“痛みの臨床研究”
座長：今村佳樹（口腔診断学教
今村佳樹
（口腔診断学教室）
本田和也
（歯科放射線学教室）
休憩
3
Session II
16:30
室）
17:15
室）
17:45
室）
顎口腔運動の基礎的研究
“オーラルジスキネジアの基礎研究”
越川憲明
（薬理学教室）
宋莉秋
（薬理学教室）
青野悠里
（薬理学教室）
座長：越川憲明（薬理学教
“神経再生のメカニズム”
座長：白川哲夫（小児歯科学教
保田将史
（小児歯科学教室）
近藤真啓
（生理学教室）
“摂食・嚥下障害の臨床”
座長：植田耕一郎（摂食機能療法学教
植田耕一郎
（摂食機能療法学教室）
辻村恭憲
（摂食機能療法学教室）
4
ポスター発表者
岩上朋代
（摂食機能療法学教室）
岡田明子
（口腔診断学教室）
加茂博士
（口腔外科学教室第 2 講座）
小柳裕子
（歯科麻酔学教室）
齋藤仁子
（摂食機能療法学教室）
篠崎貴弘
（口腔診断学教室）
正田絵美
（歯科麻酔学教室）
中川量晴
（摂食機能療法学教室）
中山渕利
（摂食機能療法学教室）
野間昇
（口腔診断学教室）
長谷川桃子 （歯科矯正学教室）
人見涼露
（摂食機能療法学教室）
溝口尚子
（摂食機能療法学教室）
宮本真紀子 （歯科麻酔学教室）
(五十音順)
5
2nd day
February 21, 2009
PROGRAM
6
10:00
Opening Remarks
Kichibee Otsuka (Nihon Univ.)
Session I: Basic and Clinical Researches in motor Disfunction
Moderator: Koichi Iwata (Nihon Univ.)
10:05
Topographic Projections from Cortex to Trigeminal Premotoneurons in Rats
Atsushi Yoshida, Ikuro Taki, Chie Iida, Shinichiro Seki, Akiko Tomita, Shinya
Yamamoto, Fumihiko Sato, Katsuro Uchino, Masahiro Nakamura and Takafumi Kato
Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry,
Osaka University
10:25
An effective way eliciting swallowing by electrical stimulation in man
K. Yamamura, M. Kurose, M. Rahman, H. Zakir, Y. Yamada.
Niigata University Graduate School of Medical and Dental Sciences, Japan
10:50
Clinical Application of Corticospinal MEP and Control of Post-Stroke Movement
Disorders by Chronic Motor Cortex Stimulation
Takamitsu Yamamoto, Hideki Oshima, Chikashi Fukaya,Yoichi Katayama
Division of Applied System Neuroscience, Department Advanced Medical Science
and Neurological Surgery, Nihon University School of Medicine
11:35
Role of motor cortex neuroplasticity in development of orofacial motor skins and
in adaptation to pain and other intraoral conditions
Barry J. Sessle
Faculty of Dentistry, University of Toronto, Canada
12:35
Lunch
7
Session II: Pain Research in Patients and Animal Models
Moderator: Barry J Sessle (Univ. Toronto)
13:40
Microglia-neuron signaling in neuropathic pain
Michael W. Salter
Program in Neurosciences & Mental Health, Hospital for Sick Children,
University of Toronto Centre for the Study of Pain
14:40
Mechanisms of central neuropathic pain
Jonathan O.Dostrovsky
Dept of Physiology, Faculty of Medicine, and Faculty of Dentistry, University of
Toronto
15:40
Break
16:00
The role of spinal microglial in neuropathic pain: Postnatal developmental changes
and the effect of early injury
Simon Beggs
Faculty of Dentistry, University of Toronto, Canada
16:40
Tooth pulp application of P2X1,2/3,3 receptor agonist produces central
sensitization in the rat medullary dorsal horn (MDH)
Pavel S. Cherkas, Jonathan O. Dostrovsky, and Barry J. Sessle
University of Toronto, ON, Canada
17:20
Involvement of paratrigeminal nociceptive neurons in temporomandibularjoint
pain
Koichi Iwata1) and Yoko Yamazaki2)
1) Department of Physiology, Nihon University School of Dentistry,
2) Department of Orofacial Pain Management, Tokyo Medical and Dental University
18:00
Closing Remarks
Barry J. Sessle (Univ. Toronto)
8
ABSTRACTs
9
Topographic Projections from Cortex to Trigeminal Premotoneurons in Rats
Atsushi Yoshida, Ikuro Taki, Chie Iida, Shinichiro Seki, Akiko Tomita,
Shinya Yamamoto, Fumihiko Sato, Katsuro Uchino, Masahiro Nakamura,
Takafumi Kato
Dept. of Oral Anatomy and Neurobiology, Graduate School of Dentistry,
Osaka University
The aim of this study was to verify features of cortical disynaptic projections to
trigeminal motor nucleus (Vmo), since it is known that the cortical direct projections
to it are rare. Injections of a retrograde tracer, Fluorogold (FG), and an anterograde
tracer, biotinylated dextranamine (BDA), were made in anaesthetized rats. We
found three kinds of brainstem areas which mainly include premotoneurons for jawopening (JO) component of the Vmo (JO premotoneurons) (e.g., reticular formation
medial to the JO component [RmJO]), premotoneurons for jaw-closing (JC)
component of the Vmo (JC premotoneurons) (e.g., intertrigeminal region [Vint]) and
the both (e.g., trigeminal oral nucleus [Vo] and juxtatrigeminal region [Vjuxt]). These
premotoneuron areas received topographic direct projections from the cerebral
cortex. The RmJO and Vint received projections mainly from the medial agranular
field (Agm) and lateral agranular field (Agl) of the cortex, respectively, while the Vo
and Vjuxt received projections mainly from the primary somatosensory cortex (S1).
The distribution of JO and JC premotoneurons receiving contact(s) from S1 neurons
were also examined quantitatively; they were found mainly in the Vjuxt and Vo.
The present study suggests that the cortical disynaptic projections to the JO and
JC components of the Vmo are consisted of several projections from the
sensorimotor cortex through JO and JC premotoneurons in the brainstem and that
these projections play a role in producing distinctive patterns of jaw-movements.
10
An effective way eliciting swallowing by electrical stimulation in man
K. Yamamura, M. Kurose, M. Rahman, H. Zakir, Y. Yamada.
Niigata University Graduate School of Medical and Dental Sciences, Japan
Objectives: Although there is considerable evidence that electrical stimulation of
the superior laryngeal nerve and the pharyngeal branch of glossopharyngeal nerve
can elicit swallowing in animals, only a few attempts have been made to elicit
swallowing by electrical stimulation in man. The aim of the present study was to
establish an effective way eliciting swallowing by electrical stimulation in man.
Methods: In four healthy volunteers, a custom-made monopolar silver electrode
connected with flexible teflon-coated multi strained stainless steel wire was
introduced into the pharynx via the nasal cavity under the endoscopical observation.
The stimulating electrode was fixed on the posterior wall of the oropharynx or
hypopharynx and the indifferent electrode was placed on the forehead. Then, 30
trains of electrical pulses (1 ms duration at 30 Hz, maximum intensity < 0.8 mA)
were delivered. Swallows were identified by visual observation of movement of
larynx and electromyographic (EMG) burst of suprahyoid muscles.
Results: Both oropharyngeal and hypopharyngeal stimulation successfully elicit
swallowing. No significant difference was noted in the threshold for eliciting
swallowing between these stimulus sites. Also, no significant difference was noted
in the latency, amplitude and duration of swallow-related EMG bursts of the
suprahyoid muscles. It was notable that the incidence of swallowing following
stimulation was higher for the hypopharyngeal stimulation (97.8%) than for
oropharyngeal stimulation (79.6%).
Conclusion: Electrical stimulation of oropharynx and hypopharynx with the use of
monopolar electrode introduced via the nasal cavity is an effective way to elicit
swallowing in man.
11
Clinical Application of Corticospinal MEP and Control of
Post-Stroke Movement Disorders by Chronic Motor Cortex Stimulation
Takamitsu Yamamoto, Hideki Oshima, Chikashi Fukaya,Yoichi Katayama
Division of Applied System Neuroscience, Department Advanced Medical Science
and Neurological Surgery, Nihon University School of Medicine
We employed the corticospinal motor evoked potential (D-wave) as a monitoring
index of motor function. Direct cortical stimulation revealed that if one electrode
was placed on the posterior half of the precentral gyrus, the D-wave could be
recorded even with 10 mm-distant bipolar cortical stimulation, and the amplitude
was larger with anode rather than cathode stimulation. Monitoring of the D-wave
enabled the function of the corticospinal tract to be evaluated selectively. It is also
useful for detection of the primary motor cortex, and we can employ D-wave for
electrode placement in chronic motor cortex stimulation.
We reported more than decade ago that motor cortex stimulation (MCS) is
sometimes useful in controlling post-stroke pain. During MCS for such purpose, we
noticed that some patients also show obvious improvement in their motor function.
This effect was not dependent on post-stroke pain control.
We analyzed characteristics of the improvement of motor function in 54 patients
who underwent MCS. Motor evoked potential was employed to identify appropriate
stimulation sites for MCS.
MCS attenuated for hemichorea-athetosis in 2 of 4 patients, distal resting or
action tremor in all of 4 patients, and proximal postural tremor in 1 of 3 patients. In
6 patients with motor weakness, Fugl-Meyer score of the upper extremity increased
around 5 to 8 points in 3 of the 6 patients. These effects resulted in significant
improvement in their motor performance. In 2 patients who continued excessive
MCS to control their complicated post-stroke pain, however, motor performance
worsened by increased rigidity and/or spasticity.
These results indicate that MCS could be a new therapeutic approach to improve
motor performance after stroke through attenuating hemichorea-athetosis, tremor,
and rigidity and/or spasticity. These effects appear to be maximized by identifying
the primary motor cortex as a stimulation site by motor evoked potential. However,
it may be important to define appropriate duration and intensity of MCS.
12
Role of motor cortex neuroplasticity in development of orofacial motor skins
and in adaptation to pain and other intraoral conditions
BARRY J. SESSLE
Faculty of Dentistry, University of Toronto
It is becoming increasingly apparent that the primary motor cortex (MI) is
important not only in the initiation and regulation of motor function but also in the
learning and adaptation of motor behaviours to an altered peripheral state. To
examine the possible role that the face MI may play in trained or semi-automatic
orofacial motor behaviours and in behavioural adaptations to an altered oral
environment, we have carried out a series of studies that have utilised intracortical
microstimulation (ICMS), reversible MI cold block, and single neurone recordings in
face MI of monkeys and rats as well as transcranial magnetic stimulation (TMS) in
humans. Our studies in monkeys have revealed that face MI plays a strategic role in
elemental and learned motor behaviours and in chewing and swallowing.
Furthermore, successful training of awake monkeys in a novel tongue-protrusion
task is associated with significant neuroplastic changes in face MI, e.g. a 20%
increase in the proportion of discrete MI efferent zones for tongue protrusion (as
revealed by ICMS) as well as marked increases in the proportions of MI neurones
with tongue protrusion-related activity and with a tongue mechanoreceptive field.
These novel findings of face MI neuroplasticity in monkeys are supported by
correlated TMS findings in humans which have revealed significantly enhanced
corticomotoneuronal excitability when humans learn the novel tongue-protrusion
task. Moreover, intraoral pain in humans can interfere with the learning of the task
and with the associated MI excitability changes. Our recent ICMS studies in rats
suggest that face MI neuroplasticity is also important in adaptation to an altered
oral environment : intraoral noxious stimulation can reduce MI excitability,
consistent with our human data, and in addition trimming or extraction of the rat’s
lower incisors or damage to the rat’s lingual nerve can result in significant changes
in the cortical motor representations of the tongue or jaw muscles.
These findings suggest that the face MI is important not only in the initiation and
regulation of orofacial motor function but also in orofacial motor skill acquisition,
reflecting dynamic and modifiable constructs that are modelled by behaviourally
significant experiences. The face MI neuroplasticity also occurring in association
with intraoral pain, an altered dental occlusion or lingual sensory loss suggests the
crucial involvement of face MI in adaptive processes in response to an altered oral
environment.
13
Selected References
Boudreau, S., Romaniello, A., Wang, K., Svensson, P., Sessle, B.J. and Arendt-Nielsen,
L. The effects of intra-oral pain on motor cortex neuroplasticity associated with
short-term novel tongue-protrusion training in humans. Pain 132: 169-178, 2007.
Sessle, B.J., Adachi, K., Avivi-Arber, L., Lee, J., Nishiura, H., Yao, D., Yoshino, K.
Neuroplasticity of face primary motor cortex control of orofacial movements. Arch.
Oral Biol. 52: 334-337, 2007.
Adachi, K., Murray, G., Lee, J.-C. and Sessle, B.J. Noxious lingual stimulation
influences the excitability of the face primary motor cerebral cortex (face MI) in the
rat. J. Neurophysiol. 100: 1234-44, 2008.
14
Microglia-neuron signaling in neuropathic pain
Michael W. Salter
Program in Neurosciences & Mental Health, Hospital for Sick Children,
University of Toronto Centre for the Study of Pain
Microglia in the dorsal horn of the spinal cord are increasingly recognized as being
crucial in the pathogenesis of pain hypersensitivity following peripheral nerve injury
(PNI). Central to the action of microglia is the P2X4 purinoceptor which is essential
for maintaining pain behaviours after PNI (Tsuda et al, Nature 424:778-783, 2003).
PNI causes a rise intracellular level of Cl and thereby to disinhibition of nociceptive
neurons in lamina I of the dorsal horn (Coull et al, Nature 424:938-942, 2003). The
rise in Cl is mediated by brain-derived neurotrophic factor (BDNF), released upon
P2X4 receptor (P2X4R) stimulation from spinal microglia, acting via TrkB receptors
on the lamina I neurons (Coull et al, Nature 438:1017-1021, 2005). Recently, we
2+
have found that stimulating P2X4Rs with ATP evokes a Ca -dependent biphasic
release of BDNF from microglia: an early phase occurs within 5 min, whereas a late
phase peaks 60 min after ATP-stimulation. The early phase of P2X4R-evoked BDNF
release is due to release of a pre-existing pool of BDNF whereas the late phase is
due to de novo BDNF synthesis. The release of BDNF is abolished by inhibiting
SNARE-mediated exocytosis. Furthermore, the P2X4R-evoked release and synthesis
of BDNF are dependent upon activation of p38-mitogen activated protein kinase
(MAPK). Together, our findings elucidate a mechanism for pain hypersensitivity
2+
following PNI through P2X4R-evoked increase in Ca and activation of p38-MAPK
leading to the synthesis and exocytotic release of BDNF from microglia. Targeting
the P2X4R-mediated pathway that mediates BDNF release provides new therapeutic
opportunities for neuropathic pain.
Supported by the Canadian Institutes of Health Research, HHMI and Neuroscience
Canada.
15
Mechanisms of central neuropathic pain
Jonathan O.Dostrovsky
Dept. of Physiology, Faculty of Medicine, and Faculty of Dentistry,
University of Toronto
Central neuropathic pain (CNP) is defined as pain arising as a direct consequence
of a lesion or disease affecting the somatosensory system within the CNS. The most
common causes are cerebrovascular lesions, multiple sclerosis and traumatic spinal
cord injuries and the incidences of developing chronic pain are around 8%, 28% and
30%, respectively. The treatment of CNP remains a major challenge. The
mechanisms giving rise to CNP are still poorly understood but are generally believed
to involve alterations in the properties of sensory neurons at the level of the
thalamus. This talk will briefly describe the main clinical features of CNP and then
review the main mechanisms that have been proposed to explain CNP. Studies we
have performed in humans during functional stereotactic surgery that relate to
some of the proposed mechanisms will be presented.
16
The role of spinal microglial in neuropathic pain:
Postnatal developmental changes and the effect of early injury
Simon Beggs
Faculty of Dentistry, University of Toronto, Canada
Neuropathic pain behaviour following peripheral nerve injury (PNI) is not
observed in neonatal rats and does not develop until rats are 4 weeks of age at the
time of surgery. Spinal microglia are known to play a key role in neuropathic pain
and here we show that dorsal horn microglial proliferation, is significantly less in
postnatal day (P) 10 rat pups than in adults, 7 days after PNI. This was confirmed by
qPCR analysis of IBA-1 mRNA and mRNA of other microglial markers, integrin-alpha
M, MHC-II DMalpha and MHC-II DMbeta. The results clearly demonstrate
immaturity of the microglial response triggered by nerve injury in the first postnatal
weeks which underlies the absence of tactile allodynia following peripheral nerve
injury in young rats.
However, tissue injury in a critical neonatal period can produce long-term
alterations in sensory processing and enhance pain sensitivity to repeated injury in
later life. Using the plantar hindpaw incision model in the rat pup, we evaluated the
response to repeat incision in adulthood to determine if prior neonatal surgical
injury alters the degree of postoperative hyperalgesia and is associated with
changes in spinal microglial activity. Hyperalgesia was quantified by recording
flexion reflex EMG responses to hindpaw mechanical stimuli and microglial activity
in the dorsal horn determined by Iba1 immunoreactivity and susceptibility to
minocycline treatment.
Reflex sensitivity was significantly greater in the repeat versus single incision
groups. Iba1 immunoreactivity in the dorsal horn was increased 3 days following
adult single incision but was apparent earlier (24 hours) and more marked at 3 days
after repeat incision. Pre-treatment with intrathecal
minocycline blocked
hyperalgesia in the repeat incision group but had no effect 24 hours following single
incision.
Neonatal hindpaw incision is associated with an enhanced response to
subsequent injury that persists until adulthood. Alterations in the time course and
degree of microglial proliferation in the spinal cord are likely to contribute to the
long-term enhancement of responses to repeat surgery. Effects of intrathecal
minocycline in the repeat incision group suggest centrally-mediated inhibition of
microglial activation. These studies have implications for perioperative pain
management and outcomes in children and adults with prior neonatal surgery.
17
Tooth pulp application of P2X1,2/3,3 receptor agonist produces
central sensitization in the rat medullary dorsal horn (MDH)
Pavel S. Cherkas, Jonathan O. Dostrovsky, and Barry J. Sessle
University of Toronto, ON, Canada
Activation of purinergic receptors is involved in mechanisms of central
sensitization. The aim of this study was to test if central sensitization in the rat MDH
is induced by application of the P2X1,2/3,3 receptor agonist αß-meATP to the tooth
pulp (TP) and blocked by the P2X1,2/3,3 antagonist TNP-ATP. TP application of
phosphate-buffered saline (PBS) produced no induction of central sensitization in
MDH nociceptive neurons: cutaneous mechanoreceptive field (RF) size (3 ± 0.8%, N
= 6, p > 0.05), responses to noxious mechanical stimuli (4.4 ± 0.7%, N = 6, p > 0.05)
and mechanical activation threshold (2.1 ± 0.3%, N = 6, p > 0.05). However,
application of αß-meATP (100 mM) to TP induced central sensitization: significant
increases in RF size (44 ± 8%, N = 12, p < 0.05) and responses to noxious stimuli (58 ±
6.3%, N = 12, p < 0.05) and decreased mechanical activation threshold (29 ± 8.2%, N
= 6, p < 0.05). Application of TNP-ATP (0.1 mM) to the TP markedly reduced the αßmeATP-induced effects on RF size (N = 6, p < 0.05), responses to noxious stimuli (N =
6, p < 0.05), and mechanical activation threshold (N = 6, p < 0.05). These results
suggest that activation of P2X1,2/3,3 receptors in peripheral tissues plays a critical
role in producing central sensitization in dorsal horn nociceptive neurons.
18
Involvement of paratrigeminal nociceptive neurons
in temporomandibular joint pain
Koichi Iwata1) and Yoko Yamazaki2)
1) Department of Physiology, Nihon University School of Dentistry,
2) Department of Orofacial Pain Management, Tokyo Medical
and Dental University
Temporomandibular joint disorders (TMJD) are recurrent diseases frequently
observed in the dental clinic. TMJD patients have a variety of symptoms such as jaw
movement disorder and TMJ pain. It is possible that the stress-related autonomic
alteration occurs in TMJD patients. However, the neural mechanisms underlying
orofacial pain and related autonomic responses associated with TMJ inflammation
remain unclear. Pa5 neurons are thought to be involved in autonomic functions such
as controlling of the cardiovascular system. The experimental TMJ inflammation
results in expression of Fos proteins in Pa5 neurons as well as in the trigeminal
spinal subnucleus caudalis (Vc). Based on these data, we hypothesized that Pa5
neurons are involved in processing trigeminal nociceptive information as well as
autonomic information related to nociception. However, the type of nociceptive
neurons in Pa5 that are involved in the processing of this information is not known.
To evaluate the involvement of paratrigeminal nucleus (Pa5) nociceptive neurons
in TMJ inflammation-induced pain and its autonomic correlates, we conducted
behavioral, single unit recording and Fos immunohistochemical studies in
anesthetized rats. Nocifensive behaviors to mechanical, heat or cold stimulation of
the lateral face over the TMJ region were significantly enhanced in the TMJ-inflamed
rats for 10-14 days after injection of complete Freund’s adjuvant (CFA) into the TMJ
and gradually decreased at the end of the 14 days observation period. Lowering of
the nocifensive threshold in TMJ-inflamed rats lasted longer in vagus nervetransected rats than vagus nerve-intact rats. A large number of Fos-like
immunoreactive (LI) cells were observed in the Pa5, and half of them were
retrogradely labeled with fluorogold (FG) injected into the parabrachial nucleus.
Background activity of Pa5 wide dynamic range and nociceptive specific neurons
was significantly higher in the TMJ-inflamed rats when compared with controls.
Responses to mechanical stimuli were significantly higher in NS neurons in the TMJinflamed rats. All thermal responsive Pa5 neurons were exclusively sensitive to cold
and the response to cold was significantly higher in the TMJ-inflamed rats compared
with control rats. Vagus nerve stimulation significantly decreased responses to
mechanical and cold stimuli as well as the background activity in TMJ-treated rats
but not in TMJ-untreated rats. The present findings suggest that populations of Pa5
neurons are nociceptive and involved in TMJ inflammation-induced pain as well as in
autonomic processes related to TMJ pain.
19