Download P199 The role of astrocytes from the Suprachiasmatic

P199
The role of astrocytes from the Suprachiasmatic
Nuclei in circadian pacemaker function.
GABR IEL A DO M INGUE Z- M ONZON1 , PAUL A V ERG A R A 2 , JOSE SEGOV I A 2 , R AUL
AGUIL A R- ROBL ERO 4
1
2
Neurociencias Cognitivas, Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Mexico, DF, MEXICO
Departamento de Fisiologia, Biofisica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Mexico, D
.F ., MEXICO
4
Neurociencias Cognitivas, Instituto de fisiologia celular, Universidad
Nacional Autonoma de Mexico, Mexico, D .F ., MEXICO
The suprachiasmatic nucleus (SCN) is comprised of a heterogeneous population of about 20,000 neurons
and astrocytes . Because their unusual activation sate manifested by its high titer of GFAP in absence of injury,
astrocytes are suspected to play a special role regulating extracellular environment in the SCN . It has been
reported that glial in SCN is involved in regulating neuronal activity; therefore, it is our interest to analyze how
the circadian rhythms after inducing apoptosis of SCN glial cells . We will reduce the number of glial cells in
the SCN using a glial specific adenoviral vector containing the apoptotic gene gas1 (AdSGas1) under the
GFAP (Glial fibrillary acidic protein) promoter . This construction has been reported to induce apoptosis in
cell lines and primary cultures of glial origin .
Wistar rats weighing from 170 to 190 g were infected under anesthesia with adenaviral vectors AdsGas1
or LacZ (control) aimed at SCN by stereotaxic injection . Animals recovered from anaesthesia and placed in
cages connected to automatized locomotion and drinking behavior recording system . First animals were
recorded two weeks under light/dark cycles (LD; 12:12 h) followed by additional two weeks in either constant
darkness (DD) or continuous light (LL) .
Results show that animals treated with Gas1 adenovirus have a significant reduction in glial population of the
SCN demonstrated by GFAP immunohistochemistry . These animals lost circadian rhythmicity when
transferred to either DD or LL; whereas control animals that were treated with LacZ adenovirus showed typical
GFAP expression in the SCN and circadian rhythms in DD and LL recordings . These results suggests that the
glial cells from the SCN have and important paper in regulating SCN circadian pacemaker function .
We thank grants from PAPIIT-DGAPA IN204811 and CONACyT 12858 . We thanks to IFC bioterio .