Circadian modulation of the ryanodine receptor type 2 in the SCN of rodents.
We examined the temporal modulation of intracellular calcium release channels in the suprachiasmatic nucleus (SCN). We found a circadian rhythm in [3H]ryanodine binding that was specific to the SCN. The peak in the rhythm occurred at CT 7 and was due to an increase in Bmax, which correlated well with immunoblots showing an increase in RyR-2 expression in the SCN. Double immunohistochemical studies showed that RyR-2 was expressed exclusively in neurons. Ryanodine and caffeine applied around CT 7-9 advanced the clock phase in a hamster brain slice preparation. No rhythm of IP3R was seen in any of the brain areas studied. Our results indicate that RyR-2 exhibits an endogenous rhythm, which influences the intracellular calcium dynamics and thus modulates SCN activity.
Díaz-Muñoz
M
M
Departamentos de Biofisica, Instituto de Fisiologia Celular, Universidad Nacional Autónoma de México, México, DF.
Dent
M A
MA
Granados-Fuentes
D
D
Hall
A C
AC
Hernández-Cruz
A
A
Harrington
M E
ME
Aguilar-Roblero
R
R
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004594:Electrophysiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007536:Isomerism; D008297:Male; D008647:Mesocricetus; D018613:Microscopy, Confocal; D051381:Rats; D017208:Rats, Wistar; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D013194:Staining and Labeling; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology
D005904:Glial Fibrillary Acidic Protein; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D002110:Caffeine