Concurrent decrease of vasopressin and protein kinase Calpha immunoreactivity during the light phase in the vole suprachiasmatic nucleus.
Vasopressin (AVP) is a major neuropeptide in the suprachiasmatic nucleus, the mammalian hypothalamic circadian pacemaker. Protein kinase Calpha is a putatively coupled intracellular messenger. Mean numbers of AVP- and protein kinase Calpha-immunoreactive neurons were determined in the suprachiasmatic nucleus of common voles, entrained to a 12:12 h light-dark (LD) cycle, at the beginning of the light period (zeitgeber time zero) and 6 h later (zeitgeber time six). At zeitgeber time zero, mean numbers of AVP- and protein kinase Calpha- immunoreactive neurons were 2194 and 9897, respectively. Both numbers decreased significantly with about 40% at zeitgeber time six. This concurrent decrease was most pronounced in the dorsomedial aspect of the suprachiasmatic nucleus. These findings are consistent with the findings of a peak of AVP release in rats during the early light phase.
Jansen
K
K
Graduate School Behavioral and Cognitive Neurosciences, Groningen, The Netherlands. k.jansen@biol.rug.nl
Van der Zee
E A
EA
Gerkema
M P
MP
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D003411:Arvicolinae; D002940:Circadian Rhythm; D003624:Darkness; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008027:Light; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D013493:Suprachiasmatic Nucleus / Q000201:enzymology / Q000378:metabolism*
D007527:Isoenzymes; D001127:Arginine Vasopressin; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha