Serotonin-stimulated glutamate release from an SCN explant culture was higher during light period.
Serotonin (5-HT) and glutamate are concerned with the input pathways to the suprachiasmatic nucleus (SCN), a center of biological rhythms in mammals. Arg-vasopressin (AVP) is one of the output paths from the SCN to other brain areas. Functional relations of 5-HT on glutamate release, which stimulates AVP release, were therefore analyzed in an SCN slice culture using a glutamate biosensor. Spontaneous release of glutamate from the SCN culture was higher during the light period than the dark period. The 5-HT-stimulated increase in glutamate release was also larger at 0900 h than at 2000 h. In addition, glutamate, but not 5-HT, increased the AVP release. These findings suggest the possibility that the 5-HT has no direct facilitatory functions in AVP release via liberation of glutamate from the SCN.
Department of Physiology, Nagoya City University Medical School, Mizuho-ku, Nagoya, Japan. yisobe@med.nagoya-cu.ac.jp
Yoshiaki
Y
Isobe
Keiji
K
Nishihara
D000818:Animals; D000831:Animals, Newborn; D001127:Arginine Vasopressin / Q000378:metabolism; D002940:Circadian Rhythm / Q000187:drug effects* / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D008027:Light; D009924:Organ Culture Techniques; D017440:Photoperiod; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology*; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000378:metabolism
D001127:Arginine Vasopressin; D012701:Serotonin; D018698:Glutamic Acid