Rw. Moyer et Dj. Kennaway, Immunohistochemical localization of serotonin receptors in the rat suprachiasmatic nucleus, NEUROSCI L, 271(3), 1999, pp. 147-150
Serotonin (5-HT) has been implicated in the regulation of circadian rhythms
through its actions on the suprachiasmatic nucleus (SCN). Recent data sugg
ests that, along with excitatory amino acids, serotonin may be important in
the neural pathway that mediates the transmission of photic information to
the circadian system. The present study uses immunohistochemistry to exami
ne the presence of three different 5-HT receptor subtypes in the suprachias
matic nucleus (5-HT2a, 5-HT2c and 5-HT7) in male albino Wistar rats. In the
SCN, there was a considerable amount of 5-HT2c-receptor-like immunoreactiv
ity, a lesser amount of 5-HT2a positive fibres and no staining with antiser
um against the 5-HT7 receptor subtype. These results are compatible with pr
evious pharmacological evidence obtained in our laboratory showing that ser
otonin acting through the 5-HT2c receptor subtype may be important in the p
hase shifting effects of light on the circadian system. (C) 1999 Elsevier S
cience Ireland Ltd. All rights reserved.