Serotonin receptor gene expression in the rat suprachiasmatic nuclei.
Serotonin (5HT) is thought to reset the biological clock in the suprachiasmatic nuclei (SCN) in vitro through a postsynaptic 5HT-1a receptor. Thus we examined 5HT receptor gene expression in the SCN by in situ hybridization. On film autoradiograms, 5HT-1c receptor mRNA showed intense SCN hybridization, while 5HT-1b receptor mRNA displayed a weaker signal. Emulsion autoradiograms additionally revealed expression of 5HT-1a and 5HT-2 receptor mRNAs by a few scattered SCN cells. 5HT-3 receptor mRNA was not detected in the SCN, although the transcript was detected elsewhere in the brain. 5HT-1d and -1e receptor mRNAs were not detected in the SCN or elsewhere in brain within the sections examined. The results do not support a major role for postsynaptic 5HT-1a receptors in resetting SCN rhythms.
Roca
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Laboratory of Developmental Chronobiology, Children's Service, Massachusetts General Hospital, Boston 02114.
Weaver
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Reppert
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D000818:Animals; D004247:DNA; D015870:Gene Expression; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000235:genetics*; D013493:Suprachiasmatic Nucleus / Q000502:physiology*
D011985:Receptors, Serotonin; D004247:DNA