5-HT1A receptor immunoreactivity in hypothalamic neurons involved in body weight control

Serotonin (5-hydroxytryptamine; 5-HT) is a regulator of feeding behavior. The effect of serotonin on food intake is believed to be primarily mediated via 5-HT1A and 5-HT2C receptors, which both are expressed in hypothalamic regions implicated in regulation of feeding behavior. Using an antiserum to the 5-HT1A receptor, immunoreactive neurons were observed in the rat supraoptic, paraventricular, arcuate and ventromedial nuclei and lateral hypothalamic area. 5-HT1A receptor immunoreactivity was demonstrated in neuropeptide Y-, agouti-related peptide-, proopiomelanocortin- and cocaine- and amphetamine-regulated transcript-containing neurons of the arcuate nucleus. In the lateral hypothalamus, 5-HT1A receptor immunoreactivity was observed in melanin-concentrating hormone- and orexin-containing neurons. The results suggest that serotonin via postsynaptic 5-HT1A receptors affects the release of peptides regulating food intake. NeuroReport 13:945-951 (C) 2002 Lippincott Williams Wilkins.