Evidence for the localization of 5HT1A binding sites on serotonin containing neurons in the raphe dorsalis and raphe centralis nuclei of the rat brain.

Precise anatomical distribution of 5HT1 binding sites has been investigated in the nuclei raphe dorsalis, raphe centralis and locus caeruleus of the rat brain. An original pattern of distribution was observed in the raphe nuclei, closely correlated to the already known distribution of 5HT containing elements. This pattern, more pronounced when 5HT1A sites were labelled, completely disappeared after lesioning by 5, 7DHT indicating the presence of this subtype of 5HT1 binding sites on 5HT containing neurons. It is postulated that these 5HT1A sites correspond in these raphe nuclei to 5HT autoreceptors.