1-5-Hydroxytryptophan-induced flat body posture in the rat: antagonism by ritanserin and potentiation after 5,7-dihydroxytryptamine.

1-5-Hydroxytryptophan (1-5-HTP)-induced flat body posture (FBP) was antagonized by ritanserin in doses that were lower than those needed to antagonize head-twitches (HTW) and forepaw treading (FPT). 5,7-Dihydroxytryptamine (5,7-DHT) potentiated 1-5-HTP-induced FBP but not HTW or FPT. Ritanserin interacted with 5-HT2 and 5-HT1c receptors. 1-5-HTP-induced FBP could be mediated by postsynaptic 5-HT1c receptors and could serve as a behavioral model of postsynaptic 5-HT1c receptor stimulation in the CNS.