LY165163 and 8-OH-DPAT have agonist effects on a serotonin responsive muscle of Aplysia.

Serotonin enhances acetylcholine-elicited contractions of buccal muscle E1 of Aplysia. To characterize the serotonin receptor, actions of ligands of specific serotonin receptor subtypes were examined. Ketanserin, an antagonist at 5-HT2 receptors, had little effect. Two 5-HT1A ligands, LY165163 and 8-OH-DPAT, mimicked the effect of serotonin, although with slower kinetics. This suggests that the peripheral serotonin receptor in Aplysia more closely resembles 5-HT1 than 5-HT2 receptors.