BLOCKAGE OF MUSCLE ACETYLCHOLINE-RECEPTORS BY THE SEROTONIN 1A RECEPTOR AGONIST 8-HYDROXY-2-(DI-N-PROPYLAMINO)TETRALIN (8-OH-DPAT)

8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a potent agonist o f type 1A serotonin receptors, interacts directly with muscle nicotini c acetylcholine receptors expressed in Xenopus oocytes. 8-OH-DPAT reve rsibly inhibits, in a non-competitive and voltage-dependent manner, th e nicotinic receptors. Our results suggest al least two interacting si tes of 8-OH-DPAT on muscle nicotinic receptors: one located within the ionic channel and another in the intracellular domain of the receptor . Our findings will help to understand the regulatory effects of serot onergic agents on nicotinic receptors as well as their complex actions in the brain, and may thus help to design more specific drugs for the rapeutic purposes.