Neuropeptides facilitate the desensitization of nicotinic acetylcholine-receptor in frog skeletal muscle endplate.

Substance P and luteinizing hormone-releasing hormone (LHRH), neurotransmitter candidates for peptidergic neurotransmission in peripheral autonomic ganglia, facilitated the desensitization of nicotinic acetylcholine (ACh)-receptor at the skeletal muscle endplate. In the presence of these peptides, the desensitization proceeded with a biphasic time course, i.e. fast and then slow components of desensitization. We suggest that neuropeptides such as substance P and LHRH may regulate the sensitivity of nicotinic ACh-receptors by modulating the process of desensitization.