Arg-Lys-Asp-Val-Tyr (thymopentin) accelerates the cholinergic-induced inactivation (desensitization) of reconstituted nicotinic receptor

Abstract

The thymic hormone thymopoietin blocks neuromuscular transmission and was proposed (Goldstein, 1974) as a modulator of synaptic conductivity. The cholinergic-induced inactivation of nicotinic receptor reconstituted into asolectin lipid vesicles was studied in the presence and in the absence of thymopentin, a synthetic pentapeptide corresponding to positions 32–36 of thymopoietin. The present data show that thymopentin accelerates desensitization of the nicotinic acetylcholine receptor, supporting the aforementioned physiological role proposed for thymopoietin. They also suggest that the hormone itself and/or a yet unidentified hormine-derived peptide fragment may act as an endogenous ligand for nicotinic acetylcholine receptor desensitization.