Arg-Lys-Asp-Val-Tyr (thymopentin) accelerates the cholinergic-induced inactivation (desensitization) of reconstituted nicotinic receptor.
1. The thymic hormone thymopoietin blocks neuromuscular transmission and was proposed (Goldstein, 1974) as a modulator of synaptic conductivity. 2. 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. 3. The present data show that thymopentin accelerates desensitization of the nicotinic acetylcholine receptor, supporting the aforementioned physiological role proposed for thymopoietin. 4. 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.
Ochoa
E L
EL
Instituto de Biologia Celular, Facultad de Medicina UBA, Argentina.
Medrano
S
S
de Carlin
M C
MC
Dilonardo
A M
AM
D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D004555:Electric Fish; D066298:In Vitro Techniques; D010446:Peptide Fragments / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism; D016305:Thymopentin; D013946:Thymopoietins / Q000494:pharmacology*; D013951:Thymus Hormones / Q000494:pharmacology*
D002038:Bungarotoxins; D010446:Peptide Fragments; D011978:Receptors, Nicotinic; D013946:Thymopoietins; D013951:Thymus Hormones; D002217:Carbachol; D016305:Thymopentin