Effects of McN-A-343, a cholinomimetic drug, on endplate currents in the frog.

Abstract

The muscarinic ganglion stimulating agent, McN-A-343 has unusual blocking actions on endplate currents (EPCs) at frog neuromuscular junctions. McN-A-343 caused depolarization by a curare-sensitive process, blocked neuromuscular transmission, depressed EPCs and reduced the time for EPC decay. These results are explained best by a nicotinic agonist action of McN-A-343 on the acetylcholine receptor to cause ion flow and the blockade by McN-A-343 of the open ion channels. The actions of McN-A-343 are similar to those of decamethonium (C-10) described by others. Unlike C-10, however, McN-A-343 did not alter the exponential character of the EPC or alter the voltage dependency of the EPC. The prototypical nicotinic agonist, dimethylphenylpiperazinium had no effect on EPC parameters of endplate clamped at -90mV.

• Authors: K Alkadhi, D D Branisteanu, E G Henderson, J J Lambert, R L Volle
• Journal: Naunyn-Schmiedeberg's archives of pharmacology (Naunyn Schmiedebergs Arch Pharmacol) Vol. 312 Issue 2 Pg. 117-21 (Jun 1980) ISSN: 0028-1298 [Print] Germany
• PMID: 6157110 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Ion Channels
• Parasympathomimetics
• Quaternary Ammonium Compounds
• Receptors, Nicotinic
• Dimethylphenylpiperazinium Iodide
• (4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride
• Atropine

Topics

• (4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride (pharmacology)
• Animals
• Anura
• Atropine (pharmacology)
• Dimethylphenylpiperazinium Iodide (pharmacology)
• Dose-Response Relationship, Drug
• In Vitro Techniques
• Ion Channels (drug effects)
• Neuromuscular Junction (drug effects, physiology)
• Parasympathomimetics (pharmacology)
• Quaternary Ammonium Compounds (pharmacology)
• Rana pipiens
• Receptors, Nicotinic (drug effects)
• Synaptic Transmission (drug effects)
• Time Factors