Abstract
The effects of a depolarizing neuromuscular blocker on electrically evoked acetylcholine (ACh) release were studied using a mouse phrenic nerve-diaphragm muscle preparation preloaded with [3H]-choline, and the changes in muscle tension were recorded simultaneously. Succinylcholine at a low concentration (1 microM) enhanced evoked [3H]-ACh release, which tended to follow the increase in peak amplitude of tetanic tension; whereas at high concentrations (10 and 30 microM), it simultaneously reduced both release and tension. Decamethonium even at 10 and 30 microM had little effect on [3H]-ACh release despite producing a significantly greater reduction in tension compared with succinylcholine. (+)-Tubocurarine (5 microM) prevented the enhancing effect of [3H]-ACh release induced by 1 microM, but not the decreasing effect induced by 10 microM succinylcholine. These results suggest that succinylcholine induced acceleration at low concentrations due to a positive feedback mechanism through presynaptic nicotinic ACh receptors and the inhibition of ACh release at high concentration contributes in part to the neuromuscular blockade.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.