ENFLURAN BLOCKIERT DEN IONENSTROM DURCH DEN NIKOTINISCHEN ACETYLCHOLINREZEPTOR

Translated title of the contribution: Enflurane blocks the ion current through the nicotine acetylcholine receptor channel

M. Scheller, J. Bufler, H. J. Schneck, C. Franke, H. Husmann, E. Kochs

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Aim: The study investigates the influence of enflurane (EN) on macroscopic currents of the nicotinic acetylcholinergic receptor channel (nAChR). This ion channel is a respresentative member of the superfamily of ligand-gated receptor channels and is better characterized than all the other receptors in respect of structure and function. Methods: For the experiments the patch-clamp technique was used to study the embryonic type of the nAChR expressed by cultured mouse-myotubes. Patch-clamp recordings were performed in the outside-out-mode from these preparations. To match the rapid desensitization kinetics of ligand-activated ion channels, a liquid filament switch technique was used for the application of agonists to the excised patches. This technique allows for change of solution within 300 μs. We used a saturating concentration of 10-4 M acetylcholine (ACh), activating almost all available ion channels on a patch. Pulses of 10-4 M ACh together with EN in different concentrations were applied repetitively. Results: The current elicited by 10-4 M ACh is reduced reversibly in a concentration-dependent manner by EN in clinically relevant concentrations: 1,44 x 10-5 M EN inhibit about 10%, 1.44 x 10-4 M 25%, 1.44 x 10-3 M 35%, and 1.44 x 10-2 M 75% of the ion flux (averaged results from 48 patches). EN decreases the time constant of the current decay. This acceleration of desensitisation kinetics is partly reversible if followed by application of 10-4 M ACh. Conclusion: In this study we were able to show that EN reduces the currents of the ligand-gated embryonic-like nAChR in clinically relevant concentrations. Volatile anaesthetics are known to influence GABA(A)-, glutamate-, and glycine-activated receptors, which are members of the same family of ligand-gated receptor-channel units. Thus, the action of volatile anaesthetics on ligand-gated receptors may play a role in the mechanism of general anaesthesia. The interaction of volatile anaesthetics with nondepolarising neuromuscular blockers may also be based on this effect at the neuromuscular junction.

Translated title of the contributionEnflurane blocks the ion current through the nicotine acetylcholine receptor channel
Original languageGerman
Pages (from-to)370-374
Number of pages5
JournalAnasthesiologie Intensivmedizin Notfallmedizin Schmerztherapie
Volume30
Issue number6
DOIs
StatePublished - 1995
Externally publishedYes

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