Local anaesthetics transiently block currents through single acetylcholine‐receptor channels.
Why the study?
Do lidocaine derivatives QX-222 and QX-314 alter single channel currents through acetylcholine receptor channels in frog muscle membranes?
Population
Chronically denervated frog muscle extrajunctional membranes
Comparison
Lidocaine derivatives QX-222 and QX-314 in… vs Agonist alone in the absence of lidocaine…
Design
Preclinical
Authors
Discussion
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Implication
Reversible open-channel block by QX-222 shown in frog endplates; extends ion-channel pharmacology but leaves open clinical translation.
Key Points
- To investigate how local anaesthetics affect currents through acetylcholine receptor channels in frog muscle tissues.
- Recorded single channel currents through ACh channels in denervated frog muscle membranes.
- Examined the effects of lidocaine derivatives QX-222 and QX-314 on the current waveforms.
- Analyzed the relationship between drug concentration and current waveform characteristics.
- QX-222 caused normal ACh channel currents to flicker and form shorter pulse bursts.
- Burst duration increases with drug concentration, while short pulse duration decreases with drug concentration.
- Blocking occurs at the center of the membrane, likely within the ionic channel.
Structured PICO
Do lidocaine derivatives QX-222 and QX-314 alter single channel currents through acetylcholine receptor channels in frog muscle membranes?
P
Population
Chronically denervated frog muscle extrajunctional membranes
I
Intervention
Lidocaine derivatives QX-222 and QX-314 in addition to the agonist suberyldicholine
C
Comparator
Agonist (suberyldicholine) alone in the absence of lidocaine derivatives
O
Outcome
Single channel currents through acetylcholine receptor channels (channel open time and burst duration)surrogate
Local anesthetics reversibly block open acetylcholine receptor channels, causing rapid flickering within bursts of channel activity.
Cite This Study
Neher et al. (1978) studied this question.