Local & Regional Anaesthesia · NEET PG Preparation Anaesthesia
Regarding the mechanism of action of local anaesthetics, which of the following statements is most accurate regarding how they exert their primary el…
Practice question from Local & Regional Anaesthesia (NEET PG Preparation Anaesthesia), with the correct answer and a step-by-step solution.
medium · MCQ · Q-4ED489
Regarding the mechanism of action of local anaesthetics, which of the following statements is most accurate regarding how they exert their primary electrophysiological effect?
- A.They bind to extracellular potassium channels and prevent repolarisation.
- B.They block voltage-gated sodium channels from the intracellular surface in their ionized form.Correct answer
- C.They block calcium channels at the neuromuscular junction.
- D.They act exclusively via un-ionised diffusion across the lipid bilayer without binding any receptor.
Solution
Local anaesthetics diffuse across the nerve membrane in their un-ionised form, become ionised intracellularly, and bind reversibly to the intracellular receptor site of the voltage-gated sodium channel, preventing the influx of sodium and propagation of the action potential.
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