VSR-0125
QUESTION
Local anaesthetics?
OPTIONS
(A) Prevent generation and propagation of impulses
(B) Affect only myelinated fibres
(C) Block calcium channels
(D) Have sympathomimetic actions in general
ANSWER
(A) Prevent generation and propagation of impulses
EXPLANATION
Local anesthetics reversibly inhibit voltage-gated sodium channels, preventing action potentials from being generated and propagated in nerve fibers. They are not restricted to myelinated fibers, do not act by blocking calcium channels as their primary mechanism, and generally lack a class-wide sympathomimetic action.
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