Neural Control and Coordination · NEET Preparation Zoology
A drug selectively blocks voltage-gated Ca2+ channels in the presynaptic membrane of a chemical synapse. What is the most immediate consequence when…
Practice question from Neural Control and Coordination (NEET Preparation Zoology), with the correct answer and a step-by-step solution.
hard · MCQ · Q-1DC3E1
A drug selectively blocks voltage-gated Ca2+ channels in the presynaptic membrane of a chemical synapse. What is the most immediate consequence when an action potential reaches the axon terminal?
- A.The action potential cannot travel along the axon
- B.Synaptic vesicles cannot release neurotransmitter into the synaptic cleftCorrect answer
- C.The postsynaptic membrane remains permanently depolarised
- D.The neurotransmitter is released continuously without stimulation
Solution
Arrival of an action potential at the axon terminal opens voltage-gated Ca2+ channels. The resulting Ca2+ influx triggers fusion of synaptic vesicles with the presynaptic membrane and neurotransmitter release. Blocking these channels prevents this release.
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