Q93 / 200 · MHT CET - Medical 2026 (25 April Shift 1) · Biology
Synaptic vesicles of pre synaptic neurons release neurotransmitter in synaptic cleft due to ________
- Correct answerAopening of $\text{Ca}^{++}$ channels due to change in voltage.
- B$\text{K}^+$ ions which diffuse out of the axon.
- C$\text{Na}^+$ which diffuses into the neuron.
- D$\text{Na}^+\text{- K}^+$ pumps become operational.
Solution
When an action potential reaches the axon terminal of a pre-synaptic neuron, it causes a change in membrane voltage (depolarization).
This depolarization leads to the opening of voltage-gated $\text{Ca}^{++}$ channels located on the pre-synaptic membrane.
The influx of $\text{Ca}^{++}$ ions into the pre-synaptic terminal triggers the synaptic vesicles to move towards and fuse with the plasma membrane.
This fusion results in the release of neurotransmitters into the synaptic cleft via exocytosis.
Answer: opening of $\text{Ca}^{++}$ channels due to change in voltage.
This depolarization leads to the opening of voltage-gated $\text{Ca}^{++}$ channels located on the pre-synaptic membrane.
The influx of $\text{Ca}^{++}$ ions into the pre-synaptic terminal triggers the synaptic vesicles to move towards and fuse with the plasma membrane.
This fusion results in the release of neurotransmitters into the synaptic cleft via exocytosis.
Answer: opening of $\text{Ca}^{++}$ channels due to change in voltage.
Hence, the correct answer is option: 'A'.