Question

question 2
1 pts
question: which type of ion channel is involved in the release of neurotransmitters from the presynaptic neuron?

• voltage - gated calcium channel
• ligand - gated sodium channel
• voltage - gated potassium channel
• ligand - gated chloride channel

Explanation:

To determine the ion channel involved in neurotransmitter release from the presynaptic neuron, we analyze each option:

• Voltage - gated calcium channel: When an action potential reaches the presynaptic terminal, it depolarizes the membrane. This depolarization opens voltage - gated calcium channels. The influx of calcium ions into the presynaptic neuron triggers the fusion of synaptic vesicles (containing neurotransmitters) with the presynaptic membrane, leading to neurotransmitter release.
• Ligand - gated sodium channel: These channels open in response to a ligand (e.g., a neurotransmitter) binding, not for neurotransmitter release from the presynaptic side. They are more involved in postsynaptic responses.
• Voltage - gated potassium channel: These channels are involved in repolarizing the neuron after an action potential. They help restore the resting membrane potential and are not directly involved in neurotransmitter release.
• Ligand - gated chloride channel: These channels are involved in inhibitory postsynaptic responses (e.g., hyperpolarizing the postsynaptic membrane) and not in presynaptic neurotransmitter release.

Answer:

A. Voltage - gated calcium channel