Final answer:
Voltage-gated Ca²+ channels are responsible for the release of neurotransmitter from a neuron.
Step-by-step explanation:
The release of neurotransmitter from a neuron is facilitated by voltage-gated Ca²+ channels. When an action potential reaches the axon terminal, voltage-gated Ca²+ channels open, allowing calcium ions to enter the cell. The increase in Ca²+ concentration inside the cell triggers the fusion of synaptic vesicles containing neurotransmitter molecules with the presynaptic membrane, resulting in the release of neurotransmitters into the synaptic cleft.