Final answer:
V-SNARE and T-SNARE proteins are activated by an electromagnetic gradient to target neurotransmitter-filled vesicles to the membrane, leading to their release through exocytosis.
Step-by-step explanation:
The electromagnetic gradient activates V-SNARE and T-SNARE proteins which target vesicles filled with neurotransmitters to the membrane for release. This process is known as exocytosis.
The V-SNARE proteins on vesicles bind with the complementary T-SNARE proteins on the target membranes, leading to the fusion of membranes and the release of vesicle contents. An action potential reaching the axon terminal triggers the opening of voltage-gated Ca²⁺ channels, and the influx of calcium ions initiates the merging of neurotransmitter-filled synaptic vesicles with the presynaptic membrane.
Consequently, the neurotransmitters are exocytosed into the synaptic cleft. This intricate process is essential for neurotransmission, facilitating communication between neurons.
When an action potential reaches the axon terminals, voltage-gated Ca²+ channels in the membrane of the synaptic end bulb open. The concentration of Ca²+ increases inside the end bulb, and the Ca²+ ion associates with proteins in the outer surface of neurotransmitter vesicles. The Ca²+ facilitates the merging of the vesicle with the presynaptic membrane so that the neurotransmitter is released through exocytosis into the small gap between the cells, known as the synaptic cleft.