Neurotransmitter secretions

Action Potential and Neurotransmitter Release

• The action potential travels down the axon and reaches the synaptic bouton.

Voltage-Gated Calcium Channels

• In the synaptic bouton, there are voltage-gated calcium channels.

• When the action potential arrives, the depolarization triggers these calcium channels to open.

• Calcium ions ($Ca^{2+}$) flow into the synaptic bouton.

Calcium-Dependent Exocytosis

• Exocytosis is calcium-dependent, a concept discussed in a previous chapter.

• The influx of calcium ions ($Ca^{2+}$) allows vesicles containing neurotransmitters to fuse with the cell membrane.

• This fusion leads to exocytosis, releasing the neurotransmitters into the synaptic cleft.

Role of Calcium

• The next step is to understand the specific role of calcium in this process.

• This mechanism has been previously discussed in the context of other cellular processes.