When does the release of ACh occur?

Acetylcholine is a neurotransmitter found in the central and peripheral nervous systems. The release of ACh (acetylcholine) is triggered by a series of events. First, an action potential that is relayed reaches the end of the axon. Depolarization at the axon terminus triggers the opening of voltage-gated calcium channels, resulting in an influx of calcium. This calcium influx enables the release of acetylcholine-containing vesicles into the synaptic cleft.