Acetylcholine Release (Presynaptic)

Acetylcholine (ACh) release at the presynaptic terminal is a fundamental process in cholinergic neurotransmission, occurring at both central and peripheral synapses. In this process, ACh is stored in vesicles within the presynaptic neuron. Upon stimulation—typically an action potential—these vesicles fuse with the presynaptic membrane and release ACh into the synaptic cleft, where it can bind to postsynaptic receptors. The process is tightly regulated by voltage-gated calcium channels, SNARE proteins, and presynaptic autoreceptors (muscarinic and nicotinic) that modulate the amount and timing of ACh release. Disruptions in this process are implicated in various neurological disorders.

Modulation of acetylcholine release via various mechanisms, including vesicle fusion inhibition (Botulinum toxin) or massive release stimulation (Black widow spider venom). Acetylcholinesterase inhibitors increase acetylcholine availability.