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Neuronal
Metazoans
Synaptic Transmission
Chemical neurotransmission across synaptic clefts between neurons.
Overview
Action potentials arriving at the presynaptic terminal open voltage-gated Ca²⁺ channels. Ca²⁺ influx triggers SNARE-mediated fusion of synaptic vesicles with the presynaptic membrane, releasing neurotransmitters into the synaptic cleft. Neurotransmitters bind postsynaptic receptors (ionotropic or metabotropic), generating excitatory or inhibitory postsynaptic potentials. Signaling is terminated by reuptake, enzymatic degradation, or diffusion.
Cellular Location
Synaptic terminals
Clinical Significance
Foundation of nervous system function; targets of SSRIs, benzodiazepines, anesthetics, nerve agents; defects underlie epilepsy, myasthenia gravis, and psychiatric disorders.