Neurotransmitterverfügbarkeit

Neurotransmission is the process by which nerve cells communicate at chemical synapses. It involves the release of chemical messengers, called neurotransmitters, from the presynaptic neuron and the response of a postsynaptic cell.

Neurotransmitter release begins when an action potential arrives at the presynaptic terminal, opening voltage-gated calcium channels and allowing Ca2+ influx. Calcium triggers the fusion of synaptic vesicles with the presynaptic membrane via SNARE proteins, releasing neurotransmitters into the synaptic cleft.

Neurotransmitters diffuse across the cleft and bind to receptors on the postsynaptic membrane. Receptors are of two main types: ionotropic receptors, which open ion channels for rapid, short-lived effects, and metabotropic receptors, which initiate slower signaling cascades through G proteins.

Termination of signaling occurs through reuptake of transmitters into the presynaptic neuron or neighboring glia, enzymatic degradation in the cleft, or diffusion away from the synapse. Neurotransmitters are grouped into small-molecule transmitters (such as acetylcholine, glutamate, GABA, glycine, and monoamines) and neuropeptides, with diverse roles in excitation, inhibition, and modulation.

Through modulation of synaptic strength and plasticity, neurotransmission shapes neural circuits and behavior. Dysregulation of neurotransmission is implicated in numerous disorders, and many drugs target specific aspects of neurotransmitter signaling.