neurotransmitera

Neurotransmitera are chemical messengers that transmit signals between nerve cells in the nervous system. They are released from the presynaptic terminal in response to an action potential, diffuse across the synaptic cleft, and bind to specific receptors on the postsynaptic cell. Depending on the receptor and signaling pathway, neurotransmitera can produce excitatory or inhibitory effects that modulate neuronal activity and information processing.

Most neurotransmitera fall into two broad classes: small-molecule transmitters, such as glutamate, GABA, glycine, acetylcholine, dopamine, norepinephrine, and serotonin; and neuropeptides, such as substance P, endorphins, and vasopressin. Small-molecule transmitters are typically stored in synaptic vesicles and released rapidly, acting via ionotropic receptors (ligand-gated ion channels) or metabotropic receptors (G protein–coupled receptors). Neuropeptides are larger and often co-released with other transmitters; they usually signal through metabotropic pathways and tend to modulate synaptic strength and circuit function rather than producing fast postsynaptic potentials.

After release, neurotransmitera are cleared from the synaptic cleft to terminate signaling. Mechanisms include reuptake by presynaptic transporters, enzymatic degradation (for example, acetylcholinesterase for acetylcholine or monoamine oxidase for monoamines), and diffusion away from the synapse. The balance and timing of neurotransmitter signaling influence learning, mood, perception, movement, and numerous other brain functions.

Disruptions in neurotransmitera signaling are linked to many neurological and psychiatric conditions. Treatments often target these systems, such as selective serotonin reuptake inhibitors, dopamine agonists, or acetylcholinesterase inhibitors, highlighting the central role of neurotransmitera in health and disease.