Neurotransmitter


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Related to Neurotransmitter: serotonin, dopamine

neurotransmitter

 [noor″o-trans´mit-er]
a substance (e.g., norepinephrine, acetylcholine, dopamine) that is released from the axon terminal of a presynaptic neuron on excitation, and that travels across the synaptic cleft to either excite or inhibit the target cell.

neu·ro·trans·mit·ter

(nū'rō-trans'mit-ĕr),
Any specific chemical agent (including acetylcholine, five amines, four amino acids, two purines, and more than 28 peptides) released by a presynaptic cell, on excitation, that crosses the synapse to stimulate or inhibit the postsynaptic cell. More than one may be released at any given synapse. The neurotransmitters released by presynaptic cells may modulate transmitter release from presynaptic cells. Nitric oxide may be a retrograde neurotransmitter, released from postsynaptic cells, to act on presynaptic cells.
[neuro- + L. transmitto, to send across]

neurotransmitter

(no͝or′ō-trăns′mĭt-ər, -trănz′-, nyo͝or′-)
n.
A chemical substance, such as acetylcholine or dopamine, that transmits nerve impulses across a synapse.

neurotransmitter

Neurosynaptic transmitter Physiology Any of a number of small neuroregulating molecules–eg, catecholamines and acetylcholine, which are synthesized in the presynaptic terminals of neurons, stored in vesicles, and cause rapid and transient depolarization near their point of release in the synaptic cleft, where it stimulates production of either excitatory or inhibitory postsynaptic potentials; neurotransmission at synapses or neuromuscular junctions is due to binding of a neurotransmitter to its cognate receptor. See Amino acid neurotransmitter, Neuropeptide, Neuroregulator. Cf Hormone.

neu·ro·trans·mit·ter

(nūr'ō-trans'mit-ĕr)
Any specific chemical agent released by a presynaptic cell, on excitation, which crosses the synapse to stimulate or inhibit the postsynaptic cell.
[neuro- + L. transmitto, to send across]

neurotransmitter

See TRANSMITTER SUBSTANCE.

Neurotransmitter

A chemical in the brain that transmits messages between neurons, or nerve cells. Changes in the levels of certain neurotransmitters, such as serotonin, norepinephrine, and dopamine, are thought to be related to bipolar disorder.

neurotransmitter

A substance stored in the synaptic vesicles that is released when the axon terminal is excited by a nervous impulse. The substance then travels across the synaptic cleft to either excite or inhibit another neuron. This is accomplished by either decreasing the negativity of postsynaptic potentials (excitation), or increasing the negativity of postsynaptic potentials (inhibition). Common neurotransmitters include acetylcholine, dopamine, endorphins, adrenaline (epinephrine), gamma-aminobutyric acid (GABA), amino acids, such as glutamate and glycine, noradrenaline (norepinephrine), serotonin and substance P. Common neurotransmitters in the retina are glutamate (the primary excitatory neurotransmitter), GABA (inhibitory), glycine (inhibitory), dopamine (excitatory) and acetylcholine (excitatory). See neuron; synapse.

neu·ro·trans·mit·ter

(nūr'ō-trans'mit-ĕr)
Any specific chemical agent released by a presynaptic cell that, on excitation, crosses synapse to stimulate or inhibit the postsynaptic cell.
[neuro- + L. transmitto, to send across]
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