Norepinephrine (NE), dopamine (DA), and epinephrine (E) are 3,4-dihydroxy phenylethylamine derivatives {catecholamine}| (CA) {biogenic amine}.
locations
Catecholamines come from tyrosine in peripheral sympathetic neurons, adrenal medulla, chromaffin tissue, and brainstem nuclei.
Adrenal medulla makes and stores catecholamines in response to stress.
metabolism
Catecholamines phosphorylate postsynaptic receptor proteins, like adenylate cyclase, in vascular smooth muscle, heart, liver, adipocytes, and many brain neurons.
Uptake into presynaptic nerve terminal inactivates catecholamines. Desipramine and cocaine inhibit uptake.
Stimulation by serotonin facilitates presynaptic catecholamine release, which increases intraneuronal cAMP, which inactivates potassium-ion channel, which allows more calcium ion in.
Phenylethylamine derivatives release catecholamines. Bretylium and guanethidine have a highly basic center, linked by one-carbon or two-carbon chain to ring, and block catecholamine release.
vesicles
Catecholamines are in membrane-bound vesicles. Reserpine interferes with catecholamine storage in vesicles. Catecholamine release from vesicles uses exocytosis. Release requires calcium ion.
functions
Catecholamines can cause tachycardia, peripheral vasoconstriction, mydriasis, and peristalsis inhibition.
Biological Sciences>Zoology>Organ>Nerve>Neural Chemical>Transmitter
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Date Modified: 2022.0224