adrenergic agonist(redirected from Adrenergics)
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adrenergic agonistA family of agents which have adrenaline-like effects, acting directly or indirectly on any of the five G-protein-coupled adrenergic receptors: apha1, alpha2, beta1, beta2, beta3.
Actions of adrenergic agonists
alpha1 receptors: Activate phospholipase C (via Gq), increasing protein kinase C activity.
alpha2: receptors Inhibit adenylate cyclase (via G1), decreasing protein kinase A activity.
beta receptors: Activate adenylate cyclase (via Gs), increasing protein kinase A activity.
Any of a group of therapeutic agents, e.g. epinephrine, that mimic or stimulate the sympathetic nervous system.
See also: agonist
Drugs that produce an effect similar to that obtained by stimulation of the sympathetic nervous system. Some of these predominantly act on the adrenergic alpha-receptors (e.g. noradrenaline (norepinephrine)), while others act on the adrenergic beta-receptors (e.g. isoproterenol). Others have little direct effect on the adrenergic receptors but enhance the release of natural catecholamine from the sympathetic nerve terminals (e.g. amphetamine, phenylpropanolamine). Sympathomimetic drugs are used (1) in the treatment of open-angle glaucoma by decreasing aqueous humour secretion and increase the outflow through the trabecular meshwork thus reducing the intraocular pressure (e.g. adrenaline (epinephrine), apraclonidine, dipivefrine hydrochloride, brimonidine tartrate), (2) dilate the pupil without affecting accommodation (e.g. phenylephrine) and (3) constrict conjunctival blood vessels (e.g. naphazoline, tetrahydrozoline). Syn. adrenergic agonist; adrenergic stimulating agent. See alpha-adrenergic agonist; mydriatic.