[Excitatory beta-adrenoreceptors on cholinergic interneurons of the myenteric plexus].
Contractile responses of small intestine segments to isopropylnoradrenaline (INA) disappeared after the blockade of M- and N-cholinoreceptors, beta-adrenoreceptors and increased after the blockade of alpha-adrenoreceptors. Infusion of acetylcholine in subthreshold doses enhanced the small intestine contractile responses to the INA. The blockade of beta-adrenoreceptors with propranolol reduced contractile responses to exogenous (i. a. administration) and endogenous (electrical stimulation of the n. vagus' efferent fibers) acetylcholine, histamine and bradykinin. Stimulation of beta-adrenoreceptors with the INA enhanced contractile responses to exogenous acetylcholine and histamine and reduced the responses to bradykinin. The data obtained suggest the existence of activating beta-adrenoreceptors, apart from alpha- and beta-inhibitory adrenoreceptors, in the small intestine. Activating beta-adrenoreceptors are situated on cholinergic interneurons of the myenteric plexus and mediate the activating effect of endogenous catecholamines upon cholinergic neurons of small intestine.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002415:Cats; D004347:Drug Interactions; D007395:Interneurons / Q000187:drug effects / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D009197:Myenteric Plexus / Q000187:drug effects / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D011950:Receptors, Cholinergic
Vozduzhdaiushchie beta-adrenoretseptory na kholinergicheskikh interneĭronakh miénteral'nogo spleteniia.