[Functional interaction between alpha- and beta-adrenoreceptors of the small intestine].
Effect of desensitization of alpha-adrenoreceptors on the functional state of beta-receptors and vice versa was studied in isolated sections of the rat small intestine. Neither blockade, nor desensitization of alpha-receptors produced any effect on the sensitivity of beta-receptors to isopropyl-noradrenaline (IPN) whereas desensitization of beta-receptors to IPN resulted in the increase of alpha-receptors sensitivity to phenylephrine with a decreased maximal reaction. In the presence of GTP (0.02 mM) and propranolol (2.00 x 10(-7) M) IPN acts as a competitive reversible auto-inhibitor, GTP fully removing the inhibitory effect of IPN on both alpha- and beta-adrenoreceptors. Existence of functional interrelationship between alpha- and beta-adrenoreceptors is suggested.
D000818:Animals; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D007545:Isoproterenol
Funktsional'noe vzaimodeĭstvie al'fa- i beta-adrenoretseptorov tonkoĭ kishki.