[Pharmacokinetic analysis of alpha- and beta-adrenoreceptors in the chick embryo amnion].
Following a stimulation with acetylcholine, the beta-adrenergic agonists adrenaline (A), noradrenaline (NA), isoproterenol (Iso) and salbutamol (Sal) induced a concentration-dependent decrease in the tone and (or) rate of amnion contraction with EC50 ISO < NA << A < Sal. Metaprolol, a specific beta 1-antagonist, induced a rightward shift in the dose-response curves of Iso, NA and A, whereas beta-antagonist butoxamine was ineffective. pA2 values for beta-antagonists were propranolol 8.3, metoprolol 7.0, butoxamine 5.6. EC50 values of alpha-adrenergic agonists form a sequence: clonidine < NA << methoxamine < phenylephrine. Specific alpha-antagonists yohimbine and idazoxan were found to antagonise competitively the effects of NA. The data obtained characterize the adrenergic receptors mediating stimulation of amniotic contractile activity as alpha 2-adrenergic receptors. Inhibition of contractile receptors in amnion is mainly mediated by beta 1-adrenergic receptor activation.
Boĭko
O V
OV
Institute of Developmental Biology of the Russian Acad. of Vavilova St., 26.
Manukhin
B N
BN
D000322:Adrenergic Agonists / Q000494:pharmacology; D018674:Adrenergic Antagonists / Q000494:pharmacology; D000650:Amnion / Q000502:physiology*; D000818:Animals; D002642:Chick Embryo; D066298:In Vitro Techniques; D007700:Kinetics; D009119:Muscle Contraction; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000502:physiology; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000502:physiology; D018342:Receptors, Adrenergic, beta-1 / Q000187:drug effects / Q000502:physiology
D000322:Adrenergic Agonists; D018674:Adrenergic Antagonists; D011942:Receptors, Adrenergic, alpha; D018341:Receptors, Adrenergic, alpha-2; D011943:Receptors, Adrenergic, beta; D018342:Receptors, Adrenergic, beta-1
Farmakokineticheskiĭ analiz al'fa- i beta-adrenoretseptorov amniona kurinogo émbriona.