Atypical beta-adrenoceptors mediate isoprenaline induced vasodilatation in the rabbit uterine vascular bed.
beta-Adrenoceptor subtype(s) mediating isoprenaline-induced vasodilator responses in the perfused rabbit uterine vascular bed was characterized. Isoprenaline induced dose-dependent reduction in perfusion pressure with -logED50 value of 5.8 +/- 0.1. Propranolol (10(-6) M) had little or no effect on isoprenaline-induced vasodilatation. Similarly, cyanopindolol (10(-6) M) did not antagonize the vasodilator response. CGP 12177, an agonist on beta 3- or beta 2- adrenoceptor mediated responses. The results would indicate that isoproterenol-induced vasodilation in the perfused rabbit (oestrus or pregnant) uterine vascular bed was mediated by atypical beta-adrenoceptors which may not be identical with those in adipose tissues or gastro-intestinal tract. In addition, the fact that pregnancy did not enhance isoprenaline-induced vasodilation would suggest that these receptors may not be involved in the hyperaemia of pregnancy.
Oriowo
M A
MA
Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005260:Female; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D010869:Pindolol / Q000031:analogs & derivatives / Q000494:pharmacology; D011247:Pregnancy / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000145:classification / Q000187:drug effects*; D014599:Uterus / Q000098:blood supply*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D014665:Vasodilator Agents; C047975:cyanopindolol; D011433:Propranolol; D010869:Pindolol; D007545:Isoproterenol; C033394:CGP 12177