title: (+/-)-Pindolol has beta 2-adrenoceptor antagonist but not agonist action on the costo-uterine muscle of the rat.
abstract: 1. The effects of isoprenaline and (+/-)-pindolol on rat isolated costo-uterine muscle have been compared. 2. Isoprenaline produced reproducible concentration-dependent inhibition of contractions, and maximal doses (less than 0.1 mumol/l) produced mean inhibition of 87, 94 and 97% of field, carbachol and potassium-stimulated preparations, respectively. 3. (+/-)-Pindolol, when effective, produced inhibition only in concentrations greater than its pA2 value (9.87) as an antagonist of isoprenaline; mean maximal effects were less than 60% of those produced by isoprenaline. 4. It is concluded that (+/-)-pindolol is a potent antagonist, but has only variable agonist action, at the beta 2-adrenoceptors of the rat costo-uterine muscle.
mesh_terms: D000319:Adrenergic beta-Antagonists; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D010869:Pindolol / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000502:physiology
chemical_list: D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D002217:Carbachol; D010869:Pindolol; D007545:Isoproterenol; D011188:Potassium