Central alpha- and beta-adrenoceptors modifying arterial blood pressure and heart rate in conscious cats.
1 In conscious unrestrained cats noradrenaline, alpha-methylnoradrenaline and clonidine, infused into the lateral cerebral ventricles (i.c.v.) caused dose-related falls in blood pressure and heart rate; both effects were abolished after i.c.v. phentolamine.2 In 12 out of 20 cats, i.c.v. isoprenaline and salbutamol when given caused dose-related pressor responses and tachycardias. These effects were abolished after i.c.v. beta-adrenoceptor blocking drugs but were unaffected by alpha-adrenoceptor blocking agents.3 In 5 out of 20 cats, i.c.v. isoprenaline regularly produced dose-related falls in blood pressure with associated tachycardias; both effects were abolished after i.c.v. beta-adrenoceptor blocking agents.4 Intracerebroventricular dopamine produced cardiovascular responses which were qualitatively similar to those produced by i.c.v. isoprenaline.5 Intracerebroventricular adrenaline produced complex responses in untreated animals but typical alpha-effects were obtained after prior i.c.v. treatment with a beta-adrenoceptor blocking agent and typical beta-effects after i.c.v. pretreatment with an alpha-adrenoceptor blocking agent.6 The cardiovascular changes produced by i.c.v. beta-adrenoceptor agonists were abolished after systemic administration of hexamethonium or bethanidine.7 The results are discussed in the light of the mode of action of beta-adrenoceptor stimulants and beta-adrenoceptor blocking agents in the treatment of hypertension.
D000420:Albuterol / Q000494:pharmacology; D000526:Alprenolol / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001627:Bethanidine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D002552:Cerebral Ventricles; D003000:Clonidine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007267:Injections; D007545:Isoproterenol / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000031:analogs & derivatives / Q000494:pharmacology; D010393:Pempidine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011217:Practolol / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011941:Receptors, Adrenergic; D013015:Sotalol / Q000494:pharmacology; D013045:Species Specificity; D013997:Time Factors
D006584:Hexamethonium Compounds; D011941:Receptors, Adrenergic; D001285:Atropine; D000526:Alprenolol; D008012:Lidocaine; D011433:Propranolol; D013015:Sotalol; D007545:Isoproterenol; D003000:Clonidine; D010393:Pempidine; D000420:Albuterol; D011217:Practolol; D004298:Dopamine; D001627:Bethanidine; D009638:Norepinephrine; D004837:Epinephrine; D010646:Phentolamine