Effects of adrenolytic drugs on the antihypertensive action of beta-blocking agents in the acute neurogenic hypertensive dog.
1. The antihypertensive action of three beta-blocking agents (dl-propranolol, dl-atenolol and butoxamine) was studied before and after pretreatment with adrenolytic drugs (reserpine and guanethidine) in acute neurogenic hypertensive (sino-aortic denervated) anesthetized dogs. 2. High doses of reserpine (2 mg/kg s.c.) suppressed both the effects of sino-aortic denervation and the antihypertensive action of dl-propranolol (1 mg/kg i.v.) 3. Pretreatment with reserpine (1 mg/kg i.p.) or guanethidine (15 mg/kg i.v.) delayed the manifestation of the antihypertensive action of dl-propranolol (1 mg/kg) observed in untreated (control) animals. 4. In a similar way, both dl-atenolol (1 mg/kg i.v.) and butoxamine (1 mg/kg i.v.) lost their antihypertensive effects after reserpinization. 5. These results indicate that the antihypertensive action of the three studied beta-blocking agents seen in debuffered animals depends upon the integrity of peripheral sympathetic nervous system under our experimental conditions. These effects are compatible with the view that beta-adrenoceptor blocking agents may exert, at least partly, their antihypertensive action through blockade of peripheral beta prejunctional adrenoceptors.
D000818:Animals; D000959:Antihypertensive Agents; D001262:Atenolol / Q000627:therapeutic use*; D002078:Butoxamine / Q000627:therapeutic use*; D003714:Denervation; D004285:Dogs; D005260:Female; D006145:Guanethidine / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D011412:Propanolamines / Q000627:therapeutic use*; D011433:Propranolol / Q000627:therapeutic use*; D012110:Reserpine / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000502:physiology
D000959:Antihypertensive Agents; D011412:Propanolamines; D002078:Butoxamine; D001262:Atenolol; D012110:Reserpine; D011433:Propranolol; D006145:Guanethidine