Mechanism of the antagonism of the hypotensive action of guanethidine by propranolol.
1. Propranolol antagonizes the hypotensive effect of guanethidine in renal hypertensive but not in adrenal demedullated renal hypertensive rats.2. Guanethidine does not interfere with the release of catecholamines from the adrenal gland which follows splanchnic nerve stimulation in cats anaesthetized with pentobarbitone.3. Guanethidine does not release or interfere with the release of catecholamines after the intravenous injection of physostigmine in the rat.4. Propranolol antagonizes the antihypertensive effect of guanethidine by potentiating the vasopressor effects of catecholamines released from the adrenal glands during the induction stage of ether anaesthesia.
D000311:Adrenal Glands / Q000378:metabolism; D000313:Adrenal Medulla / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism / Q000502:physiology; D004357:Drug Synergism; D006145:Guanethidine / Q000037:antagonists & inhibitors*; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D013153:Splanchnic Nerves / Q000502:physiology
D002395:Catecholamines; D011433:Propranolol; D006145:Guanethidine