Antagonism by some beta-adrenoceptor-blocking agents to cholinergic stimulation of skeletal muscle in vitro.
Antiacetylcholine activity some beta-adrenoceptor-blocking drugs was investigated using isolated guinea pig cremaster muscle and frog fectus abdominis muscle. On the cremaster muscle, the antagonism to acetylcholine was non competitive in K0 1313, (+/-)-INPEA and (--)-INPEA, competitive in (+)-INPEA and functional in practolol; All three INPEA isomers, practolol and propranolol behaved as noncompetitive antagonists of acetylcholine on frog rectus muscle. Caffeine-induced contractions of this muscle were partially inhibited by propranolol but not by the other drugs. It is suggested that the beta-adrenoceptor-blocking drugs produce their antiacetylcholine action by interaction with sites on the muscle which are different from the cholinceptor, and which vary between compounds and species.
D000109:Acetylcholine / Q000378:metabolism; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001001:Anura; D004983:Ethanolamines / Q000494:pharmacology; D006168:Guinea Pigs; D008698:Mesylates / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects*; D009469:Neuromuscular Junction / Q000187:drug effects*; D009570:Nitriles / Q000494:pharmacology; D011217:Practolol / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011894:Rana pipiens; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013015:Sotalol / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D004983:Ethanolamines; D008698:Mesylates; D009570:Nitriles; D011950:Receptors, Cholinergic; D011433:Propranolol; D013015:Sotalol; D000109:Acetylcholine; D011217:Practolol