Effects of bepridil and of its quaternary derivative on rat tail artery.
The effects of bepridil and its quaternary ammonium derivative (BN+) were compared, showing that: (i) both drugs inhibited K+-induced contractions with similar time courses and potencies, (ii) bepridil blocked the tonic but not the phasic component of contractions elicited by noradrenaline, whereas BN+ had no effect on noradrenaline-elicited contractions. These results, and the relative insensitivity of skinned taenia caeci to bepridil, suggest that this drug and BN+ do not act directly on contractile proteins but affect K+- and noradrenaline-induced calcium channel activities differentially.
D000818:Animals; D001158:Arteries / Q000187:drug effects; D015764:Bepridil; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002432:Cecum / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013623:Tail / Q000098:blood supply; D013997:Time Factors
D002121:Calcium Channel Blockers; D011759:Pyrrolidines; C054965:N-methylpyrrolidine; D011092:Polyethylene Glycols; D015764:Bepridil; D017830:Octoxynol; D011188:Potassium; D009638:Norepinephrine