[Effect of papaverine on the tonus and contraction of depolarized taenia coli musculature in guinea pigs].
Experiments were performed on the isolated strips of guinea pig taenia coli. The smooth muscle was depolarized in a solution with high potassium concentration (120 mM KCl). The effect of papaverine (in concentration of from 10(-5) to 3.10(-5) g/ml) on the tonus and the contractile off-response originating after the ending of longlasting strong polarizing current was investigated. It was found that: 1) papaverine abolished the concentrations induced by drugs (histamine, acetylcholine, bradykinin); 2) papaverine reduced the tonus of depolarized muscle and eliminated its increase under the effect of a rise of the external calcium concentration; 3) papaverine had no effect on the amplitude and the ascending phase of the contractile off-response; 4) papaverine accelerated the discending phase of the contractile off-response. The data obtained suggest: 1) there are chemoexcitable calcium channels in the cellular membrane which are blocked by papaverin; 2) there are calcium "leakage" channels in the cellular membrane responsible for the tone maintenance which are blocked by papaverine; 3) papaverine has a negligible effect on the electroexcitable calcium channels.
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D003106:Colon / Q000187:drug effects*; D004347:Drug Interactions; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D010208:Papaverine / Q000494:pharmacology*
D006632:Histamine; D010208:Papaverine; D002118:Calcium
Vliianie papaverina na tonus i sokrashcheniia depoliarizovannoĭ gladkoĭ myshtsy taenia coli morskoĭ svinki.