The influence of certain drugs on the response of smooth muscle to direct electrical stimulation

Neither the absence of KCl from Tyrode's solution or the presence of 2·10−7 adrenalin or 1·10−5 atropine altered the response of the smooth muscle of a section of guinea pigtaeniacoli to direct electrical stimulation. The response was depressed by 26, 39, 42, 43, 63, and 86% through the action of 4·10−5 spasmolytin, 1·10−4 dimedrol, 2·10−4 promedol, 4·10−5 dibazol, 4·10−5 papaverine, and by 2.5·10−5 2,4-dinitrophenol respectively. From published reports and our own results the explanation of the spasmolytic effects of adrenalin and atropine in smooth muscle appears to be that they act by an alteration of the condition of polarization of the smooth muscle fiber membranes, whereas papaverine appears to act both on the cell membrane and on the biochemical reaction of smooth muscle.