Some Effects of Quinidine and Quinine on the Electromyogram of the Colon

Abstract

The cat colon was exposed in vitro to two diarrheogenic agents, quinidine and quinine. Six electrodes, uniformly spaced in the long axis of the ascending colon, recorded the electromyogram before and after the addition of either quinidine hydrochloride or quinine dihydrochloride. Records were read for changes in electrical slow wave frequency and congruence, and for changes in the proportion of slow waves bearing spike potentials. Both agents significantly raised slow wave frequency at concentrations of 5 × 10–4 m . Slow wave congruence (as measured by calculating the coefficient of variation of frequency among the six electrodes) was significantly reduced by quinidine at 2 × 10–4 m and by quinine at 5 × 10–4 m . The proportion of slow waves bearing spike potentials increased significantly with quinidine at 5 × 10–4 m but not at 10–3 m .