Effect of capsaicin on electrical slow waves in the isolated cat colon

Because of the laxative effect of capsaicin, we examined the effect of that agent on the electromyogram of the isolated cat colon. At a concentration of 10(-4)M, it caused a significant reduction in the frequency of the electrical slow waves in the proximal half of the colon. Frequency fell to its lowest value, 45% of control (P less than 0-001), in the most proximal 10% of the organ below the ileocecal junction, and the effect progressively diminished along the colon. In the distal half of the colon, the change in frequency was not significant. Sectioning of the colon into segments reduced the frequency of the slow waves in the proximal half of the colon, and capsaicin, in a concentration of 10(-4)M, further reduced the frequency in the segments representing the proximal 30% of the colon. This effect of capsaicin is like that reported previously with other laxative agents.