Electromyography of the colon in the unanesthetized cat.

Abstract

The purpose of this investigation was to detect patterns of the electrical activity of colon musculature in the fasted state and after cholinergic stimulation. Up to eight needle electrodes were implanted on the serosal side, along the colon of 6 cats. Electrical recording, during the following 2 to 5 months showed spikes, oscillations and omnipresent slow waves. The slow-wave frequency was labile and varied independently in different areas of the colon. Direction of the slow-wave frequency gradient also varied. Mean slow-wave frequency was 26.5 cycles/5 min in the ascending, 27.4 in the transverse and 27.8 in the descending colon. The cholinergic agents increased spike and oscillating activity and reduced the slow-wave frequency transiently by 10 to 20%. Atropine antagonized these effects. Cholinergic effects were similar in all areas of the colon. We conclude that the colon of unanesthetized cats generates slow waves, spikes and oscillating potentials. Slow-wave frequency is labile and can be changed by cholinergic drugs.