In 15 subjects undergoing cholecystectomy (6 ascending, 4 transverse, 3 descending and 4 sigmoid), colonic electrical activities were recorded by using Teflon-coated stainless steel bipolar electrodes. Electrode leads were brought out from the recording sites through a Penrose drain; electrodes, leads, and the drain were removed 5-7 days postoperatively. Three kinds of electrical activities associated with contractions were recorded from all parts of the colon. The discrete electrical response activity was observed as short-duration (<10 s) bursts of response potentials associated with individual control potentials of electrical colonic activity. The continuous electrical response activity appeared as long-duration (>10 s) bursts of response potentials that were not related to ECA. Its mean durations were 21.55 ± 5.07, 64.94 ± 55.51, and 190.0 s in the proximal, middle, and the distal colonic segments respectively. Continuous electrical response activity occurred intermittently, and it generally did not propagate. The contractile electrical complex appeared as oscillations in the frequency range of 25-40 cycles/min and propagated in either the orad or the aborad direction. The repetition rate of the contractile electrical complex varied from 0.3 to 2 bursts/min in all segments. The duration of the contractile electrical complex when it appeared repetitively varied from 12 to 40 s in the proximal and the distal segments and from 15 to 70 s in the middle segment. These three kinds of electrical activities can explain the dual colonic motor function of temporary storage with infrequent mass movements.
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