Myoelectric spiking activity of right colon, left colon, and rectosigmoid of healthy humans.

The tip of an intraluminal probe was positioned in the cecum, and before and after a standard meal (greater than 800 kcal), the rapid myoelectrical activity of the right, the left, and the rectosigmoid colon in six healthy subjects was recorded. In each colonic site, we recorded two different patterns of spike bursts: Short spike bursts and long spike bursts, as previously described. We observed no difference in either the duration or the amplitude of the two kinds of spike bursts among the three different parts of the colon. Before the meal, the number of long spike bursts was lower in the right than in the left colon (P less than 0.01) and than in the rectosigmoid (P less than 0.01). After the meal, a significant activity increase in long spike bursts lasted 20 min in the right colon (P less than 0.001), 100 min in the left colon, and in the rectosigmoid (P less than 0.001-P less than 0.05). This activity was always significantly less intense in the right colon than in the two other sites (P less than 0.001-P less than 0.01) and was less marked in the left colon than in the rectosigmoid (P 0.01-P less than 0.05). The short spike burst activity remained unchanged. These results provide evidence for the heterogeneity of motility in the different parts of the colon, with a relative hypomotility of the right colon compared to the left colon and the rectosigmoid in the healthy human.