Circumferential coupling of electric slow waves in circular muscle of cat colon.

CHRISTENSEN, JAMES, AND RICHARD L. HAUSER. Circumferential coupling of electric slow waves in circular muscle of cat’ colon. Am. J. Physiol. 221(4): 1033-1037. 1971 .-The cat colon, opened along the antimesenteric border, was spread, serosa down, in a bath of Krebs solution. Six volume-recording electrodes, 5.8 mm apart, were placed on the circular muscle layer exposed by removal of the mucosa just caudal to the ileocecal junction. Electrodes were aligned in three axes: the estimated transverse axis (0’ axis) and +5” and -5” from the O” axis. Records were examined to determine the I) proportion of time slow waves were phase locked over all electrodes, 2) patterns of direction of phase lag, 3) apparent velocity, 4) distance over which phase lock occurred, and 5) frequency of slow waves. Phase lock occurred across all electrodes 93-97?& of the time. Directions of phase lag varied so that slow waves could spread clockwise, counterclockwise, or split simply or complexly. Split patterns predominated. Apparent velocity was 7.5-9.6 mm/set. Phase lock occurred over virtually the whole circumference of the colon. Frequency was 2.2-2.6 cycles/min. There were no apparent differences among the three axes.