Longitudinal axial coupling of slow waves in proximal cat colon.

CHRISTENSEN, JAMES, AND RICHARD L. HAUSER. Longitudinal axial coupling of slow waves in proximal cat colon. Am. J. Physiol. 22 l(1) : 246-250. 197 1 .-We studied spreading patterns of electric slow waves of circular muscle in longitudinal axis of cat colon. The colon, opened lengthwise, was pinned flat, serosa down, in a bath equilibrated with 957, OQ--5y0 CO2 at 36.5-37.5 C. Six volume-recording electrodes, put on circular muscle, exposed by removal of the mucosa, recorded slow waves simultaneously from six sites 5.8 mm apart. The first was just below the ileocecal junction. 1Ve determined proportion of time when slow waves were phase locked across all six electrodes, direction of spread and time delay while slow waves were phase locked, distance over which slow waves were phase locked, and oscillator frequency. During phase lock across all six points (67% of the time) slow waves spread orad 8.7y0, caudad 3.5y0, and split (orad proximally, caudad distally) 87.9y0 of the time. Apparent velocity orad, 2.6 & 1.1 (SD) mm/set, was less than caudad, 3.6 =t 2.1 (SD) mm/set, (P = 0.005). Distance over which phase lock occurred varied from 5.8 to 28.8 mm. Frequency was 3.12 =t 1.62 (SD) cycles/min. Distance of phase lock and direction of phase lag vary and may affect fecal flow through effects on integration and polarization of wall movements. Different apparent velocities in the two directions suggest rectification in coupling of slow-wave oscillators.