AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 6 928-G933, Copyright © 1990 by American Physiological Society
Regulation of canine jejunal transit
N. J. Soper, K. L. Geisler, M. G. Sarr, K. A. Kelly and A. R. Zinsmeister
Department of Surgery, Mayo Clinic, Rochester, Minnesota 55905.
The aim of this study was to determine what factors influence the direction
of movement of canine jejunal chyme. In four dogs, pacing electrodes were
implanted near each end of a 50-cm jejunal Vella loop, while recording
electrodes and intraluminal pressure catheters were spaced along the loop.
After recovery, the loop was perfused from either the proximal stoma
(forward flow) or the distal stoma (reversed flow), and effluent was
collected from the nonperfused stoma. The pacesetter potentials were paced
electrically in a forward (aborad) or a reverse (orad) direction. During
control conditions (forward flow-forward pacing), the mean transit time of
liquids was 2.6 +/- 0.1 min (mean +/- SE) and the static volume of the loop
was 8.8 +/- 0.3 ml. Reversing both direction of flow and direction of
pacesetter potential propagation slowed transit (4.4 +/- 0.4 min; P less
than 0.05) and increased loop volume (16.0 +/- 1.0 ml; P less than 0.01).
Reversing flow with forward pacing resulted in even slower transit (7.5 +/-
1.2 min; P less than 0.05), maintained a large volume (33 +/- 10 ml), and
increased basal pressure in the loop from -1.2 +/- 1.7 (control) to 2.3 +/-
1.6 mmHg (P less than 0.05). These observations suggest that the direction
of propagation of jejunal pacesetter potentials influences the direction of
movement of jejunal chyme but that other factors have a role as well.
