AJP - Gastrointestinal and Liver Physiology, Vol 242, Issue 1 58-G64, Copyright © 1982 by American Physiological Society
Elevated intraluminal pressure alters rabbit small intestinal transport in vivo
E. A. Swabb, R. A. Hynes and M. Donowitz
The effect of acutely increased intraluminal hydrostatic pressure (IHP) on
rabbit jejunal, ileal, and colonic water and electrolyte transport was
determined in vivo in a distended test segment and adjacent control segment
using a perfusion system with [14C]polyethylene glycol as a nonabsorbable
marker. Test-segment IHP was increased by raising the efflux catheter to
produce 10-70 cm water IHP, while control-segment IHP was held constant at
0 cm water. Acutely increased IHP up to 40 cm water in the jejunum and up
to 30 cm water in the ileum caused decreased net absorption in the jejunum
and net secretion in the ileum but caused no significant change in
control-segment transport. This indicated that IHP-induced changes in
transport were mediated by local rather than systemic effects. The
IHP-induced secretory process was dependent on the magnitude of elevation
in IHP and reversible at less than or equal to 20 cm water in the ileum. An
IHP of 30 cm water was associated with nonreversible transport changes in
the ileum. Acutely increased IHP to 70 cm water did not significantly alter
colonic transport. This experimental model is suitable for a comprehensive
investigation of the mechanism of IHP-induced changes in small intestinal
transport.
