AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 3 463-G469, Copyright © 1989 by American Physiological Society
Postprandial changes in intestinal slow-wave propagation reflect a decrease in cell coupling
D. Terasaka, A. Bortoff and L. F. Sillin
Department of Physiology, State University of New York Health Science Center, Syracuse.
The purpose of these studies was to determine the effects of feeding on
jejunal slow-wave propagation velocity (SWPV). Nine cats were instrumented
with six pairs of electrodes implanted 4 cm apart on the jejunum.
Electrical activity was recorded at the end of an 18-h fast after which
each animal was fed 60 g of canned cat food. Recordings were continued
during feeding and for several hours thereafter. This procedure was
repeated at least twice for each cat. Average SWPV (cm/s) decreased from a
fasting level of 2.28 +/- 0.20 (mean of means +/- SE) to 1.93 +/- 0.16 at
10-20 min, 1.51 +/- 0.11 at 1 h, and 1.37 +/- 0.10 at 3 h postprandially.
Corresponding SW frequencies (SWFs) were 19.6 +/- 0.3, 18.7 +/- 0.2, 19.2
+/- 0.2, and 19.0 +/- 0.2 cycles/min, respectively. The differences between
the fasting SWPV and that at 1 and 3 h were significant (P less than 0.05).
When SWPV was plotted as a function of SWF, the slopes of the corresponding
curves were also found to decrease postprandially (P less than 0.05,
fasting vs. 1 and 3 h). There was no apparent change in SW amplitude,
maximum rate of SW depolarization, or threshold. In the absence of changes
in these parameters, the divergence of the slopes at lower SWFs indicates
that the decrease in SWPV is because of increased internal resistance,
probably the result of uncoupling of intestinal muscle cells. The change is
rapid in onset and long in duration, suggesting that an uncoupling factor
is released during ingestion of a meal, and that its effect persists for
several hours.
