AJP - Gastrointestinal and Liver Physiology, Vol 268, Issue 4 650-G662, Copyright © 1995 by American Physiological Society
Prolonged ambulatory canine colonic motility
S. M. Scott, M. A. Pilot, T. G. Barnett and N. S. Williams
Surgical Research Unit, Royal London Hospital, United Kingdom.
Canine gastrointestinal motility is studied at present in animals confined
to a small cage or sling. The aims of this study were to record colonic
activity over a 24-h period in eight dogs by an ambulatory method. Motility
signals from implanted strain gauges were processed and stored via a
portable battery-operated amplifier and digital recorder housed in a
jacket. Ambulant interdigestive activity was the same as observed in
laboratory experiments, with migrating colonic motor complexes (CMCs) and
infrequent giant contractions (GCs). Feeding caused a multiphasic
alteration in motility for 582.1 +/- 18.1 min (mean +/- SE). There were
four distinct phases. During the "early" (0-2 h) postprandial period, phase
1 (mean duration: 55.1 +/- 4.0 min), which was distinguished by CMCs of
high frequency and elevated amplitude in the proximal colon, and phase 2
(78.2 +/- 6.2 min), which had CMC characteristics similar to those in the
interdigestive period, occurred. Phase 3 (218.8 +/- 13.6 min), a further
period of increased motility, and phase 4 (339.1 +/- 14.0 min),
characterized by low-amplitude long-duration CMCs, occurred during the
"late" (2 h onward) postprandial response. With the exception of phase 3,
postprandial phases were not always present following food intake, and
their expression was markedly influenced by variations in meal time and by
defecation immediately following feeding. Spontaneous defecation was
characterized by a variety of motor profiles, with a GC accompanying
two-thirds of episodes. We conclude that a more complete picture of canine
colonic motility has been documented because of the development of the
ambulatory system.
