AJP - Gastrointestinal and Liver Physiology, Vol 261, Issue 1 166-G170, Copyright © 1991 by American Physiological Society
Use of a modified Ussing chamber to monitor intestinal epithelial and smooth muscle functions
Y. F. Li, N. W. Weisbrodt, Y. Harari and F. G. Moody
Department of Surgery, University of Texas Medical School, Houston 77030.
A technique that allows the simultaneous monitoring of epithelial and
smooth muscle function was developed and used to study rat small intestine
in vitro. A Ussing chamber was modified so that a strain gauge force
transducer could be sewn to the serosal surface of an intestinal segment
clamped in the chamber. The apparatus was used to monitor short-circuit
current, potential difference, and resistance across the segment, and
contractions of the longitudinal layer of the muscularis externa. Both
spontaneous activity and responses to the application of carbachol were
recorded. Carbachol applied to the serosal side induced dose-dependent
increases in both short-circuit current and contractile force. The median
effective doses of the two responses differed, with contractions being more
sensitive to the drug. Carbachol applied to the mucosal side induced no
changes in either epithelial or contractile activities. The ability of the
serosal strain gauge transducer to monitor contractions faithfully was
tested in an organ bath in which the gut segment was attached to an
external force-displacement transducer. There was a close correlation
between the dose-dependent increase in force in response to carbachol
measured by the serosal transducer and that measured by the
force-displacement transducer (r = 0.988). Thus our technique can be used
to study simultaneously epithelial and smooth muscle functions of the
intestine.
