AJP - Gastrointestinal and Liver Physiology, Vol 253, Issue 6 745-G750, Copyright © 1987 by American Physiological Society
Temporal changes in mechanical properties of rat jejunal smooth muscle after myenteric plexus ablation
J. R. Herman and P. Bass
Environmental Toxicology Center, University of Wisconsin-Madison 53706.
We determined length-stress properties and active tension development of
rat jejunal longitudinal and circular muscle at various times after
myenteric neuron ablation. Myenteric neurons were destroyed by serosal
application of benzalkonium chloride. Active tension generation in response
to both carbachol and barium was depressed in both muscle layers up to 7
days after treatment, at which times the responses were normal. At 15 days,
circular muscle responses were still comparable to control, but
longitudinal muscle responses were significantly increased. Length-stress
parameters of circular muscle were minimally affected, while those of
longitudinal muscle were significantly altered 15 and 30 days after
treatment. These alterations include changes in resting stress and
increased active stress generation at both times. Our results suggest that
1) normal myenteric innervation is necessary for normal contractile
activity in rat jejunal smooth muscle and 2) changes in cellular or tissue
morphology or alterations in intracellular calcium homeostasis, as seen in
other tissue, may occur after myenteric plexus ablation.
