AJP - Gastrointestinal and Liver Physiology, Vol 258, Issue 6 848-G855, Copyright © 1990 by American Physiological Society
Chemical degeneration of intestinal nerves
C. T. Frantzides, J. C. Garancis, B. T. Doumas and R. E. Condon
Department of Surgery, Medical College of Wisconsin, Milwaukee 53226.
In 15 dogs, cobalt chloride solutions were infused close intra-arterially
to perfuse a short segment of the jejunum. In an additional four dogs, the
jejunum was perfused with the aqueous vehicle (perfusion control). All
animals were killed after 1 mo and tissue samples from cobalt-treated and
from nonperfused intestine (tissue comparison control) were obtained for
electron microscopic and immunohistochemical studies. Segments infused with
0.25 g/dl cobalt solution showed minimal changes; the most striking feature
was an increase of vasoactive intestinal polypeptide (VIP)- and substance
P-containing neurosecretory granules. Cobalt chloride at higher
concentrations (0.75-1.5 g/dl) induced degeneration of ganglion cells and
axons in both the myenteric and submucosal plexi. In contrast, the smooth
muscle and the mucosal cells of the cobalt-perfused intestine showed no
histological abnormalities. Immunohistochemical staining of tissues treated
with 0.75-1.5 g/dl cobalt solutions revealed absence of substance P,
Met-enkephalin, and VIP immunoreactivity in all section studied; control
segments showed the presence of all three peptides. Cobalt chloride in
concentrations of 0.75-1.5 g/dl causes degeneration of intestinal
intramural nerves and provides an experimental model suitable for studying
the role of these nerves in small intestinal function.
