AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 5 510-G514, Copyright © 1984 by American Physiological Society
Evidence for separate sympathetic regulation of fluid absorption and blood flow in the feline jejunum
H. Sjovall
Splanchnic nerve stimulation (SNS) in cats leads to a jejunal
vasoconstriction and to an enhancement of jejunal net fluid absorption. We
tested the possibility that the sympathetic fibers to the transporting
epithelium might use a ganglionic transmission mechanism different from the
one utilized by the jejunal vasoconstrictor nerves. The splanchnic nerves
were stimulated before and after a dose of hexamethonium sufficient to
entirely block the intestinal vasoconstrictor fibers. However, SNS still
increased net fluid absorption in these hexamethonium-treated animals. The
hexamethonium-resistant increase in fluid absorption during SNS was a
neurogenic effect on the jejunal segment, as it was eliminated by
mesenteric denervation and could be reproduced by stimulation of the nerves
surrounding the superior mesenteric artery. These data indicate that the
rate of jejunal fluid absorption may be regulated by sympathetic fibers
functionally distinct from the intestinal vasoconstrictor nerves.
