Neuromodulation of ion transport in porcine distal colon: npy
reduces the secretory actions of leukotrienes.
Traynor, Timothy R., David R. Brown, and Scott M. O'grady.
Department of Physiology, University of Minnesota, Minneapolis,
Minnesota 55455, Department of Veterinary Pathobiology, University of
Minnesota, St. Paul, Minnesota 55108, Departments of Physiology and
Animal Science, University of Minnesota, St. Paul, Minnesota
55108
APStracts 2:0052R, 1995.
Electrical transmural stimulation (ETS) was used to examine the
neuroregulation of electrolyte transport in the porcine distal colon.
ETS of the colonic mucosa-submucosa mounted in Ussing chambers
produced rapid and transient increases in short-circuit current (Isc)
which were inhibited 36% by serosal bumetanide suggesting that a
portion of the response may be attributed to Cl secretion. ETS
actions were dependent upon stimulus intensity and frequency and were
inhibited by tetrodotoxin and w-conotoxin. Prazosin and pyrilamine
had no effect on the mucosal responses to ETS while atropine reduced
the responses by 32%. Neuropeptide Y (NPY) also reduced the mucosal
responses to ETS up to 60% (EC50 = 17 nM). In addition, the effects
of leukotriene C4, previously shown to stimulate Cl secretion via a
neuronal pathway, were also inhibited by NPY. These results indicate
that cholinergic submucosal neurons play a role in the regulation of
epithelial ion transport and that neuropeptide Y acts as an
inhibitory neuromodulator, particularly on leukotriene-sensitive
neurons, in the porcine distal colon.
Received 14 September 1994; accepted in final form 21 February
1995.
APS Manuscript Number R517-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 7 March 1995.