The effect of neuropeptide Y on sodium, chloride and potassium transport across the rat distal colon
Open Access
- 19 July 1995
- journal article
- Published by Wiley in British Journal of Pharmacology
- Vol. 115 (6), 1071-1079
- https://doi.org/10.1111/j.1476-5381.1995.tb15920.x
Abstract
1 Neuropeptide Y (NPY; 10−10–10−7 mol l−1) reduced basal short-circuit current (Isc.) in a concentration-dependent manner in the rat distal colon but was ineffective in the proximal colon. 2 The action of NPY was dependent upon the presence of CI− and HC03- anions and was blocked by prior treatment of the tissue with a Cl− channel blocker. The decrease in Isc was associated with an increase in mucosa-to-serosa fluxes of Na+, Rb+ (K+) and Cl−, whereas the serosa-to-muc osa flux of Cl− was decreased. 3 The size of the inhibitory NPY effect was linearly correlated with the height of the basal Isc i.e. it inhibited 55% of basal secretory Isc. 4 The action of NPY was unaffected by indomethacin and tetrodotoxin, when given alone, but was abolished, when the basal Isc was decreased to values near zero by a combination of both inhibitors. This inhibition could be overcome by restoring basal Isc with prostaglandin E2, indicating that the effect of NPY is not mediated by nerves or prostaglandins, but that NPY is only effective, when anion secretion is stimulated by the spontaneous release of neurotransmitters and prostaglandins. 5 NPY inhibited the increase in Isc induced by veratridine and prostaglandin E2, but it had no effect on the Isc induced by direct stimulation of the adenylate cyclase with forskolin, or on Isc induced by stimulation of the Ca2+–pathway with carbachol. Inhibition of the response to veratridine or prostaglandin E2 by NPY showed the same dependence on the height of the Isc just prior to addition of NPY as seen in control conditions, i.e. NPY inhibited 55% of cyclic AMP-mediated secretion. 6 These results suggest that the effect of NPY is mediated by an inhibition of cyclic AMP-stimulated secretion, which is stimulated in the rat distal colon by a continuous release of prostaglandins and neurotransmitters.Keywords
This publication has 36 references indexed in Scilit:
- Evidence against direct activation of chloride secretion by carbachol in the rat distal colonEuropean Journal of Pharmacology, 1995
- Segmental heterogeneity of the rat colon in the response to activators of secretion on the cAMP-, the cGMP- and the Ca2+-pathwayActa Physiologica Scandinavica, 1991
- Actions of neuropeptide Y on basal, cyclic AMP-induced and neurally evoked ion transport in porcine distal jejunumRegulatory Peptides, 1990
- Antisecretory effects of somatostatin and vasopressin in the rat colon descendens in vitroRegulatory Peptides, 1989
- Properties of an anion-selective channel from rat colonic enterocyte plasma membranes reconstituted into planar phospholipid bilayersThe Journal of Membrane Biology, 1987
- Projections of peptide-containing neurons in rat small intestineNeuroscience, 1987
- Evidence that PGE2 stimulates intestinal epithelial cell adenylate cyclase by a receptor-mediated mechanismDigestive Diseases and Sciences, 1987
- Neuropeptide Y (NPY) and peptide YY (PYY) inhibit prostaglandin E2-induced intestinal fluid and electrolyte secretion in the rat jejunum in vivoEuropean Journal of Pharmacology, 1985
- Neuropeptide Y—a novel brain peptide with structural similarities to peptide YY and pancreatic polypeptideNature, 1982
- Effects of low-chloride solutions on action potentials of sheep cardiac Purkinje fibers.The Journal of general physiology, 1977