Neuropeptide Y: a powerful modulator of epithelial ion transport.
Neuropeptide Y (NPY) is a major gut peptide localized in the intestinal mucosa of several mammalian species. Ileal mucosa from rabbit and guinea-pig was mounted in Ussing chambers in order to study the effect of NPY on short circuit current. Neuropeptide Y inhibited the short circuit current when applied to the serosal side of the tissue. The maximum change in short circuit current was -50 +/- 6 microA cm-2 in the rabbit ileum and -49 +/- 14 microA cm-2 in the guinea-pig ileum. The EC50 was 3 X 10(-8) M in both species. Pretreatment of rabbit ileum with the alpha 2-adrenoceptor antagonist, yohimbine (1 X 10(-6) M) for 10 min did not reduce the response of the tissue to neuropeptide Y (1 X 10(-7) M). When applied serosally to rabbit ileal mucosa, the related peptide YY caused a maximum change in short circuit current of -60 +/- 13 microA cm-2; the EC50 was 2 X 10(-9) M. Isotopic flux studies in rabbit ileum showed that 1 X 10(-7) M neuropeptide Y enhanced mucosal-to-serosal Na+ and Cl- fluxes and reduced serosal-to-mucosal Cl- flux. Replacement of chloride with gluconate on both sides of the tissue significantly reduced the change in short circuit current produced by neuropeptide Y (1 X 10(-7) M), as did a similar replacement of bicarbonate. It is concluded that neuropeptide Y and peptide YY are the most potent neurotransmitters or hormones so far described in their ability to attenuate electrogenic transport in the small intestine.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009478:Neuropeptide Y; D009638:Norepinephrine / Q000494:pharmacology; D019894:Peptide YY; D010455:Peptides / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D002712:Chlorides; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D010455:Peptides; D014662:Vasoconstrictor Agents; D019894:Peptide YY; D012964:Sodium; D009638:Norepinephrine