Electrophysiological characterization of chloride secretion across the jejunum and colon of pigs as affected by age and weaning.
Hypersecretion of chloride can cause diarrhea, a disease frequently occurring in young pigs, particularly around weaning. We investigated the contribution of different channels to intestinal Cl(-) secretion as influenced by age and weaning. Jejunal and colonic epithelia from 4-month-old pigs and 4-week-old piglets were incubated in Ussing chambers and stimulated by carbachol and forskolin. Changes in short-circuit currents were taken as measure of electrogenic net Cl(-) secretion. DIDS or NPPB served to inhibit Ca-activated Cl(-)-channels and outwardly rectifying Cl(-)-channels (ORCC) or cystic fibrosis transmembrane regulator (CFTR), respectively. Depolarizing the basolateral membrane allowed to examine the influence of K(+)-channels on Cl(-) secretion. Forskolin-stimulated Cl(-) secretion was mediated by CFTR. ORCC were not involved. Carbachol-induced Cl(-) secretion could be ascribed to an enhanced driving force due to the opening of K(+)-channels, whereas Ca-dependent Cl(-) channels seemed not to be involved. In jejunum, piglets showed higher Cl(-) secretion than pigs. Two days after weaning forskolin induced an I (sc) overshoot and a faster increase in G (t). In colon, Cl(-) secretion was neither influenced by age nor by weaning. The data suggest a disposition of porcine jejunum for a higher Cl(-) secretion in young and freshly weaned piglets, which might be a natural defense mechanism as well as a predisposing factor for diarrhea.
Leonhard-Marek
Sabine
S
Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173, Hannover, Germany. sabine.leonhard-marek@tiho-hannover.de
Hempe
Julia
J
Schroeder
Bernd
B
Breves
Gerhard
G
D000375:Aging / Q000502:physiology*; D000818:Animals; D000833:Animals, Suckling; D065101:Chloride Channel Agonists; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003106:Colon / Q000502:physiology*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000037:antagonists & inhibitors; D003967:Diarrhea / Q000517:prevention & control / Q000662:veterinary; D005260:Female; D007583:Jejunum / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials; D009919:Orchiectomy; D020033:Protein Isoforms; D013552:Swine / Q000254:growth & development / Q000378:metabolism*; D013553:Swine Diseases / Q000517:prevention & control; D014886:Weaning
D065101:Chloride Channel Agonists; D018118:Chloride Channels; D020033:Protein Isoforms; D019005:Cystic Fibrosis Transmembrane Conductance Regulator