Effects of flunixin meglumine on short circuit current in equine colonic mucosa in vitro
Freeman, D.E.; Inoue, O.J.; Eurell, T.E.
American Journal of Veterinary Research 58(8): 915-919
1997
ISSN/ISBN: 0002-9645 PMID: 9256981 Document Number: 477487
Objectives:To study the effect of flunixin meglumine on short circuit current (Isc) in equine right ventral colon in vitro. Samples:Intestinal mucosa from healthy horses and ponies. Procedure:Isc was measured in mucosa from the right ventral colon mounted in Ussing chambers. In experiment 1, collection and incubation solutions were: control (no additions); flunixin meglumine, 4 mu-g/ ml; indomethacin, 10-6M; and flunixin meglumine (4 mu-g/ml) with 10-6 M prostaglandin E-2. In experiment 2, incubation conditions were: control (plain Krebs-Ringer bicarbonate (KRB) solution); flunixin meglumine, 4 mu-g/ml in KRB; chloride-free buffer solution; flunixin meglumine (4 mu-g/ml) in a chloride-free buffer solution; and plain KRB with 10-6 M prostaglandin E-2. In experiment 3, tissue from 3 groups (n = 6 each) of animals: controls, physiologic saline solution given IV at 10 minutes before euthanasia; flunixin meglumine (1.1 mg/kg of body weight, IV) given at 10 minutes before euthanasia; and treatment similar to controls, except that tissues were incubated with 8 mu-g of flunixin meglumine/ml of bathing medium. Results:Flunixin meglumine and indomethacin reduced Isc to approximately a third of control current (P lt 0.05), but coincubation with flunixin meglumine and 10-6 M prostaglandin E-2 restored Isc close to the control value. Incubation with 10-6 M prostaglandin E-2 alone did not change Isc. When chloride was substituted with isethionate, flunixin meglumine had no effect on Isc. Flunixin meglumine given before euthanasia or included at a concentration of 8 mu-g/ml in all tissue preparation and incubation solutions reduced Isc (P lt 0.05). Conclusions:Flunixin meglumine given IV or added to bathing solutions decreased Isc in equine right ventral colon by a mechanism that appeared to involve prostaglandin-mediated chloride secretion. Clinical Relevance:Our results suggest that flunixin meglumine given IV to horses at recommended doses could alter putative effects of colonic prostaglandins.