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Black walnut extract inhibits secretory pathways in equine cecum and colon via mechanisms that overlap with cyclooxygenase signaling
Author(s) -
Rivier Lauraine H,
Blikslager Anthony T
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.977.13
Subject(s) - laminitis , ussing chamber , cyclooxygenase , cecum , secretion , mannitol , chemistry , pharmacology , medicine , transepithelial potential difference , endocrinology , biology , biochemistry , horse , enzyme , ion transporter , paleontology , membrane
Disturbances in the hind‐gut have been linked to the induction of equine laminitis, presumably by initiating enteric signaling pathways that result in release of mediators that affect distant fragile vascular beds such as that in the hoof. Laminitis has been experimentally induced by gavaging with black walnut extract (BWE) toxin, leading to changes in both the gut and laminae. Cecal and colonic tissue were mounted on Ussing chambers and treated with escalating doses of BWE (0.6, 1.25, 2.5 and 5%). Changes in short circuit current (Isc), transepithelial electrical resistance, and 3 H‐mannitol fluxes were measured. BWE treatment did not affect gut barrier function as there were no significant changes in resistance or mannitol flux. However, BWE caused significant decreases in Isc when compared with controls, most likely due to inhibition of basal Cl − secretion. Pre‐treatment with the cyclooxygenase inhibitor flunixin (2.7μM) resulted in a similar reduction in Isc, which has previously been shown to inhibit Cl − secretion. Treatment with both BWE and flunixin had no additive effect, further suggesting that BWE and flunixin have overlapping signaling pathways. The precise mechanism by which BWE reduces Isc in the equine gut will require further study, but early evidence is suggestive of an inhibitory effect on Cl − secretion. This in turn may affect colonic luminal contents, with systemic effects such as laminitis.