A M Cogswell1, P J Johnson, H R Adams. 1. Department of Veterinary Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia 65211, USA.
Abstract
OBJECTIVE: To test the hypothesis that endothelium-derived nitric oxide modulates vasomotor reactivity in equine digital arteries. DESIGN: Digital arteries were isolated from adult horses, and their vasodilator properties were examined in an in vitro controlled environment. ANIMALS: Five adult horses (1 gelding, 4 mares) without evidence of hoof or vascular disease were studied. PROCEDURE: Arterial rings with or without endothelium were exposed to endothelium-dependent vasodilator drugs in the presence or absence of a pharmacologic inhibitor of the enzyme nitric oxide synthase. RESULTS: Vasodilator effects of 3 endothelium-dependent vasorelaxant agents were significantly greater in endothelium-intact vessels than in endothelium-denuded vessels. Moreover, a nitric oxide synthase inhibitor reduced vasodilator responses to endothelium-dependent vasodilators in endothelium-intact arteries, but had no discernable effects in endothelium-denuded arteries. CONCLUSIONS: These findings indicate the presence of endothelium-derived relaxing factor/nitric oxide in blood vessels of horses, and identify vascular endothelium as an endogenous modulator of vasomotor tone in the digital arteries of this species.
OBJECTIVE: To test the hypothesis that endothelium-derived nitric oxide modulates vasomotor reactivity in equine digital arteries. DESIGN: Digital arteries were isolated from adult horses, and their vasodilator properties were examined in an in vitro controlled environment. ANIMALS: Five adult horses (1 gelding, 4 mares) without evidence of hoof or vascular disease were studied. PROCEDURE: Arterial rings with or without endothelium were exposed to endothelium-dependent vasodilator drugs in the presence or absence of a pharmacologic inhibitor of the enzyme nitric oxide synthase. RESULTS: Vasodilator effects of 3 endothelium-dependent vasorelaxant agents were significantly greater in endothelium-intact vessels than in endothelium-denuded vessels. Moreover, a nitric oxide synthase inhibitor reduced vasodilator responses to endothelium-dependent vasodilators in endothelium-intact arteries, but had no discernable effects in endothelium-denuded arteries. CONCLUSIONS: These findings indicate the presence of endothelium-derived relaxing factor/nitric oxide in blood vessels of horses, and identify vascular endothelium as an endogenous modulator of vasomotor tone in the digital arteries of this species.
Authors: Rustin M Moore; Steven A Sedrish; Earnestine P Holmes; Catherine E Koch; Changaram S Venugopal Journal: Can J Vet Res Date: 2005-04 Impact factor: 1.310
Authors: Jeremy D Hubert; Thomas L Seahorn; Thomas R Klei; Giselle Hosgood; David W Horohov; Rustin M Moore Journal: Can J Vet Res Date: 2004-07 Impact factor: 1.310