Palmar digital vessel relaxation in healthy horses and in horses given carbohydrate.

Schneider, D A; Parks, A H; Eades, S C; Tackett, R L

Schneider, D A; Parks, A H; Eades, S C; Tackett, R L.

Afiliación

Schneider DA; Department of Large Animal Medicine, University of Georgia, Athens 30602, USA.

Am J Vet Res ; 60(2): 233-9, 1999 Feb.

Article en En | MEDLINE | ID: mdl-10048558

RESUMEN

OBJECTIVE: To compare in vitro smooth muscle relaxation of palmar digital vessels from healthy horses with those from horses in the prodromal stage of experimentally (carbohydrate) induced laminitis. ANIMALS: 16 adult horses. PROCEDURE: Segments of palmar digital vessels were obtained from 5 healthy horses and 6 horses given carbohydrate. Vascular rings from the palmar digital artery and vein were suspended in individual organ baths containing buffer solution and indomethacin; isometric tension was recorded, and contraction and relaxation were compared. Smooth muscle contraction in response to cumulative addition of phenylephrine was recorded in the absence and presence of 1 microM NG-nitro-L-arginine methyl ester (L -NAME). After wash out, vascular rings were preconstricted with phenylephrine (0.3 microM), and cumulative endothelium-dependent (acetylcholine-induced) and independent (nitroprusside-induced) smooth muscle relaxations were recorded in the absence or presence of L -NAME. RESULTS: Phenylephrine increased vascular smooth muscle tone in ring preparations of palmar digital arteries and veins. Addition of acetylcholine or nitroprusside induced relaxation of palmar digital artery and vein ring preparations. Use of L-NAME (1 microM) significantly reduced maximal relaxation induced by acetylcholine, but not by nitroprusside. Maximal relaxation induced by acetylcholine, but not by nitroprusside, was reduced in vascular rings prepared from carbohydrate-overloaded horses. CONCLUSION AND CLINICAL RELEVANCE: Reduced endothelium-dependent relaxation of palmar digital vessels may have a role in the pathophysiology of acute laminitis after carbohydrate overload in horses.

Asunto(s)

Pezuñas y Garras/irrigación sanguínea; Enfermedades de los Caballos/fisiopatología; Músculo Liso Vascular/fisiopatología; Traumatismos de los Tejidos Blandos/veterinaria; Acetilcolina/farmacología; Animales; Carbohidratos/efectos adversos; Endotelio/fisiología; Inhibidores Enzimáticos/farmacología; Femenino; Enfermedades del Pie/inducido químicamente; Enfermedades del Pie/fisiopatología; Enfermedades del Pie/veterinaria; Miembro Anterior/fisiopatología; Enfermedades de los Caballos/inducido químicamente; Caballos; Técnicas In Vitro; Inflamación/inducido químicamente; Inflamación/veterinaria; Masculino; Contracción Muscular/efectos de los fármacos; Relajación Muscular/efectos de los fármacos; NG-Nitroarginina Metil Éster/farmacología; Nitroprusiato/farmacología; Fenilefrina/farmacología; Distribución Aleatoria; Traumatismos de los Tejidos Blandos/fisiopatología; Vasoconstrictores/farmacología; Vasodilatadores/farmacología

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Traumatismos de los Tejidos Blandos / Pezuñas y Garras / Enfermedades de los Caballos / Músculo Liso Vascular Límite: Animals Idioma: En Revista: Am J Vet Res Año: 1999 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos

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