Abstract
Abstract Decreased blood flow caused by vasoconstriction is a hallmark of ergot alkaloid exposure. Previous research has utilized the cranial branch of the lateral saphenous vein as a model to characterize the impact of ergot alkaloids on bovine peripheral vasculature. The digital vein is more distal and closer to the hoof where damage caused by vasoconstriction occurs and may be more sensitive to ergot alkaloids. Thus, the objective was to compare contractility of the bovine lateral saphenous vein and the digital vein to increasing concentrations of ergot alkaloids. Blood vessels were collected from Holstein steers at slaughter (n = 12; 551 ±29 kg), cleaned, cut into 2-mm cross-sections, and mounted in a multi-myograph. In the myograph blood vessels were submersed in continuously gassed (95% O2/5% CO2) Krebs-Henseleit buffer. Following a 1.5-hr tension equilibration, blood vessels were exposed to a reference dose of 1x10-4 M norepinephrine. Digital and lateral saphenous veins from each steer were then exposed to increasing concentrations of a-ergocryptine (ERP), ergotamine (ERT), ergocristine (ERS), ergocornine (ERO), ergonovine (ERN), tall fescue seed extract (EXT; dilutions based on measured ergovaline concentration), lysergic acid (LSA), and lysergol (LYS) were diluted to final concentrations for use in the tissue bath of 5x10-10 to 1x10-4 M. All resultant contractile response data were normalized as a percentage of the 1x10-4 M norepinephrine response and analyzed as randomized design for effects of vein and alkaloid concentration. The maximal contractile response induced by EXT, ERT, ERO, ERS, and ERP did not differ by vein type and EXT was the most vasoactive alkaloid. The response to ERN was greater for the saphenous than the digital vein (P = 0.03) and LYS and LSA did not differ (P >0.05). These data confirm that the cranial branch of lateral saphenous vein is a representative model of peripheral vasculature of the bovine hindlimb.
Accepted Version
Published Version
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