Location: Forage-Animal Production Research
Title: Ergot alkaloids induce vasoconstriction of bovine foregut vasculature Authors
Submitted to: Joint Meeting of the ADSA, AMSA, ASAS and PSA
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2010
Publication Date: July 11, 2010
Citation: Foote, A.P., Klotz, J.L., Harmon, D.L., Bush, L.P., Strickland, J.R. 2010. Ergot alkaloids induce vasoconstriction of bovine foregut vasculature. J. Anim. Sci. 88( 2/J). Dairy Sci. Vol. 93(1)/Poult. Sci. 89(1):701. Technical Abstract: Alkaloids produced by the Neotyphodium coenophialum endophyte in association with tall fescue (Lolium arundinaceum) are imputed to cause peripheral symptoms of fescue toxicosis. We hypothesized that theses compounds could correspondingly affect foregut vasculature. The objective of this study was to determine vasoconstrictive potentials of ergovaline (ERV), ergotamine (ERT), ergocryptine (ERP), ergocristine (ERS), ergonovine (ERN), ergocornine (ERO), lysergic acid (LSA), and an ethanol-extract of ground endophyte-infected fescue seed (EXT) on right ruminal artery and vein. Segments of right ruminal artery and vein were collected from the ventral coronary groove of predominately Angus heifers (n = 7) shortly after slaughter and placed in a modified Krebs-Henseleit buffer on ice. Vessels were cleaned of excess connective tissue and fat, sliced into 2-3 mm segments and suspended in a multi-myograph chamber with 5 mL of continuously oxygenated Krebs-Henseleit buffer (95 %O2/5% CO2; pH 7.4; 37°C). Arteries and veins were equilibrated to 1.0 g and 0.5 g respectively for 90 min followed by addition of 120 mM KCl. Increasing concentrations of each compound were added to the respective chamber every 15 min following buffer replacement. Data were normalized as a % of the contractile response induced by KCl. No venous response was observed until 1x10-5M and no arterial response was observed until 1x10-6M for ERV and ERT, 1x10-5M for ERP, ERO, and ERN, and 1x10-4M for ERS. Alkaloid, concentration, and vessel affected contractility (P<0.05). A greater arterial maximal response was observed for ERO, ERT, ERV, and EXT (P<0.05) and the arterial and venous responses were not different for ERN, ERP, ERS, and LSA (P>0.05). These results indicate that ergot alkaloids have potential to alter blood supply and drainage from the bovine foregut and the differential artery and vein responses may contribute to the fescue toxicosis syndrome.