Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2006
Publication Date: 7/9/2006
Citation: Klotz, J.L., Arrington, B.C., Bush, L.P., Strickland, J.R. 2006. Response of Bovine Lateral Saphenous Vein to Increasing Concentrations of Lysergic Acid and Ergovaline. Journal of Animal Science Supplement. 84:53-54.
Interpretive Summary: not one
Technical Abstract: Lysergic acid (ergoline alkaloid) and ergovaline (ergopeptine alkaloid) have been proposed as toxic components of endophyte-infected tall fescue. As many of the symptoms of fescue toxicosis are a result of compromised circulation, the objective of this study was to examine the vasoconstrictive potentials of D-lysergic acid (n = 12) and ergovaline (n = 12) using a bovine lateral (cranial branch) saphenous vein bioassay. Segments (2-3 cm) of the cranial branch of lateral saphenous vein were collected from healthy mixed breed cattle at local abattoirs. Veins were trimmed of excess fat and connective tissue, sliced into 2-3 mm sections and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O2/5% CO2; pH = 7.4; 37'C). Tissue was allowed to equilibrate at 1 g of tension for 90 min prior to initiation of treatment additions. Increasing doses of ergovaline or lysergic acid (1x10-11 to 1x10-4 M) were administered every 15 min following buffer replacement. Data were normalized as a percent of contractile response induced by a reference dose of norepinephrine (1x10-4 M). Exposure of vein segments to increasing concentrations of lysergic acid did not result in an appreciable contractile response until the addition of 1x10-4 M lysergic acid (15.6 ' 2.3 %). Conversely, a vascular response to increasing concentrations of ergovaline was apparent at 1x10-8 M (4.4 ' 0.8%) and increased to a maximum of 69.6 ' 5.3% with the addition of 1x10-4 M ergovaline. These data indicate that only supraphysiological concentrations of lysergic acid results in vasoconstriction, but concentrations as low as 1x10-8 M ergovaline could elicit a vascular response. If other physiological systems in the animal are affected similarly, lysergic acid may only play a minor role in the manifestation of fescue toxicosis, whereas exposure to ergovaline, a much more potent vasoconstrictor, could result in appearance of fescue toxicosis symptoms. Bovine, Ergovaline, Lysergic Acid, Saphenous Vein