Vasoconstrictive Capacity of Ergopeptine Alkaloids Associated With Endophyte Infected Tall Fescue- Scope K

Fescue toxicosis has generally been associated with vasoconstriction and specifically vasoconstriction of the ergopeptine alkaloids. However, when they have been provided in pure chemical form no adverse effects have been measured, but in combination with loline alkaloids negative animal response has been observed. A comprehensive study of the ergopeptine alkaloids, their precursors or in combination with the pyrrolizidine alkaloids of the grasslendophyte biotum has not been done in attempt to determine vasoconstrictive activity of these compounds individually or in combinations. This proposal will evaluate the compounds with just the ergolene ring system, lysergic acid, and simple and complex derivatives of lysergic acid, including ergopeptine alkaloids singly and in combination with unsaturated pyrrolizidine alkaloids which are present in the biotwn in 1000-fold greater amount than the ergopeptine alkaloids. These studies will be done v'lith isolated veinal tissue from cattle. Results will provide more specific guidance to target compounds in the biotum directly involved in toxicosis.