VASOCONSTRICTIVE EFFECTS OF TALL FESCUE ALKALOIDS ON EQUINE VASCULATURE

The in vitro vasoconstrictive effects of equine arteriovenous tissues to alkaloids found in Acremonium coenophialum-infested fescue grass (e rgotamine tartrate, ergonovine maleate, and N-acetyl loline) were comp ared to those of various biogenic amines, including norepinephrine, ph enylephrine, BHT-920, and serotonin. In this initial study, both the l oline and the ergot compounds were vasoactive, although the contractil e effect was less than that of the biogenic amine compounds. The study demonstrates the potential for decreased perfusion of peripheral tiss ues in horses consuming A. coenophialum-infested fescue grass or hay.