ARS | Publication request: Tall Fescue Alkaloids Bind Serotonin Receptors in Cattle

Submitted to: Kentucky Beef Report
Publication Type: Experiment Station
Publication Acceptance Date: August 19, 2010
Publication Date: August 19, 2010
Citation: Klotz, J.L., Strickland, J.R., Bush, L.P., Brown, K.R., Aiken, G.E. 2010. Tall Fescue Alkaloids Bind Serotonin Receptors in Cattle. Kentucky Beef Report. pgs 37-43.

Technical Abstract: The serotonin (5HT) receptor 5HT2A is involved in the tall fescue alkaloid-induced vascular contraction in the bovine periphery. This was determined by evaluating the contractile responses of lateral saphenous veins biopsied from cattle grazing different tall fescue/endophyte combinations. The contractile responses of the biopsied blood vessel segments to different alkaloids (ergovaline, ergotamine, and ergocornine) were evaluated in the presence or absence of an antagonist or blocker of the 5HT2A receptor. The presence of the antagonist significantly reduced the contractile response to all three alkaloids in all three pasture types. A better understanding of how tall fescue alkaloids cause peripheral vasoconstriction will lead to better solutions for summer slump and fescue foot manifestations of the fescue toxicosis syndrome.