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A Review Of Research Articles Dealing With The Potential Effects Of Er

¡§A review of research articles dealing with the potential effects of ergot alkaloids on the growth and reproductive performance of beef cattle grazing endophytic fescue.¡¨

By

Pia A. Herring

September 20, 2001
Assignment #2
AGSC 514
Introduction

Due to the enormous amounts of money that are lost yearly to tall fescue toxicosis, there have been numerous studies conducted to try and discover the specific mechanisms of action that the toxins present in the endophytic fungus Neotyphodium coenophialum follow. Researchers have looked at the effect of the alkaloids at the cellular level, as well as observing the effects of the alkaloids on physiological responses and hormonal changes. All in an effort to try and better understand the different ways that the toxins affect susceptible animals. It is believed that if the mechanisms of action are better understood, that it would be easier to determine ways to counteract the effects of the toxins, and decrease the large amounts of money lost every year to tall fescue toxicosis.

Discussion

One of the studies that have been conducted to discover the mechanisms of action that the toxins follow looked at the mechanism from a cellular level. Larson et al. (1999) took commercially available ergopetides, lysergic acid amides, and pyrrolizidine alkaloids, N-acetyl and N-formylloline, and added them to cellular cultures of rat D2 Dopamine receptors to see if they would bind to the receptor sites. The D2 Dopamine receptors were chosen, because they regulate prolactin release; which if inhibited is a biological indicator of toxins present from the consumption of endophyte infected tall fescue. The D2 Dopamine receptors have also been implicated in cardiovascular, thermoregulatory, nervous, and adrenal functions, as well as H2O intake. What they found was that the ergopeptide and lysergic acid amides acted like endogenous dopamine and did bind to the receptor sites; as well as inhibiting cyclic AMP...