Evidence that ergovaline acts on serotonin receptors.
Ergovaline is a potent vasoconstrictor of isolated bovine uterine and umbilical arteries. Contractions to ergovaline were slow to develop and required 120 min or more to reach their maximum effect. Tissues contracted to ergovaline did not relax over a 3 hr period despite repeated changing of the bath fluid with fresh Krebs solution. This indicates a high affinity of ergovaline for its tissue receptor. Contractions to ergovaline were antagonized by ketanserin and phenoxybenzamine but not by prazosin or phentolamine. This indicates that 5-HT2 receptors but not adrenergic receptors are involved in the vasoconstriction. The results suggest that drugs effective in blocking 5-HT2 receptors may be useful in preventing or reducing the toxic symptoms due to ergovaline in animals consuming Acremonium coenophialum infected tall fescue.
Dyer
D C
DC
Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Iowa State University, Ames 50011.
D000818:Animals; D001158:Arteries / Q000187:drug effects; D002417:Cattle; D004879:Ergotamines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D011247:Pregnancy; D011985:Receptors, Serotonin / Q000187:drug effects*; D014469:Umbilical Arteries / Q000187:drug effects*; D014599:Uterus / Q000098:blood supply*; D014662:Vasoconstrictor Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D004879:Ergotamines; D011985:Receptors, Serotonin; D014662:Vasoconstrictor Agents; C076760:ergovaline