Alterations in serotonin receptor-induced contractility of bovine lateral saphenous vein in cattle grazing endophyte-infected tall fescue12
| Autor: | James C. Matthews, James L. Klotz, James A. Boling, W. R. Burris, Y. Xue, Lowell P. Bush, J. R. Strickland, K. R. Brown |
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| Rok vydání: | 2012 |
| Předmět: |
Agonist
medicine.medical_specialty geography geography.geographical_feature_category medicine.drug_class General Medicine Biology Serotonergic Pasture Ergovaline Contractility chemistry.chemical_compound Endocrinology chemistry Internal medicine Grazing Genetics medicine Animal Science and Zoology BW-723C86 5-HT receptor Food Science |
| Zdroj: | Journal of Animal Science. 90:682-693 |
| ISSN: | 1525-3163 0021-8812 |
| DOI: | 10.2527/jas.2011-4323 |
| Popis: | As part of a 2-yr study documenting the physiologic impact of grazing endophyte-infected tall fescue on growing cattle, 2 experiments were conducted to characterize and evaluate effects of grazing 2 levels of toxic endophyte-infected tall fescue pastures on vascular contractility and serotonin receptors. Experiment 1 examined vasoconstrictive activities of 5-hydroxytryptamine (5HT), α-methylserotonin (ME5HT; a 5HT(2) receptor agonist), d-lysergic acid (LSA), and ergovaline (ERV) on lateral saphenous veins collected from steers immediately removed from a high-endophyte-infected tall fescue pasture (HE) or a low-endophyte-infected mixed-grass (LE) pasture. Using the same pastures, Exp. 2 evaluated effects of grazing 2 levels of toxic endophyte-infected tall fescue on vasoconstrictive activities of (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), BW 723C86 (BW7), CGS-12066A (CGS), and 5-carboxamidotryptamine hemiethanolate maleate (5CT), agonists for 5HT(2A),( 2B), 5HT(1B), and 5HT(7) receptors, respectively. One-half of the steers in Exp. 2 were slaughtered immediately after removal from pasture, and the other one-half were fed finishing diets for >91 d before slaughter. For Exp. 1, maximal contractile intensities were greater (P 91 d. Experiment 1 demonstrated that grazing of HE pastures for 89 to 105 d induces functional alterations in blood vessels, as evidenced by reduced contractile capacity and altered serotonergic receptor activity. Experiment 2 demonstrated that grazing HE pastures alters vascular responses, which may be mediated through altered serotonin receptor activities, and these alterations may be ameliorated by the removal of ergot alkaloid exposure as demonstrated by the absence of differences in finished steers. |
| Databáze: | OpenAIRE |
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