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DEMONSTRATION OF α‐ADRENOCEPTOR ANTAGONISM BY THE 5HT 2 ANTAGONIST, KETANSERIN (R49945), IN SHEEP
Author(s) -
Nelson M. A.,
Coghlan J. P.,
Denton D. A.,
Mills E. H.,
Spence C. D.,
Whitworth J. A.,
Scoggins B. A.
Publication year - 1984
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1984.tb00872.x
Subject(s) - ketanserin , prazosin , phenylephrine , heart rate , blood pressure , antagonist , agonist , antagonism , medicine , endocrinology , serotonin , 5 ht receptor , receptor antagonist , pharmacology , chemistry , receptor
SUMMARY 1. Serotonin causes a dose related (0.1–20 μg/kg i.v.) increase in mean arterial blood pressure (MAP) and heart rate in conscious sheep. 2. Ketanserin (0.1 mg/kg per h i.v.) causes a decrease in blood pressure, and an increase in heart rate. In the presence of ketanserin, serotonin induced increases in MAP are attenuated, or abolished, but the increases in heart rate are enhanced. 3. Ketanserin (10 mg/kg per h i.v.) attenuates or abolishes the increase in blood pressure induced by the α‐adrenoceptor agonist phenylephrine in conscious sheep. When administered in the presence of the α‐adrenoceptor antagonist prazosin, ketanserin (0.1 mg/kg per h i.v.) fails to induce a further hypotensive response. 4. These data suggest that in the conscious sheep ketanserin exhibits predominantly α‐adrenoceptor antagonism.