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Effect of the thromboxane A 2 ‐mimetic U46619 on 5‐HT 1 ‐like and 5‐HT 2 receptor‐mediated contraction of the rabbit isolated femoral artery
Author(s) -
MacLennan Stephen J.,
Martin Graeme R.
Publication year - 1992
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1992.tb12761.x
Subject(s) - thromboxane a2 , contraction (grammar) , receptor , pharmacology , femoral artery , muscle contraction , thromboxane , chemistry , medicine , endocrinology , platelet
1 The influence of the thromboxane A 2 ‐mimetic U46619 (11α,9α‐epoxymethano PGH 2 ) on 5‐hydroxytryptamine (5‐HT)‐induced contractions of the rabbit isolated femoral artery has been examined. 2 In the absence of U46619, 5‐HT responses were mediated predominantly by 5‐HT 2 ‐receptors as judged by potent, surmountable antagonism by the selective 5‐HT 2 receptor antagonists, spiperone and ketanserin. Both antagonists unmasked a population of 5‐HT 1 ‐like receptors which accounted for approximately 10–15% of the 5‐HT maximum response. 3 In the presence of U46619 (3–10 n m ), 5‐HT‐induced contractions were largely resistant to blockade by 5‐HT 2 receptor antagonists since 5‐HT 1 ‐like receptor‐mediated contraction now accounted for approximately 60% of the 5‐HT maximum response. 4 These results show that activation of thromboxane A 2 receptors in a tissue possessing both 5‐HT 2 and 5‐HT 1 ‐like receptors can convert 5‐HT‐induced contraction from one mediated predominantly by 5‐HT 2 receptors to one which is mediated predominantly by 5‐HT 1 ‐like receptors.