The strong contractile effect of the thromboxane receptor agonist U-46619 in isolated human pulmonary arteries and its competitive antagonism by BM-13.505

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Abstract

Ring segments (I mm in diameter) of the pulmonary artery obtained from 16 patients undergoing thoracic surgery were mounted in tissue baths. Cumulative concentration-response curves of some prostanoids and amines were obtained, and Emax and pEC50 values calculated. Noradrenaline, phenylephrine, clonidine and serotonin (5-HT) showed low intrinsic activities. Prostaglandin F2 alpha (PGF2 alpha) induced strong contractions with an Emax of 126% of the preceding K+ (124 mM)-induced contraction, but its potency was low (pEC50 = 5.70). The thromboxane receptor agonists U-46619 and U-44069 induced strong contractions (Emax = 139% and 133% respectively) and were significantly more potent than the other drugs used (pEC50 = 8.43 and 8.30 respectively). The thromboxane receptor antagonist BM-13.505 (10(-8) to 10(-6) M) caused rightward parallel shifts of the U-46619 concentration-response curves without reduction of Emax, indicating competitive antagonism.

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Subject classification (UKÄ) – MANDATORY

  • Cardiac and Cardiovascular Systems
  • Surgery
Original languageEnglish
Pages (from-to)161-165
JournalActa Physiologica Scandinavica
Volume136
Issue number2
Publication statusPublished - 1989
Publication categoryResearch
Peer-reviewedYes