Characterization of endothelin-A receptors in the cerebral circulation.
Endothelin-1 (ET-1), a 21-amino acid peptide produced by the vascular endothelium, mediates contraction. In the present study we demonstrate that both ET-1 (Emax: 238 +/- 29% of potassium contraction) and ET-2 (Emax: 231 +/- 36%) produce strong concentration-dependent contractions of circular segments of guinea-pig middle cerebral artery, whereas ET-3 has only weak effects (Emax: 32 +/- 13%). FR 139317 (10(-6) M), a selective endothelinA (ETA) receptor antagonist, shifted the ET-1 response curve to the right (pD2:7.86 +/- 0.09 with and 8.76 +/- 0.09 without the antagonist) in a competitive manner (pA2 = 6.83). These findings are the first to show the presence of ETA receptors in cerebral vessels.
Department of Experimental Research, Malmö General Hospital, Sweden.
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Adner
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You
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Edvinsson
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects / Q000502:physiology*; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000502:physiology*; D006168:Guinea Pigs; D007211:Indoles / Q000494:pharmacology; D008297:Male; D017466:Receptors, Endothelin / Q000032:analysis*; D014661:Vasoconstriction / Q000502:physiology
D001381:Azepines; D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D007211:Indoles; D017466:Receptors, Endothelin; C079574:FR 139317