TPα and TPβ are two isoforms of the human TP receptor, the G protein-
coupled receptor (GPCR) that mediates the actions of thromboxane A
2 (TXA
2). Although their distinct physiological functions have not been fully elucidated, TPβ is believed to be responsible for vascular endothelial growth factor-
induced endothelial cell differentiation and migration whereas TPα appears to be the predominant isoform expressed in platelets. CAY10535 is a TP receptor antagonist that shows ~20-
fold selectivity for TPβ (IC
50 = 99 nM) relative to TPα (IC
50 = 1,970 nM) in the inhibition of U46619-
mediated Ca
2+ mobilization. This compound exhibits relatively poor activity on platelets (IC
50 = 985 nM) when inhibiting U-
46619-
induced platelet aggregation.
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