RO1138452 (CAY10441) is a selective and orally bioavailable antagonist of prostacyclin receptor (pKi: 8.3). It antagonizes the carbaprostacyclin-induced activation of human neuroblastoma adenylate cyclase, blocking cyclic AMP accumulation in a dose-dependent manner. Likewise, it inhibits the binding of tritiated iloprost to rodent neuroblastoma cells with a Ki of about 1.5 nM. At levels between 2-20 mg/kg in rats, CAY10441 shows significant analgesic activity in standard antinociceptive assays [1].

5-HT1A receptor (human):5.37 (pKi), 5-HT4 receptor (guinea pig):5.35 (pKi), Muscarinic M1 receptor (human):2570 nM, Muscarinic M2 receptor (human):5.88 (pKi), 5-HT2C (porcine):6.11 (pKi), Muscarinic M1 receptor (human):5.66 (pKi), PAF Receptor (rabbit):7.9 (pKi), 5-HT2C (porcine):1190 nM, α2A-adrenoceptor (human):724 nM, PAF Receptor (rabbit):52.9 nM, Muscarinic M4 receptor (human):1450 nM, I2R (rat):7 nM, Muscarinic M5 receptor (human):5.81 (pKi), 5-HT1B receptor (rat):1130 nM, α1B-adrenoceptor (rat):3280 nM, α1B-adrenoceptor (rat):5.87 (pKi), 5-HT1A receptor (human):8580 nM, Muscarinic M4 receptor (human):6.14 (pKi), α2A-adrenoceptor (human):6.49 (pKi), 5-HT4 receptor (guinea pig):8910 nM, Muscarinic M5 receptor (human):3110 nM, 5-HT1B receptor (rat):6.11 (pKi), Muscarinic M2 receptor (human):2220 nM, 5-HT2A receptor (rat):5.71 (pKi), I2R (rat):8.33 (pKi), 5-HT2A receptor (rat):3040 nM