Ro 60-0175 is an agonist of the serotonin (5-HT) receptor subtype 5-HT2 that stimulates increases in intracellular calcium levels in CHO-K1 cells expressing human 5-HT2A, 5-HT2B, and 5-HT2C receptors (EC50s = 447, 0.9, and 32 nM, respectively). It is selective for human 5-HT2A and 5-HT2C (Kis = 32 and 1 nM, respectively) over human 5-HT1A, 5-HT1D, 5-HT6, and 5-HT7, rat 5-HT1B and 5-HT3, and guinea pig 5-HT4 receptors (Kis = ≥1,995 nM), as well as adenosine A1 and A2, histamine H1-3, dopamine D1-5, α1-, α2-, and β1-adrenergic, M1-5 muscarinic, nicotinic, kainate, AMPA, and μ-, δ-, and κ-opioid receptors (IC50s = >1,000 nM), but does bind to β2-adrenergic receptors (IC50 = 251 nM). In vivo, Ro 60-0175 increases plasma levels of corticosterone, oxytocin, and prolactin in rats (ED50s = 2.43, 4.19, and 4.03 mg/kg, respectively), effects that are not inhibited by the 5-HT2C antagonist SB-242084 or the 5-HT2A antagonist MDL 100,907 (volinanserin; ).
