In vitro activity: Ocaperidone has high affinity for 5-HT2 and dopamine D2, with Ki values of 0.14 nM, 0.46 nM, 0.75 nM, 1.6 nM and 5.4 nM for 5HT2, a1-adrenergic, dopamine D2, histamine H1 and a2-adrenergic, respectively. Ocaperidone shows 5-HT1A receptor agonist activity, with a pEC50 and pKi of 7.60 and 8.08.

Kinase Assay: The membranes are prepared from frozen HA7 cells. Cells are harvested in ice-cold Tris-HCl pH 7.4, homogenized and centrifuged at 40 000×g, 4°C for 10 min. The pellet is suspended in the same buffer and centrifuged again. After the second centrifugation, the pellet is suspended in an assay buffer consisting of pargyline (10 μM) and CaCl2 (4 mM) in Tris-HCl (50 mM, pH 7.4). Membrane protein, 0.031-0.084 mg/tube, is incubated with [3H] 8-OH-DPAT (1 nM final concentration) and Ocaperidone at seven concentrations, for 30 min, room temperature. The reaction is terminated by filtration through Whatman filters, and radioactivity is counted by liquid scintillation spectrometry. The experiments are performed in triplicate. Data are analyzed using the non-linear curve fitting program EBDA/LIGAND. Results expressed as pKi values are means of three determinations.