Fig. 3.

Binding properties of commonly used V1a antagonists at mOTR, mV1aR, and mV1bR. Competition binding experiments were performed using increasing concentrations (from 10⁻¹¹ to 10⁻⁵ M) of three compounds commonly used as selective V1aR antagonists: LVA (A), the Manning compound (B), and SR49059 (C). Ligand binding was determined on membrane preparations of COS7 cells transiently transfected with mOTR (black circles), mV1aR (blue triangles), and mV1bR (red squares). Specific binding was determined in the presence of 2–4 × 10⁻⁹ M [³H]OT for mOTR and [³H]AVP for mV1aR and mV1bR; nonspecific binding was determined in the presence of OT or AVP (10⁻³ M). Each curve is the mean of triplicate determinations of a single representative experiment.