Presynaptic Selectivity of a Ligand for Serotonin 1A Receptors Revealed by In Vivo PET Assays of Rat Brain
Figure 6
Relationships between dose or plasma concentration of test drugs and 5-HT1A receptor occupancies analyzed with [11C]WAY-100635-PET data.
(A) Receptor occupancies in the hippocampus (closed circles) and raphe nucleus (open circles) plotted against oral dose of Wf-516. Regression curves were generated by the following equation: Occ = Occmax×D/(D+ED50), where Occ, Occmax, D and ED50 are 5-HT1A receptor occupancy, maximal occupancy, dose of Wf-516, and dose of Wf-516 required for 50% of maximal occupancy, respectively. Bars indicate S.E. (n = 4). (B) Receptor occupancies in the hippocampus (closed squares) and raphe nucleus (open squares) plotted against intraperitoneal dose of pindolol. Regression curves were generated by the following equation: Occ = 100×D/(D+ED50). Bars indicate S.E. (n = 3). (C) Receptor occupancies in the hippocampus (closed squares) and raphe nucleus (open squares) plotted against plasma concentration of pindolol. Regression curves were generated by the following equation: Occ = 100×C/(C+EC50), where C is plasma concentration of pindolol. Dashed and solid lines represent regressions in the hippocampus and raphe nucleus, respectively.