Lassen plot analysis applied to PET occupancy studies. Data were taken from [11 C]N-methyl-SSR504734 studies in the rhesus monkey brain at baseline and after administration of SSR504734 at doses of 1.5 mg/kg in rhesus monkey 1 (A) and 4.5 mg/kg in rhesus monkey 2 (B). Thalamus (white diamond) was not included for Lassen plot. (C) Relationship between GlyT1 occupancy (in percent) and dose of SSR504734. The relationship between GlyT1 occupancy (in percent) and dose of SSR504734 was expressed by the equation:
, where Omax is the assumed maximal occupancy (i.e., 100%), and Cp is the dose at which occupancy becomes 50%. Kd was estimated to be 1.7 mg/kg.