In vivo binding of antipsychotics to D3 and D2 receptors: A PET study in baboons with [11C]-(+)-PHNO

A regression model based on literature values of regional D2 and D3 fractions of [11C]-(+)-PHNO BPND in PUT, CAD, substantia nigra (SN), globus pallidus (GP), ventral striatum (VST), and thalamus (THA) was used to infer occupancy at D2 and D3 receptors, according to the equation BPND(drug condition)=BPND(Baseline)[low *](fD3*(1-occ(D3))+fD2*(1-occ(D2))) where fD3 and fD2 are the fractions of [11C]-(+)-PHNO BPND attributable to each receptor type, occ is the drug occupancy at each receptor type, and ED50(D3)/ED50(D2) was computed as [occ(D2)/(1-occ(D2))]/[occ(D3)/(1-occ(D3))].