DISCRIMINATIVE STIMULUS PROPERTIES OF 7-OH-DPAT, A DOPAMINE D-3-SELECTIVE RECEPTOR-LIGAND

7-Hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) is a high affini ty and selective ligand at dopamine D-3 receptors. Rats were trained t o discriminate 7-OH-DPAT (0.05 mg/kg) from drug vehicle using a food-r einforced (FR 10) two-lever operant procedure. Six out of nine rats le arned to discriminate 7-OH-DPAT, requiring a mean of 29 training sessi ons. After the training dose was increased to 0.10 mg/kg the remaining three rats reached discrimination performance criterion. The 7-OH-DPA T stimulus was dose-dependent. Doses of 0.01, 0.03, 0.056, and 0.1 mg/ kg 7-OH-DPAT produced 0, 11, 78, and 100% drug-correct lever selection , respectively, with the ED, value calculated to be 0.038 mg/kg. These results demonstrate that the D-3-selective ligand 7-OH-DPAT can contr ol differential operant responding in rats on the basis of its discrim inative stimulus properties.