Local injection of alkylating and nonalkylating dopamine receptor antagonists into rat basal forebrain: autoradiographic assessment of D2-like and D3 sites.

N-chloroethyl derivatives of 7-hydroxy-1,2,3,4-tetrahydronaphthalene (7-OH-DPAT), 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), or fluphenazine were microinjected into rat nucleus accumbens (Acc), and receptor binding quantified autoradiographically after 24 h. EEDQ reduced [3H]nemonapride (D2-like receptors) binding in Acc (by 84%) and islands of Calleja (IC; 44%), without affecting [3H](+)-7-OH-DPAT (D3); N-chloroethyl-7-OH-DPATs blocked both radioligands in Acc and IC (30%-70%); fluphenazine had no effect.