“…Neither D 2 nor D 3 receptor upregulation was detected in CPu or ACC after long-term treatment with clozapine or (ϩ)-NPA, and fluphenazine evidently increased D 2 but not D 3 binding (Tables 4 and 5 (Table 5), consistent with previous findings after antipsychotic treatment (Levésque et al 1995;). Lack of a response of D 3 receptors to repeated treatment with DA antagonists may reflect their inability to upregulate in response to prolonged blockade, perhaps paralleling their limited or inconsistent interactions with G-proteins and second- (Sokoloff et al 1990;Baldessarini and Tarazi 1996).…”