In vivo binding of the dopamine-1 receptor PET tracers [¹¹C]NNC112 and [¹¹C]SCH23390: a comparison study in individuals with schizophrenia.

ABSTRACT

RATIONALE A deficit in dopamine-1 (D1) receptor function in the prefrontal cortex is suggested to play a role in the cognitive dysfunction observed in patients with schizophrenia. However, the results from positron emission tomography imaging studies of D1 receptor levels in individuals with schizophrenia are mixed. OBJECTIVES: The aim of this investigation was to determine whether the in vivo characteristics of the different D1 receptor tracers used in previous reports, [(11)C]SCH23390 and [(11)C]NNC112, may have contributed to these discrepancies reported in the literature. METHODS: Eight patients with schizophrenia and 12 healthy control subjects were scanned with both [(11)C]SCH23390 and [(11)C]NNC112. RESULTS: [(11)C]SCH23390 and [(11)C]NNC112 binding potentials in both patients and control subjects were compared and no tracer by diagnosis interactions were observed. CONCLUSIONS: The results of this study suggest that differences in the binding of [(11)C]SCH23390 and [(11)C]NNC112 observed in previous studies are not due to differences in the in vivo behavior of these tracers.