THE DISTRIBUTION OF [C-11] COCAINE IN NORMAL AND COCAINE-SENSITIZATION MICE

[N-C-11-methyl]-cocaine ([C-11]cocaine), synthesized by N-methylation of norcocaine with [C-11]CH3I, was used to assist in imaging the variety of local distribution by positron emission tomography (PET). The radiochemical yield and the radiochemical purity after purification of [C-11]cocaine by high performance liquid chromatography (HPLC) at a sp. act. of 814 GBq/mmol were 47-58% and >99%, respectively. The time required for synthesis including the purification was 25-30 min from the end of [C-11]CH3I trapping. The physical distribution of [C-11]cocaine in organ was also investigated in mice at various time after i.v. injection. The main accumulation of radioactivity occurred in the lung, kidney and brain within 1 min after the injection. In the brain, no differences in the organ were observed except the radioactivity level in each section increased for the first 5 min, since then radioactivity decreased dramatically. Furthermore, in the behavioral sensitization model of cocaine, the peak of [C-11]cocaine uptake in each brain area was shown to be 5-15 min.