Abstract
Thein vivo binding kineties of11C-iomazenil were compared with those of11C-flumazenll binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either11C-iomazenil or11C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0,5 and 20 μg/kg).
The regional distribution of11C-iomazenil in the brain was similar to that of11C-flumazenil, but the sensitivity of11C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of11C-flumazenil binding. A significant reduction in11C-flumazenil binding in the cerebral cortex was observed with 20 μg/kg of flumazenil, whereas a relatively smaller inhibition of11C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that11C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain.
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Inoue, O., Hosoi, R., Kobayashi, K. et al. Different sensitivities to competitive inhibition of benzodiazepine receptor binding of11C-iomazenil and11C-flumazenil in rhesus monkey brain. Ann Nucl Med 15, 137–139 (2001). https://doi.org/10.1007/BF02988604
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DOI: https://doi.org/10.1007/BF02988604