Long-lasting inhibition of in vivo cocaine binding to dopamine transporters by 3β-(4-Iodophenyl)Tropane-2-Carboxylic acid Methyl Ester: RTI-55 or βCIT
✍ Scribed by Dr. N. D. Volkow; S. J. Gatley; J. S. Fowler; R. Chen; J. Logan; S. L. Dewey; Y.-S. Ding; N. Pappas; P. King; R. R. Mac Gregor; M. J. Kuhar; F. I. Carroll; A. P. Wolf
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 642 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0887-4476
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✦ Synopsis
Cocaine analogs such as 3~-(4-iodophenyl)tropane-2~-carboxylic acid methyl ester (RTI-55 or PCIT) with a higher affinity for the dopamine transporter (DAT) may be potentially useful in interfering with cocaine's actions in brain. This study evaluates the time course of the effects of RTI-55 on cocaine binding in baboon brain using PET and [llClcocaine. [l1C1Cocaine binding was measured prior to, and 90 minutes, 24 hours, 4-5 days and 11-13 days after RTI-55 (0.3 mgkg i.v.1. Parallel studies with l3H1cocaine and RTI-55 (0.5 mgkg i.v. or 2 mg/kg i.p.1 were performed in the mouse. RTI-55 significantly inhibited [llClcocaine binding at 90 minutes and 24 hours after administration. The half-life for the clearance of RTI-55 from the DAT was estimated to be 2 to 3 days in the baboon brain. In the mouse brain, RTI-55 significantly inhibited [3H]cocaine binding at 60 and 180 minutes after administration and recovery was observed at 12 hours. These results document long-lasting inhibition of cocaine binding by RTI-55 and corroborate that binding kinetics of RTI-55 in striatum observed in imaging studies with [1231]RTI-55 represents binding to DATs.
Carbon-1 1, Baboon, PET o 1995 Wiley-Liss, Inc.