Effect of reserpine-induced depletion of synaptic dopamine on [11C]Raclopride binding to D2-dopamine receptors in the monkey brain

✍ Scribed by Nathalie Ginovart; Lars Farde; Christer Halldin; Carl-Gunnar Swahn

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 63 KB
• Volume: 25
• Category: Article
• ISSN: 0887-4476
• DOI: 10.1002/(sici)1098-2396(199704)25:4<321::aid-syn2>3.0.co;2-c

✦ Synopsis

Positron emission tomography was used to examine the in vivo binding of [ 11 C]raclopride to D 2 -dopamine (DA) receptors in the striatum of two Cynomolgus monkeys after a single dose of reserpine (1 mg/kg, i.v.). A Scatchard procedure was repeated five times to follow D 2 receptor density and apparent affinity for 7 weeks after reserpine. Reserpine-induced depletion of DA lead to a marked increase in [ 11 C]raclopride binding, which was still detectable 20 days after treatment. Scatchard analyses indicated that the measured increase in [ 11 C]raclopride binding reflected an increase in receptor affinity but no evident change in receptor density (B max ). Thus, the increase in [ 11 C]raclopride binding after reserpine should correspond to a reduced competition with endogenous DA for binding to D 2 receptors. The results were used to estimate the DA-induced D 2 occupancy to be about 40% at physiological conditions.