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Effect of reserpine‐induced depletion of synaptic dopamine on [ 11 C]Raclopride binding to D 2 ‐dopamine receptors in the monkey brain
Author(s) -
Ginovart Nathalie,
Farde Lars,
Halldin Christer,
Swahn CarlGunnar
Publication year - 1997
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(199704)25:4<321::aid-syn2>3.0.co;2-c
Subject(s) - raclopride , reserpine , dopamine , dopamine receptor d2 , neuroscience , dopamine receptor , chemistry , dopamine receptor d1 , pharmacology , psychology , biology
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. Synapse 25:321–325, 1997. © 1997 Wiley‐Liss, Inc.