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Quantitative autoradiography of cocaine binding sites in human brain postmortem
Author(s) -
Biegon Anat,
Dillon Kathryn,
Volkow Nora D.,
Hitzemann Robert J.,
Fowler Joanna S.,
Wolf Alfred P.
Publication year - 1992
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/syn.890100207
Subject(s) - basal ganglia , human brain , hippocampus , binding site , dopamine , chemistry , cortex (anatomy) , thalamus , striatum , basal (medicine) , pharmacology , central nervous system , neuroscience , biology , biophysics , medicine , endocrinology , biochemistry , insulin
Quantitative autoradiography was used to study cocaine binding sites in the human brain postmortem. Triated cocaine was applied to brain sections from three drug‐ and disease‐free subjects at a low (10 nM) concentration and at a high (1 μM) concentration, the latter being in the range of brain concentrations of cocaine found in users of the drug. Nonspecific binding was assessed in the presence of 100 μM unlabeled cocaine. At low (10 nM) concentrations of labeled cocaine, the basal ganglia exhibit the highest density of binding sites, with considerably lower densities in thalamus, cortex, and hippocampus. Cocaine binding at high (1 μM) concentrations displayed a different distribution pattern, more homogeneous with some cortical regions exhibiting binding site densities close to those seen in the basal ganglia. Preliminary competition experiments with several drugs indicate that dopamine uptake inhibitors completely block cocaine binding to the basal ganglia, while serotonin uptake inhibitors were more effective in the hippocampus. These findings suggest that cocaine binds to dopamine uptake sites in the human basal ganglia postmortem but that it also interacts with other classes of binding sites, depending on the concentration and brain region examined.