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Pet studies of cocaine inhibition of myocardial norepinephrine uptake
Author(s) -
Fowler Joanna S.,
Ding YuShin,
Volkow Nora D.,
Martin Thomas,
MacGregor Robert R.,
Dewey Stephen,
King Payton,
Pappas Naomi,
Alexoff David,
Shea Colleen,
Gatley S. John,
Schlyer David J.,
Wolf Alfred P.
Publication year - 1994
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.890160407
Subject(s) - desipramine , norepinephrine transporter , benzoylecgonine , reuptake , norepinephrine , pharmacology , chemistry , dopamine uptake inhibitors , nomifensine , reuptake inhibitor , metabolite , medicine , antidepressant , dopamine , dopaminergic , receptor , serotonin , biochemistry , hippocampus
Positron emission tomography (PET), [ 11 C]cocaine, and (–)‐6‐[ 18 F]fluoronorepinephrine [(‐)‐6‐[ 18 F]NE] were used to determine the extent to which the binding of labeled cocaine in the baboon heart represents binding to the norepinephrine transporter and to characterize the functional consequences of cocaine administration on the norepinephrine transporter. Peak heart binding of [ 11 C] cocaine was high (0.038‐0.055%/g) and clearance was rapid (t 1/2 from peak: 2.5–9 min) for both tracer doses and a pharmacological dose. The binding of a tracer dose of labeled cocaine could not be inhibited by desipramine, tomoxetine, cocaine, nomifensine, or benztropine. The behavior of a pharmacological dose of [ 11 C]cocaine could not be distinguished from a tracer dose and also could not be inhibited by tomoxetine. However, pretreatment with cocaine profoundly inhibited norepinephrine uptake as assessed by (–)‐6‐[ 18 F]NE. Recovery was slow with only 48% of the baseline (–)‐6‐[ 18 F]NE uptake being recovered by 78 minutes after cocaine administration. [ 11 C]Benzoylecgonine, a vasoactive metabolite of cocaine, showed negligible retention in heart. The results of this study (i.e., the rapid clearance of cocaine from the heart, the inability to inhibit cocaine binding with desipramine and tomoxetine, and its relatively long‐lasting effects on norepinephrine uptake) reinforce the need to understand the link between cocaine pharmacokinetics and norepinephrine transporter function and its relationship to cardiotoxicity. © 1994 Wiley‐Liss, Inc.