Understanding Dopamine Mechanisms in Cocaine Addiction Using AMPT and Methylphenidate With [11C]RAC/[11C]PHNO PET
Status:
Terminated
Trial end date:
2014-06-09
Target enrollment:
Participant gender:
Summary
Studies using positron emission tomography (PET) have been used with great success in
demonstrating specific abnormalities in several facets of dopaminergic system function in
human populations (Narendran and Martinez 2009). Among the first, most consistent, and
broadly replicated of such findings in drug- (including cocaine) dependent individuals has
been the reduction in subcortical (striatal) D2/3 receptors as imaged, most commonly, by the
reversible, non-selective, D2/3 receptor antagonist radiotracer, [11C]raclopride. Certain
dissociations on D2/3 availability by radioligand ([11C]raclopride vs. [11C]PHNO) and by
brain region (striatum vs. SN; terminal vs. somatodendritic, respectively) are poorly
understood in relationship to prior antagonist tracer results. In the current study the
investigators will use pharmacological interventions (AMPT and methylphenidate) with both
antagonist and agonist radiotracers to experimentally reconcile these discordant findings and
clarify potential mechanistic inter-relationships.