Conditions: Cocaine Dependence
Allocation: NON_RANDOMIZED | Intervention model: FACTORIAL
Enrollment: 1
Healthy volunteers: yes

Brief 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.

Detailed description:

Arms:
arm 1: Subjects will receive 2 baseline PET scans with the radioligands (11C)(+)PHNO and (11C)(+)raclopride arm 2: Subjects will receive 1 PET scan following a PO dose of 60mg of methylphenidate to facilitate dopamine release with the radioligand (11C)(+)PHNO arm 3: Subjects will receive 2 PET scans following 48 hours of dopamine depletion via AMPT with the radioligands (11C)(+)PHNO and (11C)(+)raclopride

Interventions: intervention 1: Methylphenidate intervention 2: Alpha Methyl Para Tyrosine (AMPT) intervention 3: [11C]PHNO intervention 4: [11C]raclopride
Intervention descriptions: intervention 1: None intervention 2: None intervention 3: None intervention 4: None

Protocol document: