This study will, in a sample of cocaine-dependent and healthy control subjects, administer corticorelin and compare dopamine release between groups. Dopamine release will be measured using PET neuroimaging with the radiotracer \[11C\]-(+)-PHNO.
SCIENTIFIC SUMMARY The project will, in a sample of cocaine-dependent (CD) and healthy control (HC) subjects, use administration of Corticorelin, a synthetic form of corticotropin releasing factor (CRF)and PET imaging to assess dopamine (DA) transmission in addiction. We will use \[11C\]-(+)-PHNO PET to measure striatal DA receptor binding on two occasions: 1) following corticorelin administration and 2) following saline. The change in receptor binding between the two occasions (i.e., displacement of \[11C\]-(+)-PHNO by endogenous DA) will index DA release. SUBJECTS CD subjects will meet DSM-IV criteria for abuse or dependence and be \~10d cocaine abstinent at the time of PET. HC will be recruited to match CD on age, sex, education, and cigarette smoking. PRIMARY OUTCOME MEASURES We will measure \[11C\]-(+)-PHNO binding on two occasions (corticorelin, saline), with the difference between conditions indexing dopamine release; this measure will then be compared between cocaine-dependent and control subjects. We will also measure plasma cortisol and ACTH), physiological measures, and subjective craving and mood.
Study Type
OBSERVATIONAL
Enrollment
17
Each subject will receive a single dose of Corticotropin-Releasing Hormone corticorelin on a single occasion, and a volume-matched saline injection on a second occasion. Corticorelin will be administered as an intravenous infusion over a 30- to 60-second interval at a dose of 1 ug/kg body weight. \~15 minutes after Corticorelin/saline injection, \[11C\]-(+)-PHNO will be administered followed by 90 minutes of PET scanning. Primary outcome measure (\[11C\]-(+)-PHNO) as well as Secondary outcome measures (self reported feeling, hormones and physiological measures) will be obtained before saline or Corticorelin/saline injection and for 90-120 minutes following injection.
Centre for Addiction and Mental Health
Toronto, Ontario, Canada
PET measure: [11C]-(+)-PHNO binding
\[11C\]-(+)-PHNO binding on two occasions (following corticorelin and saline)
Time frame: within a month following enrollment
stress hormone levels
plasma cortisol, ACTH
Time frame: in conjunction with PET
subjective measures
subjective stress, craving, mood, drug effects
Time frame: in conjunction with PET
vital signs
heart rate, blood pressure
Time frame: in conjunction with PET
neuropsychological battery
battery of neuropsychological tasks to assess cognitive function, general intelligence, and personality.
Time frame: once following PET
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