Striatal dopamine responses to intranasal cocaine self-administration in humans.
BACKGROUND
The effect of self-administered cocaine on extracellular dopamine (DA) levels has not been measured in humans.


METHODS
Ten nondependent cocaine users underwent positron emission tomography [11C]raclopride scans following intranasal self-administration of cocaine hydrochloride (1.0 mg/kg) and placebo powder.


RESULTS
Compared with placebo, intranasal cocaine self-administration decreased [11C]raclopride binding values in the ventral limbic striatum and putamen. Individual differences in the magnitude of the [11C]raclopride response in the ventral striatum were predicted by lifetime histories of stimulant drug use.


CONCLUSIONS
The results suggest that 1) intranasal cocaine self-administration increases synaptic DA levels in human striatum and 2) prior use of stimulant drugs on the street is associated with progressively greater cocaine-induced DA responses. These dopaminergic effects might influence susceptibility to drug-seeking behavior and the progression to substance abuse.
Cox
Sylvia M L
SM
Department of Psychiatry, McGill University, Montréal, Québec H3A 1A1, Canada.
Benkelfat
Chawki
C
Dagher
Alain
A
Delaney
J Scott
JS
Durand
France
F
McKenzie
Samuel A
SA
Kolivakis
Theodore
T
Casey
Kevin F
KF
Leyton
Marco
M
D000281:Administration, Intranasal; D001479:Basal Ganglia / Q000000981:diagnostic imaging / Q000378:metabolism*; D003042:Cocaine / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010649:Phenylalanine / Q000097:blood; D049268:Positron-Emission Tomography; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism; D020891:Raclopride / Q000008:administration & dosage / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D012646:Self Administration; D014443:Tyrosine / Q000097:blood; D055815:Young Adult
D017448:Receptors, Dopamine D2; D014443:Tyrosine; D020891:Raclopride; D010649:Phenylalanine; D003042:Cocaine; D004298:Dopamine; D006854:Hydrocortisone