Stress-induced dopamine release in human medial prefrontal cortex--18F-fallypride/PET study in healthy volunteers.
BACKGROUND
In laboratory animals, environmental stressors markedly activate the mesocortical dopamine system. The present study tested whether this occurs in humans.


METHODS
The effects of a laboratory psychological stressor (Montreal Imaging Stress Task, MIST) on mesocortical dopamine release in healthy young adults (11 males, mean age ± SD, 20.6 ± 2.4 years) was measured using positron emission tomography and [(18)F]fallypride. Each subject was scanned in two separate days in counterbalanced order: one with the MIST and one with the control task. Binding potential (BP ND ) maps of the whole brain were calculated for each scan, using a simplified reference tissue compartmental model. Then BP ND was compared between subjects. Heart rate, galvanic skin response, and salivary cortisol level were measured during the scans.


RESULTS
The psychological stressor significantly decreased [(18)F]fallypride binding values in the dorsal part of the medial prefrontal cortex (dmPFC), corresponding to the rostal part of the cingulate motor zone. The greater the stress-induced decrease in [(18)F]fallypride binding in the dmPFC, the greater the stress-induced increases in heart rate.


CONCLUSIONS
The present study provides evidence of stress-induced dopamine release in the mPFC in humans, in vivo.
Department of Psychiatry, McGill University, Montréal, QC, H3A 1A1, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC, H3A 2B4, Canada.
Atsuko
A
Nagano-Saito
Alain
A
Dagher
Linda
L
Booij
Paul
P
Gravel
Krzysztof
K
Welfeld
Kevin F
KF
Casey
Marco
M
Leyton
Chawki
C
Benkelfat
D000293:Adolescent; D000328:Adult; D001549:Benzamides / Q000008:administration & dosage; D004298:Dopamine / Q000378:metabolism*; D064368:Healthy Volunteers; D006339:Heart Rate; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography; D017397:Prefrontal Cortex / Q000378:metabolism* / Q000502:physiology; D011759:Pyrrolidines / Q000008:administration & dosage; D013315:Stress, Psychological / Q000378:metabolism*
D001549:Benzamides; C094948:N-((1-allyl-2-pyrrolidinyl)methyl)-5-(3-fluoropropyl)-2,3-dimethoxybenzamide; D011759:Pyrrolidines; D004298:Dopamine
18F-Fallypride; D2/3 receptor; PET; dopamine; heart rate; mPFC; stress