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Abnormal Striatal Dopamine Transmission in Schizophrenia

[ Vol. 20 , Issue. 3 ]

Author(s):

Jerome Brunelin, Shirley Fecteau and Marie-Francoise Suaud-Chagny   Pages 397 - 404 ( 8 )

Abstract:


Despite numerous revisions and reformulations, dopamine (DA) hypothesis of schizophrenia remains a pivotal neurochemical hypothesis of this illness. The aim of this review is to expose and discuss findings from positron emission tomography (PET) or singlephoton- emission computed tomography (SPECT) studies investigating DA function in the striatum of medicated, drug-naïve or drug-free patients with schizophrenia and in individuals at risk compared with healthy volunteers.

DA function was studied at several levels: i) at a presynaptic level where neuroimaging studies investigating DOPA uptake capacity clearly show an increase of DA synthesis in patients with schizophrenia; ii) at a synaptic level where neuroimaging studies investigating dopamine transporter availability (DAT) does not bring any evidence of dysfunction; iii) and finally, neuroimaging studies investigating DA receptor density show a mild increase of D2 receptor density in basic condition and, an hyperreactivity of DA system in dynamic condition.

These results are discussed regarding laterality, sub-regions of striatum and implications for the at-risk population. Striatal DA abnormalities are now clearly demonstrated in patients with schizophrenia and at risk population and could constitute an endophenotype of schizophrenia. Subtle sub-clinical striatal DA abnormalities in at risk population could be a biomarker of transition from a vulnerability state to the expression of frank psychosis.

Keywords:

Dopamine, striatum, schizophrenia, PET; imaging

Affiliation:

EA4615, Pole EST- Prof d’Amato, CH « Le Vinatier », 95 boulevard Pinel, 69 677 BRON cedex, France.



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