title: Abnormal striatal dopamine transmission in schizophrenia.
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 single-photon- emission computed tomography (SPECT) studies investigating DA function in the striatum of medicated, drug-naive 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.
authors.affiliation: Université de Lyon, Université Lyon 1, F-69003, Lyon, France. jerome.brunelin@ch-le-vinatier.fr
authors.forename: Jerome
authors.initials: J
authors.lastname: Brunelin
authors.forename: Shirley
authors.initials: S
authors.lastname: Fecteau
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Suaud-Chagny
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D006801:Humans; D017072:Neostriatum / Q000378:metabolism / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D012559:Schizophrenia / Q000378:metabolism / Q000503:physiopathology*; D009435:Synaptic Transmission; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D004298:Dopamine