Effect of metabotropic glutamate receptor-3 variants on prefrontal brain activity in schizophrenia: An imaging genetics study using multi-channel near-infrared spectroscopy

- We explored the effect of SNPs related to GRM3 on brain activity.
- The rs274622 C carriers with schizophrenia showed lower activation than TT carriers.
- The between-genotype difference tended to be confined to the patient group.
- GRM3 may be associated with frontal glutamatergic function in schizophrenia.

BackgroundThe glutamatergic system is essential for learning and memory through its crucial role in neural development and synaptic plasticity. Genes associated with the glutamatergic system, including metabotropic glutamate receptor (mGluR or GRM) genes, have been implicated in the pathophysiology of schizophrenia. Few studies, however, have investigated a relationship between polymorphism of glutamate-related genes and cortical function in vivo in patients with schizophrenia. We thus explored an association between genetic variations in GRM3 and brain activation driven by a cognitive task in the prefrontal cortex in patients with schizophrenia.Materials and MethodsThirty-one outpatients with schizophrenia and 48 healthy controls participated in this study. We measured four candidate single nucleotide polymorphisms (rs274622, rs2299225, rs1468412, and rs6465084) of GRM3, and activity in the prefrontal and temporal cortices during a category version of a verbal fluency task, using a 52-channel near-infrared spectroscopy instrument.Results and DiscussionThe rs274622 C carriers with schizophrenia were associated with significantly smaller prefrontal activation than patients with TT genotype. This between-genotype difference tended to be confined to the patient group. GRM3 polymorphisms are associated with prefrontal activation during cognitive task in schizophrenia.