engleski

Astrocyte expression of DRD2, DRD3 and DRD4 dopamine receptors in the human orbitofrontal cortex

The dopamine system is of crucial importance for understanding human behaviour and the pathogenesis of many psychiatric and neurological conditions. The majority of studies addressing the localization of dopamine receptors (DR) in the human brain examined the expression of DR in neurons, while its expression, precise anatomical localization and possible function in glial cells have been largely neglected. Here we examined the expression of DRD2-like dopamine receptors in different astrocyte subclasses in the normal human brain. Tissue samples from medial orbitofrontal cortex (BA11/12) were taken during autopsy from six patients with no history of neurological or psychiatric disorder. Formalin-fixed, paraffin-embedded sections were stained by using novel anti-DRD2, anti-DRD3 and anti-DRD4 monoclonal antibodies. The double-labeling was performed by using an anti-GFAP antibody. We observed the strongest expression of DRD2 receptors in the white matter fibrous astrocytes, as well as in cell bodies and certain processes of layer I protoplasmic astrocytes. On the other hand, weak DRD2-immunoreactivity was observed in protoplasmic astrocytes in the lower cortical layers. Both of these findings suggest a role for astrocytes in response to dopaminergic stimulation. In conclusion, astrocytes do not solely provide support for neurons, but may also participate directly in dopaminergic transmission.

astrocytes - fibrous; astrocytes - protoplasmic; dopamine receptors; frontal cortex; human brain; schizophrenia

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