New clues about vitamin D functions in the nervous system

Abstract

Accumulating data have provided evidence that 1α,25 dihydroxyvitamin D3 [1,25-(OH)2D3] is involved in brain function. Thus, the nuclear receptor for 1,25-(OH)2D3 has been localized in neurons and glial cells. Genes encoding the enzymes involved in the metabolism of this hormone are also expressed in brain cells. The reported biological effects of 1,25-(OH)2D3 in the nervous system include the biosynthesis of neurotrophic factors and at least one enzyme involved in neurotransmitter synthesis. 1,25-(OH)2D3 can also inhibit the synthesis of inducible nitric oxide synthase and increase glutathione levels, suggesting a role for the hormone in brain detoxification pathways. Neuroprotective and immunomodulatory effects of this hormone have been described in several experimental models, indicating the potential value of 1,25-(OH)2D3 pharmacological analogs in neurodegenerative and neuroimmune diseases. In addition, 1,25-(OH)2D3 induces glioma cell death, making the hormone of potential interest in the management of brain tumors. These results reveal previously unsuspected roles for 1,25-(OH)2D3 in brain function and suggest possible areas of future research.