Functional expression of A glutamine transporter responsive to down-regulation by lipopolysaccharide through reduced promoter activity in cultured rat neocortical astrocytes.

The prevailing view is that the glutamine (Gln) transporter (GlnT/ATA1/SAT1/SNAT1) is a member of the system A transporter superfamily with the ability to fuel the glutamate/Gln cycle at nerve terminals in glutamatergic neurons. Semiquantitative reverse transcription-polymerase chain reaction revealed similarly high expression of mRNA for GlnT by rat brain neocortical astrocytes as well as neurons, with progressively lower expression by cerebellar astrocytes, hippocampal astrocytes, and whole-brain microglia in culture. [(3)H]Gln was accumulated in a temperature-dependent manner with a saturable profile in both cultured neocortical neurons and astrocytes, whereas biochemical and pharmacological analyses on [(3)H]Gln accumulation revealed the expression of both system A and system L transporters by cultured neocortical neurons and astrocytes.

Chronic vitamin D3 treatment protects against neurotoxicity by glutamate in association with upregulation of vitamin D receptor mRNA expression in cultured rat cortical neurons.

The vitamin D receptor (VDR) is believed to mediate different biologic actions of vitamin D3, an active metabolite of vitamin D, through regulation of gene expression after binding to specific DNA-response element (VDRE) on target genes. To further understand roles of both vitamin D3 and VDR in the central nervous system, we examined VDRE binding in nuclear extracts prepared from discrete rat brain regions and cultured rat cortical neurons by electrophoretic mobility shift assay. The highest activity of VDRE binding was found in the cerebellum among other brain regions examined, but sequence specific by taking into consideration the efficient competition with excess unlabeled VDRE but not with mutated VDRE.

[A mechanism for modulation of N-methyl-D-aspartate receptor channels by free ferrous ions in cultured rat cortical neurons].

Rat cortical neurons cultured in DMEM/F-12 in the absence of fetal calf serum were harvested on days 3, 6 and 9 in vitro (DIV), followed by homogenization and subsequent SDS-PAGE for immunoblotting using an antibody against MAP-2 or GFAP. Expression of MAP-2 was not markedly changed during cultivation for 3 to 9 DIV, while GFAP was profoundly expressed after 6 DIV in a manner dependent on the duration of culturing. Cortical neurons cultured for 3 DIV were pre-incubated with fluo-3 AM and then subjected to fluorescence image analysis using a confocal microscope.

Counteraction by repetitive daily exposure to static magnetism against sustained blockade of N-methyl-D-aspartate receptor channels in cultured rat hippocampal neurons.

In rat hippocampal neurons cultured with the antagonist for N-methyl-D-aspartate (NMDA) receptors dizocilpine (MK-801) for 8 days in vitro (DIV), a significant decrease was seen in the expression of microtubule-associated protein-2 (MAP-2) as well as mRNA for both brain-derived neurotrophic factor (BDNF) and growth-associated protein-43 (GAP-43), in addition to decreased viability. MK-801 not only decreased the expression of the NR1 subunit of NMDA receptors but also increased NR2A expression, without affecting NR2B expression. Repetitive daily exposure to static magnetic fields at 100 mT for 15 min led to a decrease in the expression of MAP-2, without significantly affecting cell viability or the expression of neuronal nuclei (NeuN) and GAP-43.