The effect of metheylmercury on glutamtne synthetase expression in cultured astrocytes

Glutaniine synthetase (GS) winch couverts glutamate and ammonia tu çhitaimti'1 plays essential roles in tin metabolism of neiirotra.nsmil.ters and the detoxification of ammonia in the brain. Tlio astrocyte-specific GS was found to he inhibited by very lov. concentrations of load salts and inorganic mercury, [his .itudy evaluated the effect on (IS expression in acntely-rnelhylmorcury I MeHg) exposed astrocyle culture?. A primary astrocyte culture was prepared from the cerebral cortex of new born rats and maintained for 21 days. The cells were then exposed to 10 u M Melig for fi hours or longer. Expression of G S in the control and MeHg <-xposed astrocytes were evaluated by western blotting ;md RT-PCR analyses. Total piotein was extracted from astrocyte.s and subjected to SDS-PAGF. and imirrino-detection. R.T-PCR was carried out using GS-specific primer pair and total RNA samples (0.25-1.0 ug) derived from the control and MeHg-treated astroe vtes. Results from both western blotting and HT Pt'R experiments demon-it rated significant increase in transcription of GS gene and translation of GS. I he increase in GS level in acutely-McHg exposes astrocytes presumably serve-; to aid the aMrocytes in maintaining glutamalc homeo.stasi.s in the brain. Nevertheless, the chronic effect of MeHg on rtstmrytrs ir, not clear (Supported by RIMI Nf'HK. NIH. 2 P20 R.R 1 1 58.1-02).