Figure 3
Acute METH exposure increases levels of proline without increasing glutamate levels. (A) Effect of acute METH treatment on proline levels-SH-SY5Y cells were treated acutely with METH at concentrations 200, 500, and 1000 µM. After treatment, the cells were harvested and the intracellular proline levels were measured by the acid-ninhydrin assay, that specifically detects proline. (B,C) Effect of Acute METH treatment on glutamate levels. SH-SY5Y cells were treated with increasing concentrations of METH for 24 h. Post-treatment cells were centrifuged and the cell extracts were used to measure intracellular glutamate while the cell-free supernatants were used to measure extracellular glutamate. Data are plotted as fold change in glutamate levels in METH-treated cells compared to control cells. (D–F) Effects of acute METH treatment on GLS and vGLUT1 expression—SH-SY5Y cells were treated with varying concentrations of METH under acute conditions. Cells were then harvested and cellular lysates were subjected to immunoblot analyses. (D) Representative immunoblot of GLS and vGLUT1 expression (n = 3). Densitometry analysis of GLS-1 expression in (E) and vGLUT1 expression in (F) normalized to β-actin. (G) Acute METH treatment does not induce cytotoxicity—SH-SY5Y cells were treated with increasing concentrations of METH for 24 h, following which the cells were centrifuged and culture supernatant were collected. Cytotoxicity was measured by LDH release assay (n = 3). Data presented in (A–C,E–G) are mean values of (n = 3) independent experiments conducted in triplicates with error bars representing SEM. **p < 0.005 represents statistical comparison of untreated vs METH-treated cells.
