Effect of curcumin on AMPA and kainate receptor-mediated calcium influx in cultured rat hippocampal neurons

Abstract

Objective To investigate the effect of curcumin on alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate (KA) receptor-mediated calcium influx in cultured rat hippocampal neurons. Methods The hippocampal neurons from SD rat embryos (17 days old) were cultured for 9 days, and fluorescent calcium chelator and confocal microscopy calcium imaging were used to observe the changes in intracellular free calcium in the neurons following stimulation with 100 μmol/L KA. The effect of curcumin pretreatment at different concentrations (10, 30, 50, 100, 200 and 300 μmol/L) for 30 min on 100 μmol/L KA-induced intracellular calcium changes in the neurons were evaluated, and the effect of 15 μmol/L curcumin on intracellular calcium in the neurons stimulated with 10, 30, 50, 100, 200 and 300 μmol/L KA were also assessed. Cobalt staining was used to examine the expression of calcium permeable AMPA/KA channel in the hippocampal neurons treated with 30 and 100 μmol/L KA. Results Curcumin pretreatment at different concentrations for 30 min significantly relieved the elevation of flee calcium concentration induced by 100 or 30 μmol/L KA (P<0.05), and the effect was especially obvious with 15 μmol/L KA curcumin. Both 30 and 100 μmol/L KA increased the ratio of cobalt staining-positive hippocampal neurons, and curcumin pretreatment at 15 μmol/L, but not at 5 or 30 μmol/L, significantly reduced the ratio of the positive neurons (P<0.05). Conclusion Curcumin at appropriate concentrations can modulate calcium influx mediated by AMPA and KA in cultured rat hippocampal neurons, which might be one of the anti-epileptic mechanisms of curcumin Key words: Curcumin; Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; Kainate; Calcium influx; Hippocampal neurons