Abstract
Rat cultured microglia express AMPA (α-amino-hydroxy-5-methyl-isoxazole-4-propionate)-type of glutamate receptors. Here we examined the functional change of glutamate-induced currents before and after activation of microglia with lipopolysaccharide (LPS), using the conventional whole-cell patch clamp technique under the voltage-clamp condition. Glutamate-induced currents at the holding potential of -60 mV were observed in the presence of 100 µM cyclothiazide (CTZ), an inhibitor of desensitization. After treatment of microglia with 10 µg/ml LPS for 30 minutes, the cells showed ameboidal morphology and glutamate-induced currents were significantly inhibited. Immunocytochemistry using specific antibody against GluR2 showed that the subunit was translocated from cytoplasm to cell membrane after activation of microglia with LPS. These results suggest that membrane translocation of GluR2 may contribute to the inhibition of glutamate-induced currents in activated microglia. The results also indicate that translocation of GluR2 is not restricted to neurons but also occurs in microglia. The functional change of microglia through AMPA receptors may contribute to the neuron-microglia interaction under the pathophysiological conditions. [Jpn J Physiol 54 Suppl:S140 (2004)]
