Changes in mitochondrial NAD(P)H and glutamate-induced delayed calcium deregulation in cultured rat cerebellar granule neurons

Abstract

Changes in cytosolic [Ca2+]i, mitochondrial potential (ΔVm), and mitochondrial NAD(P)H autofluorescence were compared in experiments on cultured cerebellar granule cells co-loaded with Ca2+ indicator Fluo-3FF or mitochondrial potential-sensitive probe Rh123. In the majority of neurons (94% of cells, n = 205, 28 experiments) the delayed Ca2+ deregulation (DCD) induced by Glu (100 μM) was preceded by more or less prolonged decrease in NAD(P)H, which in 57% of cells underwent a further (secondary) reduction during DCD development. To clarify the origin of these changes in NAD(P)H production during DCD we examined the effects of the protonophore FCCP on NAD(P)H increase induced by the electron chain blocker CN (3 mM) application. The data suggest that a pronounced lowering of mitochondrial pH during DCD contributed to the mechanism of Glu-induced suppression of NAD(P)H production.