Acidosis-Induced Zinc-Dependent Death of Cultured Cerebellar Granule Neurons

Abstract

Severe acidosis caused death of cultured cerebellar granule neurons (CGNs). Acidosis was accompanied by a progressive increase of the intracellular zinc ions ([Zn(2+)](i)) and decrease of [Ca(2+)](i). Zn(2+) chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), prevented the increase of [Zn(2+)](i) and acidosis-induced neuronal death. However, neuronal death was insensitive to blockade of ASIC1 channels with amiloride, as CGNs display considerably lower expression of ASIC1a than other neurons. The antioxidant trolox and menadione significantly protected neurons from acidotic death. Earlier, we demonstrated that menadione rescues neurons from the deleterious effect of inhibition of mitochondrial complex I (Isaev et al. Neuroreport 15:2227-2231, 2004). We speculate that excessive Zn(2+)-dependent production of reactive oxygen species by mitochondrial complex I may be a general motive for the induction of cell death in CGNs under acidotic conditions.

Cytosolic acidification and intracellular zinc release in hippocampal neurons

“…(2003) failed to observe any [Zn 2+ ] i elevations. In cultured cerebellar granule cells, Isaev et al. (2010) did observe [Zn 2+ ] i elevations under such conditions but the exposures lasted as long as 30 min.…”

“…2003). In cerebellar granule cells, [Zn 2+ ] i elevations were observed when the exposures to pH 6.0 were prolonged to 30 min (Isaev et al. 2010).…”

Acidosis and 5-(N-ethyl-N-isopropyl)amiloride (EIPA) attenuate zinc/kainate toxicity in cultured cerebellar granule neurons

“…The study was made on 7 9 day old cultures of cerebellar granule neurons pre pared from the cerebella of 8 day old Wistar rats by enzyme-mechanical dissociation [10]. The cerebella were washed with Ca 2+ and Mg 2+ free phosphate buffer solution (PBS; Dulbecco) and incubated in the same solution containing 0.05% trypsin and 0.02% EDTA (15 min, 37°C).…”

“…It has been demonstrated that under condi tions of calcium ion imbalance, the accumulation of Zn 2+ in intracellular zinc stores is blocked by acidosis [9]. Extracellular acidosis is accompanied by a progressive increase of [Zn 2+ ] i in cerebellar granule neurons (CGNs) [10,11]. Mild acidosis enhances AMPA receptor medi ated intracellular zinc mobilization in cortical neurons [12].…”

Proton‐dependent zinc release from intracellular ligands

“…Recently, it has been demonstrated that acid‐induced neuronal death is preceded by elevations of intracellular [Zn 2+ ] ([Zn 2+ ] i ) (Isaev et al . ), which occur owing to a Zn 2+ release from intracellular stores (Sensi et al . ; Kiedrowski , ).…”