Ca2+ -permeable acid-sensing ion channels and ischemic brain injury.

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Xiong ZG, Chu XP, Simon RP

Ca2+ -permeable acid-sensing ion channels and ischemic brain injury.

J Membr Biol. 2006 Jan;209(1):59-68. Epub 2006 Apr 17.

PubMed ID

16685601 [ View in PubMed

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Abstract

Acidosis is a common feature of brain in acute neurological injury, particularly in ischemia where low pH has been assumed to play an important role in the pathological process. However, the cellular and molecular mechanisms underlying acidosis-induced injury remain unclear. Recent studies have demonstrated that activation of Ca(2+)-permeable acid-sensing ion channels (ASIC1a) is largely responsible for acidosis-mediated, glutamate receptor-independent, neuronal injury. In cultured mouse cortical neurons, lowering extracellular pH to the level commonly seen in ischemic brain activates amiloride-sensitive ASIC currents. In the majority of these neurons, ASICs are permeable to Ca(2+), and an activation of these channels induces increases in the concentration of intracellular Ca(2+) ([Ca(2+)](i)). Activation of ASICs with resultant [Ca(2+)](i) loading induces time-dependent neuronal injury occurring in the presence of the blockers for voltage-gated Ca(2+) channels and the glutamate receptors. This acid-induced injury is, however, inhibited by the blockers of ASICs, and by reducing [Ca(2+)](o). In focal ischemia, intracerebroventricular administration of ASIC1a blockers, or knockout of the ASIC1a gene protects brain from injury and does so more potently than glutamate antagonism. Furthermore, pharmacological blockade of ASICs has up to a 5 h therapeutic time window, far beyond that of glutamate antagonists. Thus, targeting the Ca(2+)-permeable acid-sensing ion channels may prove to be a novel neuroprotective strategy for stroke patients.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Amiloride	Acid-sensing ion channel 1	Protein	Humans	Unknown	Inhibitor	Details