Calcium homeostasis modulator 1 (CALHM1) is the pore-forming subunit of an ion channel that mediates extracellular Ca~(2+) regulation of neuronal excitability

摘要

Extracellular Ca~2+ concentrations ([Ca~2+]_0) play important physiological roles in neuronal excitability (1), and in the brain these concentrations can decrease from ~1.3 mM to 0.1 mM during electrical activity and in pathophysiological situations. NALCN, a Na~+ leak channel_x is activated indirectly by low [Ca~2+]_0 by signaling through a G-protein-coupled receptor (2). The nonselective cation channel TRPM7 can be activated in hippocampal neurons by decreasing [Ca~2+]_0 (3). Additional molecular mechanisms whereby neuronal excitability is regulated by [Ca~2+]_0 remain unknown.