Extracellular calcium sensed by a novel cation channel in hippocampal neurons

作者：Zhi‐Gang Xiong, Wei‐Yang Lu, John Ferguson MacDonald · 发表于：Proceedings of the National Academy of Sciences · 年份：1997 · DOI：10.1073/pnas.94.13.7012 · 被引用次数：127 · 研究领域：Ion channel regulation and function、Neuroscience and Neuropharmacology Research、Neural dynamics and brain function

Extracellular concentrations of Ca2+ change rapidly and transiently in the brain during excitatory synaptic activity. To test whether such changes in Ca2+ can play a signaling role we examined the effects of rapidly lowering Ca2+ on the excitability of acutely isolated CA1 and cultured hippocampal neurons. Reducing Ca2+ excited and depolarized neurons by activating a previously undescribed nonselective cation channel. This channel had a single-channel conductance of 36 pS, and its frequency of opening was inversely proportional to the concentration of Ca2+. The inhibition of gating of this channel was sensitive to ionic strength but independent of membrane potential. The ability of this channel to sense Ca2+ provides a novel mechanism whereby neurons can respond to alterations in the extracellular concentration of this key signaling ion.