Spitzer N C, Ribera A B
Department of Biology and Center for Molecular Genetics, University of California-San Diego, La Jolla, USA.
J Neurobiol. 1998 Oct;37(1):190-7.
Xenopus spinal neurons serve as a nearly ideal population of excitable cells for study of developmental regulation of electrical excitability. On the one hand, the firing properties of these neurons can be directly examined at early stages of differentiation and membrane excitability changes as neurons mature. Underlying changes in voltage-dependent ion channels have been characterized and the mechanisms that bring about these changes are being defined. On the other hand, these neurons have been shown to be spontaneously active at stages when action potentials provide significant calcium entry. Calcium entry provokes further elevation of intracellular calcium via release from intracellular stores. The resultant transient elevations of intracellular calcium encode differentiation in their frequency. Recent studies have shown that different neuronal subpopulations enlist distinct mechanisms for regulation of excitability and recruit specific programs of differentiation by particular patterns of activity.
非洲爪蟾脊髓神经元是用于研究电兴奋性发育调控的近乎理想的可兴奋细胞群体。一方面，这些神经元的放电特性可在分化早期直接检测，并且随着神经元成熟，膜兴奋性会发生变化。电压依赖性离子通道的潜在变化已得到表征，引发这些变化的机制也正在被阐明。另一方面，已表明这些神经元在动作电位提供大量钙内流的阶段会自发活动。钙内流通过从细胞内储存库释放而引发细胞内钙进一步升高。细胞内钙的瞬时升高通过其频率编码分化。最近的研究表明，不同的神经元亚群采用不同的兴奋性调节机制，并通过特定的活动模式招募特定的分化程序。
