Johns Hopkins Zanvyl Krieger Mind/Brain Institute, Rm 350 Dunning Hall, and The Solomon H. Snyder Department of Neuroscience Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA.
Center for Molecular and Behavioral Neuroscience, Behavioral and Neural Science Graduate Program, Rutgers University-Newark, Newark, NJ, 07102, USA.
Sci Rep. 2019 Feb 8;9(1):1687. doi: 10.1038/s41598-018-38405-6.
Ionic currents, whether measured as conductance amplitude or as ion channel transcript numbers, can vary many-fold within a population of identified neurons. In invertebrate neuronal types multiple currents can be seen to vary while at the same time their magnitudes are correlated. These conductance amplitude correlations are thought to reflect a tight homeostasis of cellular excitability that enhances the robustness and stability of neuronal activity over long stretches of time. Although such ionic conductance correlations are well documented in invertebrates, they have not been reported in vertebrates. Here we demonstrate with two examples, identified mouse hippocampal granule cells (GCs) and cholinergic basal forebrain neurons, that the correlation of ionic conductance amplitudes between different ionic currents also exists in vertebrates, and we argue that it is a ubiquitous phenomenon expressed by many species across phyla. We further demonstrate that in dentate gyrus GCs these conductance correlations are likely regulated in a circadian manner. This is reminiscent of the known conductance regulation by neuromodulators in crustaceans. However, in GCs we observe a more nuanced regulation, where for some conductance pairs the correlations are completely eliminated while for others the correlation is quantitatively modified but not obliterated.
离子电流，无论是以电导幅度还是离子通道转录本数量来衡量，在已鉴定神经元的群体中都可能有很大的变化。在无脊椎动物神经元类型中，可以看到多种电流发生变化，同时它们的幅度也相关。这些电导幅度相关性被认为反映了细胞兴奋性的严格内稳态，从而增强了神经元活动在长时间内的稳健性和稳定性。尽管这种离子电导相关性在无脊椎动物中得到了很好的证明，但在脊椎动物中尚未有报道。在这里，我们通过两个例子证明了，鉴定的小鼠海马颗粒细胞 (GCs) 和胆碱能基底前脑神经元，离子电流之间的离子电导幅度的相关性也存在于脊椎动物中，我们认为这是一种普遍存在的现象，在许多不同物种中都有表达。我们进一步证明，在齿状回 GCs 中，这些电导相关性可能以昼夜节律的方式进行调节。这让人联想到甲壳类动物中已知的神经调质对电导的调节。然而，在 GCs 中，我们观察到一种更为细致的调节方式，对于一些电导对，相关性完全消除，而对于其他电导对，相关性虽然在数量上有所改变，但并未完全消除。
