中国神经再生研究(英文版) ›› 2024, Vol. 19 ›› Issue (12): 2602-2612.doi: 10.4103/NRR.NRR-D-23-01723

• 综述:退行性病与再生 • 上一篇    下一篇

星形胶质细胞介导的神经元缓慢内向电流的功能

  

  • 出版日期:2024-12-15 发布日期:2024-03-30

On the functions of astrocyte-mediated neuronal slow inward currents

Balázs Pál*   

  1. Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
  • Online:2024-12-15 Published:2024-03-30
  • Contact: Balázs Pál, MD, PhD, pal.balazs@med.unideb.hu.
  • Supported by:
    This work was funded by the National Research Development and Innovation Office (NKFIH-K146873) (to BP).

摘要: https://orcid.org/0000-0001-9711-3068 (Balázs Pál)

Abstract: Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extrasynaptic N-methyl-D-aspartate receptors with the contribution of astrocytes. These events are significantly slower than the excitatory postsynaptic currents. Parameters of slow inward currents are determined by several factors including the mechanisms of astrocytic activation and glutamate release, as well as the diffusion pathways from the release site towards the extrasynaptic receptors. Astrocytes are stimulated by neuronal network activity, which in turn excite neurons, forming an astrocyte-neuron feedback loop. Mostly as a consequence of brain edema, astrocytic swelling can also induce slow inward currents under pathological conditions. There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level. These events often occur in synchrony on neurons located in the same astrocytic domain. Besides synchronization of neuronal excitability, slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity. In addition, slow inward currents are also subject to non-synaptic plasticity triggered by long-lasting stimulation of the excitatory inputs. Of note, there might be important region-specific differences in the roles and actions triggering slow inward currents. In greater networks, the pathophysiological roles of slow inward currents can be better understood than physiological ones. Slow inward currents are identified in the pathophysiological background of autism, as slow inward currents drive early hypersynchrony of the neural networks. Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes. These events are related to epilepsy, but also found in Alzheimer’s disease, Parkinson’s disease, and stroke, leading to the decline of cognitive functions. Events with features overlapping with slow inward currents (excitatory, N-methyl-D-aspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke, traumatic brain injury, or epilepsy. One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation. However, to state this, more experimental evidence from greater neuronal networks or the level of the individual is needed. In this review, I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.

Key words: astrocyte, cortical spreading depolarization, gliotransmission, glutamate, neural synchronization, NMDA receptor, paroxysmal depolarizational shift, slow inward current