Department of Systems Biology, Universidad de Alcala, Alcala de Henares, 28871, Madrid, Spain.
Sci Rep. 2018 Jun 27;8(1):9735. doi: 10.1038/s41598-018-27993-y.
Superficial laminae of the spinal cord possess a considerable number of neurons with spontaneous activity as reported in vivo and in vitro preparations of several species. Such neurons may play a role in the development of the nociceptive system and/or in the spinal coding of somatosensory signals. We have used electrophysiological techniques in a horizontal spinal cord slice preparation from adult mice to investigate how this activity is generated and what are the main patterns of activity that can be found. The results show the existence of neurons that fire regularly and irregularly. Within each of these main types, it was possible to distinguish patterns of spontaneous activity formed by single action potentials and different types of bursts according to intra-burst firing frequency. Activity in neurons with irregular patterns was blocked by a mixture of antagonists of the main neurotransmitter receptors present in the cord. Approximately 82% of neurons with a regular firing pattern were insensitive to synaptic antagonists but their activity was inhibited by specific ion channel blockers. It is suggested that these neurons generate endogenous activity due to the functional expression of hyperpolarisation-activated and persistent sodium currents driving the activity of irregular neurons.
脊髓浅层拥有大量具有自发性活动的神经元，这在多种物种的活体和体外标本中都有报道。这些神经元可能在伤害性感受系统的发育和/或躯体感觉信号的脊髓编码中发挥作用。我们使用来自成年小鼠的水平脊髓切片标本中的电生理技术，研究了这种活动是如何产生的，以及可以发现哪些主要的活动模式。结果显示存在规则和不规则放电的神经元。在这两种主要类型中，根据爆发内的放电频率，可以区分由单个动作电位和不同类型爆发组成的自发性活动模式。不规则模式活动可被脊髓中存在的主要神经递质受体拮抗剂混合物阻断。大约 82%的具有规则放电模式的神经元对突触拮抗剂不敏感，但它们的活动可被特定的离子通道阻断剂抑制。这表明这些神经元由于超极化激活和持续钠电流的功能表达而产生内源性活动，驱动不规则神经元的活动。
