How sympathetic are your spinal cord circuits?
How sympathetic are your spinal cord circuits?
复制标题
DOI：
10.1113/ep085031
复制
发表时间：
2015-04-01
影响因子：
2.7
通讯作者：
Deuchars, Susan A.
中科院分区：
文献类型：
--
作者：
Deuchars, Susan A.
新发现本次审查的主题是什么？本文就缝隙连接和中间神经元在脊髓交感神经调控中的作用作一综述，并重点介绍了哪些研究进展？本文综述了这些局部脊髓回路在促进节律性自主活动和对稳态扰动做出适当反应方面的重要性，交感神经对终末器官的控制依赖于脊髓内交感节前神经元（SPNs）的活动。这些SPN在功能、神经化学、位置、下行输入和活动模式方面表现出异质性。这种异质性部分是由局部脊髓回路赋予的。我们对这些局部回路的作用的理解，包括通过专门的缝隙连接在SPNs本身之间连接的意义，是不完整的。这份报告的重点是这些回路中的神经元间和缝隙连接。缝隙连接在交感神经控制中起作用;它们位于中间外侧细胞柱中的SPN上。甲氟喹，一种阻断这些缝隙连接的化学物质，减少了脊髓切片中的局部节律活动，扰乱了工作中的心脑干准备的自主控制。这些缝隙连接在成年动物的健康和疾病中可能发挥的作用仍有待充分阐明。前交感神经间神经元位于第V、VII和X层以及中间外侧细胞柱中; X层中的神经元是GABA能的，直接抑制SPN。对SPN的GABA能输入通过激活突触和突触外受体发挥作用，这些受体在负电位下稳定膜。GABA能中间神经元有助于在脊髓中产生的节律性活动模式，因为荷包牡丹碱减少了网络振荡活动。这些研究表明，局部脊髓回路是至关重要的，使适当的水平和交感神经流出的活动模式。我们需要了解这些回路在脊髓损伤的情况下是如何被利用的。
New findings What is the topic of this review? This review focuses on the role of gap junctions and interneurones in sympathetic control at the spinal cord level.What advances does it highlight? The review considers the importance of these local spinal circuits in contributing to rhythmic autonomic activity and enabling appropriate responses to homeostatic perturbations.Sympathetic control of end organs relies on the activity of sympathetic preganglionic neurones (SPNs) within the spinal cord. These SPNs exhibit heterogeneity with respect to function, neurochemistry, location, descending inputs and patterns of activity. Part of this heterogeneity is bestowed by local spinal circuitry. Our understanding of the role of these local circuits, including the significance of connections between the SPNs themselves through specialized gap junctions, is patchy. This report focuses on interneurones and gap junctions within these circuits. Gap junctions play a role in sympathetic control; they are located on SPNs in the intermediolateral cell column. Mefloquine, a chemical that blocks these gap junctions, reduces local rhythmic activity in the spinal cord slice and disrupts autonomic control in the working heart-brainstem preparation. The role that these gap junctions may play in health and disease in adult animals remains to be elucidated fully. Presympathetic interneurones are located in laminae V, VII and X and the intermediolateral cell column; those in laminaX are GABAergic and directly inhibit SPNs. The GABAergic inputs onto SPNs exert their effects through activation of synaptic and extrasynaptic receptors, which stabilize the membrane at negative potentials. The GABAergic interneurones contribute to rhythmic patterns of activity that can be generated in the spinal cord, because bicuculline reduces network oscillatory activity. These studies indicate that local spinal cord circuitry is critical in enabling appropriate levels and patterning of activity in sympathetic outflow. We need to understand how these circuits may be harnessed in the situation of spinal cord injury.