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首页> 外文期刊>Progress in brain research >Spinal sympathetic interneurons: their identification and roles after spinal cord injury.
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Spinal sympathetic interneurons: their identification and roles after spinal cord injury.

机译：脊髓交感神经元：脊髓损伤后的鉴定和作用。

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摘要

Primary afferent neurons rarely, if ever, synapse on the sympathetic preganglionic neurons that regulate the cardiovascular system, nor do sympathetic preganglionic neurons normally exhibit spontaneous activity in the absence of excitatory inputs. Therefore, after serious spinal cord injury "spinal sympathetic interneurons" provide the sole excitatory and inhibitory inputs to sympathetic preganglionic neurons. Few studies have addressed the anatomy and physiology of spinal sympathetic interneurons, to a great extent because they are difficult to identify. Therefore, this chapter begins with descriptions of both neurophysiological and neuroanatomical criteria for identifying spinal sympathetic interneurons, and it discusses the advantages and disadvantages of each. Spinal sympathetic interneurons also have been little studied because their importance in intact animals has been unknown, whereas the roles of direct projections from the brain to sympathetic preganglionic neurons are better known. This chapter presents evidence that spinal sympathetic interneurons play only a minor role in sympathetic regulation when the spinal cord is intact. However, they play an important role after spinal cord injury, both in generating ongoing activity in sympathetic nerves and in mediating segmental and intersegmental sympathetic reflexes. The spinal sympathetic interneurons that most directly influence the activity of sympathetic preganglionic neurons after spinal cord injury are located close to their associated sympathetic preganglionic neurons, and the inputs from distant segments that mediate multisegmental reflexes are relayed to sympathetic preganglionic neurons multisynaptically via spinal sympathetic interneurons. Finally, spinal sympathetic interneurons are more likely to be excited and less likely to be inhibited by both noxious and innocuous somatic stimuli after chronic spinal transection. The onset of this hyperexcitability corresponds to morphological changes in both sympathetic preganglionic neurons and primary afferents, and it may reflect the pathophysiological processes that lead to autonomic dysreflexia and the hypertensive crises that may occur with it in people after chronic spinal injury.
机译：原发传入神经元很少（如果有的话）在调节心血管系统的交感神经节前神经元上发生突触，在没有兴奋性输入的情况下，交感神经节前神经元通常也不会自发活动。因此，在严重的脊髓损伤后，“脊髓交感神经元”为交感神经节前神经元提供了唯一的兴奋性和抑制性输入。很少有研究针对脊柱交感神经元的解剖学和生理学，因为很难识别。因此，本章首先介绍了用于识别脊髓交感神经元的神经生理学和神经解剖学标准，并讨论了每种方法的优缺点。脊髓交感神经元的研究也很少，因为它们在完整动物中的重要性尚不明确，而从大脑直接投射到交感神经节前神经元的作用是众所周知的。本章提供的证据表明，当脊髓完好无损时，脊髓交感神经元在交感神经调节中仅扮演次要角色。然而，它们在脊髓损伤后起重要作用，既在交感神经中产生持续的活动，又介导节段性和节间性交感神经反射。脊髓损伤后最直接影响交感神经节前神经元活动的脊髓交感神经元位于其相关的交感神经节前神经元附近，介导多节段反射的远距离节段的输入通过脊髓交感神经节间神经元多突触传递至交感神经节前神经元。最后，在慢性脊髓横断后，有毒和无害的体细胞刺激更容易激发交感神经元，而抑制交感神经元的可能性较小。这种高兴奋性的发作与交感神经节前神经元和原发性传入神经的形态学变化相对应，并且可能反映了导致慢性神经损伤后人自主神经反射不良和高血压危机的病理生理过程。

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