Commissiong J W
Fed Proc. 1981 Nov;40(13):2771-7.
A synopsis is made of the kinds of monoaminergic terminals that are found in the ventral horn of the spinal cord, and of the physiological effects these monoamines exert on interneurons (INs), alpha motoneurons (alpha-MNs), and gamma motoneurons (gamma-MNs). It is suggested that in addition to the usual transmitter mechanism involving the activation of fast ionic conductances, monoamines in the ventral horn may function as neuromodulators and as part of the neuronal control for a limb. Experiments are then described in which it is shown that the monoamines can exert selective effects on INs, alpha-MNs, and gamma-MNs. The activation of gamma-MNs in the spinal cord partly depleted of 5-hydroxytryptamine (5-HT) is a striking example of that selectivity. The neurochemical basis of the physiological effects of monoamines on the cord is briefly reviewed. It is suggested that after the administration of dihydroxyphenylalanine (DOPA), all three major monoamines--dopamine (DA), norepinephrine (NE), and 5-HT--could be involved in mediating the physiological effects of DOPA. The evidence for the presence of dopaminergic nerves in the cord is briefly described, and their possible physiological significance is discussed.
本文综述了在脊髓腹角发现的单胺能终末的种类，以及这些单胺对中间神经元（INs）、α运动神经元（α-MNs）和γ运动神经元（γ-MNs）产生的生理效应。研究表明，除了涉及快速离子电导激活的常见递质机制外，腹角中的单胺可能作为神经调质发挥作用，并作为肢体神经元控制的一部分。随后描述了一些实验，这些实验表明单胺可以对INs、α-MNs和γ-MNs产生选择性作用。脊髓中γ-MNs的激活在5-羟色胺（5-HT）部分耗尽的情况下，就是这种选择性的一个显著例子。本文简要回顾了单胺对脊髓生理效应的神经化学基础。研究表明，在给予二羟基苯丙氨酸（DOPA）后，所有三种主要单胺——多巴胺（DA）、去甲肾上腺素（NE）和5-HT——都可能参与介导DOPA的生理效应。本文简要描述了脊髓中多巴胺能神经存在的证据，并讨论了它们可能的生理意义。
