Descending command systems for the initiation of locomotion in mammals
Descending command systems for the initiation of locomotion in mammals
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DOI：
10.1016/j.brainresrev.2007.07.019
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发表时间：
2008-01-01
影响因子：
--
通讯作者：
Pearson, Keir G.
中科院分区：
文献类型：
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作者：
Jordan, Larry M.;Liu, Jun;Pearson, Keir G.
脑干中参与运动启动的神经元包括产生下行束的谷氨酸能、去甲肾上腺素能 (NA)、多巴胺能 (DA) 和血清素能 (5-HT) 神经元。谷氨酸拮抗剂阻断中脑运动区诱导的自发运动，谷氨酸激动剂诱导脊髓动物的运动。脊髓的 NA 和 5-HT 输入起源于脑干，而下行多巴胺能通路起源于下丘脑。作用于 NA、DA 或 5-HT 受体的激动剂促进或诱导脊柱动物的运动。位于锥体旁区 (PPR) 的 5-HT 神经元在分离的新生大鼠脑干脊髓标本中受到刺激时会产生运动，它们构成了第一个解剖学上离散的脊髓突出神经元组，被证明参与哺乳动物运动的启动。成年大鼠在跑步机上运动时，PPR 中的神经元被激活。 PPR 引起的运动由 S-HT7 和 5-HT2A 受体介导，5-HT7 拮抗剂可阻断猫、大鼠和小鼠制剂中的运动，但对缺乏 5-HT7 受体的小鼠几乎没有作用。 S-HT 在 5-HT7 敲除小鼠中诱导的活动是有节律的，但屈肌和伸肌运动核以及脊髓左右两侧之间的协调被破坏。在成年野生型小鼠中，5-HT7 受体拮抗剂会损害运动，产生类似于 5-HT7 敲除小鼠中 5-HT 诱导的活动模式。 5-HT7 受体拮抗剂对成年 5-HT7 受体敲除小鼠的运动影响减弱。我们得出的结论是，PPR 是下行 5-HT 命令通路的来源，该通路通过 5-HT7 和 5-HT2A 受体激活 CPG。需要进一步的实验来定义假定的谷氨酸、DA 和 NA 命令途径。 (c) 2007 Elsevier B.V. 保留所有权利。
Neurons in the brainstem implicated in the initiation of locomotion include glutamatergic, noradrenergic (NA), dopaminergic (DA), and serotonergic (5-HT) neurons giving rise to descending tracts. Glutamate antagonists block mesencephalic locomotor region-induced and spontaneous locomotion, and glutamatergic agonists induce locomotion in spinal animals. NA and 5-HT inputs to the spinal cord originate in the brainstem, while the descending dopaminergic pathway originates in the hypothalamus. Agonists acting at NA, DA or 5-HT receptors facilitate or induce locomotion in spinal animals. 5-HT neurons located in the parapyramidal region (PPR) produce locomotion when stimulated in the isolated neonatal rat brainstem-spinal cord preparation, and they constitute the first anatomically discrete group of spinally-projecting neurons demonstrated to be involved in the initiation of locomotion in mammals. Neurons in the PPR are activated during treadmill locomotion in adult rats. Locomotion evoked from the PPR is mediated by S-HT7 and 5-HT2A receptors, and 5-HT7 antagonists block locomotion in cat, rat and mouse preparations, but have little effect in mice lacking 5-HT7 receptors. S-HT induced activity in 5-HT7 knockout mice is rhythmic, but coordination among flexor and extensor motor nuclei and left and right sides of the spinal cord is disrupted. In the adult wild-type mouse, 5-HT7 receptor antagonists impair locomotion, producing patterns of activity resembling those induced by 5-HT in 5-HT7 knockout mice. 5-HT7 receptor antagonists have a reduced effect on locomotion in adult 5-HT7 receptor knockout mice. We conclude that the PPR is the source of a descending 5-HT command pathway that activates the CPG via 5-HT7 and 5-HT2A receptors. Further experiments are necessary to define the putative glutamatergic, DA, and NA command pathways. (c) 2007 Elsevier B.V. All rights reserved.