Spatiotemporal characteristics of 5-HT and dopamine-induced rhythmic hindlimb activity in the in vitro neonatal rat
Spatiotemporal characteristics of 5-HT and dopamine-induced rhythmic hindlimb activity in the in vitro neonatal rat
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DOI：
10.1152/jn.1996.75.4.1472
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发表时间：
1996-04-01
影响因子：
2.5
通讯作者：
Kjaerulff, O
中科院分区：
文献类型：
--
作者：
Kiehn, O;Kjaerulff, O
1.在新生大鼠的体外脊髓制备中，用5-羟色胺（5-HT; 10-100 μ M）或多巴胺（0.1-1.0 mM）诱导节律性活动，其中一个完整的后肢连接。采用多种肌电记录方法研究活动模式，并比较5-HT和多巴胺诱发活动的时空特征.多巴胺诱导的节律活动缓慢（周期持续时间：2.2-70.1 s）且不规则，而5-HT诱导的节律活动快速（周期持续时间：1.3-5.1 s）且规则.在5-HT和多巴胺诱导的节律性活动中，髋屈肌和髋内收肌、半膜肌（髋伸肌）以及控制踝和足的肌肉的肌肉活动时间相似.与此相反，显着的差异，在由5-HT诱导的模式与多巴胺诱导的相比较，发现在股二头肌，半腱肌，和四头肌肌肉。股二头肌和半腱肌（功能性髋伸肌和膝屈肌）在5-HT诱导的活动中总是伸肌样的，而在多巴胺中，这些肌肉显示屈肌样爆发和双爆发以及伸肌样爆发。在多巴胺中也遇到股二头肌和半腱肌缺乏EMG活动。在股直肌、股外侧肌和股内侧肌（主要功能：膝关节伸展）中，5-HT的活动以屈肌样爆发为主，而多巴胺的活动则转移到以伸肌样模式为主。屈肌和伸肌爆发持续时间和周期持续时间之间的关系比成年动物的自发活动所描述的更多变。从P0到P4，肌肉活动的相对时间是稳定的。0-1天的大鼠和2-4天的大鼠之间最重要的区别是老年动物的屈肌-伸肌转换延迟。切断所有背根后，后肢肌肉活动的复杂时间相对不变。最后，屈肌和伸肌活动和腹根放电之间的关系被确定。发现L2前根的爆发与单纯屈肌同相，而L5前根的爆发与伸肌同相.我们的结论是，5-HT和多巴胺可以激活脊髓中央模式发生器（CPG），已经在出生时能够产生不同的运动活动模式。因此，调制输入似乎能够重新配置的CPG产生特定的电机输出。
1. Rhythmic activity was induced with either serotonin (5-HT; 10-100 mu M) or dopamine (0.1-1.0 mM), in the in vitro spinal cord preparation of neonatal rats, with one intact hindlimb attached. Patterns of activity were investigated with multiple EMG recordings and the spatiotemporal characteristics of 5-HT- and dopa mine-induced activity compared.2. Dopamine-induced rhythmic activity was slow (cycle duration: 2.2-70.1 s) and irregular, whereas rhythmic activity induced by 5-HT was fast (cycle duration: 1.3-5.1 s) and regular.3. During 5-HT- and dopamine-induced rhythmic activity, the timing of muscular activity was similar for hip flexors and hip adductors, for semimembranosus (hip extensor), and for muscles controlling the ankle and the foot.4. In contrast, notable differences in the phase in the pattern induced by 5-HT compared with that induced by dopamine were found in the biceps femoris, semitendinosus, and quadriceps muscles. Biceps femoris and semitendinosus (functional hip extensors and knee flexors) were always extensor-like during 5-HT-induced activity, whereas in dopamine, these muscles displayed flexor-like bursts and double bursts as well as extensor-like bursts. Lack of EMG activity in biceps femoris and semitendinosus was encountered also in dopamine. In rectus femoris, vastus lateralis, and vastus medialis (main function: knee extension), the activity was dominated by flexor-like bursts in 5-HT, whereas in dopamine the activity was shifted to a predominantly extensor-like pattern.5. The relationship between flexor and extensor burst duration and cycle duration was more variable than described for locomotor activity in adult animals.6. The relative timing of muscle activity was stable from P0 to P4. The most important difference between rats aged 0-1 days and rats aged 2-4 days was a delayed flexor-extensor transition in older animals.7. The complex timing of hindlimb muscle activity was relatively unchanged after transecting all dorsal roots.8. Finally, the relationship between flexor and extensor activity and ventral root discharges was determined. It was found that the L2 ventral root burst was in phase with simple flexors while the L5 burst coincide with the extensor phase.9. We conclude, that 5-HT and dopamine can activate spinal central pattern generators (CPGs) that already at birth are able to produce distinct patterns of motor activity. Modulatory inputs thus seems to be able to reconfigure the CPGs to produce specific motor outputs.