Noga B R, Kettler J, Jordan L M
Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
J Neurosci. 1988 Jun;8(6):2074-86. doi: 10.1523/JNEUROSCI.08-06-02074.1988.
The purpose of this study was to determine the distribution of cells in the medial reticular formation (MRF) and the pontomedullary locomotor strip (PLS), which can induce locomotion when activated. Controlled microinjections of neuroactive substances (Goodchild et al., 1982) into the MRF or PLS were made in order to activate cell bodies in those areas. The ability of trigeminal receptive field stimulation to induce locomotion before and after drug infusion into the PLS was also assessed since the PLS and the spinal nucleus of the trigeminal nerve are similar in their anatomical distribution. Experiments were performed on precollicular-postmamillary decerebrate cats walking on a treadmill. Injections of glutamic acid (GA; 500 nmol) into the MRF produced locomotion that was antagonized by infusion of glutamic acid diethyl ester into the same spot. Decreases in the current threshold for locomotion produced by electrical stimulation of the MRF were observed when the MRF was infused with either GA (40-80 nmol), DL-homocysteic acid (DL-HCA; 200 nmol), or picrotoxin (PIC; 15 nmol). Injections of GA (100 nmol), DL-HCA (700 nmol), PIC (10-50 nmol), and substance P (2 nmol) into the PLS also produced locomotion. Locomotion produced by injections of PIC into the PLS was blocked by infusion of equal amounts of muscimol or GABA. Effective PLS injection sites were all confined to the trigeminal spinal nucleus or immediately ventral and medial to this in the adjacent lateral reticular formation. Trigeminal nerve peripheral field stimulation evoked locomotion after microinjection of PIC into the PLS, although this same facial stimulus was not effective prior to drug injection. We conclude that the MRF and PLS regions of the cat brain stem contain cells that produce locomotion when chemically stimulated, and we suggest that the PLS is closely related to or synonymous with the spinal nucleus of the trigeminal nerve. Furthermore, we suggest that stimulation of trigeminal afferents is analogous to stimulation of segmental afferent pathways in the production of locomotion (Sherrington, 1910; Jankowska et al., 1967; Afelt, 1970; Budakova, 1972; Grillner and Zangger, 1979).
本研究的目的是确定内侧网状结构（MRF）和脑桥延髓运动带（PLS）中的细胞分布，这些区域被激活时可诱发运动。为了激活这些区域的细胞体，向MRF或PLS中控制性微量注射神经活性物质（Goodchild等人，1982年）。由于PLS和三叉神经脊髓核在解剖分布上相似，因此还评估了在向PLS注入药物前后，三叉神经感受野刺激诱发运动的能力。实验在跑步机上行走的中脑前-乳头体后去大脑猫身上进行。向MRF中注射谷氨酸（GA；500 nmol）可产生运动，而向同一部位注入谷氨酸二乙酯可拮抗该运动。当向MRF注入GA（40 - 80 nmol）、DL-高半胱氨酸（DL-HCA；200 nmol）或印防己毒素（PIC；15 nmol）时，观察到电刺激MRF产生运动的电流阈值降低。向PLS中注射GA（100 nmol）、DL-HCA（700 nmol）、PIC（10 - 50 nmol）和P物质（2 nmol）也可产生运动。向PLS中注射PIC所产生的运动可被注入等量的蝇蕈醇或GABA所阻断。有效的PLS注射部位均局限于三叉神经脊髓核或其紧邻的外侧网状结构中该核的腹内侧。在向PLS中微量注射PIC后，三叉神经外周野刺激可诱发运动，尽管在药物注射前相同的面部刺激无效。我们得出结论，猫脑干的MRF和PLS区域含有在化学刺激时产生运动的细胞，并且我们认为PLS与三叉神经脊髓核密切相关或同义。此外，我们认为在运动产生过程中，刺激三叉神经传入纤维类似于刺激节段性传入通路（Sherrington，1910年；Jankowska等人，1967年；Afelt，1970年；Budakova，1972年；Grillner和Zangger，1979年）。
