Kinjo N, Atsuta Y, Webber M, Kyle R, Skinner R D, Garcia-Rill E
Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock 72205.
Brain Res Bull. 1990 Mar;24(3):509-16. doi: 10.1016/0361-9230(90)90104-8.
Previous anatomical studies demonstrated the presence of descending projections from the physiologically identified mesencephalic locomotor region (MLR) to the medioventral medulla (MED) in the cat. The present experiments were designed to determine if a similar low threshold locomotion-inducing area is present in the rat medulla. In addition, the nature of the neurochemical control of this area of the brain was explored using localized injections of neurochemical agents in the decerebrate rat during locomotion on a treadmill. A region virtually identical to that reported in the cat was found to lead to controlled locomotion on a treadmill following stimulation at low amplitude currents (less than or equal to 60 microA). Injections of cholinergic agonists into the MED of the rat induced locomotion which could be blocked by injections of cholinergic antagonists. In addition, injections of GABA antagonists were found to induce stepping which could be blocked by injections of GABA or GABA agonists. Substance P (SP) also was found to induce walking following injection into the MED of the rat. Injections of an excitatory amino acid agonist (NMDA) also were found to induce locomotion in the rat. These effects were blocked by injections of an excitatory amino acid antagonist (APV). Since these results had not been reported for the cat MED, a short series of experiments revealed that the MED in the cat also responded to NMDA.
以往的解剖学研究表明，在猫中，从生理上确定的中脑运动区（MLR）到延髓腹内侧（MED）存在下行投射。本实验旨在确定大鼠延髓中是否存在类似的低阈值运动诱导区域。此外，在去大脑大鼠在跑步机上运动期间，通过在该脑区局部注射神经化学试剂，探索了该脑区神经化学控制的性质。发现在低幅度电流（小于或等于60微安）刺激后，一个与猫中报道的区域几乎相同的区域会导致在跑步机上出现可控制的运动。向大鼠的MED注射胆碱能激动剂可诱导运动，而注射胆碱能拮抗剂可阻断该运动。此外，发现注射GABA拮抗剂可诱导踏步，而注射GABA或GABA激动剂可阻断该踏步。向大鼠的MED注射P物质（SP）后也发现可诱导行走。注射兴奋性氨基酸激动剂（NMDA）也发现可诱导大鼠运动。这些效应可被注射兴奋性氨基酸拮抗剂（APV）阻断。由于猫的MED尚未报道过这些结果，因此进行了一系列简短实验，结果表明猫的MED对NMDA也有反应。
