Departamento de Biomedicina da Faculdade de Medicina da Universidade do Porto, Instituto de Investigação e Inovação em Saúde, Instituto de Biologia Molecular e Celular, Porto, Portugal.
Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
Elife. 2021 Aug 10;10:e65247. doi: 10.7554/eLife.65247.
Brain injuries can interrupt descending neural pathways that convey motor commands from the cortex to spinal motoneurons. Here, we demonstrate that a unilateral injury of the hindlimb sensorimotor cortex of rats with completely transected thoracic spinal cord produces hindlimb postural asymmetry with contralateral flexion and asymmetric hindlimb withdrawal reflexes within 3 hr, as well as asymmetry in gene expression patterns in the lumbar spinal cord. The injury-induced postural effects were abolished by hypophysectomy and were mimicked by transfusion of serum from animals with brain injury. Administration of the pituitary neurohormones β-endorphin or Arg-vasopressin-induced side-specific hindlimb responses in naive animals, while antagonists of the opioid and vasopressin receptors blocked hindlimb postural asymmetry in rats with brain injury. Thus, in addition to the well-established involvement of motor pathways descending from the brain to spinal circuits, the side-specific humoral signaling may also add to postural and reflex asymmetries seen after brain injury.
脑损伤可中断从皮质传递至脊髓运动神经元的下行神经通路。在这里，我们证明了在完全横断胸段脊髓的大鼠后肢感觉运动皮质的单侧损伤可导致 3 小时内后肢姿势不对称，表现为对侧弯曲和不对称后肢退缩反射，以及腰脊髓内基因表达模式的不对称。损伤引起的姿势效应被垂体切除术消除，并且可被来自脑损伤动物的血清输注模拟。垂体神经激素β-内啡肽或精氨酸加压素的给药可在未受伤动物中引起特定于侧肢的反应，而阿片类和加压素受体拮抗剂可阻断脑损伤大鼠的后肢姿势不对称。因此，除了明确涉及从大脑到脊髓回路的运动通路的参与外，侧特定的体液信号也可能导致脑损伤后出现的姿势和反射不对称。
