Left-right side-specific endocrine signaling complements neural pathways to mediate acute asymmetric effects of brain injury

• Main Authors: Nikolay Lukoyanov, Hiroyuki Watanabe, Liliana S Carvalho, Olga Kononenko, Daniil Sarkisyan, Mengliang Zhang, Marlene Storm Andersen, Elena A Lukoyanova, Vladimir Galatenko, Alex Tonevitsky, Igor Bazov, Tatiana Iakovleva, Jens Schouenborg, Georgy Bakalkin
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2021-08-01
• Series: eLife
• Subjects: neuroendocrine signaling; brain injury; neurohormones; postural asymmetry; nociceptive withdrawal reflex; left-right side
• Online Access: https://elifesciences.org/articles/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.