Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan.
Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015, Japan.
J Physiol Sci. 2021 May 21;71(1):15. doi: 10.1186/s12576-021-00799-w.
This study aimed to clarify whether the reflex excitation of muscle sympathetic nerves induced by contractions of the skeletal muscles modulates their contractility. In anesthetized rats, isometric tetanic contractions of the triceps surae muscles were induced by electrical stimulation of the intact tibial nerve before and after transection of the lumbar sympathetic trunk (LST), spinal cord, or dorsal roots. The amplitude of the tetanic force (TF) was reduced by approximately 10% at 20 min after transection of the LST, spinal cord, or dorsal roots. The recorded postganglionic sympathetic nerve activity from the lumbar gray ramus revealed that both spinal and supraspinal reflexes were induced in response to the contractions. Repetitive electrical stimulation of the cut peripheral end of the LST increased the TF amplitude. Our results indicated that the spinal and supraspinal somato-sympathetic nerve reflexes induced by contractions of the skeletal muscles contribute to the maintenance of their own contractile force.
本研究旨在阐明骨骼肌收缩引起的肌肉交感神经反射兴奋是否调节其收缩性。在麻醉大鼠中，在切断腰交感干（LST）、脊髓或背根之前和之后，通过刺激完整的胫神经来诱导比目鱼肌的等长强直收缩。在切断 LST、脊髓或背根 20 分钟后，强直力（TF）的幅度减少了约 10%。从腰灰交通支记录的节后交感神经活动表明，收缩会引起脊髓和中枢反射。反复刺激 LST 切断的外周端可增加 TF 幅度。我们的结果表明，骨骼肌收缩引起的脊髓和中枢躯体交感神经反射有助于维持其自身的收缩力。
