Department of Biochemistry and Biophysics, Vilnius University, M.K.Čiurlionio g. 21/27, Vilnius 03101, Lithuania.
Exp Brain Res. 2012 Jul;220(1):23-8. doi: 10.1007/s00221-012-3111-y. Epub 2012 May 13.
The transient suppression of motor activity in the spinal cord after a cutaneous stimulus is termed the cutaneous silent period (CSP). It is not known if CSP is due to suppression of the premotor network or direct inhibition of motoneurons. This issue was examined by intracellular recordings from motoneurons in the isolated carapace-spinal cord preparation from adult turtles during rhythmic scratch-like reflex. Electrical stimulation of cutaneous nerves induced CSP-like suppression of motor nerve firing during rhythmic network activity. The stimulus that generated the CSP-like suppression of motor activity evokes a polysynaptic compound synaptic potential in motoneurons and suppressed their firing. This compound synaptic potential was hyperpolarizing near threshold for action potentials and was associated with a substantial increase in conductance during the CSP in the motor pool. These results show that direct postsynaptic inhibition of motoneurons contributes to the CSP.
皮肤刺激后脊髓运动活动的短暂抑制称为皮肤静息期（CSP）。目前尚不清楚 CSP 是由于前运动网络的抑制还是运动神经元的直接抑制所致。本研究通过在成年龟的甲壳-脊髓分离标本中，在节律性抓挠样反射期间对运动神经元进行细胞内记录，对这一问题进行了研究。在节律性网络活动期间，皮肤神经的电刺激诱导运动神经放电的 CSP 样抑制。引起运动活动 CSP 样抑制的刺激在运动神经元中引发了一种多突触复合突触后电位，并抑制了它们的放电。这种复合突触后电位在动作电位的阈电位附近超极化，并与 CSP 期间运动池中的电导显著增加有关。这些结果表明，运动神经元的直接突触后抑制有助于 CSP。
