Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados, del Instituto Politécnico Nacional, Avenida Instituto Politécnico Nacional 2408, México DF 07360, México.
J Physiol. 2013 May 15;591(10):2629-45. doi: 10.1113/jphysiol.2013.253351. Epub 2013 Mar 11.
In the anaesthetized cat, the acute section of the saphenous (Saph) and/or the superficial peroneal (SP) nerves was found to produce a long-lasting increase of the field potentials generated in the dorsal horn by stimulation of the medial branch of the sural (mSU) nerve. This facilitation was associated with changes in the level of the tonic primary afferent depolarization (PAD) of the mSU intraspinal terminals. The mSU afferent fibres projecting into Rexed's laminae III-IV were subjected to a tonic PAD that was reduced by the acute section of the SP and/or the Saph nerves. The mSU afferents projecting deeper into the dorsal horn (Rexed's laminae V-VI) were instead subjected to a tonic PAD that was increased after Saph and SP acute nerve section. A differential control of the synaptic effectiveness of the low-threshold cutaneous afferents according to their sites of termination within the dorsal horn is envisaged as a mechanism that allows selective processing of sensory information in response to tactile and nociceptive stimulation or during the execution of different motor tasks.
在麻醉猫中，发现急性切断隐神经（Saph）和/或腓浅神经（SP）可导致刺激腓肠神经内侧支（mSU）时在背角产生的场电位长时间增加。这种易化与 mSU 脊髓内末端紧张性初级传入去极化（PAD）水平的变化有关。投射到 Rexed III-IV 层的 mSU 传入纤维受到紧张性 PAD 的影响，而 SP 和/或 Saph 神经的急性切断可降低这种紧张性 PAD。相反，投射到背角更深层（Rexed V-VI 层）的 mSU 传入纤维受到紧张性 PAD 的影响，在 Saph 和 SP 急性神经切断后增加。根据其在背角中的终止部位，对低阈值皮肤传入纤维的突触有效性进行差异控制，可作为一种机制，允许选择性地处理感觉信息，以响应触觉和伤害性刺激，或在执行不同的运动任务期间。
