Differential presynaptic control of the synaptic effectiveness of cutaneous afferents evidenced by effects produced by acute nerve section.
Differential presynaptic control of the synaptic effectiveness of cutaneous afferents evidenced by effects produced by acute nerve section.
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急性神经切片产生的效应证明了皮肤传入突触有效性的突触前差异控制。
DOI：
10.1113/jphysiol.2013.253351
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Chávez,D
中科院分区：
文献类型：
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作者：
Rudomin,P;Jiménez,I;Chávez,D
关键点·我们在麻醉猫中研究了隐神经和腓浅神经急性切断对腓肠神经传入神经突触有效性的影响。·我们发现，这些神经的急性部分产生了持久的腓肠诱发场电位增加。与此同时，终止于Rexed's板层III-IV的腓肠神经传入显示出紧张性初级传入去极化减少，而投射到背角更深处（Rexed's板层V-VI）的腓肠神经传入则显示出紧张性初级传入去极化增加。这表明，根据其在背角内的终止位点，低阈值皮肤传入的突触有效性的差异控制提供了响应于触觉和伤害性刺激或在执行不同的运动任务期间选择性处理感觉信息的手段。发现隐神经（Saph）和/或腓浅神经（SP）的急性部分通过刺激腓肠神经（mSU）的内侧分支产生背角中产生的场电位的持久增加。这种促进作用与mSU椎管内末梢的紧张性初级传入去极化（PAD）水平的变化相关。mSU传入纤维投射到Rexed的椎板III-IV受到紧张性PAD，减少了SP和/或Saph神经的急性部分。相反，更深地投射到背角（Rexed的椎板V-VI）的mSU传入神经受到紧张性PAD的影响，该PAD在Saph和SP急性神经节段后增加。根据其在背角内的终止部位，对低阈值皮肤传入的突触有效性的差异控制被设想为允许响应于触觉和伤害性刺激或在执行不同运动任务期间选择性处理感觉信息的机制。
Key points•We investigated, in the anaesthetized cat, the effects of acute section of the saphenous and superficial peroneal nerves on the synaptic effectiveness of the sural nerve afferents.•We found that acute section of these nerves produced a long‐lasting increase of the sural‐evoked field potentials. At the same time, sural afferents ending within Rexed's laminae III–IV showed a reduced tonic primary afferent depolarization, while sural afferents projecting deeper into the dorsal horn (Rexed's laminae V–VI) instead showed increased tonic primary afferent depolarization.•It is suggested that a differential control of the synaptic effectiveness of the low‐threshold cutaneous afferents according to their sites of termination within the dorsal horn provides means for a selective processing of sensory information in response to tactile and nociceptive stimulation or during the execution of different motor tasks.AbstractIn 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.