Propriospinal Neurons of L3-L4 Segments Involved in Control of the Rat External Urethral Sphincter
Propriospinal Neurons of L3-L4 Segments Involved in Control of the Rat External Urethral Sphincter
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DOI：
10.1016/j.neuroscience.2019.11.013
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发表时间：
2020-01-15
期刊：
影响因子：
3.3
通讯作者：
de Groat, William C.
中科院分区：
文献类型：
--
作者：
Karnup, Sergei, V;de Groat, William C.
尿道外括约肌（EUS）、横纹肌和膀胱（BL）平滑肌的活动协调对于有效排尿至关重要。在这项研究中，我们研究了在L3/L4脊髓（SC），可能有一个重要的作用，在EUS-BL协调大鼠的神经元的形态和电生理特性。在P18-P20雄性大鼠的EUS中注射共表达荧光标记物的伪狂犬病毒（PRV）后，通过逆行跨突触追踪鉴定EUS相关的SC神经元。追踪发现不仅EUS运动神经元在L 6/S1，但也在X层的L 6/S1和L3/L4 SC的中间神经元。荧光标记的神经元的生理特性进行了评估，在SC切片的全细胞记录，然后重建的生物胞素填充的神经元。从横向或纵向切片的神经元过程的重建表明，一些L3/L4神经元的轴突投射到腹内侧索（VMf），轴突延伸到尾部。其他神经元的轴突投射在X和VII层。L3/L4神经元的树突分布于X层和VII层。大多数L3/L4神经元对去极化电流表现出紧张性放电。在横向切片局灶性电刺激（FES）在VMF或在X和VII层引起逆向轴突尖峰和/或兴奋性突触反应在L3/L4神经元，而在纵向切片FES引起兴奋性突触输入的网站高达400克沿着中央管。很少观察到抑制性输入。这些数据表明，L3/L4 EUS相关的电路包括至少两个神经元群体：节段性中间神经元和propriospinal神经元投射到L 6/S1。(C)2019年IBRO。由爱思唯尔有限公司出版。保留所有权利。
Coordination of activity of external urethral sphincter (EUS) striated muscle and bladder (BL) smooth muscle is essential for efficient voiding. In this study we examined the morphological and electrophysiological properties of neurons in the L3/L4 spinal cord (SC) that are likely to have an important role in EUS-BL coordination in rats. EUS-related SC neurons were identified by retrograde transsynaptic tracing following injection of pseudorabies virus (PRV) co-expressing fluorescent markers into the EUS of P18-P20 male rats. Tracing revealed not only EUS motoneurons in L6/S1 but also interneurons in lamina X of the L6/S1 and L3/L4 SC. Physiological properties of fluorescently labeled neurons were assessed during whole-cell recordings in SC slices followed by reconstruction of biocytin-filled neurons. Reconstructions of neuronal processes from transverse or longitudinal slices showed that some L3/L4 neurons have axons projecting toward and into the ventro-medial funiculus (VMf) where axons extended caudally. Other neurons had axons projecting within laminae X and VII. Dendrites of L3/L4 neurons were distributed within laminae X and VII. The majority of L3/L4 neurons exhibited tonic firing in response to depolarizing currents. In transverse slices focal electrical stimulation (FES) in the VMf or in laminae X and VII elicited antidromic axonal spikes and/or excitatory synaptic responses in L3/L4 neurons; while in longitudinal slices FES elicited excitatory synaptic inputs from sites up to 400 gm along the central canal. Inhibitory inputs were rarely observed. These data suggest that L3/L4 EUS-related circuitry consists of at least two neuronal populations: segmental interneurons and propriospinal neurons projecting to L6/S1. (C) 2019 IBRO. Published by Elsevier Ltd. All rights reserved.