Effects of BDNF and NT-3 on development of Ia/motoneuron functional connectivity in neonatal rats.
Effects of BDNF and NT-3 on development of Ia/motoneuron functional connectivity in neonatal rats.
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BDNF 和 NT-3 对新生大鼠 Ia/运动神经元功能连接发育的影响。
DOI：
10.1152/jn.1999.81.5.2398
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Mendell,LM
中科院分区：
文献类型：
--
作者：
Seebach,BS;Arvanov,V;Mendell,LM
BDNF和NT-3对新生大鼠Ia/运动神经元功能连接发育的影响 在新生大鼠中研究了神经营养因子给药和通过酪氨酸激酶（trk）免疫粘附素（与IgG重链融合的trk受体胞外结构域）给药去除神经营养因子对节段性反射发育的影响。在出生后第0、2、4和6天通过皮下注射递送脑源性神经营养因子（BDNF）、神经营养素-3（NT-3）、trkB-IgG和trkC-IgG。在离体脊髓半切模型上，于生后第8天，对刺激L5背根后，在L5运动神经元胞内记录到的EPSP进行电生理分析。与对照组相比，BDNF处理导致更小的单突触EPSP和更长的潜伏期。当BDNF与trkB-IgG隔离时，EPSP振幅变得显著更大，表明BDNF对新生儿这种突触的发育具有滋补作用。用NT-3处理导致较大的EPSP，但在施用trkC-IgG后观察到的降低不显著。神经营养因子对高频背根刺激或运动神经元特性的反应几乎没有影响。与对照组相比，BDNF处理的大鼠多突触成分被夸大，NT-3后减少。与对照新生儿一样，NT-3和trkB-IgG处理的制剂中最大的单突触EPSP在基强度值相对较大的运动神经元中观察到，可能是那些生长最快的运动神经元。我们的结论是，补充NT-3和BDNF管理的新生儿可以影响发展Ia/运动神经元突触在脊髓中，但相反的净效应。
Effects of BDNF and NT-3 on development of Ia/motoneuron functional connectivity in neonatal rats. The effects of neurotrophin administration and neurotrophin removal via administration of tyrosine kinase (trk) immunoadhesins (trk receptor extracellular domains fused with IgG heavy chain) on the development of segmental reflexes were studied in neonatal rats. Brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), trkB-IgG, and trkC-IgG were delivered via subcutaneous injection on days 0, 2, 4, and 6 of postnatal life. Electrophysiological analysis of EPSPs recorded intracellularly in L5motoneurons in response to stimulation of dorsal root L5was carried out on postnatal day 8 in the in vitro hemisected spinal cord. Treatment with BDNF resulted in smaller monosynaptic EPSPs with longer latency than those in controls. EPSP amplitude became significantly larger when BDNF was sequestered with trkB-IgG, suggesting that BDNF has a tonic action on the development of this synapse in neonates. Treatment with NT-3 resulted in larger EPSPs, but the decrease noted after administration of trkC-IgG was not significant. Neurotrophins had little effect on the response to high-frequency dorsal root stimulation or on motoneuron properties. Polysynaptic components were exaggerated in BDNF-treated rats and reduced after NT-3 compared with controls. As in control neonates the largest monosynaptic EPSPs in NT-3 and trkB-IgG-treated preparations were observed in motoneurons with relatively large values of rheobase, probably those that are growing the most rapidly. We conclude that supplementary NT-3 and BDNF administered to neonates can influence developing Ia/motoneuron synapses in the spinal cord but with opposite net effects.