Hofstetter C P, Card J P, Olson L
Department of Neuroscience, Karolinska Institutet, Retziusväg 8, 17177 Solna, Sweden.
Exp Neurol. 2005 Jul;194(1):128-38. doi: 10.1016/j.expneurol.2005.01.028.
The sympathetic innervation of lumbar dorsal root ganglia (DRGs) and the possible presence of spinal cord circuits connecting primary sensory afferents to the sympathetic outflow to DRGs were investigated. We used simultaneous tracing of the sympathetic input to and sensory output from DRGs. Adult male rats received unilateral microinjections of the Bartha strain of pseudorabies virus into four lumbar DRGs. At 24 h post-inoculation, productive infection was detected in both DRG neurons and sympathetic postganglionic neurons. Infection of spinal cord neurons was first observed in sympathetic preganglionic neurons of the intermediolateral column. Subsequently, the infection spread to the contralateral intermediolateral column, the area around the central canal and the superficial dorsal horn layers. To investigate the relationship between infected spinal cord neurons and primary afferents from the corresponding DRGs, we injected pseudorabies virus for retrograde tracing together with cholera toxin B for anterograde tracing. We found that infected LIV/LV and LX neurons were in close apposition to cholera toxin B labeled afferents. Importantly, immunohistochemical detection of bassoon, a pre-synaptic zone protein, identified such contacts as synapses. Together, this suggests synaptic contacts between primary sensory afferents and neurons regulating sympathetic outflow to corresponding DRGs.
研究了腰段背根神经节（DRG）的交感神经支配以及脊髓中连接初级感觉传入神经与DRG交感神经输出的回路的可能存在情况。我们同时追踪了DRG的交感神经输入和感觉输出。成年雄性大鼠单侧向四个腰段DRG微量注射伪狂犬病病毒的Bartha株。接种后24小时，在DRG神经元和交感神经节后神经元中均检测到有效感染。脊髓神经元的感染首先在中间外侧柱的交感神经节前神经元中观察到。随后，感染扩散到对侧中间外侧柱、中央管周围区域和浅背角层。为了研究受感染的脊髓神经元与来自相应DRG的初级传入神经之间的关系，我们注射伪狂犬病病毒进行逆行追踪，并注射霍乱毒素B进行顺行追踪。我们发现，受感染的腰4/腰5和腰6神经元与霍乱毒素B标记的传入神经紧密相邻。重要的是，对突触前区蛋白巴松管进行免疫组化检测，确定这些接触为突触。综上所述，这表明初级感觉传入神经与调节相应DRG交感神经输出的神经元之间存在突触联系。
