Madison R, Davis J N
Brain Res. 1983 Jun 27;270(1):1-9. doi: 10.1016/0006-8993(83)90785-0.
Peripheral noradrenergic fibers from the superior cervical ganglion (SCG) appear in the hippocampal formation of the adult rat central nervous system following damage to the medial septal nucleus or its afferent fibers. The appearance of these fibers coincides with a significant and substantial increase in the concentration of norepinephrine in the dentate gyrus and in the ability of synaptosomes made from the dentate to take up [3H]norepinephrine (NE) in vitro. Up to 7 weeks following a medial septal lesion, dentate norepinephrine levels are significantly lower if the sympathetic preganglionic trunk has been sectioned at the time septal lesions are made. By contrast, the uptake of [3H]NE into dentate synaptosomes is not affected by the preganglionic section. Furthermore, if the sectioned preganglionic trunk is allowed to reinnervate the SCG, the dentate NE concentration rapidly returns to levels equivalent to dentates with intact sympathetic preganglionic trunks. In addition to the ingrowth of the sympathetic fibers, central noradrenergic fibers display a sprouting or 'pruning' response to medial septal lesions. These data show that afferent input regulates the neurotransmitter concentration during sympathetic ingrowth while retrograde influences from the target appear to regulate the density or extent of the growing fibers. The experimental findings are discussed in light of the hypothesis that the hippocampal formation is capable of producing a sympathetic growth factor following septal denervation.
来自颈上神经节（SCG）的外周去甲肾上腺素能纤维，在成年大鼠中枢神经系统的海马结构中，于内侧隔核或其传入纤维受损后出现。这些纤维的出现与齿状回中去甲肾上腺素浓度的显著大幅增加以及由齿状体制备的突触体在体外摄取[3H]去甲肾上腺素（NE）的能力增强相吻合。在内侧隔损伤后长达7周的时间里，如果在进行隔损伤时切断交感神经节前干，齿状回中的去甲肾上腺素水平会显著降低。相比之下，[3H]NE摄取到齿状回突触体的过程不受节前切断的影响。此外，如果让切断的节前干重新支配颈上神经节，齿状回中的NE浓度会迅速恢复到与交感神经节前干完整的齿状回相当的水平。除了交感神经纤维的长入，中枢去甲肾上腺素能纤维对内侧隔损伤还表现出一种发芽或“修剪”反应。这些数据表明，传入输入在交感神经长入过程中调节神经递质浓度，而来自靶标的逆行影响似乎调节生长纤维的密度或范围。根据海马结构在隔神经去支配后能够产生一种交感生长因子的假说，对实验结果进行了讨论。
