Borhegyi Z, Leranth C
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut 06520-8063, USA.
J Comp Neurol. 1997 Jul 21;384(1):41-58. doi: 10.1002/(sici)1096-9861(19970721)384:1<41::aid-cne3>3.0.co;2-l.
Light and electron microscopic substance P (SP) immunostaining was performed on hippocampal sections of colchicine-pretreated, control, untreated fimbria-fornix-transected (5 days), as well as perforant path-stimulated Sprague-Dawley rats fixed in 5% acrolein. Numerous SP-immunoreactive neurons could be observed in the stratum oriens of the Ammon's horn and subiculum, fewer were seen in the dentate hilar area and stratum radiatum of CA2 and CA3, and even fewer were seen at the border between the CA1 strata radiatum and the lacunosum moleculare of CA1 subfield. A higher dose of colchicine resulted in SP immunoreactivity in a large population of granule cells and mossy axon terminals. The entire CA2 region, the stratum oriens of CA1, CA3, and the subiculum were densely innervated by SP-containing axon terminals. A homogeneous SP innervation was found in the stratum radiatum of CA1. Only a few SP fibers were seen adjacent to the granule cell layer. Symmetric axosomatic contacts were seen between SP-containing boutons and somata in the stratum oriens of the Ammon's horn. However, throughout the hippocampal formation, the majority of SP-containing axons formed axodendritic symmetric synapses. A dense population of SP-immunoreactive boutons that formed axodendritic asymmetric synapses was observed in the strata oriens and radiatum of the CA3a and CA2 regions, and a few were found in the supragranular and subgranular layers of the dentate gyrus. Fimbria-fornix transection resulted in a marked loss of SP fibers in the strata oriens, pyramidale, and radiatum of the CA3a and CA2 subfields. In perforant pathway-stimulated animals, a population of granule cells and a large number of mossy axon terminals were immunoreactive for SP. These observations suggest two sources of SP innervation to the hippocampal formation: one arising from intrinsic sources (interneurons and granule cells) and one arising from extrinsic sources, most likely the supramammillary region.
对用秋水仙碱预处理、对照、未处理的穹窿-海马伞横断（5天）以及经穿通通路刺激的Sprague-Dawley大鼠（固定于5%丙烯醛中）的海马切片进行了光镜和电镜下的P物质（SP）免疫染色。在海马角的原层和下托中可观察到大量SP免疫反应性神经元，在齿状回门区以及CA2和CA3的辐射层中较少见，而在CA1辐射层与CA1亚区分子层之间的边界处则更少见。更高剂量的秋水仙碱导致大量颗粒细胞和苔藓轴突终末出现SP免疫反应性。整个CA2区域、CA1、CA3的原层以及下托都被含SP的轴突终末密集支配。在CA1的辐射层中发现了均匀的SP支配。在颗粒细胞层附近仅可见少数SP纤维。在海马角原层中，含SP的终扣与胞体之间可见对称的轴-体接触。然而，在整个海马结构中，大多数含SP的轴突形成轴-树突对称突触。在CA3a和CA2区域的原层和辐射层中观察到大量形成轴-树突不对称突触的SP免疫反应性终扣，在齿状回的颗粒上层和颗粒下层中也发现了少数。穹窿-海马伞横断导致CA3a和CA2亚区的原层、锥体层和辐射层中SP纤维明显减少。在经穿通通路刺激的动物中，一群颗粒细胞和大量苔藓轴突终末对SP呈免疫反应性。这些观察结果提示海马结构的SP支配有两个来源：一个来自内在来源（中间神经元和颗粒细胞），另一个来自外在来源，很可能是乳头体上区。
