Saito H
Department of Anatomy, Juntendo University School of Medicine, Tokyo, Japan.
Am J Anat. 1990 Nov;189(3):213-35. doi: 10.1002/aja.1001890305.
The innervation of the guinea pig spleen was investigated by electron microscopy. Unmyelinated nerve fibers in the capsulotrabecular and arterial systems were found to contain large and small granular and small agranular synaptic vesicles in their terminals and are thought to be sympathetic adrenergic in nature. They influence the contraction of the smooth muscle cells by diffusion innervation in these systems. These nerve terminals were also scattered in both the red and the white pulp. Pulp nerves wrapped by Schwann cells were further enclosed by myofibroblastic reticular cells. This condition revealed that the pulp nerves pass through the connective-tissue spaces of the reticular fibers, which contain elastic fibers, collagenous fibrils, and lamina densa-like materials of the usual basement laminae. One of the target cells for the pulp nerves is considered to be the myofibroblastic reticular cell in the reticular meshwork. Neurotransmitter substances released from the naked adrenergic nerve terminals travel through the reticular fibers and may play a role, by both close association innervation and diffusion innervation, in the contraction of reticular cells to expose the reticular fibers. At the exposed sides, connective-tissue elements of the reticular fibers are bathed with blood plasma, and the included naked nerve terminals, devoid of Schwann cells but with basement laminae of these cells, face free cells at some distance or are in close association with free cells, especially lymphocytes, macrophages, and plasma cells. The close ultrastructural relationship between the naked adrenergic nerve terminals and immunocytes strongly suggests that there is an intimate relationship between the immune system and the sympathetic nervous system through both close association innervation and diffusion innervation. Thus splenic adrenergic nerves of the guinea pig may play a triple role in 1) contraction of smooth muscle cells to regulate blood flow in the organ, 2) induction of the exposure of reticular fibers by contraction of the reticular cells in order to form a close relationship of the nerve terminals with the immunocytes, and 3) subsequent neuroimmunomodulation of the immunocytes.
通过电子显微镜对豚鼠脾脏的神经支配进行了研究。发现包膜小梁和动脉系统中的无髓神经纤维在其终末含有大小不等的颗粒状和小的无颗粒突触小泡，被认为本质上是交感肾上腺素能的。它们通过这些系统中的扩散性神经支配影响平滑肌细胞的收缩。这些神经终末也散布在红髓和白髓中。被施万细胞包裹的髓质神经进一步被肌成纤维网状细胞包绕。这种情况表明髓质神经穿过网状纤维的结缔组织间隙，这些间隙包含弹性纤维、胶原纤维和通常基底膜样的致密层状物质。髓质神经的靶细胞之一被认为是网状网络中的肌成纤维网状细胞。从裸露的肾上腺素能神经终末释放的神经递质物质穿过网状纤维，并可能通过紧密关联神经支配和扩散性神经支配在网状细胞收缩以暴露网状纤维方面发挥作用。在暴露的一侧，网状纤维的结缔组织成分被血浆浸润，包含的裸露神经终末，没有施万细胞但有这些细胞的基底膜，与游离细胞有一定距离或紧密相连，特别是淋巴细胞、巨噬细胞和浆细胞。裸露的肾上腺素能神经终末与免疫细胞之间紧密的超微结构关系强烈表明，通过紧密关联神经支配和扩散性神经支配，免疫系统与交感神经系统之间存在密切关系。因此，豚鼠脾脏的肾上腺素能神经可能在以下三个方面发挥作用：1）平滑肌细胞收缩以调节器官内的血流；2）通过网状细胞收缩诱导网状纤维暴露，以便神经终末与免疫细胞形成紧密关系；3）随后对免疫细胞进行神经免疫调节。
