电击足底对大鼠下丘脑视上核及室旁核加压素样细胞的影响

本实验用特异性兔抗精氨酸加压素血清对正常和受到不同时间电击足底刺激的雄性大鼠下丘脑组织切片作了免疫细胞化学染色,观察了视上核和室旁核内加压素样细胞的形态学变化,并以显微分光光度计和显微图象分析仪列这些细胞内加压素样物质的相对含量和细胞截面积的变化进行了研究,以期对这种应激条件下下丘脑加压素释放与否问题有一较直观的了解。结果显示,电击组与对照组相比,视上核和室旁核细胞内加压素样物质减少,细胞胞体缩小。早期下丘脑垂体束细串珠样纤维增多,后期减少。正中隆起内带加压素样纤维染色略变淡,外带内细串珠状加压素样纤维增加。视上核和室旁核某些加压素样细胞的树状突起的变化较为特殊。一些向第三脑室侧壁和脑底面神经胶质板投射的树突在电击组染色依旧很深,并出现了许多大的串珠样结构,提示这些树突有向第三脑室和蛛网膜下腔分泌加压素样物质的可能。上述结果说明电击足底刺激视上核和室旁核细胞的神经分泌机能增强,可能通过下丘脑垂体束向垂体后叶,经正中隆起外带门脉血管向垂体前叶以及通过树突向脑脊液中释放加压素样物质增加。

INFLUENCE OF FOOT-SHOCK ON VASOPRESSIN-LIKE CELLS IN SUPRAOPTIC AND PARAVENTRiCULAR NUCLEI OF HYPOTHALAMUS IN RAT

Normal and foot-shocked (FS) (with different time duration) rat's hypothalamic tissue sections were stained immunocytochemically with rabbit anti-arginine vasopressin (VP) serum. The morphological variations of VP-like cells in supraoptic (SON) and paraventricular (PVN) nuclei were observed under light microscope. The relative contents of VP-like materials in the section area of those cells were investigated with microscopic photometer (OPTON) and microscopic image analysis system (KONTRON) to reveal whether hypothalamic VP-like materials was release or not under this kind of stress condition.The results show that, compared with the control group, the VP-like materials in SON and PVN cells of the foot-shocked animals are decreased and the size of those cell bodies is reduced. Meanwhile, the number of VP-like beaded-fibers in hypothalamo-neurohypophyseal tract is increased in the early stage (5 minute FS group) and decreased later (30 minute FS group). The number of VP-like beaded-fiber in the external zone of median eminence is increased in all FS groups. The morphological variations of some dendrites are distinct. The density of VP-like materials in those dendrites that projected towards the third ventricle and the basal surface of the brain remains high in FS groups. Besides, there appeared a few large beaded-like structures. These phenomena suggest that it is possible for these to secrete VP-like materials into cerebrospinal fluid. It is concluded that the secreting activity of VP-like cells in SON and PVN is accelerated under FS stress and VP-likematerial is released by these cells to blood stream via hypothalamo-neurohypophysis fibers and, probably, to adenohypophysis through portal veins and to cerebrospinal fluid via dendrites.