大鼠投射到垂体后叶的加压素样免疫反应神经元与第三脑室室管膜及软脑膜的关系

本文运用WGA-HRP逆行标记与加压素免疫组织化学相结合的双标记方法,观察了大鼠投射到垂体后叶的加压素神经元在第三脑室周围的分布及其形态特点。发现双标记神经元主要分布在视前区平面、室旁核后大细胞亚核平面处第三脑室的背侧份、交叉上核平面处第三脑室的腹侧份。细胞为圆形、梭形、多角形和梨形。它们嵌入室管膜细胞之间,或紧贴室管膜下层,部分突起伸向第三脑室。在视上核主部和交叉后部,均见到较多的双标记细胞,主部细胞发出许多突起形成丛,伸向脑腹侧面,与蛛网膜下腔的脑脊液非常接近。作者认为,位于第三脑室周围和软脑膜下投射到垂体后叶的加压素神经元,与脑脊液非常接近,提示它们自脑脊液获得信息,调节垂体后叶加压素的释放,还可能向脑脊液中分泌加压素。

RELATIONSHIP BETWEEN THE POSTERIOR PITUITARY PROJECTING VASOPRESSIN-LIKE IMMUNOREACTIVE NEURONS AND THE EPENDYMA OF THE THIRD VENT-RICLE AND THE PIAMATER IN THE RAT

By combining WGA-HRP retrograde tracing and immunohistochemical methods,the characteristics of the vasopressin(VP)-like immunoreactive neurons, which project to the posterior pituitary were studied. They were located subependymally, and predominately along:(1) the dorsal wall of the third ventricle at the preoptic area and posterior magnocellular paraventricular nucleus levels, (2) the ventral wall of the third ventricle at the suprachiasmatic nucleus level, and (3) at the floor of the third ventricle. Four types of the cells could be distinguished. They were found to squeeze in between the ependymal cells, bring themselves very close to the cerebrospinal fluid (CSF),or to be situated in the subependymal layer, sending some of their processes into the ependyma. The double labelled neurons were also detected subpially in the supraoptic nucleus (SON) and the retrochiasmatic nucleus. A large number of dendrites from the neurons in the SON extended toward the CSF in the subarachnoidspace. In summary, the VP-like immunoreactive neurons which projected to the posterior pituitary were very close to the CSF. It is, therefore, proposed that these neurons may monitor changes in the CSF and adjust the secretion of VP in the posterior pituitary. They may also release VP directly into the CSF.