Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Ciudad de México, México.
Coordinación General de Servicios Experimentales, Microscopía Electrónica, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Ciudad de México, México.
PLoS One. 2023 May 26;18(5):e0286399. doi: 10.1371/journal.pone.0286399. eCollection 2023.
In humans, the pituitary gland is covered by a fibrous capsule and is considered a continuation of the meningeal sheath. However, in rodents some studies concluded that only the pars tuberalis (PT) and pars nervosa (PN) are enwrapped by the pia mater, while others showed that the whole gland is covered by this sheath. At PT the median eminence subarachnoid drains cerebrospinal fluid (CSF) to its cisternal system representing a pathway to the hypothalamus. In the present study we examined the rat pituitary capsule to elucidate its configuration, its physical interaction with the pituitary border and its relationship with the CSF. Furthermore, we also revisited the histology of the pituitary cleft and looked whether CSF drained in it. To answer such questions, we used scanning and transmission electron microscopy, intracerebroventricular infusion of Evan´s blue, fluorescent beads, and sodium fluorescein. The latter was measured in the pars distalis (PD) and various intracranial tissues. We found a pituitary capsule resembling leptomeninges, thick at the dorsal side of the pars intermedia (PI) and PD, thicker at the level of PI in contiguity with the PN and thinner at the rostro-ventral side as a thin membrane of fibroblast-like cells embedded in a fibrous layer. The capsule has abundant capillaries on all sides. Our results showed that the CSFs bathe between the capsule and the surface of the whole gland, and ciliate cells are present in the pituitary border. Our data suggest that the pituitary gland intercommunicates with the central nervous system (CNS) through the CSF.
在人类中，垂体被纤维囊所覆盖，被认为是脑膜鞘的延续。然而，在啮齿动物中，一些研究得出结论，只有结节部（PT）和神经部（PN）被软脑膜包裹，而另一些研究则表明整个腺体都被这种鞘所包裹。在 PT 处，正中隆起蛛网膜下腔将脑脊液（CSF）排入其脑池系统，代表了通往下丘脑的途径。在本研究中，我们检查了大鼠垂体囊，以阐明其结构、与垂体边界的物理相互作用及其与 CSF 的关系。此外，我们还重新研究了垂体裂的组织学，并观察了 CSF 是否在其中排出。为了回答这些问题，我们使用了扫描和透射电子显微镜、脑室内伊文思蓝、荧光珠和荧光素钠的灌注。后者在远侧部（PD）和各种颅内组织中进行了测量。我们发现了一种类似于软脑膜的垂体囊，在中间部（PI）和 PD 的背侧较厚，在与 PN 相邻的 PI 水平较厚，在头腹侧较薄，呈一层嵌入纤维层的成纤维细胞样细胞的薄膜。囊的所有侧面都有丰富的毛细血管。我们的结果表明，CSF 浸润在囊和整个腺体表面之间，纤毛细胞存在于垂体边界处。我们的数据表明，垂体通过 CSF 与中枢神经系统（CNS）进行交流。
