| Summary: | 博士 === 國立臺灣大學 === 解剖學研究所 === 93 === The mammalian epiphysis (pineal gland) and neurohypophysis (posterior lobe of pituitary gland) originated ependymal cell of the roof and the floor of the third ventricle from central nerve canal respectively. In certain species, the pineal gland contains neurons and/or neuron-like peptidergic cells, The nature and cytological features of these neuronal cells, in addition to the pinealocytes, interstitial cells need to be classified. Posterior pituitary consists of pituicytes, the modified astrocytes and the predominant cellular type in the neurohypophysis, Development and the role of pituicytes still has many aspects remain to be clarified so far; and axons, originating from neurons in supraoptic and paraventricular nuclei synthesizing vasopressin and oxytocin. The neuronal intermediate filaments include not only the neurofilament triplet proteins but also α-internexin and peripherin. Both α-internexin and peripherin are expressed in the neurons of CNS and PNS during development. In adult, peripherin is found abundantly in the neurons of peripheral nervous system, and α-internexin is present mainly in the neurons of central nervous system. We employ neuronal intermediate filaments as probes into developing central neural glands of mouse.
Results from the immunohistochemistry and Western blot indicated that, not only pineal but also posterior lobe of pituitary, both α-internexin and peripherin were start constants expression at P21 and the neuronal triplets proteins were steady display at P90 for pineal gland and at P30 for neurohypophysis. α-internexin and peripherin are colocalized in the perikarya of some cells in the different age of mouse pineal gland. In aged (P360) mouse pineal gland, the expression of neuronal intermediate filaments is augmented as compare with that of the other adult stages. Results from the in situ hybridization and RT-PCR, showed that the number of the mRNA labeling cells of α-internexin and/or peripherin at P7 were the most numerous among all the age stages in mouse pineal. Taken all data together, we concluded that α-internexin-mRNA positive cells are generally more numerous than peripherin-mRNA positive cells during development, and therefore, we suggested that α-internexin-mRNA positive cells were more widely spread than peripherin-mRNA positive cells in pineal gland. In the neurohypophysis, by the in situ hybridization, the mRNAs of α-internexin and peripherin were unexpectedly found in the pituicytes. α-Internexin and NFM mRNAs were also detected in neurohypophysis of developing mouse by mean of RT-PCR. More studies are needed to elucidate the neuronal nature of these specialized glial cells, pituicytes in the neurohypophysis.
In summary, neurohypophysis is earlier than epiphysis not only in start developing time but also in mature period. The phenomenon may cause by more variety and complexity of pineal gland than posterior lobe of pituitary. That needs more investigation about both central glands existing peripherin.
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