Changes of TH Immunoreactivities and Melatonin Treatments in the Rat Brain by Chronic Stress / 대한해부학회지

These experiments were performed to investigate the effect of saline, melatonin, stress, stressedmelatonin on TH immunoreactivity in rat brain. The animals were injected with melatonin (1 mg/kg, i.p.) after electric shocks for 15days. The results were as follows; 1. TH immunoreactive neurons in brain (the number of staining neuron & the stain intensity in LC and parietal cortex, the stain intensity in arcuate nucleus and median eminence of cerebral cortex) were significantly increased in stressed group compared with all the other groups. 2. TH immunoreactive neurons in brain (the number of staining neuron & the stain intensity in LC and parietal cortex, the stain intensity in arcuate nucleus and median eminence of cerebral cortex were significantly decreased in stressed-melatonin treated group compared with stressed group but were significantly increased compared with the other groups. These experiments indicate that its increase is inhibited by melatonin treatment even though, stress increases TH immunoreactivity in LC and Par.

THE ESTABLISHMENT OF MODEL FOR PRIMARY CULTURED TANYCYTES / 解剖学报

Objective Tanycytes(TAs) is a specialized eppendymal glia that locates mostly in the ventral lateral wall of the ventricle III and median eminence(ME).Due to its peculiar location and directly exposure to the cerebrospinal fluid,blood,neuroendocrine hormones and neurons,tanycytes play an important role in the brain barrier system,brain-CSF neurohumoral circuit and immune-neuroendocrine network.They maintain immature characters during the adulthood and have naturally conducted the neuroregeneration process in the adult hypothalamus of mammal animals.This research was designed to identify tanycytes(TAs) in postnatal 7 days of Wistar rats and then establish the cell model of TAs for further study.Methods Tanycytes of postnatal 7 days of Wistar rats were identified by the immunohistochemical technology using glial fibrillary acidic protein(GFAP) and vimentin(VIM),which are the intermediate filament markers of glia cells.The qualitative analysis was performed by the NADPH-d stain of nitric oxide sythenase(NOS).Primary TAs model was established by the cell culture technique and identified by the same methods as in vivo.Results Primary cultured TAs expressed VIM,GFAP and NOS which was identical with those in vivo.Conclusion Cell model of TAs from postnatal 7days of Wistar rats in vitro has been established and TAs could be used as a proper substrate for transplanting.

THE ULTRASTRUCTURAL CHARACTERISTICS AND THEIR FUNCTIONAL SIGNIFICANCES OF THE ARCUATE NUCLEUS AND MEDIAN EMINENCE / 解剖学报

The ultrastructural characteristics of the arcuate and median eminence in the rat have been studied by means of folmaldehyde-osmic acid fixation method. The observations showed that there are two kinds of neurons (dark and light) in the arcuate nucleus which might be responsible for producing both dopamine and releasing hormones. The tanycytes of the ependyma of the third ventricle run longitudinally through various zones of the median eminence and reach the perivascular space of the portal capillaries. The neurosecretory substance-containing nerve terminals may travel between ependymal cells or end around the basal membrane of the capillaries of the median eminence, even keep close to the endothelial fenestrae of "open-type capillary". The axo-somatie and axo-dendritic synapses are formed at the soma and dendrites of neurons of the arcuate nucleus. Both agranular type and granular type axo-axonic synapses are encountered in the fibrous zone of the median eminence. There are also synaptic connections between the basic processes and the large granular vesicles containing nerve terminals in the palisade zone of the median eminence. The ultrastructural characteristics mentioned above suggest that (1) the releasing (or inhibiting) hormones of the hypothalamus might be released into the portal capillaries from nerve terminals directly or into the cerebro-spinal fluid of the third ventricle and then uptaken by the tanycytes, and transported to the portal capillaries by their processes. (2) each step of synthesis, storage, transport and release of the releasing (or inhibiting) hormones could be regulated by nervous mechanism