Morphological Changes in Vasopressin-immunoreactive Neurons in the Hypothalamus of the Aged Rats / 체질인류학회지

The role of neuropeptides in the central nervous system (CNS) has received increasing attention. Numerous peptide molecules are found in the mammalian CNS and many of them are thought to act as either neurotransmitters or neuromodulators. The neuropeptides found in high concentration in the hypothalamus include vasopressin (VP), vasoactive intestinal polypeptide, somatostatin, and oxytocin. The main approches to assess the involvement of neuropeptides can be focused on functions affecting the aging of the brain. Morphological aging of the CNS has been characterized by degenerative changes of fiber connections and cell loss, although degeneration does not always occur to the same extent throughout various parts of the brain and, moreover, varies for different cell types. Despite of many studies in VP containing neurons , there exist discrepancies in results about the changes of aged rat brain. The aim of the present study is, therefore, to investigative possible changes in the number and morphology of VPimmunoreactive neurons with aging in each area of the hypothalmus of the aged rats. As a result, the number of VP-immunoreactive neurons was decreased in hypothalamus nucleus of aged group. Especially, in VP-immunoreactive neurons of hypothalamus, the size of neuronal cell body and nuclei in aged group is larger than in young group and the fiber density of immunoreactivity neurons of median eminance (ME) in aged group is stronger than in young group. But, the total number of VP-immunoreactive neurons in the suprachiasmatic nucleus (SCN) of the aged group is larger than in the young group. These studies indicate the involvement of VP-immunoreactive neurons in aging process of hypothalamus, and aging process may affect the synthesis of VP in the neurons of hypothalamic nuclei. Whereas, in VP expression, aging process induces an enlargement of the cell size of surviving neurons to compensate.

Effect of Maternal Thyroxine Treatment on the Postnatal Development of Brain-derived Neurotrophic Factor-containing Purkinje Cell in Fetal Alcohol Effects in the Rat Cerebellum / 체질인류학회지

Maternal alcohol abuse is thought to be the common cause of mental retardation. Even moderate maternal alcohol consumption may produce fetal alcohol effects with behavioral and learning difficulties, if the drinking is associated with malnutrition. Especially, continuous alcohol consumption during critical period of brain development is very likely to produce fetal alcohol effects. The aims of this study are to investigate whether exogenous thyroxine treatment to alcohol -fed dams may ameliorate the detrimental effects of alcohol on the postnatal development of BDNF -containing Purkinje cell of the cerebellar cortex of the offspring. The morphological features of the growth and maturation were observed at 0, 7, 14, 21, 28 postnatal days via immunohistochemistry. In addition, electron microscopic finding of BDNF -containing Purkinje cell at P14 was also examined. Time -pregnant rats were divided into three groups. Alcohol -fed group received 35 calories of liquid alcohol diet daily from gestation day 6; control pair -fed group was fed a liquid diet in which dextrin replaced alcohol isocalorically; alcohol +/-T4 group received 35 calories liquid alcohol diet and exogenous thyroxine subcutaneously. As a result, a similar developmental pattern of BDNF -immunoreactive Purkinje cells was observed in control pair - fed and alcohol+/-T4 group on and after P14. These cells of alcohol -fed group showed immature features. Single -layer arrangement of these cells in alcohol -fed group was not completely achieved throughout postnatal life. Electron microscopic observations of BDNF -immunoreactive Purkinje cells at P14 revealed large nucleus, small cytoplasm, small amount of ribosomal collection and rudimentary cytoplasmic organelles in alcohol -fed group. The morphology of BDNF -immunoreactive Purkinje cell in alcohol +/-T4 group was similar to that in control pair -fed group. It was characterized by numerous short segments of rough endoplasmic reticulum, many of which showed a tendency of parallel alignment that suggested an attempt at Nissl body configuration. The cytology of Golgi complexes was also found within the cytoplasm in perinuclear location. Those observed differences of postnatal maturation patterns between alcohol -fed and alcohol +/-T4 group may indicate the beneficial effects on the postnatal development of BDNF -containing Purkinje cells in cerebellar cortex in the pups of thyroxine -treated alcohol -exposed dams. These results suggest that the increase of BDNF synthesis during early postnatal life caused by maternal administration of exogenous thyroxine may ameliorate fetal alcohol effects as a result of the dysthyroid state following maternal alcohol abuse.

Study on intertwin growth discordancy / 대한주산의학회잡지

No abstract available.