노화흰쥐의 시상하부에서 vasopressin과 vasoactive intestinal polypeptide 면역반응 신경세포의 형태학적 변화

Abstract

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 are thought to act as either neurotransmitters or neuromodulators. The neuropeptides found in high concentration in the hypothalamus include vasopressin(VP), vasoactive intestinal polypeptide (VIP), somatostatin(SOM), oxytocin(OXY). 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 neurons VP and VIP containing, 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 VP and VIP-immunoreactive neurons with aging in each area of the hypothalmus of the aged rats. As a result, the number of VP and VIP-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. Moreover, the VIP-immunoreactive neurons in Arc of aged group is significantly smaller than in the young group and no change in the size of neuronal cell body and nuclei in aged group. These studies indicate the involvement of VP and VIP-immunoreactive neurons in aging process of hypothalamus, and aging process may affect the synthesis of VP and VIP in the neurons of hypothalamic nuclei. Whereas, in VP expression, aging process induces an enlargement of the cell size of surviving neurons to compensate.