碩士 / 國立陽明大學 / 神經科學研究所 / 95 / Neuronal migration is essential for the establishment of normal brain organization during development. Hippocampus is the key brain region for learning and memory. Malformation of hippocampus will result in mental retardation and epilepsy in children. Kv3 channels, a group of voltage-gated K+ (Kv) channels, are required for repetitive firing at high frequency in mature neurons. Recent studies indicated that Kv3 channels were expressed in migrating neurons during chick hindbrain formation. To investigate the role of Kv3 channels in neuronal migration, a useful first step was to map their distributions in rat hippocampus at various developmental stages by immunohistochemistry. We found that Kv3.4 was expressed in new born neurons migrating radially from the ventricular zone to the primordial plexiform layer during the embryonic day E12.5~E15.5. In addition, Kv3.4 appeared in a stream of GABAergic interneurons, which originate from the striatum, migrate tangentially via cerebral cortex, and finally arrive at hippocampus during E15.5~E19.5. Interestingly, Kv3.4 disappeared from both radially and tangentially migrating neurons soon after they arrived at the destinations. In summary, Kv3.4 was transiently expressed in both the radially and tangentially migrating neurons during the development of hippocampus. Our data suggest that dysfunction of Kv3.4 may result in mental retardation and epilepsy in children, due to the malformation of hippocampus during pregnancy. In contrast, Kv3.3 was expressed in parvalbumin- and somatostatin-positive interneurons located in the pyramidal cell layer since the postnatal day 9. These Kv3.3(+) neurons also co-expressed Kv3.1b or Kv3.2. These results suggest that Kv3.3, as well as Kv3.1b and Kv3.2, may protect us from epilepsy resulted from neuronal over-excitation in the hippocampus since the early postnatal stage.
| Identifer | oai:union.ndltd.org:TW/095YM005291004 |
| Date | January 2007 |
| Creators | Ming-Xin Lin, 林明勳 |
| Contributors | Meei-Ling Tsaur, 曹美玲 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 61 |
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