| Project/Area Number |
10557009
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Miyazaki Medical College |
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Principal Investigator |
KANNAN Hiroshi Miyazaki Med. College, Dept. Physiol., Professor, 医学部, 教授 (00049058)
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| Co-Investigator(Kenkyū-buntansha) |
KUWAKI Tomoyuki Chiba University, Graduate School of Medicine, Dept. Autonomic Physiology, Professor, 大学院・医学研究院, 教授 (80205260)
KANITAKE Takato Miyazaki Med. College, Dept. Physiol., Assistant, 医学部, 助手 (20234461)
HANAMORI Takamitsu Miyazaki Med. College, Dept. Physiol., Associate Professor, 医学部, 助教授 (20041858)
KATO Kazuo Miyazaki Med. College, Dept. Physiol., Assistant (80284834)
ISHIZUKA Yuta Miyazaki Med. College, Dept. Psychiatry, Lecturer (20264377)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | autonomic nervous activity / cardiovascular system / awake animals / renal excretory function / hypothalamic single unit activity / unit recording electrode / micro-movable manipulator / multiple data processing / 遺伝性多飲マウス / アンジオテンシンII / 循環系応答 / 飲水行動 / 動脈圧受容器反射 / 自由行動・意識下実験 / マウス / 心血管系反応 / 神経ペプチド / ニューロメジン / グレニン / 病態モデル / 慢性実験 / ノックアウト / トランスジェニック |
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| Research Abstract |
Techniques to create transgenic organisms or animals with targeted mutations ('knockout' mutants) have become increasingly important tools in neuroscience over the past few years. As always, new techniques, besides providing new tools to investigate problems or to test hypothesis, also give rise to unforeseen difficulties which take time to overcome. So far, most genetic animals constructed have been mice, whose brains are quite hard to manipulate (e.g., stimulation of discrete areas and unit recordings are difficult to achieve with mice in the freely-moving condition). Therefore, we devised the following procedures to perform physiological studies in mice.
(1) Construction of a metabolic cage for small animals such as mice that is regulated by means of a personal computer and allows the experimenter to record cardiovascular parameters without disturbing the animal's movement or twisting the recording lead wires and vascular catheters. For studies involving the central nervous system, i
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t is often desirable to record, stimulate, and/or deliver drugs to discrete regions of the brain. Although this can be carried out somewhat routinely in anesthetized preparations, it has long been recognized that anesthesia may confound the interpretation of studies of the central regulation of cardiovascular function and body fluid balance. Therefore, it was necessary to develop a procedure for carrying out similar experiments in animals that are awake. The floor of the plastic cage was upturned to release the twist of the cable leads and catheters as the animal moved ; this was performed by signals detected with an inertia sensor.
(2) A system for simultaneously displaying multiple parameters on a monitor screen with variable sweep speed was constructed to elucidate the long-term trend of signals whereby the amplitude of the action potentials and the noise levels provide cue information about the relative location of the recording electrodes and neurons under study. This system is useful to evaluate the advancement of the recording electrodes. In addition, computer programs for multi-variable analysis and three-dimensional illustrations were constructed.
(3) Recording methods for single-unit activity in freely-moving animals have been improved as follows : (a) First, we improved the recording electrodes, which are made of stainless micro wires coated with Formvar. We found that electrodes with high impedance are suitable to record single-unit activity with a high signal-to noise ratio efficiently. Therefore, stainless micro wires were insulated several times with a thin Epoxy solution, (b) Second, a miniature skull-mounted microdrive that permits discrete dorsoventral movement of the fine-wire recording electrodes was constructed to advance the fine-wire electrode as well as to isolate single-unit activities, (c) Third, a head-mounted voltage follower was employed to condition and stabilize the neuronal signals prior to transmission or for further signal processing. These methods were followed in order to integrate these three elements into a working electrophysiological recording procedure in freely-moving small animals. Less
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