2001 Fiscal Year Final Research Report Summary
The role of septohippocampal cholinergic system in hippocampal theta activity
Project/Area Number |
11610085
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
実験系心理学
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Research Institution | Fukuoka Prefectural University |
Principal Investigator |
KAMETANI Hideki Fukuoka Prefectural Univ. Dept. Human Sociol. Professor, 人間社会学部, 教授 (20167349)
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Project Period (FY) |
1999 – 2001
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Keywords | Hippocampus / Medial Septum / Theta activity / Microdialysis / Acetylcholine / Sleep-wakefulness / Rat |
Research Abstract |
It has been suggested that septohippocampal cholinergic system is involved in hippocampal theta activity. The present study was conducted to elucidate the role of cholinergic system to produce hippocampal theta using microdialysis coupled with simultaneous polygraph recording in rats. First, acetylcholine (Ach) release from dorsal hippocampus (HC), frontal cortex (FCTX), and striatum (STR) was measured to clarify the cholinergic activity during the sleep -wakefulness. The results showed profound state-dependent fluctuations in Ach output in these forebrain areas. In HC, Ach levels during waking with movement (active waking; AW) increased nearly 400 % compared to slow wave sleep (SWS). Rate of Ach release during paradoxical sleep (PS) was as high as that during AW. In contrast, Ach levels during waking without movement (quiet waking; σW) was significantly lower than those during AW and PS but higher than SWS. Similar results were obtained in FCTX and STR. Therefore, it can be concluded that Ach output increases during theta-related state such as active voluntary movement and PS. Second, several cholinergic drugs were infused into the medial septum and changes in hippocampal EEG were analyzed. Physostigmine and carbachol induced the increase in theta activity whereas cholinergic antagonist, atropine, blocked this increase. Therefore, a cholinoceptive mechanism in the medial septum might be involved in hippocampal theta activity. Based on these results, a functional role of septohippocampal cholinergic system and hippocampal theta were discussed.
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Research Products
(7 results)