| Project/Area Number |
11670074
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Fukushima Medical University School of Medicine |
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Principal Investigator |
KAYAMA Yukihiko Fukushima Medical University Sch.of Med. Department of Physiology, Professor, 医学部, 教授 (30035224)
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| Co-Investigator(Kenkyū-buntansha) |
KOYAMA Yoshimasa Fukushima Medical University Sch.of Med. Department of Physiology, Associate Professor, 医学部, 助教授 (80183812)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | acetylcholine neuron / laterodorsal tegmentum / hypothalamus / prolactin / orexin / paradoxical sleep / wakefulness |
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| Research Abstract |
We have investigated neural mechanisms of sleep and wakefulness mainly by means of recording neuronal activity in the brainstem, which may have some relation with another center for sleep control, the hypothalamus. The aim of this project is to see whether there are direct functional connections between brainstem cholinergic neurons and the hypothalamus, and which transmitter may be utilized in the connection.
Effects of electrical stimulation of the preoptic area, posterior hypothalamus, thalamus or frontal cortex was observed while single neuronal activity of cholinergic neurons was recorded in the laterodorsal tegmental nucleus. Both antidromic and orthodromic responses were evoked most frequently when the preoptic area was stimulated. The result suggests that the preoptic area is the most important structure both as a receiver of the cholinergic projection and as a server to influence cholinergic neuronal activity.
As a candidate of transmitter of hypothalamic neurons acting on the brainstem cholinergic neurons, effects of prolactin, which had been shown to increase paradoxical sleep when infused intraventricularly, was examined on neuronal activity of the cholinergic neurons. A small amount of prolactin was ejected locally with air pressure from drug electrode attached in close vicinity of tip of the recording electrode. Only small number of the cholinergic neurons were excited by the prolactin. The result was not due to bad skill of the experiment, since orexin ejected similarly excited the cholinergic neurons dose-dependently for 1 to several minutes.(Orexin is in feeding center neurons of the lateral hypothalamus.) The experiments thus show that action of prolactin on the brainstem cholinergic neurons is not so strong as we expected at the beginning of this project, but they receive some strong influence from the hypothalamus ; orexin is surely one of transmitters of the hypothalamic neurons acting on the brainstem neurons.
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