1991 Fiscal Year Final Research Report Summary
Basic and Clinical Studies on Humoral Control of Sleep
| Project/Area Number |
01480279
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Psychiatric science
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| Research Institution | Shiga University of Medical Science |
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Principal Investigator |
KATO Nobumasa Shiga Univ Med Sci, Dept of Psychiatry, Associate Professor, 医学部, 助教授 (10106213)
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| Co-Investigator(Kenkyū-buntansha) |
TSUNASHIMA Koichi Natl Centre Neurol Psychiat, Div Men Tal Dis Res, Res Fellow, 神経センター・神経研究所, 研究員 (30197743)
IIDA Hideharu Shiga Univ Med Sci, Dept of Psychiarty, Assistant, 医学部, 助手 (50184354)
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| Project Period (FY) |
1989 – 1991
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| Keywords | DSIP / Dopamine / Serotonin / Growth hormone / Thyroid-stimulating hormone / Prolactin / Circadian rhythm / Thermoregulation |
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| Research Abstract |
The humoral control of sleep mechanisms was investigated in terms of 1) possible roles of delta sleep-inducing peptide (DSIP) as one of slow-wave promoting substances, and 2) secretary pattern of growth hormone (GH) during slow wave sleep (SWS).
A sensitive enzyme immunoassay (EIA) method for measuring DSIP in body fluids was developed in the laboratory. This method was unable to detect DSIP-like material in human and rat tissues. Plasma DSIP levels were measured throughout 24 h in healthy male subjects and diurnal variations of circulatory DSIP concentrations were found. Besides its known sleep-promoting effect, we found the thermoregulatory action of DSIP in rats. DSIP as well as its phosphorylated form (P-DSIP) was found to potentiate dopamine- or serotonin-induced hypothermia in rats at the ambient temperature. Pharmacological study showed this thermoregulatory action of DSIP was exerted via 5-HT 1A receptors. Zopiclone, one of non-benzodiazepine hypnotics was demonstrated to increa
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se DSIP contents in the rat brain dose-dependently. These findings may further present significant roles of DSIP in modulating sleep and sleep-related phenomena.
An ultra-sensitive EIA method of human GH was introduced to evaluate 24 h secretary pattern in normal condition and in sleep-deprived condition. The lowest level of basal plasma GH was as low as 10 pg/ml, which could be detected for the first time by this method. Twenty-four hour secretory rhythm of GH in normal and delayed sleep phase suggested the presence of ultradian rhythm in GH secretion. Prolactin and thyroid-stimulating hormone (TSH) were also measured in the same samples. Prolactin was found to be elevated during sleep and prolactin secretion appeared to be promoted after REM sleep. Furthermore, the relationship between hormone secretion and initiation of the first SWS was studied in more detail by frequent determinations of plasma GH and prolactin in 5-min intervals. GH secretion increased 10 min after the initiation of SWS, and the pattern of prolactin secretion was found to be almost identical with GH secretion. Namely, GH secretion, prolactin secretion and the first SWS processes were somehow synchronized one another with a short delay. TSH secretion had its own secretory pattern with higher values during night, which normally was inhibited by sleep. Less
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