JAPANESE JOURNAL OF BIOMETEOROLOGY
Online ISSN : 1347-7617
Print ISSN : 0389-1313
ISSN-L : 0389-1313
Volume 28, Issue 2
Displaying 1-8 of 8 articles from this issue
  • Y MORITA, T NAKAMURA, K UCHIDA
    1991 Volume 28 Issue 2 Pages 51-56
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    The photosensory pineal organ of poikilotherm animals has an important role in the biological rhythms. Neuronal mechanisms to process photic information were analyzed on the basis of electrophysiological studies. Achromatic and chromatic systems were referred to be responsible for the intensity and wavelength information processing, respectively. For the achromatic system two types of neuronal networks were proposed. In the first type, photoreceptors make synapses directly with an achromatic ganglion cell, and in the second type, the interneuron participates in the processing. In the latter case, two models were introduced. (1) An interneuron integrates the signals from photoreceptors having different sensitivities and different kinds of transmitters. The interneuron transmitts the information to the ganglion cell. (2) An achromatic ganglion cell receives the signal from photoreceptors which are affected by other photoreceptors having higher sensitivity through an interneuron. For the chromatic process, photoreceptors having high sensitivity at middle wavelengths activate a chromatic ganglion cell through an interneuron, while UV-sensitive photoreceptors directly inhibit the ganglion cell.
    Through these neuronal networks in the pineal organ, the daily and annual rhythm in photic environment may be converted to the biological rhythm.
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  • —Relation to human sleep rhythm—
    Ken-ichi HONMA
    1991 Volume 28 Issue 2 Pages 57-65
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    In rats, circadian rhythms in locomotor activity are regulated by a pacemaker (s) in the suprachiasmatic nucleus (SCN) which entrains to light-dark cycles. However, locomotor rhythms in the circadian domain appear under restricted daily feeding or chronic treatment with methamphetamine in rats with bilateral SCN lesions. These SCN-independent circadian rhythms do not entrain to light-dark cycle but to restricted daily feeding or periodic forced activity, and interact with the SCN-dependent circadian rhythm with predictable manners from the oscillation theory. On the other hand, the circadian system in human is unique for its multioscillator characteristics. The circadian rhythm in deep body temperature has common properties to the SCN-dependent circadian rhythm in rats, while properties of the circadian rhythm in sleep and wakefulness are different from the SCN-dependent circadian rhythm in many aspects, but rather similar to the SCN-independent rhythm, especially to the methamphetamine-induced rhythm. The interaction between the SCN-dependent and -independent circadian rhythms in rats is a good animal model for the human circadian system.
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  • [in Japanese], [in Japanese], [in Japanese]
    1991 Volume 28 Issue 2 Pages 67-76
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1991 Volume 28 Issue 2 Pages 77-83
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • O KASHIMURA, Y YANAGIDAIRA, A SAKAI, G UEDA
    1991 Volume 28 Issue 2 Pages 85-93
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    The present study was conducted to examine the sympathetic nervous activities, urinary catecholamine metabolitites, induced by running exercise in exercise-trained rats and chronic cold exposure in cold acclimated rats. The rats were randomly divided into the warm acclimated (WA, n=20), cold acclimated (CA, n=20) and exercise trained (ET, n=20) groups. ET rats were trained by running on a treadmill 1 hour daily, 6 days a week for a period of 8 weeks at about 35 m/min. Analysis of the urinary catecholamine metabolites, VMA and HVA, was performed by a high performance liquid chromatography. It was shown that when the animals underwent a cold exposure test at 5°C for 1 hour, oxygen consumptions ( VO2) in WA rats increased only slightly, whereas VO2 in ET and CA rats increased very markedly. It was found that increases of the urinary VMA and HVA excretions by the treadmill exercise in ET rats was significantly lower than that obtained by cold exposure in CA rats. The rise in colonic temperature was significantly 3-fold higher with exercise running for 1 hour in ET rats than with chronic cold exposure in CA rats. Exercise training showed to suppress brown adipose tissue's weight (BAT) . It has been suggested exercise training-induced hyperthermia and norepinephrine (NE) secretion would be an antagonistic adaptation of BAT nonshivering thermogenesis. In conclusion, the present study indicates that the improved capacity for cold-induced thermogenesis in the ET group may not be ascribed to enhanced nonshivering thermogenic response to NE.
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  • F YAMAZAKI, N KONDO, H IKEGAMI
    1991 Volume 28 Issue 2 Pages 95-106
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    This study was conducted to determine the roles of central and peripheral mechanisms of sweating during exercise. Six healthy males each performed 40-min bicycle exercise at 500, 700 and 900 kpm/min at ambient temperature of 25°C (45%RH) . Rectal temperature (Tre), mean body temperature (Tb), mean skin temperature, local sweat rate, frequency of sweat expulsions, etc. were measured. The following results were obtained: 1) Slopes of relationship between local sweat rate and body temperature changed with a breaking point at specific temperature (Tre and Tb were about 37.7°C and 36.8°C, respectively) during exercise. 2) The rate of increase in mean skin temperature peaked at the above breaking point. 3) With the increase in work rate, the local sweat rate for a given body temperature (Tre, Tb) became higher. 4) The sensitivity of central sudomotor and sweat gland decreased when mean body temperature exceeded 36.8°C. 5) With the increase in work rate, central sudomotor activity was enhanced, but no distinct change could be detected in sweat gland activity. It was concluded that a remarkable change occurs in the central and peripheral mechanisms for sweat regulation at a mean body temperature of about 36.8°C during exercise.
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  • M NAKASHIMA, A SAITO, K ENDO, K MATSUBATASHI
    1991 Volume 28 Issue 2 Pages 107-115
    Published: August 01, 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    Kyoto University Medical Research Expedition to Xixabangma 1990 (KUMREX'90) carried up a retino-camera (CR4-45NM, CANON) to the Base Camp (BC 5, 020m) of Mt. Xixabangma (8, 027m) to observe the incidence of the high altitude retinal hemorrhage (HARH) . As the result, very high incidence of HARH among Himalayan-Newcomer (NC) s was observed. Binocular HARHs were observed among 90% of NCs climbed above 6, 000m. Whereas it was observed only among 53% (monocular) (binocular; 21%) of Himalayan-Experienced (HE) s climbed to the top. About 80% of NCs revealed mild HARH already on the arrival to BC, whereas only 13% of HEs did it. None of them with HARH complained any symptoms. This phenomenon seems to be not illness but normal human response to high altitude.
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  • 1991 Volume 28 Issue 2 Pages 124
    Published: 1991
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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