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Volume 25 (1975)
- Issue 6 Pages 665-
- Issue 5 Pages 563-
- Issue 4 Pages 401-
- Issue 3 Pages 241-
- Issue 2 Pages 93-
- Issue 1 Pages 1-
Volume 25, Issue 5
Displaying 1-9 of 9 articles from this issue
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Seiki HORI, Heikichiro IHZUKA, Akira INOUYE1975 Volume 25 Issue 5 Pages 563-573
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIn studies of heat tolerance in man, a hot bath has been sometimes used as heat stress. Sweating under water is not used for dissipation of heat, thus, assessment of heat tolerance with hot water bath methods is expected to be considerably different from that with the hot air method. Applying our indices methods for assessment of heat tolerance, therefore, the hot water bath method as a heat tolerance test was compared with that of exposure to hot air. The physiological responses to heat and heat tolerance were examined in 8 male college students in a hot air environment and in hot water at 39°C and 39.5°C. After staying for 30min in a climatic chamber with a temperature of 30°C D. B. with 70% relative humidity, sweating in air was produced by immersion of both legs to just below the knees into a 42°C water bath with stirring. Each subject was then immersed into a hot water bath of 39°C or 39.5°C up to the neck for 30min after 30 minutes' rest. Experiments on another group of 6 male students were made with hot bath of 38°C. Sweat rate and sweat Na concentration in an air environment were fairly well correlated with those in hot baths, while increase in rectal temperature was poorly correlated with that in hot baths. When assessed with our indices method, heat tolerance evaluated in an air environment did not always run parallel with that in hot baths. Such a discrepancy in heat tolerance assessed in hot air and in hot water appears to be explained chiefly by unusefulness of sweat produced under water for cooling the body in hot baths.View full abstractDownload PDF (1010K) -
Akihiro KUROSHIMA, Tomie OHNO, Osamu HAYAMI, Ikuko FUJITA1975 Volume 25 Issue 5 Pages 575-584
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffect of a high-fat diet (HF) containing 50% fat by calorie on metabolic responses to swimming exercise at 32°C or 25°C for 30min in rats was investigated. HF produced significant elevations of blood free fatty acid (FFA) and ketone body concentrations at rest. Swimming at 32°C produced similar increases in blood FFA of both a standard diet (SD) and HF groups. Swimming at 25°C caused a greater rise of blood FFA level in SD group, while there were no significant changes in HF group. Blood ketone body concentration showed similar increases at both 32°C and 25°C in SD group, while in the HF group it did not increase at either 3°C2 or 25°C. In the fasting state for 18hr, swimming at 32°C resulted in significant increases in blood FFA levels in both groups, although the extent of increment was smaller in the HF group. Blood ketone body did not increase significantly in both groups. There was a significant positive correlation between blood FFA and ketone body levels when the results were combined at rest and after exercise in both groups in the fed state, while such a relation was not observed in the fasting state. Swimming induced significant increases in blood lactate concentrations, however, the extent of increment was markedly greater in swimming at lower temperatures and in the HF group.
These results suggest that HF is not necessarily favorable for the exercise function because HF feeding causes less increments of blood FFA and ketone bodies and more lactate production in response to exercise.View full abstractDownload PDF (950K) -
Norio AKAIKE, Masayasu SATO1975 Volume 25 Issue 5 Pages 585-597
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSImmediately after application of procaine or lidocaine to the surface of the tongue a transient response occurs in the glossopharyngeal nerve, while a depolarization of a few mV associated with an increase in the input resistance was observed in taste cells. When applied to the tongue for a long time, procaine and lidocaine depressed responses in the glossopharyngeal nerve to chemical stimulation of the frog tongue. The depressant effect is strongest on quinine response, next on responses to salts, and weakest on response to acid. Under the action of the local anesthetics both the magnitude of depolarization and the amount of input resistance change in taste cells, produced by stimulation by various chemicals, are small compared with those observed in normal cells. The action of anesthetics on the depolarization in taste cells is also strongest on quinine response and weakest on acid response. The results indicate that the local anesthetics exert a depressant action on taste cells by inhibiting changes in the membrane conductance and generation of depolarization, which are produced by chemical stimuli and are responsible for impulse initiation at sensory nerve terminals.View full abstractDownload PDF (1385K) -
Kiichiro ABE1975 Volume 25 Issue 5 Pages 599-604
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe isolated cells of rabbit adrenal glands were separated by the method of sedimentation at a linear gradient of albumin concentration and incubated with 14C-cholesterol. The corticosterone and cortisol produced by the separated cells were fractionated by thin-layer chromatography and the radioactivities in these steroids were measured. The more rapidly sedimenting cells showed a greater ratio of cortisol production to corticosterone production than the more slowly sedimenting cells. This phenomenon is not due to the decrease of corticosterone production per cell by the former, but to the increase of cortisol production per cell. These results suggest that the rabbit adrenal cortex may be composed of the cells that produce corticosterone and cortisol in different ratio, i. e., physiologically heterogeneous cells.View full abstractDownload PDF (567K) -
Yasuo WADA, Masayosi GOTO1975 Volume 25 Issue 5 Pages 605-620
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of external pH on the electrical and mechanical properties were investigated on the bullfrog atrium under voltage-clamped and unclamped conditions with double-gap method in order to elucidate the principal site of pH action. On rising the pH (5.3-8.3) a marked positive inotropic effect and an increase in rate of rise of action potential were produced with a shortening of the plateau duration. The potassium contracture was also augmented. Under voltage-clamped conditions, fast (If) and slow inward currents (Is) as well as delayed outward current were enhanced indicating a definite action of pH on the surface membrane. Is-dependent and independent contractile tensions in response to a small (70mV, 0.2sec) and large depolarizing pulses (200mV, 1.0 sec) were both strengthened.
Excess caffeine (20mM) Ringer solution augmented the effects of pH, while Ca-free La (1mM) Ringer solution abolished, suggesting a minor role of the sarcoplasmic reticulum in the pH effects. A contracture in Na-free high Ca (80mM) solution was enhanced by lowering external pH. This effect was eliminated after DNP (2mM) which affects the mitochondria.
These results indicate that the changes in external pH act mainly on the sarcolemma and a rise of pH produces the positive inotropic effects by enhancing the Ca-influx due to Is as well as Na-Ca exchange mechanism, although the mitochondria tended to show a minor counter action.View full abstractDownload PDF (6553K) -
Naoki FUKUSHIMA, Shinji ITOH1975 Volume 25 Issue 5 Pages 621-631
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSChanges in rectal and skin temperatures following intraventricular injection of norepinephrine and receptor specificity of the response in the rat were investigated.
Intraventricular injection of norepinephrine in a small dose (6μg) produced a slight elevation in rectal temperature, but in larger amounts (25-50μg) the result was a dose-dependent hypothermia associated with a marked rise in skin temperature. No change was observed in oxygen consumption after intraventricular injection of norepinephrine (25μg).
Intraventricular injection of phenoxybenzamine prior to norepinephrine blocked hypothermia and skin temperature elevation which are normally observed following norepinephrine injection, while propranolol given in the same way showed less or no effect. Intraventricular injection of phenylephrine produced a dose-dependent hypothermia, whereas a no does-response relationship was obtained with isoproterenol.
These results suggest that in the rat the hypothermic effect of norepinephrine injected intraventricularly is mediated by the action of central alpha receptors.View full abstractDownload PDF (1060K) -
Toru HASHIMOTO, Yoshifumi KATAYAMA, Keiichi MURATA, Ikuo TANIGUCHI1975 Volume 25 Issue 5 Pages 633-644
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSResponses of individual fibers of the cat cochlear nerve to Japanese monosyllabic speech sounds were described. Responses were analyzed by making post-stimulus time histograms and “pitch-synchronous” period histograms. Almost all neurons responsive to speech sounds showed repetitive discharges synchronous with the pitch period irrespective of their characteristic frequencies (CF). The frequency relation between the tuning characteristics of single neurons and the spectral distribution of the stimulus was systematically investigated to find out stimulus parameters to produce the “pitch-synchronous” impulse discharges. It was found that the neurons responded to vowels if the latter contained formants with frequencies near the neurons' CFs.View full abstractDownload PDF (11099K) -
Kiyoshi YAMAMOTO, Kikuo KASAI, Tamio IEIRI1975 Volume 25 Issue 5 Pages 645-658
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSAfter gonadectomy and subsequent daily supplements of 17β-estradiol or testosterone propionate, the anterior pituitary of rats was excised intact, incubated in vitro with 14C-leucine, and the radioactivity incorporated into prolactin and growth hormone was counted. Employing appropriate parameters calculated from hormone radioactivity counts both in the incubated tissue and the incubation medium, two unit functions of the anterior pituitary, hormone synthesis and release, were studied. The results showed that in female rats both estrogens and androgens enhance prolactin synthesis and release functions, and also growth hormone release function, but depress the growth hormone synthesis function. In male rats, androgens do not appear to be effective with any of the pituitary functions studied, but estrogens are similarly effective as in female rats. These findings indicate that estrogens play an essential role in controlling both synthesis and release of prolactin and also of growth hormone in female rats, but androgens do not play any significant role in male rats. Our results, obtained from direct measurements of two unit functions of the pituitary, were compared with numerous previous studies, in which indirect functional parameters of the pituitary were employed. In addition, acute effects of the gonadal steroids as the result of a single injection were presented, the results of which were partially consistent with chronic effects mentioned above.View full abstractDownload PDF (1563K) -
Hiroyuki SUGA, Yoshinobu NUMAO1975 Volume 25 Issue 5 Pages 659-664
Published: 1975
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSA method of preparing an in situ papillary muscle in an excised, cross-circulated heart was developed and its basic contractile properties were studied. The preparation was instituted without any interruption of coronary perfusion with arterial blood. The coronary perfusion pressure was 103±8 (SD, 10 muscles) mmHg. The temperature of the perfusing blood was kept at 37°C. The preparation beat at a regular rate of 97±16beats/min. The maximal developed force of contraction, which was measured with a specially devised isometric force transducer, was 60±13g. When this was divided by the cross sectional area of the papillary muscle, it was 630±66g/cm2. The developed force and heart rate were stable for 4 to 6hr as long as anesthesia of the support dog was well maintained. When the coronary perfusion pressure was reduced to 50mmHg, the developed force decreased by 33±24%. On occlusion of both common carotid arteries of the support dog, the developed force increased by 38±17% while the coronary perfusion pressure was kept unchanged.View full abstractDownload PDF (538K)
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