The Japanese Journal of Physiology
Print ISSN : 0021-521X
Volume 30, Issue 6
Displaying 1-13 of 13 articles from this issue
  • Hideaki NITTA, Mitsuo ISHIZAWA
    1980 Volume 30 Issue 6 Pages 815-826
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    The physiological significance of endogenous prostaglandin (PG) on spontaneous contractions in isolated circular muscles of the guinea-pig stomach was investigated.Contents of the E and F types of PG were measured by radioimmunoassay as PGE2 and PGF.The isolated circular muscles contained 17.04±2.12ng PGE2/g tissue (n=12) and 9.38±0.62ng PGF/g tissue (n=12), and released 0.36±0.04ng PGE2/g tissue/min (n=10) and 0.14±0.01 ng PGF/g tissue/min (n=12) into the solution. These contents and releases of PGs were reduced by treatment with indomethacin (ID50=0.3μEg/ml).Indomethacin (0.1-6μEg/ml) increased the amplitude of spontaneous contractions dosedependently, while high concentrations (20μEg/ml) conversely depressed it.Physiological concentrations of exogenously applied PGE2 (0.03-0.35ng/ml) markedly suppressed spontaneous contractions in the presence and absence of indomethacin (3μEg/ml), while PGF in concentrations of 0.35-3.54ng/ml slightly increased them. Therefore, these results suggested that spontaneous contractions in circular muscles were largely influenced by the E type of endogenous PG, not by the F type. The indomethacin-induced increase in the amplitude of spontaneous contractions was not affected by intrinsic nerves and was accompanied by an increase in spike discharges on the slow wave and 45Ca uptake in the muscle cells.These observations suggested that the E type of endogenous PG in circular muscles might play a suppressive role in spontaneous contractions by inhibiting spike generation on the slow wave.
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  • Takashi NISHINO
    1980 Volume 30 Issue 6 Pages 827-840
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    In 8 anesthetized cats the acute respiratory responses to laryngeal stimulation were studied under various levels of chemical drive. Under air breathing condition with strong stimulation the animals showed either cough or apnea, whereas with relatively weak stimulation the animals showed smooth reduction in respiration due to a decrease in tidal volume and prolongation of both inspiratory and expiratory time.Although the inhibitory effect of laryngeal stimulation on tidal volume was independent of the level of chemical drive, the inhibition of respiration, when analyzed in terms of decrease in the minute ventilation, was greater the higher the chemical drive regardless of the type of chemical stimulus.
    Although bilateral vagotomy decreased the threshold of stimulus intensity for changes in respiratory pattern, especially under hypoxia, the effects of laryngeal stimulation on respiratory pattern in vagotomized animals were qualitatively similar to those obtained in the intact animals. We concluded that laryngeal stimulation has a direct action on the central respiratory mechanism regulating respiratory duration and that the interaction between laryngeal stimulation and chemical drive causes multiplicative inhibitory effects on ventilation.
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  • Kaoru YANAGIHARA, Akinori NOMA, Hiroshi IRISAWA
    1980 Volume 30 Issue 6 Pages 841-857
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    The pacemaker activity of the S-A node cell was explained by reconstructing the pacemaker potential using a Hodgkin-Huxley type mathematical model which was based on the reported voltage clamp data.In this model four dynamic currents, the sodium current, iNa, the slow inward current, is, the potassium current, iK, and the hyperpolarization-activated current, ih, in addition to a time-independent leak current, il were included. The model simulated the spontaneous action potential the current voltage relationship, and the voltage clamp experiment in normal Tyrode solution of the rabbit S-A node.Furthermore, the changes of activity induced by the potassium current blocker Ba2+, by applying constant current, acetylcholine, and epinephrine were also reconstructed.
    It was strongly suggested that the pacemaker depolarization in the S-A node cell is mainly due to a gradual increase of is during diastole, and that the contribution of ik is much less compared to the potassium current iK2 in the Purkinje fiber pacemaker depolarization. The rising phase of the action potential was due to is and the plateau phase is determined by both the inactivation of is and activation of ik.
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  • Mamoru FUJIMOTO, Minoru HONDA
    1980 Volume 30 Issue 6 Pages 859-875
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    A triple-barreled Na+, K+-selective microelectrode was constructed with liquid ion exchangers for Na+ (monensin) and K+ (Corning #477317) to measure the intracellular Na+ and K+ activities ((Na) i and (K) i) of a single cell and its membrane potential (EM), simultaneously. The tip of the triple-barreled assembly was made less than 0.6μm in outside diameter.
    Prior to in vivo measurements, some physicochemical properties of microelectrodes were examined in vitro for the slope constant, selectivity coefficient, electrical resistance, and pH effect, as well as measurements of the activity coefficient of ions in blood serum and Ringer solution.
    Carrying out direct micropunctures on single cells of the sartorius muscle and renal proximal tubule of bullfrogs in vivo, we obtained the following results:(1) In sartorius muscle, the average (Na)i was 14.8mEq/liter, the (K)i 64.5mEq/liter, and the EM -68.2mV.(2) In proximal tubule cells, the average (Na)i, (K)i and EM were 16.8, 63.0mEq/liter and -65. 9mV, respectively.(3) There were significant correlations in the proximal tubule between (K)i and EM, and inversely between (Na)i and EM, and between (Na)i and (K)i.These facts may somehow be related to both the activity of Na+ -K+ exchange pump and the osmotic equilibrium of water across the membrane.
    Further, several problems inherent in the multibarreled microelectrode were discussed from the practical point of view.
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  • Noriaki TAKEGUCHI, Yoshihiro NISHIMURA, Isamu HORIKOSHI
    1980 Volume 30 Issue 6 Pages 877-886
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Bullfrog gastric mucosa can secrete acid in vitro for more than 24 hr.In Ca2+-deficient media, the acid secretion measured by pH stat method gradually decreased to cease about 200min after the start of immersion in the media.When A23187 or quinidine, which are known to mobilize Ca2+ from the intracellular pools, was present on the submucosal side, a prolongation of the duration of acid secretion in the absence of Ca2+ was found.Dibutyl c-AMP also induced a similar prolongation.Histamine or theophylline not only prolonged the duration of acid secretion but also transiently increased the acid secretory rate over the control level.Based upon the known fact that there are different intracellular Ca2+ compartments, i.e. one related to the process of acid secretion and the other to the maintenance of junctional complexes, the present results of drug effects were discussed especially in regard to their Ca2+ mobilizing effects.Cessation of acid secretion in a K+-and Ca2+-deficient solution occurred much more quickly than that in a Ca2+-deficient or a K+-deficient medium.
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  • Juro IRIUCHIJIMA, Yasuhiro TERANISHI, Chieko EGUCHI
    1980 Volume 30 Issue 6 Pages 887-896
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Aortic flow and arterial pressure were observed in conscious rats by means of an electromagnetic flowmeter probe implanted around the ascending aorta and an arterial cannula inserted into the abdominal aorta through a femoral artery.When the rat was transposed to a new box from its usual one, heart rate, cardiac output and peak flow acceleration were increased but arterial pressure remained unchanged.Total peripheral resistance was decreased.This response complex of the cardiovascular system to change of habitat was designated as “transposition repsonse.” After β adrenoreceptor blockade with propranolol, transposition no longer increased heart rate, cardiac output or peak flow acceleration but markedly increased arterial pressure and total peripheral resistance.The response was essentially unchanged by atropinization or adrenalectomy.Besides cardiac excitation and adrenergic vasoconstriction, the response includes a A adrenergic vasodilatation, which is at least in part mediated by transmitters released at the sympathetic nerve endings and presumably equivalent to the cholinergic vasodilatation in the cat and dog.
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  • Ichiji TASAKI, Kunihiko IWASA, Robert C. GIBBONS
    1980 Volume 30 Issue 6 Pages 897-905
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    A nerve impulse travelling along a crustacean nerve was found to be accompanied by a small, rapid movement of the nerve surface.The movement was 10-20nm in amplitude and was concurrent with a rise in the “swelling pressure” of the order of 5mg/cm2 for a nerve bundle.Initiation of an action potential at the site of cathodal polarization was preceded by a small, slow mechanical change in the nerve fiber.Anodal polarization produced a large mechanical change of the opposite sign.Tetrodotoxin and procaine suppressed rapid mechanical changes.
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  • Hiroyuki SUGA, Takakazu HAYASHI, Machiko SHIRAHATA, Ishio NINOMIYA
    1980 Volume 30 Issue 6 Pages 907-919
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Left ventricular systolic pressure volume area (PVA) has been reported to be a reliable predictor of cardiac oxygen consumption rate per beat (VO2) in a given heart with a stable inotropic background. PVA has been defined as the specific area in the pressure-volume (P-V) plane that is bounded by the end-systolic and end-diastolic P-V relationship lines and the systolic segment of the P-V loop trajectory.In the present experimental study, we separated PVA into two parts: EW and PE.EW is the area surrounded by the P-V loop, corresponding to the external mechanical work. PE is the area surrounded by the endsystolic and end-diastolic P-V lines and the relaxation segment of the P-V loop, corresponding to what is considered the end-systolic elastic potential energy in terms of a time-varying elastance model of the ventricle. We attempted to find an optimal weighting coefficient K of PE for the best correlation between Vo2 and PVAW=EW+K·PE, changing K from 0 to infinity. Results in 7 canine excised cross-circulated hearts showed that PVAW best correlated with VO2 at K=1.03±0.03 (SE). Since PVAW at K=1 is identical with the original PVA, we concluded that PVA could serve as a reliable predictor of VO2. PVA is concluded to be physiologically significant in the coupling between cardiac mechanics and energetics.
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  • Toshiaki NEYA, Friedlich-Karl PIERAU
    1980 Volume 30 Issue 6 Pages 921-934
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Unit responses of dorsal horn neurons (DHNs) of rats to thermal stimulation of the scrotal skin were recorded extracellularly. Fifty-five out of 74 DHNs increased their activity during scrotal skin warming, while the activity of 14 neurons was accelerated by cooling. Tonic activities of 3 neurons were inhibited by warming (inverse warmreactive). Two neurons demonstrated a complex response and were activated during cooling and warming. Most of the warm-reactive and all of cold-reactive DHNs had steep sigmoid temperature-activity-relation curves with a temperature-dependent range of 1-5°C.
    Injections of 5-10 mg/kg CaCl2 into the lower abdominal aorta produced excitation in 30 out of 33 warm-reactive DHNs and inhibition in 3 neurons. Only 3 out of 8 cold-reactive DHNs demonstrated inhibition, while the remaining 5 were activated. All three inverse warm-reactive neurons were inhibited. DHNs which exclusively reacted to mechanical stimuli or did not respond to any peripheral stimulation were not affected by peripheral Ca administration. The results suggest that a number of cold-reactive DHNs receive inputs from warm-and cold-sensitive afferents and that there may exist such double innervation in some warmreactive DHNs as well.
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  • Akihiro KUROSHIMA, Takehiro YAHATA, Tomie OHNO
    1980 Volume 30 Issue 6 Pages 935-943
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    In order to ascertain possible involvement of polyamines in the physiological regulation of brown fat function, effect of temperature acclimation on the polyamine contents of this tissue and effects of polyamines on the noradrenaline-induced thermogenesis of isolated brown adipocytes were investigated in rats. Daily urinary excretion of polyamines measured collectively for spermidine and spermine per body weight was decreased in heat acclimation and increased in cold acclimation. Polyamine concentrations per fresh weight of brown fat showed extremely low values compared with those of other tissues previously reported. Putrescine and spermidine contents per fat-free dry matter of brown fat were decreased in cold acclimation. but were not affected in heat acclimation. Spermidine and spermine inhibited the noradrenalineinduced thermogenesis of brown adipocytes dose-dependently. These results suggest that polyamines regulate the heat production of brown adipose tissue in an inhibitory way and cold acclimation potentiates heat production of this tissue by reducing polyamine levels.
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  • Miharu MIYAMURA, Noriaki FUJITSUKA, Hideji MATSUI
    1980 Volume 30 Issue 6 Pages 945-953
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    The ventilatory response to carbon dioxide at rest was determined repeatedly by the rebreathing method;three successive CO2 response lines, with 30-min intervals, were examined in 12 healthy male subjects.Overall mean slopes obtained at 30, 60 and 90min were 2.95, 2.47 and 2.28 liters/min⋅mmHg, respectively, the difference being statistically not significant.However, the slopes of four high responders, who were subjects with higher slopes than that of the mean values obtained here, decreased significantly (p<0.05) at 60min as compared with the 30min test, but this did not occur in the other subjects.Better reproducibility in obtaining the CO2 response slope in the high responders was observed in the first rather than the 60 or 90min trials, suggesting incomplete recovery in the humoral agents released during the CO2 test. These results indicated that the CO2 response curve by rebreathing should be determined carefully, especially in the high responder, taking into consideration its individual variability and the interval in consecutive measurements.
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  • Mitsuru SAITO, Hideji MATSUI, Miharu MIYAMURA
    1980 Volume 30 Issue 6 Pages 955-959
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Blood flows of the calf and thigh at rest and after submaximal and maximal exercise were determined by the venous occlusion method in 6 healthy subjects before and after physical training for 5 weeks.It was found that the magnitude of the flow after training was significantly (p<0.05) decreased when measured immediately after submaximal exercise, while there were no significant differences found with respect to both calf and thigh blood flows measured immediately after maximal exercise before and after training.
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  • Shiro KASAI, Waka TERASAWA, Hiroaki KODAMA, Takashi TERASAWA
    1980 Volume 30 Issue 6 Pages 961-965
    Published: 1980
    Released on J-STAGE: June 07, 2011
    JOURNAL FREE ACCESS
    Erythroid colony formation in vitro was enhanced by β-agonist, etiocholanolone and spleen extract from irradiated rats. While propranolol completely blocked the effect of β-agonists, the effect of etiocholanolone was little, and that of spleen extract was not affected by this β-blocker.
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