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Volume 33 (1983)
- Issue 6 Pages 875-
- Issue 5 Pages 687-
- Issue 4 Pages 507-
- Issue 3 Pages 309-
- Issue 2 Pages 151-
- Issue 1 Pages 1-
Volume 33, Issue 6
Displaying 1-17 of 17 articles from this issue
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Ishio NINOMIYA, Naoki NISHIURA, Katsuro SHIMOMURA1983 Volume 33 Issue 6 Pages 875-886
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSUsing a biotelemetry system, the electrocardiogram (ECG) was continuously measured over 24hr in a given environmental condition in 8 normal human subjects. The frequency of ventricular excitation rhythm (VER) was obtained from inverse of R-R interval of ECG. This study was undertaken to be informed of the variation of VER over 24hr in resting normal subjects with different ages. The averaged frequency of VER per day (VERd) and its relative coefficient of variation (CV) ranged from 1.44 to 1.01Hz (mean: 1.24Hz) and 26 to 10% (mean: 20%) with age of 10 to 73 years (mean: 42 years). VERd and CV showed a tendency to decrease with age.
The VERd histogram showed not a normal distribution but a multimodal distribution. Two or three large positive deviations, denoted as L, N, and H modal components, from the normal distribution curve were detected. The mode of L and H modal components was 1.01 and 1.37Hz, respectively. The frequency distribution of L and H modal components changed with relation to a circadian rhythm and sleep-wakefulness cycles. An hourly histogram of ventricular excitation rhythm (VERh) frequently showed an unimodal distribution and the relative coefficient of variation of VERh ranged from 7.9 to 13.3% which was smaller than that of CV. The mode of VERh histogram changed in association with the circadian rhythm, the sleep-wakefulness cycles and a fluctuation period of 2 to 3hr.View full abstractDownload PDF (948K) -
Juro IRIUCHIJIMA1983 Volume 33 Issue 6 Pages 887-894
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSConditions for secretion of pressor amounts of vasopressin were sought in conscious, water-replete rats. The characteristic lowering of arterial pressure on injection of a vasopressin antagonist was used to detect vasopressin secretion in pressor amounts. The absence or marked abatement of both baroreceptor impulses and adrenomedullary secretion were found necessary for secretion of vasopressin in pressor amounts : the vasopressin antagonist lowered arterial pressure in rats with sinoaortic denervation and ganglion blockade or adrenalectomy. Besides baroreceptor activity and adrenomedullary secretion, anesthetics were also found inhibitory on vasopressin release in pressor amounts. The adrenomedullary hormone signaling the presence of adrenomedullary activity to the vasopressin releasing mechanism was identified as noradrenaline and not adrenaline. It is suggested that the vasopressin pressor mechanism is recruited to sustain arterial pressure when the sympathoadrenal system fails.View full abstractDownload PDF (579K) -
Kaoru KOMETANI, Kazuhiro YAMADA1983 Volume 33 Issue 6 Pages 895-908
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe relation between shortening heat and sarcomere length was studied using fiber bundles from frog semitendinosus muscles as well as using whole muscles. The initial sarcomere length was varied between 2.0 and 3.66μm. Shortening heat was estimated as the excess heat produced after a rapid isovelocity release in a 3sec tetanus at 0°C. The isometric control heat was measured in the same tetanus, before and after the period of shortening. The unstimulated whole muscles showed a large thermoelastic absorption of heat when released at sarcomere lengths longer than 2.5μm, and the apparent shortening heat was negative at very long sarcomere lengths. The apparent shortening heat was corrected by subtracting the thermoelastic heat absorption by assuming that the thermoelastic effect was also present in releases of active muscles. The corrected shortening heat decreased linearly with increasing sarcomere length in the range 2.29-3.66μm, intersecting the length axis at 3.73±0.21μm. The thermoelastic heat absorption at long sarcomere lengths was substantially reduced in fiber bundles, suggesting that the parallel elasticity responsible for the thermoelastic effect is mainly present outside muscle cells. The corrected shortening heat in fiber bundles also decreased linearly with increasing sarcomere length, intersecting the length axis at 3.84±0.25μm. Thus the results on fiber bundles, also based on correction but the extent of which is substantially smaller than in whole muscles, are in agreement with the results on whole muscles. The results are interpreted to mean that shortening heat is produced by the interaction of thick and thin filaments in contracting muscle.View full abstractDownload PDF (1032K) -
Kazuhiro YAMADA, Masaru TANOKURA1983 Volume 33 Issue 6 Pages 909-919
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWe have designed and constructed a 25mm diameter chamber in order to study the phosphorus nuclear magnetic resonance (31P NMR) spectra from a considerable mass of toad and frog muscles (16 sartorii weighing 5-10g) which were maintained in a well-oxygenated condition at 4°C. We have thus been able to measure the biochemical changes that accompany contraction and recovery with improved time-resolution. Using this apparatus it is shown that splitting of phosphocreatine (PCr) continues for a few minutes after relaxation. Subsequently the PCr is rebuilt by oxidative processes in the familiar way, with a time constant_??_10min. By studying tetanic contractions of various durations we have shown that the time-course of the post-contractile PCr splitting is similar to that of the heat production that cannot yet be accounted for by known chemical changes. Myosin and actomyosin ATPase reactions most likely underlie the post-contractile ATP utilization. The results suggest that the post-contractile ATP utilization is responsible for the unexplained enthalpy mentioned above.View full abstractDownload PDF (764K) -
Takao KOMABAYASHI, Keiko NAKANO, Takayuki NAKAMURA, Minoru TSUBOI1983 Volume 33 Issue 6 Pages 921-930
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe mechanism of amylase and sialic acid releases stimulated by pilocarpine or high K+ medium was investigated in the slices of dog submandibular glands. The release of both amylase and sialic acid was dose-dependently increased by pilocarpine and a considerable release was observed at pilocarpine concentrations of more than 1μM. Similar effects were observed when K+ concentration in the medium was increased and the maximal response was observed at 75mM K+. The release of amylase and sialic acid by pilocarpine or K+ considerably decreased by removing Ca2+ from the medium and the slices. The release of amylase in the Ca2+-deficient slices was nearly recovered by the addition of 2.5 and 5.0mM Ca2+, whereas that of sialic acid was recovered by only 60-75%. Ca2+ inhibitors, La3+ and verapamil, and calmodulin inhibitors, trifluoperazine, prenylamine, and W-7, significantly inhibited the release of amylase and sialic acid induced by the stimulants. These results suggest that the release of amylase and sialic acid stimulated by pilocarpine or K+ is dependent on the presence of Ca2+, and that the activation of calmodulin is involved in the process of the release.View full abstractDownload PDF (804K) -
Kenji KUBA, Setsuko TAKESHITA1983 Volume 33 Issue 6 Pages 931-944
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe mechanism of depressant effects of Ca2+ on the acetyl-choline (ACh)-activated ion channel conductance was studied in frog muscle fibers. Increasing the extracellular Ca2+ ((Ca2+)o) suppressed the increase in the end-plate conductance induced by iontophoretic application of ACh and shifted the reversal potential for a neurally-induced end-plate current to a more negative value. The single channel conductance obtained by current fluctuation analysis was reduced at a high (Ca2+)o. The decay phase of a neurally-induced end-plate current was slightly prolonged at a high (Ca2+)o (18mM), while that of miniature end-plate current and the open time of the end-plate channel measured by noise analysis remained unchanged under the same condition. The Hill coefficient and apparent dissociation constant as measured by quantitative iontophoresis of ACh and comparison of the end-plate response with a theoretical model (DREYER and PEPER, 1975) were not affected by raising (Ca2+)o, while the maximum conductance increase was suppressed. These results suggest that the depressant effect of Ca2+ on the end-plate channel is not due to the effects on surface charges of the membrane, affinity of ACh to the ACh-receptor or binding to intrachannel sites, but presumably arises from the effect on another site involved in the regulation of ion permeation of the receptor-channel complex.View full abstractDownload PDF (1034K) -
Hideaki KANAYA, Masa TAKAUJI, Torao NAGAI1983 Volume 33 Issue 6 Pages 945-954
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe properties of caffeine contracture and potassium contracture in fatigued single fibers were examined in detail using frog semitendinosus muscle, Rana japonica. Fatigue was caused by repetitive stimulation at 2Hz. The dose-response curve of caffeine contracture in the fatigued fibers was shifted toward the right; the threshold concentration of caffeine for the contracture in normal fibers was 1.5 mM, whereas that in fatigued fibers was 5mM. However, in the presence of 25mM K+ or 0.01% Triton X-100, caffeine contractures occurred sufficiently at the lower concentrations (3-5mM) even in the fatigued fibers. Furthermore, in the fatigued fibers, the peak tension of the initial component of biphasic potassium contracture with 60 or 80mM KCl (Cl constant; 120mM) was slightly inhibited, whereas the secondary component of the contracture was markedly inhibited. These results indicate that the permeability to caffeine of the transverse tubular membrane (T-membrane) of the fibers and the Ca influx in response to the direct depolarization of T- membrane with K+ are markedly inhibited in the fatigued fibers.View full abstractDownload PDF (709K) -
Asako KANO-KAMEYAMA, Takeshi HOSHI1983 Volume 33 Issue 6 Pages 955-970
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSSodium/D-glucose cotransport carriers solubilized from intestinal brush border membranes were purified and incorporated into liposomes made of soybean phospholipids, and transport properties of the reconstituted system were studied. The brush border membrane vesicles prepared from guinea pig small intestine were first treated with deoxycholate and papain in order to remove unnecessary membrane proteins, and then the remaining membrane proteins were solubilized with Triton X-100. The solubilized proteins were fractionated by gel-filtration according to molecular size and the fractions containing proteins of molecular weight of around 340K daltons were further separated by chromatofocusing according to isoelectric point. The Na+ gradient-dependent overshoot uptake of D-glucose was seen when the proteins which were finally eluted in the pH range of 5.0-5.5 were incorporated into the liposomes. The proteins purified and incorporated into liposomes could be visualized on sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis as a single band of 160, 000 dalton glycoprotein. The proteoliposomes constructed with the purified proteins revealed about 20-fold higher accumulation of D-glucose as compared with those constructed with unpurified membrane protein extracts. Kinetically, however, the reconstituted system revealed somewhat different characteristics from those of the native brush border membrane vesicles, i.e. retarded time course of overshooting uptake and an S-shaped relationship between 1-min uptake of glucose (the quasi-initial rate of glucose uptake) and glucose concentration. The reciprocal of the uptake rate was linearly proportional to the reciprocal of the square of glucose concentration and the estimated Hill coefficient was about 2.View full abstractDownload PDF (1397K) -
Yoshimi MIYAMOTO, Yoshimi NAKAZONO, Tadashi HIURA, Yasunori ABE1983 Volume 33 Issue 6 Pages 971-986
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSDynamic characteristics of ventilation, cardiac output, and gas exchange during sinusoidally varying work rates for the periods from 1 to 12min and impulse work rate with a duration of 10sec were studied on five healthy men in an upright position. Changes in work rate were given by controlling externally the electromagnetic braking system of a bicycle ergometer. Stroke volume, heart rate, and cardiac output during exercise were determined continuously by using an automated impedance cardiograph. Breath by breath determination in minute ventilation, respiratory frequency, tidal volume, oxygen consumption, carbon dioxide output, end-tidal pressures of oxygen and carbon dioxide, and gas exchange ratio were conducted. From these and steady-state response data amplitude and phase relations between each variable and the input work loads were obtained utilizing the frequency analysis techniques. The response characteristics to sinusoidal stimuli were well represented by first-order models with time constants for VE, VCO2, VO2, and Q averaging 75, 67, 52, and 36sec, respectively. The kinetics of HR closely resembled that of Q. There was a close link between both the dynamics of VE and VCO2. On the other hand, the responses to impulse stimuli were better described by second-order models in which fast and slow response components were connected in parallel. However, the contribution of the fast component to total response was small. Although this response may support in its form the neurohumoral concept to explain exercise hyperpnea, a tight linkage was observed between VE and VCO2 responses to impulse stimuli. Thus, hyperpnea during the unsteady-state of exercise may be explained by the cardiodynamic hypothesis.View full abstractDownload PDF (1099K) -
Hisaharu KOHZUKI, Yasunori ENOKI, Susumu SAKATA, Susumu TOMITA1983 Volume 33 Issue 6 Pages 987-994
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWe devised a rapid and simple method to obtain oxygen dissociation curve (ODC) for a small amount of blood with simple equipment. This system achieved the gas-blood equilibrium within 3min. Oxygen saturation of the equilibrated blood was measured spectrophotometrically while the pH, PCO2, and PO2 was measured with a Radiometer blood gas analyzer system. Whole procedures to construct ODC from the 6 point measurements could be performed within 1hr. The standard ODC for 25 normal Japanese adults showed a mean P50 of 27.6±1.1Torr (pH 7.40, PCO2 40Torr, 37°C), a slightly higher value than previously reported. The discrepancy, however, can be eliminated when corrected for a slightly lower SO2 by the present procedure. The standard curves for the adult blood at pH 7.20 and 7.60 and for the cord blood at pH 7.40 were also described. The "single point" procedure, a much quicker approach to measure the P50 (ABERMAN et al., 1975), was scrutinized by comparing with the "whole curve" method. The P50's by the two methods were not significantly different, mean±S.D. of the differences being 0.4±2.5 Torr (n=126) for the adult blood at pH 7.40, PCO2 40Torr and 37°C. Similar results were obtained for the adult blood at pH 7.20 and 7.60 and for the cord blood at 7.40. We concluded that the "single point" method was sufficiently accurate and reliable.View full abstractDownload PDF (505K) -
Kazuyuki KANOSUE, Kenzo AKAZAWA, Katsuhiko FUJII1983 Volume 33 Issue 6 Pages 995-1009
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSChanges in stretch reflex responses were examined in two types of motor task, force control and position control, by applying a small quick stretch to the middle finger extensor digitorum communis (EDC) muscle at an unpredicted time and observing activities of single motor units. Subjects were asked to maintain a constant extending isometric force at the metacarpophalangeal (MP) joint for force control, and to maintain a constant middle finger position against an applied force for position control. No significant differences in the tonic activities of EDC motor units were seen between the two types of motor task when the same force was exerted about the MP joint. Tonic activities of the EDC muscle and its antagonists were thus similar for both types of motor task. Ten of the eighteen motor units investigated showed obvious reflex responses (increase in firing rate) with latencies of 30-60msec after the stretch. This reflex response was greater for position control than for force control, given the same operating conditions of tonic force, finger position, and activities of motor units. Enhancement of the stretch reflex for position control was also observed in surface electromyograms of the same muscle.View full abstractDownload PDF (1160K) -
Kenji AKAZAWA, Norimasa MORI, Tadayoshi KOSUGI, Osamu MATSUO, Hisashi ...1983 Volume 33 Issue 6 Pages 1011-1018
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe localization and changes of fibrinolytic activity during the process of ovulation were investigated by the fibrin slide method. In regular estrous cycle rats, fibrinolytic activity first appeared in the external area of the follicle wall (stigma) at 12hr before ovulation. No activity was noted in the follicular cavity at this time. A peak of activity was seen at 2hr before ovulation. After ovulation, the activity decreased markedly. The activity was completely inhibited on fibrin slides to which 10-2M trans-aminomethyl-cyclohexane carboxylic acid had been added. No activity was observed on plasminogen-free fibrin slides. These results suggest that fibrinolytic activity is one of the important factors involved in the rupture of the mature follicle wall, and that the fibrinolytic activity is due to plasminogen activator activity.View full abstractDownload PDF (1007K) -
Hiroshi NOSE, Taketoshi MORIMOTO, Kanae OGURA1983 Volume 33 Issue 6 Pages 1019-1029
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSDehydration amounting to about 10% of body weight was induced in adult male rats by exposure to a hot, dry environment (D.B.T., 36°C; R.H., 20%) over 6 to 8hr. The volumes of total water (TW), extracellular fluid (ECF), and plasma (PV) were determined both on individual tissues and on the whole body using the constant dry weight as well as 51Cr-EDTA and 125I-RIHSA dilution methods. Total body water (TBW), intracellular (ICF), and interstitial (ISF) fluid volumes were calculated from these data.
The 10% loss of body weight caused a decrease in TBW by 17% from the control value; 41% of this loss was from ICF, 47% from ISF, and 12% from PV. The decrease of ISF was proportional to that of PV and the water loss from ICF was caused by an increase in plasma osmolality. As to the water loss from organs, 40% of the whole body water loss came from muscle, 30% from skin, 14% from bone, and 14% from viscera. The G.I. tract had the highest tendency to lose water while the brain and liver showed the least.
These findings suggest that under heat-induced dehydration, both the extra- and intracellular fluid compartments of muscle and skin play an important role in the compensation of water loss and in the maintenance of circulation to the brain and liver.View full abstractDownload PDF (840K) -
Osamu MATSUO, Tetsuhiro SAKAI, Yasuo TAKAKURA, Hisashi MIHARA1983 Volume 33 Issue 6 Pages 1031-1037
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThree different synthetic chromogenic substrates (H-glutamyl-glycyl-L-arginine-p-nitroanilide (S-2227), pyro-glutamyl-glycyl-L-arginine- p-nitroanilide (S-2444), and H-D-isoleucyl-L-prolyl-L-arginine p-nitroanilide (S-2288)) were investigated for use in the measurement of plasminogen activator activity with high molecular weight urokinase (H-UK), low molecular weight urokinase (L-UK), and tissue plasminogen activator (TPA). The three substrates were hydrolyzed by both TPA-type and UK-type plasminogen activator. As regards the amidolytic activity of S-2227, TPA exhibited a weaker amidolytic activity, and L-UK a stronger activity. In the case of the amidolytic activity of S-2444, no great difference between the three activators was observed in terms of Vmax. As regards the amidolytic activity of S-2288, L-UK exhibited a stronger activity, and TPA a weaker activity. It is suggested that the molecular size of the synthetic chromogenic substrate was too small when compared to natural substrate (fibrin), and therefore that fibrin-binding sites around the catalytic site in TPA are not recognized.View full abstractDownload PDF (454K) -
Masaki KAMEYAMA, Tatsuto KIYOSUE, Michimasa SOEJIMA1983 Volume 33 Issue 6 Pages 1039-1056
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe inward rectifier K channel in rabbit ventricular cells was studied by the patch-clamp method. Single channel currents were recorded in giga-sealed cell-attached patches with 150mM K+ in the pipette. The slope conductance in the membrane potential range from -140 to -40mV was 46.6±6.7pS (mean±S.D., n=16), and was reduced by decreasing [K+] in the pipette (20 or 50mM). The channel was blocked by an application of Cs+ or Ba2+ (0.04-1mM) in the pipette. Outwardly directed current, recorded with 50mM K+ in the pipette, revealed the inward rectification of the single channel current. The probability of the channel being open was 0.33±0.05 (n=10) at the resting potential (RP=-81.7±1.7mV, n=16) with 150mM K+ in the pipette, and it decreased with hyperpolarization. The mean open time of the channel was 178±25msec (n=6) at RP. The closed time of the channel seemed to have two exponential components, with time constants of 11.0±2.0msec and 1.92±0.52sec (n=6) at RP. The slower time constant was increased with hyperpolarization. The averaged patch current recorded upon hyperpolarizing pulses demonstrated a time-dependent current decay as expected from the single channel kinetics. The results indicated that the inward rectifier K+ current has time- and voltage-dependent kinetics.View full abstractDownload PDF (1202K) -
Makoto WAKUI, Hachiro INOMATA1983 Volume 33 Issue 6 Pages 1057-1060
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSCo2+ suppressed the mechanical responses evoked by field stimulations and by application of noradrenaline (NA) in the smooth muscle of guinea-pig vas deferens. However, the membrane excitation and force development evoked by depolarizing currents were not much affected in the Co2+ treatment. It is proposed that Co2+ suppresses NA induced contraction by inhibiting the development of the membrane depolarization.View full abstractDownload PDF (298K) -
Masaru SORIMACHI1983 Volume 33 Issue 6 Pages 1061-1066
Published: 1983
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe isolated neurohypophysis of the rat was incubated with a medium lacking Ca and vasopressin release was induced by reintroduction of Ca (2mM). The response to Ca was greatly enhanced after treatment with a medium containing ouabain or lacking K. The enhanced release of vasopressin by ouabain was dependent on the concentration of external Na. The results suggest that inhibition of Na pumps leads to a rise in internal Na, thereby activating Na-dependent Ca influx mechanism associated with vasopressin release.View full abstractDownload PDF (424K)
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