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Volume 36, Issue 1
Displaying 1-19 of 19 articles from this issue
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Masayosi GOTO1986 Volume 36 Issue 1 Pages 1-14
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe characteristics of depolarization-induced automaticity in myocardium and the mechanisms presumably responsible for their occurrence and maintenance were discussed in relation to ionic channels and ion transport systems of the cell membrane. The initiating mechanisms of automaticity were subdivided into oscillatory potentials of increasing amplitude, spontaneous slow depolarization and sustained depolarization of the membrane, and various possible causes of these potential changes were described. As for the mechanisms responsible for the maintenance of automaticity, phase 4 depolarization, afterdepolarization and triggered activity were considered with special reference given to the excitability recovery characteristics during the diastolic period. Thus, various factors were responsible for modifying the automaticity. Also, intracellular Ca fluctuations which induce oscillatory potentials, afterdepolarizations, or even supernormal periods of excitability appear to play a cardinal role. Clarification of the intracellular Ca metabolism in relation to internal membrane systems such as the sarcoplasmic reticulum and mitochondria should yield pertinent information resulting in a better understanding of these events.View full abstractDownload PDF (1179K) -
Saburo HOMMA, Yoshio NAKAJIMA, Kenji HAYASHI, Shinobu TOMA1986 Volume 36 Issue 1 Pages 15-24
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSConduction of an action potential along skeletal muscle fibers was graphically displayed by unidimensional latency-topography, UDLT. Since the slopes of the equipotential line were linear and the width of the line was constant, it was possible to calculate conduction velocity from the slope. To determine conduction direction of the muscle action potential elicited by electric stimulation applied directly to the muscle, surface recording electrodes were placed on a two-dimensional plane over a human muscle. Thus a bi-dimensional topography was obtained. Then, twelve or sixteen surface electrodes were placed linearly along the longitudinal direction of the action potential conduction which was disclosed by the bi-dimensional topography. Thus conduction velocity of muscle action potential in man, calculated from the slope, was for m. brachioradialis, 3.9±0.4m/s; for m. biceps brachii, 3.6±0.2m/s; for m. sternocleidomastoideus, 3.6±0.4m/s. By using a tungsten microelectrode to stimulate the motor axons, a convex-like equipotential line of an action potential in UDLT was obtained from human muscle fibers. Since a similar pattern of UDLT was obtained from experiments on isolated frog muscles, in which the muscle action potential was elicited by stimulating the motor axon, it was assumed that the maximum of the curve corresponds to the end-plate region, and that the slopes on both sides indicate bi-directional conduction of the action potential.View full abstractDownload PDF (2006K) -
Takashi AKASU1986 Volume 36 Issue 1 Pages 25-42
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe effects of luteinizing hormone releasing hormone (LHRH) on cholinergic transmission were studied at the neuromuscular junction of the frog. Brief application of LHRH produced a prolonged increase in the amplitude of end-plate potentials (e.p.p.s), which lasted 20 to 30min after removal of LHRH. LHRH (0.4-1μM) increased in the quantal content of the e.p.p. dose-dependently, while having no effect on the quantal size. LHRH (0.4-1μM) did not affect the frequency and the amplitude of miniature end-plate potential (m.e.p.p.). At a high concentration (8μM), however, LHRH consistently produced an increase in the frequency and a decrease in the amplitude of m.e.p.p. The acetylcholine-induced end-plate current (ACh current) produced by iontophoretic application of ACh was reversibly and dose-dependently reduced by LHRH (4.6-46μM). An analysis with a dose-response curve of the ACh current revealed that LHRH decreased the sensitivity of the nicotinic receptor in a noncompetitive manner. These results suggest that LHRH at low concentrations facilitates neuromuscular transmission by increasing ACh-release from the presynaptic nerve terminals, while at higher concentrations it depresses transmission post-synaptically. Possible mechanisms of these LHRH actions are discussed.View full abstractDownload PDF (1174K) -
Masaji MOCHIZUKI, Tomoko KAGAWA1986 Volume 36 Issue 1 Pages 43-63
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSTo describe the overall gas exchange rates in red blood cells (RBC), a computer program for solving the diffusion equations for O2, CO2, and HCO3- that accompany the chemical reactions of Bohr- and Haldane-effects was developed. Three diffusion equations were solved alternatively and repeatedly in an increment time of 2ms. After solving the diffusion equations the PO2, O2 saturation (SO2), PCO2, pH, and HCO3- content were corrected by using the Henderson-Hasselbalch equation, where the buffer value was newly derived from the CO2 dissociation curve. In computing the Haldane effect, the buffer value was taken to be 44mmol•l(RBC)-1•pHc-1, so that the change in intracellular dissolved CO2 caused by the SO2 change was fully compensated by the subsequent CO2 diffusion. The oxygenation and deoxygenation rate factors of hemoglobin were assumed to be 2.09•(1-S)2.02 and 0.3s-1•Torr-1, respectively. The PO2 change due to the Bohr-shift was computed from Hill's equation, in which the K value was given by a function of the intracellular pH. When the parameter values thus far measured were used, the computed Bohr- and Haldane-effects coincided well with the experimental data, supporting the validity of the equations. The overall gas exchange profiles calculated in the pulmonary capillary model showed that the CO2 equilibration time was significantly longer than the oxygenation time.View full abstractDownload PDF (1316K) -
Toru TAKEUCHI, Nobuyuki TERADA, Shozo KOYAMA1986 Volume 36 Issue 1 Pages 65-76
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSChanges in hepatic hemodynamics during blood pressure oscillations caused by the side pressure exertion procedure (SPEP) were studied in anesthetized rabbits. The brain was excluded from systemic circulation except for one of the common carotids, which was compressed with stepwise elevated pressure. In normovolemia, the hepatic arterial flow (HAF) increased as the systemic arterial pressure (SAP) rose up to 140mmHg, and then decreased as SAP rose further. With the rise of SAP, the portal venous flow (PVF) initially rose slightly, followed by a nearly constant decrease. Hemorrhaging influenced slightly the changes of HAF and PVF with the SAP rise. After volume loading, SAP and PVF markedly increased but HAF changed little. However, the initial increase in HAF with the SAP rise was markedly depressed by volume loading. PVF conspicuously decreased without initial increase with the rise in SAP. The hepatic vascular bed has a mechanism that prevents expected decrease of blood flow after hemorrhaging and during neurogenic hypertension. The interaction among HAF, PVF, and PVP may be involved in this mechanism.View full abstractDownload PDF (842K) -
Yoshimichi YAMAMOTO, Ken HOTTA1986 Volume 36 Issue 1 Pages 77-90
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSElectrical responses to brief electrical stimulation were investigated in the cerebral artery of a guinea-pig using a microelectrode. A single brief stimulus (0.05ms) induced a spike potential followed by a depolarizing slow-potential, and these events were associated with muscle contraction. An outward current injected into the smooth muscle cell induced spike potential but failed to induce depolarizing slow-potential. These activities persisted in the presence of TTX (10-6M), guanethidine (5×10-6M), or atropin (10-5M). TEA (5mM) enhanced the amplitude of the spike potential, but not that of the depolarizing slow-potential. When the external Na was reduced, the membrane transiently hyperpolarized. During this period, the depolarizing slow-potential could be evoked. In a Cl-deficient solution, the membrane depolarized and the amplitude of the depolarizing slow-potential decreased. From these observations it is believed that the contribution of K, Na, or Cl is minor. In a 20mM-Ca solution, a brief stimulation induced neither spike potential nor depolarizing slow-potential, but did induce a hyperpolarizing slow-potential. The hyperpolarizing slow-potential was also induced in a Na-deficient solution, but only after completion of Na re-distribution across the membrane. These observations suggest that a substance released by brief stimulation produces a prolonged change in ionic conductances of the smooth muscle membrane, allowing the muscle to contract for a certain period.View full abstractDownload PDF (1057K) -
James P. BUTLER, Masao NAKAMURA, Hidetada SASAKI, Takao SASAKI, Tamots ...1986 Volume 36 Issue 1 Pages 91-106
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSA simple theory of lung elasticity and its interaction with bronchi was developed which led to the specific results. The experimental procedure for establishing these results used lobar bronchi from excised dog lungs, following TAKISHIMA, et al. ((1975) J. Appl. Physiol., 38: 875-881). First, we found a semi-direct technique for measuring Poisson's ratio (σ) of lung parenchyma and the effect of lung parenchyma on bronchi (interdependence), σ was measured at 0.424±0.045; no correlation was observed between σ and the elastic recoil pressure of the lung (PL). The interdependence increased with a corresponding increase in PL and reduced bronchial volume. Second, we predict that a relationship exists between the specific compliances of intact and excised bronchi, and the specific compliance of the surrounding parenchyma. We suggest that the parenchyma is more important than the bronchus itself in determining the specific compliance of the intact bronchi.View full abstractDownload PDF (972K) -
Yoshimi IKEMOTO, Atsuko YATANI, Yutaka IMOTO, Hiroyuki ARIMURA1986 Volume 36 Issue 1 Pages 107-121
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSEffects of two general anesthetics, halothane and thiamylal, on the fast sodium inward current (INa) of enzymatically isolated single rat ventricular cells were studied under current clamp and voltage clamp conditions. A suction pipette technique was used for potential measurement, current injection and internal perfusion of isolated cells. In current clamp experiments, sodium action potential was elicited in a Ca-free Co Krebs solution and the action potential was reduced by 0.5% halothane and 5×10-5M thiamylal. In voltage clamp experiments, the calcium current was suppressed by replacing Ca with Co and the potassium current was eliminated by replacing K with Cs and adding 4-aminopyridine and tetraethylammonium. Both anesthetics decreased INa, in a dose dependent manner, without changing the shape of the current-voltage curve. Halothane (1%) shifted the steady state inactivation curve in a negative direction along the potential axis by 8.5±2mV (mean±S.D., n=4). Thiamylal, 5×10-5 and 10-4M, shifted the curve in a negative direction by 4.4±0.8mV (n=5) and 8.6±3.2mV (n=5), respectively. Both agents slightly reduced the maximum sodium conductance (gNa). Halothane (1%) increased half recovery time from inactivation measured at -80mV from 30±15 to 80±25ms (n=4). Thiamylal (10-4M) prolonged it at -75mV from 50±20 to 110±15ms (n=5). With a test pulse duration of 50ms, neither drug produced a use-dependent inhibition of INa. Halothane and thiamylal depress the INa of cardiac muscles mainly by shifting the steady state inactivation curve in a negative direction along the potential axis. Relatively small prolongation of half recovery time from inactivation and no sign of use-dependent inhibition suggest a molecular mechanism which differs in some respects from the local anesthetics. Key words: halothane, isolated single cells, rat myocardium, sodium current, thiamylal.View full abstractDownload PDF (1129K) -
Hitoshi KOMURO, Tetsuro SAKAI, Akihiko HIROTA, Kohtaro KAMINO1986 Volume 36 Issue 1 Pages 123-137
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSSpontaneous action potentials were monitored from multiple sites in the bullfrog atrium using a voltage-sensitive merocyaninerhodanine dye together with a 100-element photodiode matrix array, and we have assessed the spread of the excitation from the pacemaker. Isochrone curves of conduction were obtained by timing the initiation of the action potential-related optical signals: we constructed maps of the spread. Excitatory waves appeared to conduct radially from the pacemaking area over the atrium, and the conduction velocity in the left atrium exceeded that in the right atrium.View full abstractDownload PDF (1065K) -
Contribution of the Receptor and Basolateral Membranes to the Resting Potential of a Frog Taste CellYukio OKADA, Takenori MIYAMOTO, Toshihide SATO1986 Volume 36 Issue 1 Pages 139-150
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSContributions of the receptor and basolateral membranes to the resting potential in bullfrog taste cells were studied by replacing the superficial and interstitial fluids of the tongue by various salines. When the interstitial K+ concentration ([K+]0) was increased to 100mM, the resting potential decreased by 45%. A similar increase in superficial [K+]0 decreased the resting potential by 15%. A simultaneous increase in both superficial and interstitial [K+]0 to 100mM decreased the resting potential by 60%. Total removal of Na+ from either the superficial or interstitial fluid increased the resting potential by 40%. Ouabain (10-4M) in the interstitial fluid decreased the resting potential by 30%, while the drug in the superficial fluid had no effect. Amiloride (10-3M) in the superficial fluid hyperpolarized the cells to 145%, while the drug in the interstitial fluid caused no change in the resting potential. Ca2+ -free superficial saline reduced the resting potential to 75%. Interstitial Ca2+ did not affect the resting potential. Total removal of either superficial Cl- or interstitial Cl- did not change the resting potential. These results suggest: 1) Na+ and K+ move across the receptor and basolateral membranes of the taste cell down their electrochemical gradients, 2) Na+ is extruded from the taste cell by the Na-K pump which exists only in the basolateral membrane, 3) the resting potential of a frog taste cell consists of the diffusion potentials of Na+ and K+ across the receptor and basolateral membranes, and the potential resulting from the activity of the electrogenic Na-K pump in the basolateral membrane.View full abstractDownload PDF (742K) -
Satipati CHATTERJEE, Bandana CHAKRAVARTI1986 Volume 36 Issue 1 Pages 151-162
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe maximum aerobic capacity (VO2 max) of young untrained Bengali girls aged between 22-24 years after maximum workload as determined by bicycle ergometer, standard step test and a treadmill is studied in 22 subjects. It was found that the VO2 peak in the treadmill exercise was significantly higher than that obtained by the step test and bicycle ergometer, in that order. On each type of ergometer, VO2 max was found to be positively correlated with body weight, body surface area, maximal pulmonary ventilation and maximal oxygen pulse.View full abstractDownload PDF (731K) -
Hideo INABA, Tetsuro OHWADA, Jiro SATO, Tadanobu MIZUGUCHI, Hiroyuki H ...1986 Volume 36 Issue 1 Pages 163-175
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSEffects of hemoglobin concentration (Hb), pH, and body temperature (T) on the relationships between ΔlogPO2/ΔT and PO2 were studied by means of a mathematical model using a Newton-Raphson iteration method. The functions between ΔlogPO2/ΔT and PO2 were affected by the above three factors. New equations considering the effects of Hb, pH, and T were proposed by modifying the equation reported by Severinghaus: ΔlogPO2/ΔT=(L+(U-L)/(A(vPO237)B+1))(10-2) where U=3.15-0.45(7.4-pH37) L=0.68-0.09(7.4-pH37) A=5.86(exp10(0.074(T)-0.294(7.4-pH37)-11))((Hb)0.913) B=6.33(exp10(-0.0051(T)))((Hb)-0.113)+0.24(7.4-pH37) and vPO237 is virtual PO237 which may exist when PO237 is corrected to standard conditions (pH=7.4, BE=0) by the following equations: vPO237=PO237(exp10(fB(7.4-Ph37)-0.0013(BE))) fB=(PO237/26.6)0.08-1.52 where fB is the Bohr factor. The above equations provided values of ΔlogPO2/ΔT which fit closely to those obtained by the complex iteration method with maximum differences of less than 1.3×10-3 at T=27, indicating that maximum % errors for PO2 at T (PO2T) are less than 3.0% at T=27 and that our equations can be applied over a wide range of Hb, Ph37 and T.View full abstractDownload PDF (742K) -
Yoshiyuki HONDA, Yoshio OHYABU, Midori SATO, Hidenori MASUYAMA, Yoshit ...1986 Volume 36 Issue 1 Pages 177-187
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSCross-sectional studies on hypercapnic and hypoxic ventilatory chemosensitivities were performed in 71 children ranging in age from 7 to 18yrs. The subjects were classified into 6 successive 2-year age groups. CO2 ventilatory response was measured by rebreathing 5% CO2 in O2, a slight modification of the method originally proposed by Read. The results were evaluated when the CO2-ventilation feedback control system was supposed to have attained the open-loop condition. Hypoxic ventilatory response was measured by the isocapnic progressive hypoxia test. To obtain good reproducibility in the ventilatory response, end-tidal PCO2 was maintained at 5mmHg higher than the resting condition throughout the test. Normalized ventilatory responses to CO2 by body surface area (S/BSA) progressively decreased from the 7-8 through the 11-12yr groups, and then tended to decrease further in a more gradual manner with increasing age. This trend was very similar to the normalized CO2 output (VCO2/BSA), but did not parallel so closely the normalized O2 intake (VO2/BSA). When ventilatory and metabolic parameters were normalized by body weight (BW), or the lean body mass (LBM), qualitatively similar relationships between CO2 sensitivities and metabolic parameters were also obtained. Contrary to the hypercapnic response, hypoxic ventilatory chemosensitivities were not significantly different among the 6 different age groups. We concluded that normalized hypercapnic chemosensitivity decreased during growth and corresponded well with decreased CO2 output per unit body mass.View full abstractDownload PDF (719K) -
Tsuyoshi NAKACHI, Nobusada ISHIKO1986 Volume 36 Issue 1 Pages 189-208
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe relationship between the gustatory input and motor output in the glossopharyngeo-hypoglossal reflex was analyzed on the basis of neuronal activities in the solitary tract and hypoglossal motor nuclei of bullfrogs. Concentration-response relations for NaCl, quinine and acetic acid, obtained from the glossopharyngeal (IXth) nerve and simultaneously recorded from the hypoglossal (XIIth) nerve, were expressed relative to the response of each nerve to 1M NaCl. Compared with a relatively small amount of the afferent input for acid, the reflex motor output was much larger in the relative value. A similarly high output relation was obtained for warmed saline but not for quinine and cooled saline. Although the responsiveness of the nucleus tractus solitarius neurons to 1M NaCl and 1mM quinine was not significantly different from that of the hypoglossal motoneurons, responses to 10mM acetic acid were greater in the latter neurons than in the former by a factor of about 5.2. These phenomena were consistent with those in the peripheral nerves. The solitary tract neurons responsive to NaCl, quinine and acid showed both the phasic and tonic components of discharges. According to classification by a transiency index, the discharge mode became more phasic for the hypoglossal motoneurons responsive to NaCl and quinine, but more tonic for those responsive to acid. The above-mentioned chemoreflex is thus regulated by the intrinsic neural network which sends signals to the XIIth nerve after modifying not only the amount but also the temporal pattern of gustatory nerve signals for a particular taste.View full abstractDownload PDF (1435K) -
Yasuichiro FUKUDA1986 Volume 36 Issue 1 Pages 209-213
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe frog sinus venosus shows spontaneous regular pacemaker activity, even in the absence of extracellular Ca2+. When an α-adrenergic blocking agent (phentolamine) is applied, the rate of pacemaker activity, height of action potential, rate of slow diastolic depolarization, and the maximum diastolic potential become strongly dependent upon the extracellular Ca2+ concentration.View full abstractDownload PDF (362K) -
Hiroshi NOSE, Masahiro MORITA, Takiko YAWATA, Taketoshi MORIMOTO1986 Volume 36 Issue 1 Pages 215-218
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSA method to measure circulating blood volume continuously on a conscious rat was developed using the dilution method of 51Cr-labelled red cell and changes in blood volume after drinking and food intake were monitored. In splenectomized rats, the blood volume showed a transient decrease of 0.1-0.2ml/100g body wt. about 30min after food intake, while increasing by 0.1-0.4ml/100g body wt. after water ingestion. Thus, blood volume showed fluctuations following water and food intake ranging from 2-8% of the circulating blood volume.View full abstractDownload PDF (259K) -
Yoshio MARUYAMA, Akinori NISHIYAMA, Teiichi TESHIMA1986 Volume 36 Issue 1 Pages 219-223
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSGiga-seal patch-clamp single-channel current recording was applied to the basolateral cell membrane of human salivary gland acinar cells. The results indicate that the presence of Ca2+- and voltage-activated K+-channel having a unit conductance of 160pS and Ca2+-activated Na+ permeable channel, having a unit conductance of 15pS.View full abstractDownload PDF (340K) -
Minoru SATO, Katsuaki YOSHIZAXI, Hayao KOYANO1986 Volume 36 Issue 1 Pages 225-230
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESS[3H]leucine was injected into the nodose ganglion of the rabbit following ipsilateral supranodose vagotomy to eliminate the vagal efferent fibers. Labeled materials were transported in afferent fibers of the vagus nerve at fast transport rates of 12cm/day and slow transport of 3-5cm/ day. In particular, axoplasm protein occupied about 40% of the highly labeled component of the slow transport, and the rate of this component was 1.8-2.5cm/day. It was assumed that the highly labeled component was transported to the diaphragm region within at least 8 days and to the gastrointestinal region within 10 days.View full abstractDownload PDF (423K) -
Takashi UENO, Takamitsu SEKINE1986 Volume 36 Issue 1 Pages 231-235
Published: 1986
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSCa2+-pump of sarcoplasmic reticulum was partially purified and solubilized with Triton-X100 in the presence of excess phospholipids. Vesicles were reconstituted by removal of Triton with Amberlite XAD-2 and the subsequent freeze-thaw/sonication method (Kasahara, M. and Hinkle, P. C. (1977) J. Biol. Chem., 252: 7384-7390). In the reconstituted system, H+ was ejected during Ca2+ uptake and in the initial Ca2+ uptake, the molar ratio of ejected H+ to Ca2+ was found to be about 1 in the presence of a permeant anion, SCN-.View full abstractDownload PDF (374K)
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