巻号一覧
29 巻, 2 号
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津田 泰夫1979 年 29 巻 2 号 p. 103-117
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーIn frog atrium, K depletion exerts initial, and late positive inotropic effects. The initial effect on the membrane potential, current and tension components was studied using a double gap method under voltage clamped and unclamped conditions. In both cases, the presence of the initial effect was demonstrated. The effect was clearer in preparations in which a positive inotropic effect to toxic doses of ouabain (10-6 M) had already been attained. This suggests that the initial phase is independent from Na-pump inhibition. Voltage clamp study revealed that the slow inward calcium current (ICa) was enhanced transiently after K depletion concomitant with an augmentation of ICa-dependent phasic tension.ICa-independent tonic tension was not altered at this initial phase. For the enhancement of ICa, two mechanisms appeared to be involved, one an enhancement of gCa and the other a faster and/or longer opening of the slow channel.
These results indicated that an enhancement of ICa together with the wellknown prolongation of action potential were the cause of the initial positive inotropic effect of K depletion.抄録全体を表示PDF形式でダウンロード (1451K) -
竹内 亨, John W. MANNING, 宮川 清1979 年 29 巻 2 号 p. 119-130
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーAfter the blood supply to the head was surgically limited to one common carotid artery in rabbits, the artery was compressed by exertion of stepwise elevated side pressure on a segment of the artery. Systemic arterial pressure rose and began to oscillate when the side pressure was increased to 50 to 60 mmHg. The oscillations were regular and occurred at a rate of 3 to 4 per minute with a wave height of 15 to 45 mmHg. Concomitant with systemic pressure oscillations, and in near synchrony were undulations in the perfusion pressures recorded during constant flow from the vascularly isolated abdominal skin, skeletal muscle and small intestine. With the graded elevation of side pressure on the common carotid artery, mean systemic pressure and perfusion pressure showed a nearly exponential relation. The ratio between the two variables was slightly less than one below the systemic pressure of 120 mmHg and rapidly increased above this level. At ratios greater than one, the peripheral resistance undulations in the isolated areas gave a larger minimum and maximum, a sharper contour and, particularly in the skin, a phase lag in the period of the wave form when compared to the systemic pressure oscillations. These observations highlight the differences in response characteristics of peripheral resistance vessels and those of cardiac output and different consecutive parts of the systemic arteries during periods of intense sympathetic activation.抄録全体を表示PDF形式でダウンロード (1249K) -
青峰 正裕1979 年 29 巻 2 号 p. 131-138
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe kinetics of the inhibitory action by N-ethylmaleimide (NEM) on ICa-independent tonic tension in bullfrog atrial muscle was studied under voltage-clamped conditions, using the double sucrose gap method. The higher the concentration of NEM became, the larger was the rate of decrease of the tonic tension. In addition, the tension decreased with time of exposure to NEM. When the rate of the decrease of the tonic tension was plotted as a function of NEM concentration, the curve showed saturation kinetics of the Michaelis-Menten type with respect to NEM concentration, following the characteristics of a carriermediated process. Moreover, in the presence of excess Ca or half quantity of Na in Ringer solution, the curve showed sigmoidal kinetics. This probably indicates that the condition of either an excess of Ca or a reduction of Na in Ringer solution is apparently a cooperative effector of the inhibitory action of NEM, suggesting that the carrier protein responsible for the generation of tonic tension may be an allosteric protein. Finally, the relationship between ICa-independent tonic tension and the Na-Ca exchange mechanism which is supposed to be a powerful candidate for generating tension was discussed.抄録全体を表示PDF形式でダウンロード (812K) -
土居 勝彦, 黒島 晨汎1979 年 29 巻 2 号 p. 139-150
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe effect of short and repetitive exposure to cold (5°C, 4 hr/day for 2 weeks) from the birth up to the 14th day of newborn rats on the thermal regulation in adulthood and on the tolerance to cold was investigated. After being exposed to cold, they were transferred to a room at 25°C (N-CA). The control rats were raised at 25°C (N-WA). An acute cold exposure test was performed by placing the animals in a room at 5°C under urethane anesthesia. Electrical activity of neck muscles as an index of shivering was recorded.
The colonic temperature fell at a significantly slower rate in N-CA rats with less shivering than in N-WA ones. Nonshivering thermogenesis tested by norepinephrine was significantly greater in N-CA rats than in N-WA ones. These results suggest that N-CA rats developed improved cold tolerance accompanied by greater nonshivering thermogenesis. Such a phenomenon in N-CA lasted for 18 weeks after the termination of cold exposure. Adult rats subjected to the same scheme of cold exposure (A-CA)(5°C, 4 hr/day, 2 weeks) showed essentially the same results as seen in N-CA, but its improved cold tolerance and elevated nonshivering thermogenesis disappeared 4 weeks after the termination of cold exposure. Extirpation of interscapular brown adipose tissue immediately before the cold test did not appreciably affect the cold tolerance in N-CA and A-CA rats. The colonic temperature at the onset of shivering was significantly lower in N-CA as well as A-CA rats than in each of the corresponding control rats, indicating a shift of the shivering threshold to lower temperature values in the animals exposed intermittently to cold.
These results indicate that an infantile experience with cold results in a greater and longer sustained ability to tolerate cold in adulthood, characterized by enhanced nonshivering thermogenesis.抄録全体を表示PDF形式でダウンロード (1204K) -
登倉 尋実, Jürgen ASCHOFF1979 年 29 巻 2 号 p. 151-157
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーLocomotor activity was recorded from three squirrel monkeys, Saimiri sciureus, housed singly in cages inside a sound-proof chamber. Each animal was exposed twice to each of three conditions: continuous dim illumination (dim LL), continuous bright illumination (bright LL), and conditions in which the animal could turn on bright light by itself (self-controlled light-dark cycle: LDS). The mean circadian period, τ, the activity time, α, and the amount of activity, A, were computed for each single condition. It was found that, in LL, τ, α and A were positively correlated with the intensity of illumination. In LDS, τ was longer and A larger than in either dim or bright LL. The lengthening of τ in squirrel monkeys by a self-controlled light-dark cycle is compared with similar findings in birds and man, and is discussed in view of the observation that the τ-characteristics of diurnal mammals deviate from those known from other diurnal species of vertebrates.抄録全体を表示PDF形式でダウンロード (694K) -
梶塚 隆光1979 年 29 巻 2 号 p. 159-172
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe effects of a single electrical stimulus upon the longitudinal and circular muscles of rabbit small intestine were investigated and the differentiation between phasic and tonic contractions was examined. A weak stimulus caused a phasic contraction and a stronger stimulus evoked both phasic and tonic contractions. The evoked phasic contraction was of an all-or-nothing nature, while the evoked tonic contraction was graded. Strength-duration curves of longitudinal and circular muscles were obtained for both phasic and tonic contractions which could be differentiated by the values of rheobase and chronaxie. In the presence of verapamil or methoxyverapamil (D 600) the tonic contraction, but not the phasic contraction, could be evoked by a single strong stimulus, while in the presence of sodium nitroprusside the phasic contraction, but not the tonic contraction, could be provoked by a single strong stimulus. The phasic and tonic contractions differed in their strengthduration curves and drug responses.抄録全体を表示PDF形式でダウンロード (1586K) -
高野 成子, 毛利 元彦, 永坂 鉄夫1979 年 29 巻 2 号 p. 173-180
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe thermogenic response and rectal temperature (Tre) of newborn rats (0 to 32 days old) on exposure to various ambient temperatures (Ta) were investigated. The O2 consumption ( Vo2 in ml·min-1 per 100 cm2 surface area) was measured for one rat at a time by means of a closed circuit system. The results were that (1) within the thermal neutral ranges, Tre stood at 36-37°C regardless of the age and the value of Vo2 was lowest at the age of 6-7 days, after this period increasing and reaching a level of 1.4 ml·min-1·cm-2×10-2 after 18-21 days old (the weaning period);(2) the thermogenic response to cold (ΔVo2/-ΔTa) was higher at ages prior to the weaning period than after the weaning period;(3) in spite of the higher thermogenic responses, Tre decreased markedly on exposure to cold prior to the weaning period, because of a poor development of thermal insulation; and (4) the achievement of homeothermy of the rat at subneutral temperatures was observed after the weaning period.抄録全体を表示PDF形式でダウンロード (816K) -
田中 義文1979 年 29 巻 2 号 p. 181-193
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーInfusion experiments with Ringer's solution were performed on 5 splenectomized dogs with continuous monitoring of blood volume and hematocrit. The plasma volume was calculated from these data and followed during the infusion and also during the recovery period. Applying electrical equivalent simulation analysis to the result of the plasma volume, the capacitance of the interstitial fluid space and the transvascular filtration coefficient of water in the whole body were determined simultaneously. The mean values of the capacitance and the coefficient were 5.91 ml/kg-mmHg and 0.314 ml/min-kg-mmHg, respectively. From this simulation study, a transfer function which predicts the fluid shift between the vascular system and the interstitial fluid space was also derived. Using the transfer function, predictions of the changes in plasma volume are possible from any given rate of infusion.抄録全体を表示PDF形式でダウンロード (1250K) -
尾崎 毅1979 年 29 巻 2 号 p. 195-209
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe effects of repetitive electrical stimulation of a node of Auerbach's plexus on both longitudinal and circular muscles were investigated by simultaneous recording of both muscle contractions. L-formed muscle strips, longitudinal and circular muscle strips, were made from a segment of rabbit small intestine. One strip was cut along, another strip was cut at 90° to the oral-anal axis. The longitudinal muscle strip was peeled and Auerbach's plexus was exposed. Under a stereodissecting microscope the stimulating electrode, with tip diameter of 5-10μm, was placed on a node of Auerbach's plexus situated at the junction of both muscle strips. Repetitive electrical stimulation of a node produced a mainly excitatory effect on spontaneous contractions of an orally-directed longitudinal muscle strip, excitatory and inhibitory effects on an anally-directed longitudinal muscle strip and a mostly excitatory effect on a circular muscle strip which always appeared with a delay after that on the longitudinal muscle. In a few instances the inhibitory effect of nodal stimulation was observed on the circular muscle. The evoked excitatory effect of longitudinal muscle was mainly due to a cholinergic mechanism, while that of circular muscle was partially due to cholinergic and partially noncholinergic activity. The evoked inhibition was nonadrenergic.抄録全体を表示PDF形式でダウンロード (1852K) -
吉崎 和男, 西川 弘恭, 山田 誠二, 森本 武利, 亘 弘1979 年 29 巻 2 号 p. 211-225
発行日: 1979年
公開日: 2011/06/07
ジャーナル フリーThe 31P-NMR technique was used for the monitoring of intracellular pH and studying its heterogeneity in the femoral biceps muscle of Rana catesbiana under anaerobic conditions.
The value of intracellular pH of fresh muscle calculated from the chemical shift of intracellular inorganic phosphate (P1) was 7.3 on average and the line width of P1 was about 0.2 ppm. As the line width determined by the relaxation mechanism was 0.099 ppm, the Pi signal in fresh muscle was concluded to consist of overlapped narrow components, which indicated the heterogeneity of muscular pH (about 0.2 pH unit).
Living muscle showed gradual acidification due to glycolysis and the decrease in heterogeneity. When glycolysis was suppressed by iodoacetic acid, slight alkalization due to the breakdown of creatine phos phate was observed. When the Lohmann reaction was suppressed by 2, 4-dinitro- 1 -fluorobenzene, rapid acidification accompanied by the appearance of a new acidic component was observed with the onset of ATP decrease. This new component was not detected in the muscle pretreated with glycerol to disrupt the transverse tubules. Therefore, it is likely that this new acidic component originates in the intracellular compartment, and not in the cellular difference.抄録全体を表示PDF形式でダウンロード (1552K)
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