All issues
Successor
Volume 27 (1977)
- Issue 6 Pages 687-
- Issue 5 Pages 525-
- Issue 4 Pages 391-
- Issue 3 Pages 267-
- Issue 2 Pages 135-
- Issue 1 Pages 1-
Volume 27, Issue 4
Displaying 1-10 of 10 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tadaaki SUMI1977 Volume 27 Issue 4 Pages 391-398
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIn rabbits, lightly anesthetized with ether, tetanic stimulation of the superior laryngeal nerve (SLN) displaced the jaw toward opening and reduced the amplitude of cortically evoked rhythmic jaw movements. With increased intensity of stimulus, the effects became remarkable and the opened jaw movement ultimately ceased. Reflex swallowing in reaction to weak electrical stimuli of SLN or to a small amount of water squirted into the oropharynx yielded a brief and instantaneous cessation of rhythmic jaw movements with the jaw open. Strong electrical stimuli to the nerve or a squirt of relatively large amount of water into the oropharynx prolonged the duration of both swallowing and the cessation of rhythmic jaw movements for about 1.0 sec.
Reflex swallowing yielded a burst of activity for about 300 msec in the mylohyoideus and silence for a longer period in the masseter. Spontaneous activity of the masseter was moderately decreased during the nerve stimulation and, when swallowing occurred, this decrease became prominent for a short period.View full abstractDownload PDF (852K) -
Takashi UCHIDA, Naoto SUZUKI1977 Volume 27 Issue 4 Pages 399-411
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe photically evoked secondary response of the visual cortex was studied in a rabbit anesthetized with pentobarbital sodium. The following results were obtained: 1) The secondary response (P2) under anesthesia was a simple positive potential having a long latency and resembled the primary response (P1) in waveform. 2) The latency of P2 shortened gradually as the recovery from anesthesia proceeded. 3) P2 was usually smaller than P1 in amplitude when evoked with a strong flash, but larger than P1 when evoked with a weak flash.4) Electrical stimulation of the superior colliculus (SC) induced in the visual cortex a positive potential which had a long latency comparable to that of P2. On the contrary, stimulation of the lateral geniculate body (LGB) evoked a short latency, positive potential similar to 131, but failed to evoke a positive potential comparable to P2. 5) A partial lesion of LGB led to a decrement of P1, while lesion of SC resulted in a decrement of P2. 6) Cooling of SC resulted in a rapid reduction and disappearance of P2 as well as the negative potential in SC. 7) There were a considerable number of visual cortical neurons which fired commonly during the phases of P1 and P2. These results suggest that P2 might be derived through the extrageniculo-cortical system which is relayed at SC. The mechanism by which P2 was manifested under anesthesia was discussed.View full abstractDownload PDF (1319K) -
Keizo SHIRAKI, Toshio YAMADA, Hisato YOSHIMURA1977 Volume 27 Issue 4 Pages 413-421
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSSports anemia induced by tennis training or exercising on a bicycle ergometer was studied in healthy male students. Since the anemia has been attributed to an increased susceptibility of red blood cells to lysis during exercise and influence by the nutritional status of the individuals has been suggested, the relation of sports anemia to the nutritional conditions of the subjects and to osmotic fragility of red cells were studied in groups by controlling protein levels in diets.
Anemia was most pronounced and the recovery from it was most prolonged in subjects with low protein diets, while it was least pronounced and the recovery was most rapid in subjects with high protein diets. The extent of increase in osmotic fragility of red cells was highest in subjects with low protein diets, and lowest in subjects with high protein diets.The erythropoietic responses to the exercise were different among the dietary groups; i. e., an early increase in blood reticulocytes in subjects with high protein diets and a late increase in subjects with low protein diets were observed during the course of training.
From above observations, we conclude that the extent of anemia is closely related to protein intake from the diets and that it is one of adaptive processes of individuals to strenuous physical training rather than an exaggeration of the physiological process of erythrocyte destruction.View full abstractDownload PDF (1011K) -
Teruo NAKAYAMA, Yoshito OHNUKI, Ken-ichi NIWA1977 Volume 27 Issue 4 Pages 423-437
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSDuring light work using the arm in a warm environment, skin temperatures of the arms and chest fell and remained at lower levels during work. The fall in skin temperature during work was not observed in a cool environment. The fall in skin temperature was nearly proportional to work intensity and was observed in both static and dynamic work. Leg work of moderate intensity produced an initial decline and a subsequent rise in skin temperatures of the hands, thighs and legs. A significant fall in skin temperature was observed not only in the foot but also in inactive regions such as the epigastrium. The mean skin temperature remained practically unchanged during work. The fall in skin temperature during work was not due to increased evaporative cooling, but was the result of segmental vasoconstriction probably caused as a reflex in the spinal cord by non-thermal afferents from exercising muscles or moving tissues. The effect of thermoregulatory vasodilation was reduced by the reflex vasoconstriction caused by non-thermal factors. The rise in internal temperature during work could be explained by decreased heat loss due to persistently lower skin temperature.View full abstractDownload PDF (1533K) -
Takehiko SEMBA, Tsuyoshi MIZONISHI, Yoshihito IKEDA, Yusho NAGAO1977 Volume 27 Issue 4 Pages 439-450
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe variations in both tonus and rhythmical motility of the intestinal musculature are known to affect profoundly intestinal blood fiow. In the present study, the influence of marked reflex inhibition of intestinal tone on the blood flow through an intestinal segment was investigated in the dog. Experiments were performed under conditions of both normal circulation and cross-circulation. Inhibitory reflex was elicited by elevating the intraluminal pressure of a loop or by electrical stimulation of the intestinal wall.
Fluctuations of blood flow during the intestinal inhibitory reflex were observed with normal circulation. Arterial and venous blood flows decreased in the initial period of intestinal relaxation, and recovered within 30 sec although reflex inhibition still remained. This is an autoregulatory escape phenomenon. In successive periods, arterial and venous blood flows decreased again due to “the venous-arteriolar response” and then recovered to the quiescent level. The decrease in venous blood flow corresponded to an increase of the degree of oxygen saturation in the venous blood.
The decreases in arterial and venous blood flows were observed during the inhibitory reflex even when the intestinal circulation was maintained by the cross-circulation. Two different patterns, i. e., the parallel and reversed patterns, were distinguished in correlation with venous blood flow and oxygen saturation. The autoregulatory escape phenomenon could not be elicited in the experiments in the cross-circulation system because variation of the systemic blood pressure during inhibitory reflex was limited to±4%.View full abstractDownload PDF (1140K) -
Hiroshi NISHIYE1977 Volume 27 Issue 4 Pages 451-466
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effect of Ca2+ concentration and temperature on the recovery of membrane potential after investigating lesions using sucrosegap technique in the guinea-pig papillary muscles were studied. At certain temperatures, this recovery showed increased accerelation with increasing Ca2+ concentration. The relation between rate constant of the recovery and Ca2+ concentration was quite similar to that of the reaction between an enzyme and substrate. This relationship could be expressed by the equation Y=xn/(Km+xn), where Y is the normalized rate constant and x the Ca2+ concentration. The coefficient, n, was evaluated by performing Hill's plot. The value of n largely changed between 1 and ca.2 at 32°C-37°C. The input resistance fell at the instant of formation of a lesion and started to rise with recovery of membrane potential. The resistance change after lesion formation was also observed in the potassium-Tyrode's solution in which Na+ was substituted with K+. The concentration-rate relationship of Ca2+ in the healing-over seems to indicate that Ca2+ binds to some molecules in the junctional membrane and produce a structural change of intercalated disc which brings about the healing-over. The large change of n suggests that Ca2+ has a cooperative action in the healing-over process, or alternatively that the state of membrane lipids has some effect on the process.View full abstractDownload PDF (1689K) -
Yushi ITO, Hikaru SUZUKI, Hirosi KURIYAMA1977 Volume 27 Issue 4 Pages 467-481
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of caffeine and procaine on the membrane and mechanical properties of the smooth muscles of the rabbit main pulmonary artery were investigated using microelectrode and voltage clamp methods. Caffeine (>0.5mM) depolarized the membrane and increased ionic conductance. On the other hand, procaine (>2.5mM) depolarized the membrane, generated spikes and reduced the ionic conductance of the membrane. When depolarization-contraction relations were observed, the threshold depolarization to evoke contraction and the amplitude of the contraction were not affected by 5mM procaine. However, the mechanical threshold was raised and the mechanical response was suppressed by treatment with 5 and 10mM caffeine or 10mM procaine. Procaine and caffeine accelerated the depletion of Ca++ from the stored sites in Ca-free (EGTA) solution, and suppressed the mechanical responses induced by chemical stimulation. Caffeine and procaine suppressed the increase in ionic conductance and depolarization produced by noradrenaline or prostaglandin F2α. Caffeine also suppressed the mechanical response induced by the above agents. Procaine suppressed the noradrenaline induced contraction, but accelerated the prostaglandin F2α induced contraction. From the above results, it is concluded that caffeine and procaine act not only on Ca-stored sites in the cell but also on the surface membrane. The actions of these agents were not competitive with each other, thus suggesting that the properties of the internal membrane structures, which is assumed to be a main Ca-storage site, are not exactly the same as those in striated muscles.View full abstractDownload PDF (1507K) -
Hidenobu MASHIMA1977 Volume 27 Issue 4 Pages 483-499
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSA frog ventricular muscle strip could be fully tetanized by alternating current stimulation at 10Hz and 20V/cm in a solution containing 9mM Ca2+.During isometric tetanus, the controlled release was made and the shortening velocities against various loads were measured.The isometric force was varied by reducing the stimulus intensity in K+-rich solution, or by reducing the external Ca2+ concentration. The force-load-velocity relation was described by a simple hyperbolic equation:(P+A)(ν+b) =b(F+A), A=(F/Fm) a for shortening, and (2F-P+A')(-ν+b') =b'(F+A'), A'=(F/Fm) a' for lengthening, where F is the isometric force, Fm is the maximum isometric force at the optimal muscle length, Lm, P is the load, ν is the velocity, a, b, a' and b'are constants. The values of constants were a/Fm=0.51, b=0.75 Lm/sec for shortening and a'/Fm=0.39, b'=0.75 Lm/sec for lengthening at 20°C. At muscle lengths shorter than 0.92 Lm, the internal load defined as the difference between the external load and calculated load at a given velocity increased in proportion to both the velocity and the decrease in muscle length.View full abstractDownload PDF (1674K) -
Saburo MATSUBARA, Toshio SAKAI, Kohji HASHIZUME1977 Volume 27 Issue 4 Pages 501-509
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSCl--induced contraction was studied in a skinned fiber dissected from toad sartorius muscle. When K-methanesulphonate in a relaxing solution was replaced isotonically with KCl, the skinned fiber contracted due to ‘depolarization’-induced Ca++release on the SR. Contraction was induced by superfusing the fiber with solutions containing different concentrations of Cl-. In the presence of 2mM EGTA, the Cl--induced contraction developed when the relaxing solution was replaced by a Crsolution which contained up to 20mM Cl-, while contraction started at 15mM-Cl-in the presence of 0.5mM EGTA. The peak tension of the Cl--induced contraction depended on Clconcentration without obeying the all-or-none law.When the fiber was treated with 1.5mM caffeine, the threshold for the Cl--induced contraction was significantly lowered.
In spite of previous application of Cl- at different concentrations below 80mM, the skinned fiber contracted by sudden increase in Cl-concentration, and the tension versus Cl-concentration curve revealed almost the same shape as that in a fiber equilibrated with Cl--free solution. This suggests that the SR membrane is repolarized after transient depolarization caused by elevation of Cl-concentration.View full abstractDownload PDF (917K) -
Isao KOSAKA, Isao OOTA, Toshiko SUZUKI, Torao NAGAI1977 Volume 27 Issue 4 Pages 511-524
Published: 1977
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effect of the extracellular Ca depletion on potassium contracture was investigated in single fibers isolated from frog semitendinosus muscle mainly in relation to its time and Na dependency. The shortening of plateau duration and the increase in the rate of relaxation of the potassium contracture appeared within 3-5 sec and 15sec, respectively, after the fiber was immersed in Ca-free Na Ringer solution containing 1mm ethylene glycol bis (β-aminoethyl ether)-N, N'-tetraacetic acid (EGTA)(EGTA-Na Ringer solution) or Ca-free choline Ringer solution containing 1mm EGTA (EGTA-choline Ringer solution). These effects were independent of the presence or absence of extracellular Na. In EGTA-Na Ringer solution, the potassium contracture tension was inhibited only by about 20% after 20-90min andwas abolished after 120min. The inhibition of the peak tension was accelerated by the depletion of extracellular Na;in EGTA-choline Ringer solution, the tension was gradually inhibited by about 20 during the first 7min and abolished after 10-12min. When the peak tension of potassium contracture was abolished in EGTA-choline Ringer solution, the depolarization by Ca depletion was about 10mV and the caffeine contracture was sufficiently produced. The results suggest that the inhibition of the potassium contracture tension in EGTA-choline Ringer solution is due to the dissociation of excitationcontraction coupling. On the basis of these results, an aspect of the inactivation of the potassium contracture was proposed.View full abstractDownload PDF (1653K)
- |<
- <
- 1
- >
- >|