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Volume 24 (1974)
- Issue 6 Pages 569-
- Issue 5 Pages 463-
- Issue 4 Pages 359-
- Issue 3 Pages 249-
- Issue 2 Pages 135-
- Issue 1 Pages 1-
Volume 24, Issue 4
Displaying 1-7 of 7 articles from this issue
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Masayosi GOTO, Yasuo WADA, Masahiko SAITO1974 Volume 24 Issue 4 Pages 359-375
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1) Development and fall of tension during depolarization in the bullfrog atrial muscle were studied using a double gap voltage clamp arrangement.
2) Phasic and tonic tension developments and the following decay were noticed in the tension produced by depolarizing pulse of different durations and amplitudes. The phasic component appeared in response to a short-lasting pulse (0.1-0.2 sec), and reached a peak tension at around 73 mV depolarization, being depressed for stronger pulses. La (1 mM) and Mn ions (5 mM) eliminated the component.
3) Tonic contraction was generated by long-lasting depolarization. The development of tension was not affected by these ions, but increased in strength and duration of depolarizing pulse up to 170 mV and 1.0 sec.
4) When a depolarizing pulse was sustained, the tonic tension decayed gradually after the peak. The tension decay was composed of three different phases, initial retardation, relatively rapid relaxation and extremely slow final relaxation.
5) The rapid relaxation phase appeared exponential with time when an excess tension above provisional final tension (sustained tension) was plotted, but the time constant increased with strength of depolarization.
6) Logarithm of the final tension appeared proportional to the membrane depolarization in between 20 to 100 mV. Under the simultaneous presence of La (1 mM) and caffeine (10 mM) the tension decay during depolarization was abolished resulting in a marked elevation of the final tension.
7) The final tension under normal conditions was considered to be equilibrium tension between the tonic tension and relaxing components, and thus, at least three components, the phasic and tonic tensions and a relaxing factor, appeared to control muscle contraction during depolarization.View full abstractDownload PDF (8772K) -
Tomiyasu KOYAMA, Susumu NAKAJIMA1974 Volume 24 Issue 4 Pages 377-388
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIn order to measure a rapid change in pulmonary blood flow the suitability of a glow discharge gas analyser for the continuous analysis of C2H2 was examined. The analyser was originally designed for continuous analyses of O2 and CO2 in expired air. However, we found that it responded specifically to C2H2, when a gas mixture containing 5% O2, 40% CO2 with a balance of N2 was used as a carrier gas and a negative voltage of 20 V was applied to the proximal collector electrode against the distal. Under these conditions the C2H2 current was reproducible within 0.1 mmHg, the base line drift was smaller than 1 mmHg/hr and the 90% response time was about 0.6 sec. This method was applied to analysis of C2H2 in expired air in combination with a constant rate expiration technique. When a C2H2 gas mixture was inhaled and expired at a constant rate, the observed C2H2 curves agreed with the theoretical ones calculated at the pulmonary blood flow rates obtained separately with the conventional breath-holding method. The decay rate of the C2H2 curve showed a rapid change within 1.5 sec when exercise and a Valsalva-like maneuver were made during continuous expiration, suggesting a quick alternation in pulmonary blood flow.View full abstractDownload PDF (1114K) -
Masahiko SATOU1974 Volume 24 Issue 4 Pages 389-402
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1. The electrical responses obtained at various levels of the olfactory pathway when the nose of the himé salmon, a landlocked Pacific salmon, Oncorhynchus nerka, was infused with an odorous solution, were analyzed in terms of the frequency components by means of active band-pass filters.
2. The responses of the olfactory nerve appeared over a wide frequency range (20-315 Hz, the major frequency component being 40-125 Hz). It was composed of two kinds of frequency components, i.e., the 20-125 Hz components, which did not adapt during the stimulation, and the 125-315 Hz components, which adapted rapidly.
3. The responses in various regions of the olfactory bulb appearing in a narrower and lower frequency range (3.15-20 Hz, the major frequency component being 5-8 Hz) were compared with those from the olfactory nerve. They consisted of two kinds of frequency components, i.e., the 3.15-5 Hz components, which did not adapt during the stimulation, and the 5-20 Hz components, which adapted rapidly.
4. The responses in various regions of the olfactory lobe were almost identical with those of the olfactory bulb.
5. The activities in the 5-12.5 Hz frequency components were also seen in the responses obtained from both the olfactory lobe and the olfactory bulb on the contralateral side.
6. It is suggested that an asynchronous firing of the olfactory nerve fibers is largely converted to a synchronous one at the levels of the olfactory bulb.
7. The signal propagation through the olfactory pathway and the controlling mechanism of olfactory adaptation are discussed.View full abstractDownload PDF (1451K) -
Uichiro KISHIMOTO1974 Volume 24 Issue 4 Pages 403-417
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe voltage clamp method was used for determining transmembrane impedance of the internodal cell of Chara. Between 1 Hz and 1 kHz the impedance locus on a complex plane was generally not a circular arc, but could be successfully simulated by equivalent circuit models having two time constants.View full abstractDownload PDF (3965K) -
Kiyoshi MORIYA, Hiroshi MAEKUBO, Shinji ITOH1974 Volume 24 Issue 4 Pages 419-431
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of norepinephrine infusion on rectal temperature, plasma FFA concentration and its turnover rate were studied in intact and functionally eviscerated rats.
Norepinephrine infusion caused a greater increase in the rectal temperature, and less elevation in plasma FFA concentration in cold-acclimated rats in comparison with the changes in warm-adapted control rats.
Norepinephrine infusion also brought about a significant increase in the turnover rate of plasma FFA in both groups of rats. The regression coefficient of plasma FFA turnover rate versus FFA concentration was greater in cold-acclimated group than in the controls. It was assumed that peripheral capacities of FFA uptake were greater in cold-acclimated rats than in the controls.
The thermogenic effect of norepinephrine in eviscerated rats did not differ from that in non-eviscerated rats. The infusion caused an increase in the rectal temperature in eviscerated cold-acclimated rats, but not in warm-adapted ones. Norepinephrine infusion produced a similar marked elevation in plasma FFA concentration in both eviscerated coldacclimated and warm-adapted rats, while increase in FFA turnover rate was much greater in the former group than in the latter. The regression coefficient of plasma FFA turnover rate on its concentration was greater in eviscerated cold-acclimated rats than in the controls.View full abstractDownload PDF (1300K) -
Takuro OSA, Takashi KATASE, Tateki SHIBATA1974 Volume 24 Issue 4 Pages 433-450
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of placental extract (and perfusate) obtained from humans or rats were studied by recording the electrical and mechanical activities of pregnant rat and mouse myometria.
1) Membrane potential of circular muscle cells of pregnant rat myometrium ranged between 50-60 mV. Slow potentials amounting 20-30 mV dominated the circular muscle cells in contrast to spike potentials in the longitudinal cells.
2) The placental extract (as well as rat uterine perfusate) reduced the magnitude of spontaneous contractions of myometrial strips of mouse and rat. The inhibitory effect on contractile response became more pronounced when Mg ions were present in the bathing media. The extracts did not cause a significant change in the membrane potential or action potential discharge, but the compound action potential recorded extracellularly was depressed.
3) The extracts potentiated the mechanical response, when the myometrial tissue from pregnant animals was treated with β-blocking agent (10-7g/ml propranolol) or with bretylium (10-5g/ml).
4) It was argued that placenta and endometrium of the pregnant animal release bioactive substances including a certain inhibitory agent which may cause the depressant effect on the conducting mechanism of excitation, possibly through an indirect action in releasing the endogenous catecholamines.View full abstractDownload PDF (9347K) -
Takashi KATASE1974 Volume 24 Issue 4 Pages 451-461
Published: 1974
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1. Effects of bicarbonate removal and of decreasing external pH on the mechanical and electrical activities in isolated strips of the guinea pig uterus were investigated.
2. When bicarbonate was reduced at 37°C, a high degree of contractile activity was observed, which was associated with high frequency spike activity. However, when the same experiment was repeated at 21°C, the activity was suppressed. These sustained contractions were produced whether the HCO-3-free solution was acid (pH: about 6) in the presence of 3% CO2, or the solution was alkaline (pH: about 8) in the absence of CO2.
3. When the pH of the solution was decreased to 6 by 5mM tris malate buffer, the mechanical activity was also increased in the presence of 15.5mM HCO-3.
4. In low Cl- (7 mm) Krebs solution the mechanical activity depended on the substitute for Cl-: substitution with isethionate reduced or stopped the activity, while substitution with NO-3 increased the activity. The increase in activity on HCO-3 removal was less in isethionate solution and much larger in NO-3 solution.
5. At a lower temperature (21°C), HCO-3 removal suppressed the activity when O2 containing 3% CO2 was bubbled through the solution.
6. It is suggested that HCO-3 removal and acidification increase Cl-permeability of the membrane and that this leads to high spontaneous activity. It is also possible that modification of the external buffer system may affect the internal pH and metabolism, which in turn modifies spontaneous activity.View full abstractDownload PDF (910K)
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