All issues
Successor
Volume 38 (1988)
- Issue 6 Pages 753-
- Issue 5 Pages 591-
- Issue 4 Pages 399-
- Issue 3 Pages 233-
- Issue 2 Pages 115-
- Issue 1 Pages 1-
Volume 38, Issue 5
Displaying 1-13 of 13 articles from this issue
- |<
- <
- 1
- >
- >|
-
Masaji MOCHIZUKI1988 Volume 38 Issue 5 Pages 591-605
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe kinetic energy of a gas molecule dissolved in an aqueous solution in the stationary state is inversely proportional to its solubility according to the distribution law of kinetic energy between the gas and liquid phases. From the difference in solubility, it is deduced that the gas molecule undergoes a change in energy in the passage across a heterogeneous interface, which is countered by a difference in energy level, or a gap in partial pressure, between the two sides. In order words, unless there is the gap in partial pressure, which has hitherto been disregarded in solving the diffusion equation, it is impossible to equalize the efflux of gas molecules with the influx. The relationship between the gap in partial pressure and the transfer rate is theoretically derived from the difference in solubility. The transfer rate is evaluated by multiplying the gap size by the transfer coefficient η, which in turn is expressed by an equation containing the unique value, k, for conductivity across the interface. Comparing the theoretical and experimental transfer coefficients obtained across the gas-liquid interface, the k value at which a gas traverses the liquid side per unit difference in partial pressure is estimated to be 6.58×10-3cm•s-1•Atm-1. Gas solubility in the RBC membrane is estimated to be ca. 22% of that in water, regardless of gas type, for O2, CO, and CO2. The increase in transfer coefficient across the RBC membrane by convection is explained by an additional change in kinetic energy in extracellular fluid attributable to an external force. The reduction in the transfer coefficient in the presence of increased protein is ascribed to an increase in kinetic energy of the membrane at the RBC boundary. The solubility in the membrane is linearly related to added protein concentration.View full abstractDownload PDF (1112K) -
Atsuko MASUDA, Poul-Erik PAULEV, Yoshikazu SAKAKIBARA, Byungchul AHN, ...1988 Volume 38 Issue 5 Pages 607-618
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSNine normal male subjects were studied at three levels of exercise (0, 40, and 80W). Single vital capacity breath test was applied at rest and during exercise (phases 2 and 3). Minimum minute ventilation found within 4 breaths following the test was compared to the control value. Significant depression in minute ventilation was invariably observed. The minute ventilation was depressed more and more with increasing intensity of exercise. A significant difference was found between exercise and rest. However, the relative contribution of chemoreceptor activity remained the same 10-20% at all exercise levels. The magnitude of ventilatory depression (ΔVresp)in phase 2 was larger than that in phase 3, when work rate increased to 80W, both relative and absolute.
A significant part of the exercise hyperpnea is due to peripheral chemoreceptor activity. The peripheral chemoreceptor activity is greater in phase 2 than in phase 3 at work rates of light to moderate intensity.View full abstractDownload PDF (839K) -
Mamoru FUJIMOTO, Nobuko HAGIWARA, Takahiro KUBOTA, Kunihiko KOTERA1988 Volume 38 Issue 5 Pages 619-641
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSUsing a direct cellular micropuncture technique with double-barreled ion-selective microelectrodes, we investigated the effect of dibutyryl-cyclic AMP (db-cAMP) on the membrane potential and the transport of Na+, K+, and H+ in doubly-perfused bullfrog proximal tubules. The peritubular membrane potential difference (EM) and the intracellular K+, Na+ activities ((K)i, (Na)i) or intracellular and luminal pH were monitored continuously after peritubular administration of db-cAMP (10-3-10-4M). Results: 1) db-cAMP hyperpolarized the EM by 8.0mV with an increase of (K)i by 4.8mEq/l; 2) the peritubular administration of high K+ (13.5 and 50mM) solutions depolarized the EM by 11.5 and 41.5mV, respectively. The high K+ perfusate with db-cAMP produced a depolarization to the same level as that in simple high K+ perfusion without db-cAMP; 3) db-cAMP transiently blocked the luminal acidification concomitantly with a cellular alkalinization by about 0.1 pH; and 4) db-cAMP caused a decrease of (Na)i by 5.0mEq/l. Conclusions: 1) cAMP causes an increase of K+ permeability in the peritubular membrane; 2) cAMP induces a cytosol alkalosis by enhancing incorporation of H+ into the subcellular vesicles, thus favoring the activation of Na+/K+ pump; and 3) cAMP, in effect, suppresses the Na+/H+ exchange mechanism in the luminal membrane and transiently blocks the proximal urinary acidification.View full abstractDownload PDF (2412K) -
Hiroshi HASUO, Takashi AKASU1988 Volume 38 Issue 5 Pages 643-658
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSIntracellular and voltage-clamp recordings were made from sympathetic B neurons to investigate an interaction between peptidergic and cholinergic responses in bullfrog sympathetic ganglia. Stimulations of both 3rd-5th (0.2Hz) and 8th (30Hz) spinal nerves evoked the fast excitatory postsynaptic potential (EPSP) superimposed with the late slow EPSP at the same sympathetic neuron. The amplitude of fast EPSPs was decreased during the course of the late slow EPSP in a majority of sympathetic neurons. The mean depression of the fast EPSP amplitude was 51±4% (n=24). The quantal content of the fast EPSP was also depressed by 54±3% (n=10) during the late slow EPSP. Acetylcholine- induced depolarization (ACh potential) and current (ACh current) produced by an ionophoretic application of ACh were not reduced during the late slow EPSP. Bath-application of LH-RH (40nM-4μM) depressed the fast EPSP in a concentration-dependent manner; at a concentration of 1μM, it produced a 63±8% (n=8) depression of the quantal content of the fast EPSP. LH-RH (1-4μM) depressed the frequency of the miniature (M) EPSPs by 25±4% (n=5) of control. Antagonists for luteinizing hormone- releasing hormone (LH-RH) receptor, [D-Phe2, 6, Pro3]-LH-RH and [D- pGlu1, D-Phe2, D-Trp3, 6]-LH-RH, prevented the presynaptic inhibition of the fast EPSP induced by LH-RH. These results suggest that the fast EPSP is depressed during the late slow EPSP by decreasing the evoked release of ACh from presynaptic nerve terminals in bullfrog sympathetic ganglia.View full abstractDownload PDF (1125K) -
Yoshito KINOSHITA, Akihiko IRIMAJIRI1988 Volume 38 Issue 5 Pages 659-675
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe fluoroprobe technique using a potential-sensitive dye, diS-C3(5), was applied to isolated enterocytes in order to correlate membrane potential changes with Na+/sugar cotransport. Cells were prepared from the chicken small intestine by enzymatic (Dispase) treatment combined with mechanical agitation. In the presence of Na+, addition of D-glucose (2mM) to the suspension of cells doped with the dye (1.8μM) gave rise to Na+-dependent increases in fluorescence indicative of depolarization of the cell membrane potential. The pH optimum for this response was ca. 7.3. Similar but smaller fluorescence increases were also evoked by D-galactose, α-methyl-D-glucoside, and 3-O-methyl-D-glucose, all known to be actively accumulated by enterocytes in a Na+-dependent fashion. These monosaccharide-evoked fluorescence changes were suppressed by lowering the extracellular Na+ concentration or by phlorizin. Monosaccharides with no reported Na+ requirement induced no such fluorescence responses. A disaccharide, maltose, elicited a smaller fluorescence increase which also was Na+ dependent and phlorizin inhibitable; this was interpreted as due to a possible supply of D-glucose by the membrane-bound disaccharidase systems. No change was observed with lactose, sucrose, or trehalose, however. The glucose-evoked fluorescence changes correlatable with depolarization were also confirmed using another carbocyanine, diO-C5(3). These results demonstrate that fluorescence from diS-C3(5) or diO-C5(3) can be a good measure for cotransport-associated membrane potential changes in isolated intestinal epithelial cells.View full abstractDownload PDF (1543K) -
Masuo SHIRATAKA, Fumiaki MARUMO, Kenji ANDO, Toshiro SATO1988 Volume 38 Issue 5 Pages 677-687
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSPlasma concentration and urinary excretion of immunoreactive human atrial natriuretic peptide (ir-hANP), aldosterone, and vasopressin were measured, and renal function and blood pressure were determined in six healthy male subjects in three periods of different sodium intake: the control (172mEq/day), low (20mEq/day), and high (285mEq/day) sodium period. Both plasma concentration and urinary excretion of ir-hANP increased significantly in the high sodium period but did not change between the control and low sodium periods. On the contrary, aldosterone increased and vasopressin decreased in the low sodium period but did not change between the control and high sodium periods. These results may point out the reciprocal action of both endocrine systems. The glomerular filtration rate changed in parallel with sodium intake whereas the fractional excretion of sodium decreased only in the low sodium period, probably reflecting the action of aldosterone.
It is concluded from these results that the atrial peptide may be an important component in the regulation of body fluid in the high sodium loading of physiological range but its action may be limited to the control of glomerular filtration rate.View full abstractDownload PDF (707K) -
Hiroaki TAKEKURA, Toshitada YOSHIOKA1988 Volume 38 Issue 5 Pages 689-697
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe effects of acute endurance running on the metabolic profiles of rat skeletal muscle were studied. Male Wistar strain rats were continuously run on a treadmill for 1h (speed, 35m/min; grade, 0 degrees). Soleus (SOL) and extensor digitorum longus (EDL) were removed after 30-min running, and a 0, 1, 6, 24, 48, and 72h post-exercise, and enzymes activity (CK, LDH, PFK, PK, SDH, and MDH) and substrates contents (glycogen and pyruvate) were measured biochemically. The time course of the enzyme activities showed two distinct patterns: CK, LDH, SDH, and MDH showed two peaks, at 0 and 24h post-exercise, while PFK and PK showed one peak at 0h post-exercise. The activities of glycolytic enzymes and CK in EDL and oxidative enzymes in SOL showed marked changes after exercise. The glycogen level was lowest at 0h post-exercise in both muscles and recovered to resting level by 24h post-exercise. Pyruvate increased with running and showed the highest value at 1h post-exercise. Increased oxidative capacity of skeletal muscle in response to the acute endurance exercise dropped gradually to the resting level by 48h post-exercise. An endurance exercise may induce a flexible adaptation on the oxidative capacity within skeletal muscle. We conclude that the respective time course of the enzyme activities must be considered when discussing metabolic changes that occur with acute endurance exercise.View full abstractDownload PDF (747K) -
Takashi NAKAHARI, Manabu MIYAMOTO, Hideyo YOSHIDA, Haruo TANAKA, Yusuk ...1988 Volume 38 Issue 5 Pages 699-712
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe electrical impedance of the dog submandibular gland, as an indicator of changes in extracellular fluid (ECF) volume, was measured at 5kHz, 500kHz, and 5MHz at intervals of 10s during secretory stimulation, because the conductivity calculated from impedance at low frequencies reflected the ECF volume. The decrease in conductivity occurred in the first minute of stimulation. Its decrease was more marked during stimulation after circulatory arrest. Salivary secretion under intact circulation consists of two phases: an initial secretion occurring in the first minute of stimulation with a high secretory rate and a steady secretion continuing during stimulation at a constant rate. A decrease in conductivity occurred in the initial secretion. Within a few minutes following the cessation of stimulation, the conductivity increased to a level higher than the resting one with an intact circulation, while the blood flow remained several times higher than in the resting state. The conductivity of the gland slowly recovered to the prestimulation level over a 30-min period. The histological examination revealed that the main compartment of the ECF change was the interlobular space. Impedance and histological studies showed that the ECF volume of salivary glands changes dynamically during secretion. On the other hand, the cellular volume also increased in the initial secretion of an isolated gland. Its increase suggested that the fluid was transported to the lumen via a cellular pathway as well as a paracellular pathway in the initial secretion.View full abstractDownload PDF (1439K) -
Takashi NOZAWA, Yoshio YASUMURA, Shiho FUTAKI, Nobuaki TANAKA, Masaaki ...1988 Volume 38 Issue 5 Pages 713-728
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWe studied the efficiencies from oxygen consumption (VO2) to external mechanical work (EW), from VO2 to the systolic pressure-volume area (PVA), and from PVA to EW, and the effects of cardiac output and contractility index (Emax) on these efficiencies in the left ventricle of open-chest, right-heart-bypassed dogs. PVA is an intermediate form of energy between VO2 and EW. PVA, EW, and Emax were determined by an abrupt occlusion of the ascending aorta. The right-heart bypass allowed us to collect all coronary venous return for VO2 measurement. The EW/VO2 efficiency ranged between 4 and 21%, the PVA/VO2 efficiency ranged between 5 and 27%, and the EW/PVA efficiency ranged between 60 and 95%. At a given Emax, EW/PVA efficiency was independent of cardiac output, but PVA/VO2 and EW/VO2 efficiencies increased with cardiac output. An increase in Emax by dobutamine increased EW/PVA efficiency, but decreased PVA/VO2 and EW/VO2 efficiencies. We could theoretically account for these changes in EW/PVA, PVA/VO2, and EW/VO2efficiencies of the in situ heart by the VO2-PVA relation and its dependence on Emax that we had observed.View full abstractDownload PDF (1196K) -
Seiji YAMADA, Masahiro KUBO, Yoshiaki HAYASHIDA1988 Volume 38 Issue 5 Pages 729-733
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSLymph flow into the thoracic duct of rats is reduced by 60% through immobilization with anesthesia. From this reduction, changes of the autonomic nervous activity by α-chloralose accounts for 20%. Pancuronium bromide blocking of the skeletal neuromuscular junction reduces lymph flow in the anesthetized rats by an additional 4%.View full abstractDownload PDF (361K) -
Joseph D. BRUTON1988 Volume 38 Issue 5 Pages 735-739
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSGlycerol treatment (0.4 or 1.2M) altered but did not abolish twitch, tetanus, potassium, or caffeine contractures in the rat soleus at 37°C. The use of nitrate Krebs or lithium Krebs greatly reduced the effects of 1.2M glycerol treatment on potassium contractures. The data indicate that the rat soleus is relatively resistant to the uncoupling effects of glycerol treatment and that both lithium and nitrate largely prevent these effects.View full abstractDownload PDF (288K) -
Mitsuko HAMAMURA, Tatsushi ONAKA1988 Volume 38 Issue 5 Pages 741-746
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWhether plasma vasopressin (VP) mediates footshock-induced analgesia was examined in conscious rats. Footshocks significantly increased threshold temperature of tail flick and plasma VP as reported previously. Intravenous VP increased the threshold only in doses that are considered to elevate plasma VP to a level more than 500 times higher than that after footshocks. In addition, posterior pituitary stimulation increased plasma VP to a level ten times higher than that after footshocks but did not significantly change the threshold. It is therefore highly likely that plasma VP is not involved in footshock-induced analgesia.View full abstractDownload PDF (482K) -
Akihiko ISHIHARA1988 Volume 38 Issue 5 Pages 747-751
Published: 1988
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSATPase reaction profiles of intrafusal fibers in the muscle spindle of the soleus muscle of 135-week-old rats were examined. Nuclear bag1 fibers contained an acid- and alkaline-labile form of the enzyme or an acid-labile and alkaline-stabile form, nuclear bag2 fibers contained an acid- and alkaline-stabile form, and nuclear chain fibers contained an acid-labile and alkaline-stabile form. These results indicate that the enzyme histochemical heterogeneity of intrafusal fibers is well-preserved during ageing.View full abstractDownload PDF (1044K)
- |<
- <
- 1
- >
- >|