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Volume 37 (1987)
- Issue 6 Pages 967-
- Issue 5 Pages 761-
- Issue 4 Pages 559-
- Issue 3 Pages 341-
- Issue 2 Pages 169-
- Issue 1 Pages 1-
Volume 37, Issue 6
Displaying 1-10 of 10 articles from this issue
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Yoshio NAKAJIMA, Saburo HOMMA1987 Volume 37 Issue 6 Pages 967-977
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSNerve impulses are generally regarded as spike train and analyzed by use of various kinds of so-called time series analyses. Cross-correlation analysis is used to reveal temporal and/or spatial relationships between more than two spike trains in the neuronal circuit, in which two neurons are synaptically connected or two neurons are independent but receive a common input. Three main characteristics of discharge dependency between two neurons become clear from the cross-correlation histogram: 1) the direction of dependency; 2) the latency of interaction; and 3) the type of functional connections between the neurons. We reviewed the cross-correlation analysis from these points of view: 1) what is cross-correlation analysis; 2) what are primary and secondary effects; 3) what kinds of functional information can be obtained from the shape of the primary effect; 4) how sensitively cross-correlation can detect neuronal interaction; 5) how to express quantitatively the primary effect; 6) what kinds of extension technique are available from cross-correlation; and 7) research trends using cross-correlation analysis.View full abstractDownload PDF (956K) -
Tadashi KASHIWAGURA, Takaki KAGAYA, Noriaki TAKEGUCHI1987 Volume 37 Issue 6 Pages 979-993
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSEffects of caffeine on gluconeogenesis and urea synthesis of rat isolated hepatocytes were investigated in the presence of hormonal agonists. Phenylephrine at 10μM stimulated 1.7-fold gluconeogenesis and 1.9-fold (compared to control) urea synthesis from 4mM glutamine. Stimulative effects of caffeine in the range from 0.1 to 10mM were biphasic depending on its concentration, and it showed maxima at about 1mM. Caffeine at 1mM stimulated 2.1-fold gluconeogenesis and 2.4-fold urea synthesis. Caffeine without phenylephrine did not stimulate both syntheses. These effects of caffeine and phenylephrine diminished in the absence of extracellular Ca2+. Results on uptake of 45Ca2+ into hepatocytes and change in quin-2 fluorescence indicated that phenylephrine induced Ca2+ influx into the cell and consequently increased the intracellular Ca2+ concentration, [Ca2+], and that the addition of caffeine did not further stimulate the effect of phenylephrine on [Ca2+]. Therefore, we suggest that stimulation of gluconeogenesis and urea synthesis by phenylephrine is due to increase in [Ca2+]. Since caffeine is known to inhibit phosphodiesterase, the additional stimulation of both syntheses by caffeine plus phenylephrine may be due to the synergistic effect of increases in cAMP and [Ca2+]. The increase in the rates of gluconeogenesis and urea synthesis similarly depended on the caffeine concentration. Furthermore, the ratio of [acetoacetate]/[3-OH-butyrate] which shows intramitochondrial redox state, also depended on the caffeine concentration, indicating a possible coupling of the redox function of mitochondria with [Ca2+].View full abstractDownload PDF (1050K) -
Toshiharu OBA, Takako AOKI, Guo-hua LIU, Ken HOTTA1987 Volume 37 Issue 6 Pages 995-1003
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSTo evaluate usefulness of Ag+ contracture as a tool for elucidating the mechanism underlying the excitation-contraction coupling, the effects of tetracaine on Ag+ contracture were compared with those on K+ and caffeine contractures in frog skeletal muscle. Tetracaine less than 100μM shortened the duration of 120mM K+ contracture, without affecting tension amplitude. At higher concentrations of tetracaine, K+ contracture was inhibited dose-dependently and the duration shortened. Treatment of the fibers with 20-500μM tetracaine for 3min did not block the contracture induced by 25mM caffeine. Effects of tetracaine on Ag+ contracture were similar to those on K+ contracture. In the presence of 200μM tetracaine, 41% inhibition was observed in 120mM K+ contracture, while 43% in 100μM Ag+ contracture. Also, 200μM tetracaine completely inhibited the contractures induced by 40mM K+ or 5μM Ag+. These findings suggest that the Ag+ may induce contractures via its action on the T/SR junction, not a direct action on the SR. Therefore, understanding the mechanism involved in the development of Ag+ contracture would be helpful to elucidate the mechanism of excitation-contraction coupling.View full abstractDownload PDF (649K) -
Hideki ITO, Koh MATSUDA, Akio SATO, Hideo TOHGI1987 Volume 37 Issue 6 Pages 1005-1017
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe present experiment was performed to investigate the effect of stimulating the parasympathetic superior laryngeal nerve (SLN) on thyroid blood flow and its mediator substances in urethane-chloralose anesthetized rats. Thyroid blood flow was measured by counting number of blood drops from a thin catheter inserted into the thyroid vein. SLNs were cut bilaterally and their peripheral portions were electrically stimulated. Electrical stimulations (intensity, 10V; pulse duration, 0.5ms) of SLNs increased thyroid blood flow in a frequency-dependent manner as stimulus frequencies increased from 2 to 40Hz. The intravenous administration of atropine (0.5mg/kg) reduced these responses, but did not abolish them. The basal secretion rate of vasoactive intestinal peptide (VIP). from thyroid glands in the resting state was nearly zero (0.25±0.14pg/(kg•min)). SLN stimulation increased markedly the VIP secretion rate to 3.40±0.64pg/(kg•min). The VIP secretion responses evoked by SLN stimulation remained in atropinized rats. Furthermore, exogenously applied VIP increased the thyroid blood flow dose-dependently. These results suggest that SLN stimulation increases the thyroid blood flow by dilating thyroid blood vessels via activation of cholinergic and non-cholinergic (probably VIP-containing) nerve fibers. Thus, these parasympathetic vasodilation systems may play a supplementary role in regulating the secretion of thyroid hormone by changing the thyroid blood flow in addition to the role of hormonal regulation by the thyroid stimulating hormone (TSH).View full abstractDownload PDF (1021K) -
Masahiro MORITA1987 Volume 37 Issue 6 Pages 1019-1029
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSTo analyze the change in blood volume after intestinal absorption, circulating blood volume was continuously monitored in rats after infusion of various solutions into the small intestine. Arterial and venous catheters were connected to a system for continuous monitoring of blood volume by the dilution method using 51Cr-labeled erythrocytes. Test solutions (tap water, 0.45, 0.9, 1.8% NaCl, 0.45% NaCl with 2% glucose, and 5% glucose) were infused at a rate of 1ml/100g body wt. for 10min through a duodenal catheter. After the infusion, blood volume increased except in the 1.8% NaCl group, which showed a transient decrease in blood volume by about 10%. The rate of blood volume increase was highest in the 0.45% NaCl with 2% glucose group and lowest in the 1.8% NaCl group. The retention ratio of infused solution in the vascular space was almost identical among the groups and was about 22%. These results indicate that the rate of increase in blood volume after intestinal administration of fluid is modified by the osmolality of the fluid and Na-glucose co-transport, whereas the retention ratio of the infused fluid in blood is constant.View full abstractDownload PDF (727K) -
Kohachi TANIGUCHI, Hisashi OGAWA1987 Volume 37 Issue 6 Pages 1031-1049
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWhile applying the Fast Fourier Transform to the instantaneous frequency responses to sinusoidal indentations of the cutaneous mechanoreceptor afferent units in frogs, we examined quantitatively the dynamic responses of these units. In two kinds of slowly adapting (SA) units, i.e., frog type I and frog type II units, and in rapidly adapting (RA) type I units, the instantaneous frequency responses could be reconstructed by summation of the DC component and the major 3-5 harmonics in the power spectra. In both types of SA units, the fundamental wave was the largest in power of the spectrum, but in the RA units, the 2nd harmonic was the largest. In SA units, the phase of the fundamental wave advanced by 20-55° relative to the sinusoidal stimulation, but the phase of the 2nd harmonic of the RA units advanced by ca. 90°. The magnitude of each component in the power spectra, especially the fundamental wave of the two SA units and the 2nd harmonics of the RA unit, increased with an increase in stimulus amplitude and frequency. The phases of thee harmonics in both SA and RA types were fairly constant over varying amplitudes and frequencies of sinusoidal stimulation. The present findings indicate that both the frog type I and type II cutaneous mechanoreceptor afferent units detect both indentation magnitude and positive velocity, and that the RA type I cutaneous mechanoreceptor afferent units detect the stimulus velocity.View full abstractDownload PDF (1424K) -
Yoshiaki HABARA, Akihiro KUROSHIMA1987 Volume 37 Issue 6 Pages 1051-1056
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSPlasma cAMP response to glucagon was enhanced after cold acclimation. Cold-acclimated rats also showed an enhanced production of hepatic cAMP in response to glucagon. In both brown and white fat tissues, cAMP contents increased after cold acclimation. Enhancement of cAMP formation in the liver and fat tissues may partly contribute to an enhanced nonshivering thermogenesis during cold acclimation.View full abstractDownload PDF (417K) -
Onkar TRIPATHI, Aruni BHATNAGAR1987 Volume 37 Issue 6 Pages 1057-1060
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSThe extracellular fluid space in rabbit SA node and atrial trabeculae was measured with 14C-inulin and 14C-sucrose. A larger 14C-inulin space in SA node than in the atrial tissue, indicated a greater extracellular fluid space in the former, and could be due to caveolae on the pacemaker cell membrane.View full abstractDownload PDF (295K) -
Hiroyuki SOEDA, Fujio SAKUDO1987 Volume 37 Issue 6 Pages 1061-1065
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSApplication of NaCl to the frog tongue produced a sodium influx through the dorsal epithelium. The flux was distinctly faster through those of the palatal epithelium and the skin, and may influence taste reception in frogs.View full abstractDownload PDF (345K) -
Mieczyslaw POKORSKI, Miroslaw RYBA1987 Volume 37 Issue 6 Pages 1067-1073
Published: 1987
Released on J-STAGE: July 28, 2006
JOURNAL FREE ACCESSWe sought to address the contribution of the ventral medullary intermediate (I) areas to respiratory regulation in the close loop condition. The experiments were done on anesthetized, spontaneously breathing cats. The transient and steady-state neural respiratory output responses to longlasting cooling of the I areas and to vagotomy and hyperoxia performed during the cooling period were investigated. Cooling of the I areas resulted in an initial transient inhibitory response followed by respiratory output increase in the steady-state, provided other respiratory inputs were maintained intact. This investigation calls into question the crucial role of the I areas in regulation of respiration in the close loop condition.View full abstractDownload PDF (515K)
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