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Volume 28 (1978)
- Issue 6 Pages 721-
- Issue 5 Pages 557-
- Issue 4 Pages 401-
- Issue 3 Pages 249-
- Issue 2 Pages 109-
- Issue 1 Pages 1-
Volume 28, Issue 5
Displaying 1-11 of 11 articles from this issue
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Tohru YOSHIOKA, Atsushi ASANUMA, Keiji YANAGISAWA, Yasuji KATSUKI1978 Volume 28 Issue 5 Pages 557-567
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSStimulating effects of various mono- and divalent cations on the lateral-line organ were theoretically analysed by use of the site binding chemical adsorption model with the principle of “hard and soft acids and bases.” A linear relation between the softness parameter and the logarithmic value of the intrinsic association constant was obtained for the cations of Na, K, Tl, Ag, Ca, Mg, and Cd. The order of effectiveness of these cations agreed with that of the intrinsic association constant. Using these values for various cations, the critical concentration of divalent cations necessary to suppress the effect of monovalent cations was calculated and compared with the experimental values. The calculated concentration of the hard divalent cations (Ca2+, Mg2+), which suppressed the effect of the hard monovalent cations (K+, Na+), agreed with the experimental concentration. The same relations were obtained between the suppressive effect of a soft divalent and a soft monovalent cation.
The chemical adsorption of Ag+ on the lateral-line organ of Xenopus laevis was investigated by using a transmission electron microscope equipped with an X-ray microprobe analyser in order to get further confirmation of this model. Silver applied to the lateral-line organ was found around a kinocilium but not in the hair cells of the lateralline organ. Thus chemical adsorption of the cation on the surface of the receptor membrane was directly proved.View full abstractDownload PDF (3883K) -
Takashi YASUDA, Toshio SHIMONO1978 Volume 28 Issue 5 Pages 569-581
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1. Thalamo-cortical (T-C) neurones projecting their axons to the motor cortex were recorded intra- or extra-cellularly in the anterior ventral and lateral ventral nuclear complex of the thalamus in lightly nembutalized cats. The T-C neurones were identified as responding antidromically to stimulation of the motor cortex, and were examined in connection with effects of stimulation of the centrum medianumparafascicular complex (CM), pallidum (Pal), cerebellar nuclei (CN) and mesencephalic reticular formation (RF).
2. The T-C neurones were classified into two groups, A and B. The A-group neurones responded neither to stimulation of CM nor to that of Pal. By contrast, the B-group neurones were activated from either CM, Pal or both. The effect of RF stimulation was facilitatory in many of the A-group neurones whereas it was mostly inhibitory in the B-group neurones. CN stimulation activated most of the T-C neurones in both A and B groups.
3. The A-group neurones were categorized as the deep T-C neurones mediating the deep T-C response of the cortex (the early surface-positive deep-negative component of the augmenting response) and the B-group neurones as the superficial T-C neurones mediating the superficial T-C response of the cortex (the recruiting response and the late surface-negative-deep-positive component of the augmenting response). Desynchronization of electrocorticograms in response to RF stimulation was suggested to result from inhibition of the superficial T-C neurones and facilitation of the deep T-C neurones.View full abstractDownload PDF (1595K) -
Kenji KITAMURA1978 Volume 28 Issue 5 Pages 583-601
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSLongitudinal muscle of the rabbit jejunum usually generated burst discharges, whereas circular muscle mainly generated slow potential change. Membrane potential was higher, and the space and time constants were larger in circular muscle than in longitudinal muscle. Current-voltage relationship exhibited anomalous rectification by depolarization of membrane in longitudinal muscle cells, and delayed rectification in most circular muscle.
Excitatory junction potentials (e.j. p.s) were recorded from both muscles and inhibitory junction potentials (i. j. p.s) were recorded from only circular muscle. The e.j.p.s consisted of muscarinic e.j.p.s and atropineresistant e.j.p.s, but only the latter were recorded from circular muscle. The i.j.p.s were not affected by either or both a- and β-blockers, butwere blocked by TTX.
From mechanical and electrical responses of both muscle layers induced by field stimulation, it was postulated that four different types of nerve fibres innervate the jejunum muscles:(I) cholinergic excitatory nerves, (H) non-adrenergic and non-cholinergic inhibitory nerves (or purinergic nerves), (III) non-adrenergic and non-cholinergic excitatory nerves and (IV) adrenergic inhibitory nerves. In the longitudinal muscle, (I) was dominant, but (II) was also found. In the circular muscle all four types were found to exist.
Effects of adrenergic nerve stimulation on the membrane potential was not detected by stimulation below 10 Hz, although externally applied noradrenaline at 5.9×10-8 M had a relaxing effect.View full abstractDownload PDF (1983K) -
Masashi KURAHASHI1978 Volume 28 Issue 5 Pages 603-610
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSTissue specificities in inhibitory action of excess triiodothyronine (T3) on creatine uptake from the plasma and the effect of denervation of the muscle on the inhibitory action were studied in rats with the use of radioactive creatine. The uptake of radioactive creatine of all muscles studied significantly diminished after T3 (100μg/100 g, s.c.) injection, while that of brain was not affected by T3 treatment. Tissue specificity of the T3 action on creatine uptake was consistent with that of previously known T3 action on oxygen consumption. The responses to inhibitory action of T3 on creatine uptake were not different in different types of the skeletal muscles. Although the uptake of radioactive creatine of denervated muscles was significantly lower than that of controls, inhibitory action of T3 on creatine uptake was similarly observed in denervated muscles as well as in normal ones. These results indicate that T3 has a direct effect on muscle cell per se and the inhibitory action of T3 on creatine uptake by the muscle is closely related to T3 action on the energyrequiring process in cell membrane.View full abstractDownload PDF (890K) -
Masayosi GOTO, Atsuko YATANI, Yasuo TSUDA1978 Volume 28 Issue 5 Pages 611-625
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effects of exogenously applied adenosine on the membrane potentials, currents and tension components of the bullfrog atrium were analysed under voltage clamped and unclamped conditions with the double sucrose-gap method.
Adenosine above 10-3 M produced a prolongation of action potential accompanied by a slight augmentation of contraction which was followed by a sustained depression. The recovery was slow. Under voltage clamp conditions, adenosine merely produced a negative inotropic effect depressing ICa-dependent and -independent tensions. In the membrane currents, INaf, Is(ITa), Ix and background current (Ib) were all depressed. In the presence of adrenaline, the increased Is, Ix and contraction were inhibited by adenosine in a lower dose (10-5-10-3 M), and the inhibition of Is and ICa-dependent tension were more prominent in the presence of than in the absence of adrenaline. Under the effect of ATP, which has a catecholamine-like action, similar selective inhibitions were observed. It was concluded that adenosine has a sustained stabilizing action on the myocardium to survive, especially in the presence of adrenaline, by depressing the augmented ICa and contraction.View full abstractDownload PDF (8774K) -
Tatsuhiko KAWARABAYASHI1978 Volume 28 Issue 5 Pages 627-645
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIn 12-15-day pregnant rat myometrium, spikes of the longitudinal muscle were discharged spontaneously in bursts, while the circular muscle had predominantly a plateau potential. In the longitudinal muscle, phenylephrine (10-7 g/ml) slightly decreased the duration of the burst discharge and suppressed the contraction by β-adrenoreceptor stimulation. In the circular muscle, phenylephrine (10-7 g/ml) prolonged the duration of the plateau potential leading to an increase in tension without changing the amplitude of plateau, membrane potential and membrane conductance by α-adrenoreceptor stimulation. The effects of phenylephrine on the circular muscle in various ionic environments were observed. In K-free solution, spike generation ceased but phenylephrine depolarized the membrane, generated the prepotential with spikes and prolonged plateau duration. In low-Ca solution, spontaneous spike generation ceased and electrically evoked spikes showed short plateau duration. Phenylephrine restored the membrane activity and prolonged the plateau duration. Excess Ca showed either prolonged (<5 mM) or reduced (>8 mM) the plateau duration, but phenylephrine consistently prolonged plateau duration. When Cl was replaced with either Br or benzene sulphonate, the former prolonged plateau duration and increased the excitability, whereas the latter reduced plateau duration and suppressed the spontaneous activity. Phenylephrine prolonged plateau duration in both Cl-deficient solutions. When NaCl was replaced bycholine-Cl, leaving 15.7 mM Na remaining in NaHCO3 buffer, phenylephrine action completely ceased. The ionic mechanism involved in phenylephrine action is discussed.View full abstractDownload PDF (2032K) -
Takuro OSA, Masao WATANABE1978 Volume 28 Issue 5 Pages 647-658
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effects of catecholamines on the circular muscle of myometria in pregnant rats at term (21st and 22nd days) were investigated by recording electrical and mechanical responses. Slow potentials were found to be the dominant activity in the morning on the 21st day of pregnancy, and spike potentials were manifested on the 22nd day. The α-excitation of catecholamines in the circular muscle was represented by mechanical potentiation, prolongation of the slow potential and depolarization of the membrane. In contrast, the β-inhibition was mechanical inhibition, depression of the slow potential and hyperpolarization. Noradrenaline at a concentration of 6×10-6 M caused excitatory action in the circular muscle on the 21st day of pregnancy, while the effect becameinhibitory on the 22nd day of pregnancy. Results obtained by the use of adrenergic agonists and antagonists led to the conclusion that the reversal of the effect of noradrenaline could be ascribed largely to the enhancement of the β-action, the mechanism of which was brought about probably through the endogenous change in the steroid hormone secretion at the very end of pregnancy.View full abstractDownload PDF (1340K) -
Toshikatsu YOKOTA, Yasuo NISHIKAWA, Sakae OHNO1978 Volume 28 Issue 5 Pages 659-667
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSElectromyographic responses of extrinsic tongue muscle motor units to innocuous mechanical stimulation of the mandibular mucosa were studied in urethane-chloralose anesthetized cats. The mechanical stimulation either excited or inhibited spike discharges in some extrinsic tongue muscle motor units when applied to the alveolar gingival musosa on the lingual side. Excitatory receptive fields of styloglossal motor units were predominantly ipsilateral, and the molar and second premolar gingivae were the most effective. In contrast, excitatory receptive fields of hyoglossal motor units were predominantly contralateral, the molar gingiva being most effective. In genioglossal motor units, only the ipsilateral alveolar gingiva was excitatory, while ipsi- and/or contralateral alveolar gingivae were inhibitory. The inhibitory receptive field was located in the molar and/or second premolar alveolar gingivae. When an anesthetic spray was applied to the mucosal surface, the reflex response completely disappeared, indicating its origin to be located in the stimulated gingival mucosa. After cutting the lingual nerve, reflex responses to mechanical stimulation of the premolar and molar gingival mucosa was abolished. It was concluded that the premolar and molar gingival mucosa constitutes a part of the afferent source for the linguo-hypoglossal reflex.View full abstractDownload PDF (2386K) -
Shikio INUBUSHI, Toshinori KOBAYASHI, Tomokazu OSHIMA, Shizuo TORII1978 Volume 28 Issue 5 Pages 669-688
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1. Intracellular recordings were made from 92 neurones in the precruciate cortex of encephale isole and midpontine pretrigeminal preparations of the cat. 2. All but only one of these cells showed appreciable changes in the membrane potential during the transition from the cortical slow wave phase to the EEG arousal occurring spontaneously or induced by stimulating the midbrain reticular formation. Thus, 38 cells were depolarized (D-type cells), 48 cells hyperpolarized (H-type cells) and 5 cells showed an early hyperpolarization and a later depolarization (mixed type). 3. The latency of intracellular responses to reticular stimulation was shorter in the D-type cells than the H-type or mixed-type cells, and shorter for each of the D- and H-types in the cells of the superficial layers than those of the deep layers. 4. The D-type cells were distributed widely through laminae I to V, but the majority was sampled in lamina II. The H-type cells were located in laminae III-VI with the mode at the upper half of lamina III. The mixed-type cells were mostly located in laminae V and VI. 5. Antidromically identified slow pyramidal tract (PT) cells (n=9) all belonged to the D-type, and fast PT cells either to the H-(n=11) or the mixed type (n=4). 6. These results suggest that the EEG arousal is a state composed of both excitatory and inhibitory responses of cortical cells which are processed from the superficial to the deep layers.View full abstractDownload PDF (5129K) -
Shikio INUBUSHI, Toshinori KOBAYASHI, Tomokazu OSHIMA, Shizuo TORII1978 Volume 28 Issue 5 Pages 689-708
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1. Changes in the resting potential and the effective membrane resistance were measured in 77 cells in cat precruciate cortex during the transition from cortical slow wave phase to EEG arousal. 2. These 77 neurones were classified into the recipient cells of the following five different actions on the EEG arousal:(1) postsynaptic excitation (E cells), (2) postsynaptic inhibition (1 cells), (3) disinhibition (DI cells), (4) disfacilitation (DF cells) and (5) disfacilitation followed by excitation (DF-E cells). 3. The location of E cells ranged from laminae I to V, but the majority was found in lamina II. Most I cells were located in the upper half of lamina III, and a few in lamina V. DF, DI and DF-E cells existed deeply from the lower half of lamina III to laminae V- I. 4. Slow pyramidal tract (PT) cells (n=6) all belonged to the E cell group, whereas fast PT cells were divided into the DF (n=10) and DF-E cell groups (n=4). 5. It is postulated that the EEG arousal is initiated with a direct excitation of laminae I-II cells, followed by excitation and inhibition to the upper lamina III cells and further processed to laminae III-VI cells with indirect excitation, inhibition, disinhibition and disfacilitation. The model of four vertical transmission relays is proposed to depict the cascade pattern of information being processed through the cortex during the EEG arousal.View full abstractDownload PDF (2260K) -
Hiroshi KAWATA1978 Volume 28 Issue 5 Pages 709-720
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of hypertonic urea solution on potassium contracture were investigated in a bullfrog ventricular strip. In a medium of three times hypertonic urea, the contracture induced by 100 mm potassium solution was markedly inhibited whereas the twitch contraction was augmented in the hypertonic urea solution. The extent, as well as the time course, of the membrane depolarization produced by high potassium solution was essentially identical in both isotonic and hypertonic conditions. Endogeneous catecholamine does not seem to participate in this inhibition since the treatment with propranolol did not modify the results. Thus, the possibility of the well-known catecholamineinduced inhibition of potassium contracture can be excluded. The myocardial contractility was never suppressed, or even augmented, at this stage of urea perfusion although a prolonged hypertonic urea perfusion gradually suppressed the contractility. It was suggested that hypertonic urea exerts its negative inotropic action on the potassium contracture independently of its positive inotropism on the twitch contraction by accelerating the uptake of the activator calcium ion to some undefined intracellular sites.View full abstractDownload PDF (8040K)
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