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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-
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Volume 28, Issue 4
Displaying 1-10 of 10 articles from this issue
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Enrique LOPEZ1978 Volume 28 Issue 4 Pages 401-412
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSDenervated frog's semitendinosus muscles were studied. No differences in resting potential were found between denervated and control fibres. Spontaneous discharges of fibrillation potentials were recorded from random points along the length of denervated fibres. The frequency of the potentials varied between 2 and 30/sec; the duration of the discharges varied between 5 and 120 sec. Each potential originated from a prepotential, reversed the sign of the membrane potential between 10-20 mV, and was followed by a transient hyperpolarization. The time courseof the spontaneous potential produced by a fibre was slower than that of a spike elicited by an electrical pulse applied to the same fibre. After the cessation of a train the fibrillation potentials were replaced by small rhythmic potentials 10-15 mV in amplitude ; this activity lasted for periods as long as 7 min. Some reduction of the resting potential was usually observed during the discharge of a train of fibrillation potentials, however, repolarization occurred after the end of electrical activity and a second discharge of full size fibrillation potentials could be observed in most of the fibres.
Mechanical activity was not always present. When observed, it was reduced to light movements unable to eject the microelectrode. In general, no one-to-one correlation could be observed between fibrillation potentials and mechanical activity. In those fibres in which the correlation was present, the tension developed by a single fibrillation was less than 0.2 kg/cm2. Some denervated fibres developed tetanus-like contractions, the maximal tension developed by these fibres was less than 1.0 kg/cm2. The data are discussed according to the current ideas on generation of fibrillation potentials.View full abstractDownload PDF (11237K) -
Yasuyuki KITADA1978 Volume 28 Issue 4 Pages 413-422
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effects of various cations on water fibers in the frog (Ranacatesbeiana) tongue were investigated. The following results were obtained.
1. Water fibers responded well to Ca2+ and Sr2+
2. SO2-4 did not inhibit the Ca2+ response. Cl- at high concentrations had an inhibitory effect on the response to high. Ca2+ stimulation. However, when the Ca2+ concentration was low, Cl- did not induce any inhibition. Therefore, low Ca2+ stimulation (0.1 mM CaCl2) was used to examine the inhibitory effect of cation.
3. MgCl2 and MgSO4 strongly inhibited the response to low Ca2+ stimulation. The inhibition by Mg salts was not caused by anion but by Mg2+.
4. The Ca2+ response was inhibited by various cations. The order of the inhibitory effects of cations was as follows: La3+ >Mn2+=Mg2+≥Ni2+ > Co2+ > monovalent cations (Na+, K+, NH4+ and choline+).
5. The Sr2+ response, as well as the Ca2+ response, was inhibited by Na+and Mg2+.View full abstractDownload PDF (909K) -
Kosei ISHII, Kazuko ISHII1978 Volume 28 Issue 4 Pages 423-431
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIn the toad, Bufo vulgaris, the pulmocutaneous artery, which is innervated by a fine branch of the laryngeal nerve, was shown to be a reflexogenic area affecting the systemic blood pressure. Distension of the vascularly isolated pulmocutaneous artery evoked falls in systemic blood pressure. Impulses in bursts, synchronous with the systolic rise of the blood pressure, were recorded from the peripheral cut end of the laryngeal nerve when all branches, save the one innervating the pulmocutaneous artery, had been divided. Differing from mammalian baroreceptors, those in toads occurred with a marked latency in response to rises in blood pressure. A hyperbolic relation was obtained between the pressure and the latency. Existence of these baroreceptors in pulmocutaneous artery was confirmed in preparations in vitro. Punctate stimulation was used to localize the baroreceptive site.View full abstractDownload PDF (872K) -
Tadashi CHUJO1978 Volume 28 Issue 4 Pages 433-445
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSExperiments were done to elucidate properties of the late N-wave which was induced in vitro in thin sections of the olfactory cortex of the rat in response to stimulation of the lateral olfactory tract. The late N-wave decreased in size at a stimulation rate of more than once every 90 sec or at temperatures higher than 27°C. The late N-wave was suppressed in the presence of GABA, picrotoxin or bicuculline or in the Clfree medium. Penicillin or pentylenetetrazol, which blocked actions of GABA on the presynaptic potential, also suppressed the late N-wave. The late N-wave first appeared at postnatal ages of 18-25 days. The late N-wave reversed in polarity when recorded from the deep layers of the sections or from the cut surface of the sections. Single cells in the deep portions of the sections discharged during the late N-wave. Cells in the superficial layers fired just before or after the late N-wave. In order to explain these observations, a neuronal model for generation of the late N-wave was presented.View full abstractDownload PDF (1262K) -
Masaru KAWAMURA, Hideyo YABU1978 Volume 28 Issue 4 Pages 447-460
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of ruthenium red on isotonic KCl induced contracture (K-contracture), cellular 45Ca uptake and 45Ca binding to surface membranes were examined in the smooth muscle cells of guinea pig taenia coli. These results were compared with those using lanthanum (La3+).
The tonic component of the K-contracture was selectively inhibited by 1 mM ruthenium red. In contrast, 1 mivt La3+ inhibited the phasic component of the K-contracture to a large extent. Use of 1 mM ruthenium red selectively inhibited the tonic component of K-contracture and caused a marked decrease in cellular 45Ca uptake in that component of K-contracture. In contrast, 1 mM La3+ largely inhibited the phasic component and caused a significant decrease in cellular 45Ca in that component. According to Scatchard plot analysis, there are two kinds of Ca2+ binding sites of high and low affinity, respectively, on the surface membrane of the taenia coli. One mM ruthenium red suppressed those of low affinity more strongly than those of high affinity. In contrast, 1 mM La3+ suppressed high affinity sites more markedly than low affinity sites.
Based on these results, it seems possible to conclude that ruthenium red mainly blocks the initial binding sites linked with Ca2+ influx which is related to the production of the tonic component while La3+ blocks those sites related to the phasic component of the K-contracture of guinea pig taenia coli.View full abstractDownload PDF (4581K) -
Toshifumi MORIMOTO, Hiromitsu TAKEBE, Iwao SAKAN, Yojiro KAWAMURA1978 Volume 28 Issue 4 Pages 461-471
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSDepression of the mandible in the decerebrate cat induced retraction of the tongue. The mechanism of this jaw-tongue reflex was analyzed by recording electromyographic activity from the temporal and styloglossal muscles as representative masticatory and extrinsic tongue muscles, respectively. Tongue muscle activity was elicited when the mouth was opened beyond 10° while the threshold for the masticatory muscle activities was around 2°. Neither sectioning of the masseteric nerve nor anesthetization of the temporomandibular joint capsule affected the tongue muscle activities. In contrast, exfoliation of the temporal muscle from the temporal bone greatly reduced the effects of jaw depression. When the isolated coronoid process of the mandible was stretched downwards, activities were evoked in the tongue muscle. Repetitive electrical stimulation at a frequency of 100 Hz to the temporal nerve activated the tongue muscle, and the threshold of reflex activation was between 1.3 and 1.7 times threshold of the temporal nerve. Vibratory stimuli applied to the mandible at frequencies below 130 Hz were also effective in evoking tongue muscle activity. However, when the frequency was above 135 Hz, tongue muscle activity was not induced although activity was still observed in the masticatory muscles. These results indicate that the jaw-tongue reflex is elicited mainly by proprioceptors in the temporal muscle, and that they may probably be the Golgi tendon organs and the secondary endings rather than the primary endings of the muscle spindle.View full abstractDownload PDF (1254K) -
Makoto TAKADA, Hideo HAYASHI1978 Volume 28 Issue 4 Pages 473-483
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSWe have developed a new simple procedure for separating the epidermis from the dermis of the bullfrog (Rana catesbeiana)(freezing and scraping off the skin), and extracting microsomal fraction from the epidermis. The effects of Cd on the ATPase activity of the microsomal fraction was investigated by varying Na and/or K concentrations in the reaction medium. The higher the concentration of Cd, the larger the decreases were found in both activities of ouabain-sensitive ATPase and ouabain-insensitive ATPase in the range of Cd concentration from 10-7 M to 10-3M. The activity of ouabain-sensitive ATPase (Na, K-ATPase) was completely inhibited by 1 mm Cd. The amount of Cd uptake into the whole skin was about 150μ/kg wet weight. This concentration of Cd was sufficient to inhibit the Na, K-ATPase activity of the microsomes. The mechanisms underlying the three types of Cd effects on the frog skin were discussed in relation to the Na, K-ATPase activity.View full abstractDownload PDF (1171K) -
Kazuo TODA1978 Volume 28 Issue 4 Pages 485-497
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffect of electro-acupuncture (EA) on the jaw opening reflex induced by tooth pulp stimulation was investigated in Wistar albino rats. The amplitude of the digastric muscle EMG (dEMG) evoked by stimulation of the lower incisor tooth pulp was measured as the magnitude of the reflex and estimated as an indicator of the EA effect. Acupuncture needling was given at one meridian point of Ho-Ku and two other nonmeridian points in one forepaw. Compound action potentials of ulnar, median and radial nerves elicited by 15 min EA stimulation at 45 Hz through the needling points were recorded from the brachial plexus innervating the same acupunctured forepaw.
Of the above-mentioned three nerves, the afferent volleys in the radial nerve were. found to be the most effective to suppress the dEMG during EA stimulation. The EA stimulation of the Ho-Ku point showed a greater effect than that of nonmeridian points. There was a significant correlation between the amplitude of Aβ fibers in the compound action potentials elicited by EA stimulation and the dEMG suppression.
To confirm the so-called morphine-like action of EA that has recently been proposed, levallorphan (LORFAN ®), antagonist of morphine, was administered before and after EA stimulation. In the premedicated case, no suppression of the dEMG occurred. In the postmedicated case, on the contrary, the dEMG responses which were reduced during 15 min EA stimulation recovered more rapidly than in the case without LORFAN. These results suggest that the afferent impulses conducted along Aβ fibers mainly in the radial nerve cause the release of endogeneous morphine- like substances in specific central nervous areas for suppressing the dEMG activity.View full abstractDownload PDF (1374K) -
Masayoshi HIMUKAI, Yuichi SUZUKI, Takeshi HOSHI1978 Volume 28 Issue 4 Pages 499-510
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe properties of glycylglycine and glycine transport across the mucosal border of the epithelium were studied in isolated guinea pig ileum. The initial influxes of both substances obeyed simple Michaelis- Menten kinetics, but the values of the kinetic parameters were greatly different between two substances; Jmax and Kt for glycine were 290 nmo·cm-2·min-1 and 27 mM, and those for glycylglycine were 57.4 nmol·cm-2·min-1 and 3.4 mM, respectively. Total replacement of Na+ in the mincubation medium with mannitol completely suppressed the cellular uptake of glycine, while it reduced glycylglycine uptake Only slightly. The omission of Na+ caused a slight increase in Kt for glycylglycine (from 3.4 mM at 100 mM Na+ to 5.2 mM at 0 mM Na+) without changing the value of Jmax· Glycylglycine taken up by the epithelial cells had been completely hydrolysed into glycine within 2-min incubation period. The results of the present study seem to indicate that there are entirely distinct transport systems for glycine and its dimer and that the membrane digestion and subsequent transport as the monomer may not be involved in the absorption of glycylglycine.View full abstractDownload PDF (1307K) -
Yasunobu OKADA, Akihiko IRIMAJIRI, Wakoh TSUCHIYA, Akira INOUYE1978 Volume 28 Issue 4 Pages 511-525
Published: 1978
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe transmural potential difference of isolated rat duodenum and the membrane potential of its epithelial cell were examined during changes of the ionic medium at both warm (31-35°C) and cold temperatures (2-5°C). In the range of low external K+ concentrations, cooling produced an immediate and reversible depolarization of the membrane potential (around -10 mV) greater than that estimated from a simple thermodynamic temperature effect (RT/F). Such a temperature sensitive component of the membrane potential at 31 was completely abolished by anoxia and serosal ouabain. Readmission of K+ to the bathing fluid of duodenum previously deprived of K+ and loaded by Na+ caused a remarkable transient hyperpolarization of the epithelial membrane, which was abolished by serosal ouabain. Decreases in the value of transmural potential difference were also produced by cooling, anoxia and serosal ouabain, but these were so small that concurrent changes in the membrane potential could be regarded as chiefly reflecting changes in the effective emf of the cell. Thus, an electrogenic Na+-K+ exchange pump located on the serosal membrane of the duodenal epithelial cell was shown to contribute significantly to the membrane potential under normal conditions (up to around -7 mV). The coupling ratio of Na+-efflux and K+-influx associated with this pump was estimated by the Mullins-Noda equation (1963) to be approximately 4: 3 under the physiological steady-state conditions.View full abstractDownload PDF (1588K)
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