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Volume 30 (1980)
- Issue 6 Pages 815-
- Issue 5 Pages 671-
- Issue 4 Pages 491-
- Issue 3 Pages 313-
- Issue 2 Pages 143-
- Issue 1 Pages 1-
Volume 30, Issue 2
Displaying 1-15 of 15 articles from this issue
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Syomatu YOKOYAMA, Tsuyoshi OZAKI1980 Volume 30 Issue 2 Pages 143-160
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSUsing a peeled longitudinal muscle strip which was attached to an intestinal segment of rabbit, the effects of gut distension upon the activities of both the neurons within Auerbach's plexus and the intestinal muscle were investigated. Spontaneous neuronal and muscular discharges were recorded by means of a micropipette electrode which was placed on a node of the exposed Auerbach's plexus. Contractions of the peeled longitudinal muscle strip were simultaneously recorded. Gut distension caused an excitatory or inhibitory effect on mechanosensitive eurons. The neurons whose spontaneous discharges showed a frequency increase during muscle contraction and a frequency decrease during muscle relaxation at zero intraluminal pressure responded to gut distension as well as to stretching of the longitudinal muscle with excitation. The neurons which did not show any correlation in thier discharge frequency with muscle contractions responded to gut distension as well as to stretching of the longitudinal muscle with inhibition. Additional neurons were found in small numbers whose spontaneous activity did not relate in frequency to muscle contractions and did not change by gut distension. In all cases of gut distension the excitatory effect on longitudinal muscle as well as on intestinal segment, namely the peristaltic movement, were observed. Removal of mucosa did not affect the abovedescribed effects of gut distension. It was concluded that gut distension causes an excitatory effect on specific mechanosensitive neurons in Auerbach's plexus which regulate the contractions of intestinal muscle and produce the peristaltic movements.View full abstractDownload PDF (2027K) -
Hiromichi OHKAWA1980 Volume 30 Issue 2 Pages 161-177
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSMechanical properties and drug sensitivity of the circular smooth muscle obtained from the muscularis mucosa of the gastroesophageal junction of the guinea pig were studied. Spontaneity was observed in strips of the tissue. Electrical stimulation (0.1 msec) produced large, rapid contractions which differed from twitch-like contractions produced in the outer circular muscle layer of the gastroesophageal junction. Responses of the smooth muscle of the muscularis mucosa were blocked by atropine but not by d-tubocurarine. Repetitive stimulation induced an initial contraction followed by relaxation in a spontaneously active preparation. The initial contraction was blocked by atropine and tetrodotoxin and the relaxation was inhibited by propranolol, guanethidine and tetrodotoxin. Catecholamines, other than isoprenaline, raised the level of tone of preparations obtained from both the muscularis mucosa and the outer circular muscle layer. Responses of the circular smooth muscle were not influenced by catecholamines. Excitatory effects of catecholamines were completely blocked by α-blockers. Isoprenaline inhibited responses and the action of isoprenaline was antagonized by propranolol. Acetylcholine was excitatory and the effect was antagonized by atropine. These results suggest that there are two types of smooth muscle in the muscularis mucosa. In one type, adrenergic α-receptors are excitatory, , β-receptors inhibitory and cholinergic receptors are muscarinic. In the other type, adrenergic receptors are β-inhibitory and cholinergic receptors are muscarinic. Circular smooth muscle of the muscularis mucosa seems to be innervated with excitatory cholinergic nerves and inhibitory adrenergic nerves. Responses of specific smooth muscle seem to be less sensitive to some of the drugs used.View full abstractDownload PDF (1770K) -
Masahiro KAMATA1980 Volume 30 Issue 2 Pages 179-204
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe membrane potentials of the smooth muscle cells of the sphincter of Oddi, gall bladder or common bile duct of the guinea pig was -56, -40 or -54 mV, respectively. The length constant of the tissue of the sphincter of Oddi was 1.7 mm and this value was larger than that measured in hypertonic solution. The smooth muscle cells of the gall bladder and common bile duct were always spontaneously active, while this was not the case with cells from the sphincter of Oddi, nevertheless, electrical stimulation consistently produced spike generation. Acetylcholine depolarized the membrane and increased the spike frequency in muscle cells of the sphincter of Oddi, gall bladder and common bile duct. However, noradrenaline produced α-adrenergic inhibitory action in the sphincter of Oddi and common bile duct, and α-adrenergic excitatory action in the gall bladder. Isoprenaline, a β-adrenergic agent, induced an inhibitory action in the above three regions. Prostaglandin E1(PGE1) suppressed the membrane activity in the sphincter of Oddi, and this response was similar to that observed in the circular muscle of the intestine. In the gall bladder, PGE1 accelerated the membrane activity. astrin and secretin did not affect the smooth muscle activity of the gall bladder but these agents slightly suppressed electrical and mechanical activities in the sphincter of Oddi. On the other hand, cholecystokinin markedly accelerated the electrical and mechanical activities in the gall bladder but these actions were weak in the sphincter of Oddi. Muscle properties of the smooth muscle cells of the biliary system are discussed in relation to the mechanism of bile expulsion through the sphincter of Oddi.View full abstractDownload PDF (8314K) -
Masa TAKAUJI, Masaaki TSUTSUURA, Torao NAGAI1980 Volume 30 Issue 2 Pages 205-218
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe characteristics and the mechanism of the biphasic potassium contractures, i.e., an initial rapid contraction (initial component) and a slow secondary contraction (secondary component) were investigated in detail using single twitch fibers from the semitendinosus muscles of the frog, Rana japonica. The present experiments confirmed the results of COSTANTIN (1971) and STEFANI and CHIARANDINI (1973) and further demonstrated that larger diameters (75-100 μm) of single fibers are required as one of the conditions for obtaining a biphasic potassium contracture. In addition, the effects of calcium removal from the external medium and the various agents, i.e., 2.5 μm dantrolene, 5 mM manganese ions, 7.5 mm procaine, 0.5 mM verapamil and 6. 5 mM lincomycin on the initial and secondary components were examined. The pretreatment of a single fiber with calcium-free Ringer solution or with dantrolene or manganese ions mainly inhibited the secondary component, while it slightly or moderately inhibited the initial component in keeping with its steepness. In contrast, procaine, verapamil and lincomycin mainly inhibited the initial component, changing slightly or moderately the secondary component. It could be concluded, therefore, that the excitation-contraction coupling, i.e., the activation process of the initial component differs from that of the secondary component.View full abstractDownload PDF (1354K) -
Yasuyuki KITADA, Kyuhachiro SHIMADA1980 Volume 30 Issue 2 Pages 219-230
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSImpulse discharges from a single water fiber elicited by stimulation of the frog tongue with Ca2+ were recorded. The inhibitory mechanism of Na+ and Mg2+ on the Ca2+ response was quantitatively studied.
1. A dose-response curve for Ca2+ was obtained. The impulse frequency increased with increasing Ca2+ concentrations and was saturated at 1-5 mM. The results were explained by assuming that Ca2+ interacts reversibly with a receptor site, X, at the surface of the receptor membrane and the reaction obeys the mass action law, and that the magnitude of the response is directly proportional to the number of CaX. The apparent dissociation constant for CaX was 5.9×10-5 M.
2. Na+ antagonized the effect of Ca2+. Addition of Na+ to Ca2+ stimulating solution shifted the log dose-response curve for Ca2+ to the right in a graded and parallel manner, as the concentration of Na+ was increased. A model was proposed in which Na+ competes with Ca2+ for X by forming inactive NaX and Na2X.
3. Mg2+ as well as Na+ antagonized the effect of Ca2+. The inhibitory effect of Mg2+ was greater than that of Nat. Addition of Mg2+ to Ca2+ stimulating solution shifted the log dose-response curve for Ca2+ to the right without altering the slope. The results were consistent with the hypothesis that there is competition between Mg2+ and Ca2+, and that Mg2+ can combine with X to form MgX which is inactive. The apparent dissociation constant for MgX was 5.2×10-5 M. This value for MgX was very similar to that for CaX.View full abstractDownload PDF (1092K) -
Isao OOTA, Itaru NAGAI, Torao NAGAI1980 Volume 30 Issue 2 Pages 231-241
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effects of SCN on the twitch responses, the duration of the active state during a single twitch and the negative afterpotential were examined in relation to the exposure time of frog single fibers to SCN-Ringer solution. SCN potentiated the twitch tension and prolonged the duration of twitch. These effects of SCN depended on the exposure time and on the SCN concentration. However, the plateau tension of tetanus was not affected by SCN. The potentiated twitch tension completely recovered its control value, although it required a considerably longer time. SCN enhanced the amplitude of negative afterpotential and prolonged its duration, but these effects of SCN did not depend on the exposure time or on the SCN concentration. On the other hand, the duration of the active state was prolonged by lengthening of the exposure time and by increasing the SCN concentration. These results indicate that a close relation exists between twitch potentiation and the prolongation of the duration of the active state, but not the negative afterpotential. On the basis of these results, the sites of action of SCN and the mechanism of twitch potentiation by SCN are discussed.View full abstractDownload PDF (1174K) -
Yasushi SAKAI1980 Volume 30 Issue 2 Pages 243-256
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEffects of phospholipase C(PLC) on factors involved in smooth muscle contraction were investigated in longitudinal muscle of the guinea pig antrum. This agent irreversibly reduced spontaneous contraction and action potentials; partially after 30 min and, sometimes, completely after 60 min of exposure to PLC. The membrane depolarized about 8 mV from the control level in 30 min and 16 mV in 60 min. ACh- and KCl-induced contracture were inhibited in an external Ca2+ concentration range from zero to three times normal. The phasic component of KCl-induced contracture was abolished occasionally in normal Ca2+ concentration, and frequently in Ca2+ -free solution. Ca-uptake by antrum tissue, which was the same for control, ACh-, and KCl-induced contracture before PLC treatment, was not statistically different in PLCtreated control, but the value decreased during ACh-induced, and increased during KCl-induced contracture after PLC treatment. The contents of phosphatidylcholine and phosphatidylethanolamine were reduced slightly after PLC treatment, but this reduction was statistically significant. Substantial damage and modification of physical characteristics appeared in electron micrographs of PLC-treated preparations. From the results it was concluded that changes in Ca2+ transport and membrane structural damage both contribute to inhibition of smooth muscle activity by PLC.View full abstractDownload PDF (3340K) -
Differences in Effects between Epidermal and Dermal Cadmium ApplicationsMakoto TAKADA, Hideo HAYASHI1980 Volume 30 Issue 2 Pages 257-269
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEpidermal application of 2 mm-cadmium (Cd2+) to the SO2-4-Ringer's solution bathing the whole frog skin increased its short circuit current (SCC) significantly, whereas the dermal application did not, in most cases. When Cd2+ was applied to the epidermal side, the uptake of cadmium by the skin was approximately 150 μM/kg wet weight, but the uptake by the skin from the dermal side was about eight times as large. In the isolated epidermis, the epidermal application of Cd2+ increased the SCC, whereas the dermal application decreased it. The amount of cadmium taken up by the isolated epidermis was approximately the same when the cation was applied to either epidermal or dermal side. These seemingly contradictory results can probably be explained by the barrier-hypothesis which is supported by the results of an electron probe X-ray microanalysis. In the case of the epidermal application, the junction between s. corneum and s. granulosum may act as an outside barrier for cadmium translocation. For the dermal application of Cd2+, the sieve layer in the dermis, where a large amount of calcium is deposited, may probably exert its effects as an inside barrier by the mechanism of Cd-Ca exchange process. Tela subcutanea, the basement membrane and its adjacent tissue may be also inside barriers, though their role as a diffusion barrier may be considered to be weaker than that of the sieve layer.View full abstractDownload PDF (7267K) -
Toshiyasu OGASAWARA, Seishi KATO, Takuro OSA1980 Volume 30 Issue 2 Pages 271-285
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe membrane potential was about -50 mV, and the spontaneous membrane activity was composed of an irregular discharge of action potentials in the longitudinal muscle of the ovariectomized rat uterus. The membrane potential was increased slightly, and repetitive spike potentials were generated on a plateau potential in uteri of ovariectomized rats injected daily with 5 μg estradiol benzoate, until the steady effect was built up in 3-4 days. The phasic contraction resulted in a relaxation upon exposure to the isotonic K solution containing 2.2 mm Ca, then a tonic contraction developed in ovariectomized uterus. The phasic contraction decayed slightly and it proceeded into a tonic contraction in estrogen-treated uteri. The amplitude of the tonic contraction became larger when the external Ca concentration was raised, and the dose-response relationship shifted to the lower range of the external Ca concentration in the estrogen-treated uterus. In the Ca-depleted solution, the tonic contraction subsided and a contraction was generated when Mn was applied. The change in the configuration of the K-contractures depending on the estrogenic treatment was ascribed to an increase in the Ca influx upon K-depolarization forming greater tonic contraction.View full abstractDownload PDF (1531K) -
Kenju MIKI, Keizo SHIRAKI, Sueko SAGAWA, Taketoshi MORIMOTO1980 Volume 30 Issue 2 Pages 287-290
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSMethods to quantitate changes in plasma volume based on changes in the hematocrit, which have been widely used in human subjects and large animals, were tested in small animals, such as rats. A modified equation was derived for application of the hematocrit method to small animals.View full abstractDownload PDF (381K) -
Masahiro AOMINE1980 Volume 30 Issue 2 Pages 291-295
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe time constant of reactivation process ofICa-independent tonic tension in bullfrog atrial muscle was temperature-dependent and cyanide-sensitive. The cyanide effect and theQ10 value (2.8) of the time constant of the reactivation process suggest that the tonic tension is at least partially mediated by some metabolic process.View full abstractDownload PDF (549K) -
Akihiro KUROSHIMA1980 Volume 30 Issue 2 Pages 297-300
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSCold acclimation induced an increase of spin-lattice relaxation time (T1) of proton nuclear magnetic resonance in rat brown adipose tissue with concomitant increase of water content, while heat acclimation did not effect T1 of this tissue, although its water content was significantly decreased. Temperature acclimation did not affect either T1 or water content of neck muscle.View full abstractDownload PDF (380K) -
Kiyokazu KITAMURA, Yoshifumi YASUDA, Miharu MIYAMURA, Hideji MATSUI1980 Volume 30 Issue 2 Pages 301-304
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSCalf and thigh blood flows in both of right and left legs were measured simultaneously after isometric contraction of the right thigh muscle. Isometric contraction was performed at a force of about 50 % of maximal voluntary contraction for 15 sec. The thigh blood flow of the right leg increased immediately after voluntary contraction in all subjects, while the calf blood flow of right leg decreased conversely in spite of exercised ipsilateral leg.View full abstractDownload PDF (337K) -
Tomio SHINGAI1980 Volume 30 Issue 2 Pages 305-307
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSWater responses elicited by application of water on the laryngeal mucosa were observed in the superior laryngeal nerve fibers in the rat. The response was augmented by K+ ions and was depressed by Na+ ions, while anions (Cl-, F-, SO42-, benzoate) showed no noticeable effect.View full abstractDownload PDF (299K) -
Noriaki FUJITSUKA, Tetsuo OHKUWA, Miharu MIYAMURA1980 Volume 30 Issue 2 Pages 309-312
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSLactic acid concentration of venous blood was determined in healthy male subjects after strenuous exercise with and without breathholding. It was found that in all subjects the peak and total values of lactate during recovery was higher in the breathing run than in the breath-holding run, though the running time was the same.View full abstractDownload PDF (398K)
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