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Volume 30 (1980)
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- Issue 3 Pages 313-
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Volume 30, Issue 3
Displaying 1-14 of 14 articles from this issue
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Susumu KORENAGA1980 Volume 30 Issue 3 Pages 313-331
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe ontogenic change in properties of muscle membrane and neuromuscular junctions in fast (m.extensor propatagialis longus;EPL and m.pectoralis major;PM) and slow (m.anterior latissimus dorsi; ALD) muscle fibers of normal and inherited dystrophic chickens were investigated.In normal and dystrophic EPL and ALD, the membrane potential increased between 3and 6weeks ex ovo, and remained much the same value until 30weeks ex ovo.There was no apparent difference in membrane potential between both strains.In ALDs of both strains, the threshold depolarization for the spike generation remained the same until 10weeks ex ovo but thereafter the spike became abortive in shape. In EPLs of both strains, the threshold potential shifted to a hyperpolarized level following the increase in membrane potential.In PM and EPL of both strains, length constant, time constant of the membrane, membrane resistance and cell diameter increased, whereas input resistance decreased. However, the above changes in the various membrane parameters appeared to be more significant in dystrophic chickens than in normal ones at 3-6weeks ex ovo.A part of these changes in the various parameters could not be explained by increased cell diameter alone.Changes in the membrane property during the progress of aging in dystrophic chickens appeared simultaneously in both muscles.The properties of m.e.p.p.s. and e.p.p.s in ALD and EPL in the normal chicken showed specific patterns such as slow and fast muscles, respectively.However, in ALD and EPL, no difference in the properties of acetylcholine receptor and acetylcholine release from nerve terminals between both strains was observed. These results suggest that pathological changes in the muscle cell are evident both in the membrane and the contractile properties but not in the neuromuscular junction.View full abstractDownload PDF (3290K) -
Teijiro NATSUI, Tsutomu YAMAZAKI, Shun-ichi KUWANA1980 Volume 30 Issue 3 Pages 333-344
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe effects of a sudden decrease in alveolar CO2 concentration (FCO2) on phrenic nerve activity (PNA) were studied in anesthetized and paralyzed cats.The vago-sympathetic and carotid sinus nerves were sectioned.The peak of integrated PNA was used as an index of the central inspiratory activity.
1) FCO2 decreased immediately and curvilinearly after hyperventilation. However, PNA did not change during the initial period of hyperventilation. After this time delay (Dt), the PNA began to decrease linearly over a certain period and finally disappeared.Toff, the time from the onset of hyperventilation to the disappearance of PNA, was in the range of 30-250 sec.This was related to both the level of FCO2 in a control period and the rate of decrease in FCO2 during hyperventilation, but Dt was mostly independent of these values.Mean (with SD) Dt was 10.68±7.01 sec (n=68, from 6 cats).
2) VCO2, the quantity of CO2 eliminated through the lung during Toff, was measured in each experimental run.The VCO2 was directly proportional to the level of control FCO2 and, at a given level of control FCO2, was almost identical, irrespective of the different rates of decrease in FCO2.
3) We concluded that Dt is the time required for a change in the hydrogen ion concentration, [H+], in the brain interstitial fluids bathing the central chemosensitive structures, and that the central inspiratory activity, in the absence of the peripheral chemoreceptors, will be a single function of the [H+] in these fluids.View full abstractDownload PDF (1140K) -
Toshifumi KUMAI, Hiromichi NOMURA1980 Volume 30 Issue 3 Pages 345-355
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe pH effects on frog gustatory responses to alkali-metal and alkali-earth-metal chloride salts were examined using single fungiform papilla preparations. Responses to 0.1-0.5 M NaCl were clearly dependent upon the pH of the stimulating solutions. The responses increased as the pH decreased from 6.5 to 4.5 and were almost completely suppressed at pH's above 6.5. There was no significant difference in the pH dependency of the response among alkali-metal chlorides. HCl solutions elicited only a poor response under conditions in which the water response was suppressed by the simultaneous presence of a low NaCl concentration. Responses to alkali-earth-metal chlorides varied in their pH dependency. Response to CaCl2 was slightly affected by pH changes from 4.5 to 9.0, response to SrCl2 was considerably suppressed in the alkaline region, and responses to BaCl2 and MgCl2 were strongly suppressed at pH's above 6.5. BeCl2 solutions showed less marked stimulating effects over the pH range tested.
The differences in pH dependency described above suggest the existence of two kinds of receptor sites, one being pH-insensitive sites responsible for the calcium response and the other pH-sensitive sites responsible for the sodium response. A cross-adaptation test appeared to support this possibility. Assuming that the pH effect mentioned is related to changes in the state of ionization of the receptor molecule, the pKa of the ionizable group responsible for the sodium response was determined to be approximately 5.5.View full abstractDownload PDF (2122K) -
Tetsuji HIRONAKA, Shoji MORIMOTO1980 Volume 30 Issue 3 Pages 357-363
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSIntracellular chloride concentration in frog sartorius muscle was determined at 20°C utilizing ionic permeability change of the membrane for an ion-selective electrode.The membrane potential and external potassium concentration relation was obtained with changes in pH.Using the constant field equation with a condition given by the crossing point in the two relations obtained with the two different pH, the intracellular chloride concentration was estimated to be 3.7±0.18 mM (mean±S.E.M.) with a 0.76 of the activity coefficient for chloride in Ringer's solution.The chloride potential (-88.5±1.26 mV) was significantly positive to the resting potential (-94.8±1.09 mV), suggesting that a chloride pump may be working in the frog skeletal muscle.The existence of the chloride pump was supported further by the fact that the depolarization induced by the pH increase became smaller with cooling and finally disappeared when cooled below 5°C.View full abstractDownload PDF (694K) -
Shinji ITOH, Goro KATSUURA, Ryoji HIROTA1980 Volume 30 Issue 3 Pages 365-375
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSEarlier observations that food restriction for a short periodof time in the morning produced an altered circadian rhythm of plasma corticosterone having the peak just before feeding time, and that the elevated plasma corticosterone levels declined promptly immediately after food presentation were confirmed.After a 14-day restricted feeding schedule, where food was given from 11: 00 to 13: 00, if food was not given, elevated levels of plasma corticosterone were sustained for at least 1 hr and then declined gradually.On the other hand, if food was given 2 hr earlier than the scheduled time, the peak at 11: 00 disappeared.The conditioned peak of plasma corticosterone was maintained for at least 3 days after the restricted feeding schedule if hypertonic saline, but not tap water, was given without food in male rats and ovariectomized female ones.When female rats were treated with lysine vasopressin for 5 days 10 min before the food presentation, highly elevated levels of plasma corticosterone were found at the time of food presentation.However, administration of cortisol 2 hr before the feeding time blocked the effect of vasopressin.The results suggest that vasopressin is involved in the acquisition and consolidation of the conditioned circadian rhythm of plasma corticosterone induced by restricted feeding.View full abstractDownload PDF (1050K) -
Masaaki FUJIMOTO, Tsuneo TOMITA1980 Volume 30 Issue 3 Pages 377-392
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSUsing the bullfrog retina, depth profiles of Burkhardt's PNR and of the ERG are compared under various recording conditions. When the retina is voltage-annulled so that there is no ERG potential outside the retina, the depth profile of the ERG changes to resemble that of the PNR.When there is current annullment so that there is no ERG current outside, the depth profile of the PNR changes to resemble that of the ERG.Our evidence suggests that Burkhardt's PNR can be further analyzed into a PNR proper, which consists of an initial fast negativity followed by a slow negativity, and a local ERG dominated by the b-wave.View full abstractDownload PDF (1448K) -
Toshiro SATO, Masuo SHIRATAKA, Noriaki IKEDA, Daniel VEGA, Stanley M. ...1980 Volume 30 Issue 3 Pages 393-413
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe isolated kidney of the dog was perfused with autologous blood through an oxygenator.Responses of arterial input pressure (PI), venous pressure (PV), and venous flow (UV) were measured during sinusoidal forcing of arterial inflow (UA) at 5 to 1, 000 cpm superimposed on a steady-state flow level.Pre-(RA) and postglomerular (REV) resistances, and compliances of artery (CA) and glomeruli (CG) were estimated based on a network model and using the Bode diagram of gains PI/U<>A, UV/UA.The data were evaluated by the least square method with a digital computer.The mean values of the parameters normalized for the average weight of the kidney (64.5g) were: CA=0.0027 ml/mmHg, CG=0.088, RA=0.45 mmHg·min/ml, and REV=0.35.Mean arterial pressure (PA) and glomerular pressure (PG) were 111 and 50 mmHg, respectively.The regression lines of PG against PA were significantly different at high and low PA, this being taken as a manifestation of autoregulation of the renal circulation.PG values were less than those given by the classical study of Winton but close to those recently obtained on mutant rats with a direct puncture method by Brenner et al.
It is concluded that the present study has given an experimental background with which we may continuously estimate, under more intact conditions, circulatory parameter values by monitoring pressures and flows which respond to external perturbations.View full abstractDownload PDF (1839K) -
Soichi YOSHIDA, Tetsuro KUGA1980 Volume 30 Issue 3 Pages 415-426
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSElectrical activities have been recorded in a preparation consisting of the pelvic region and the upper ureter of the guinea pig.Train field stimulation of the pelvic region evoked a train of nerve action potentials followed by a multiphasic smooth muscle action potential after a latency of about 2.5-8.0 sec.This smooth muscle response was abolished by tetrodotoxin and dibucaine, and also by cholinergic blocking agents.The response was, furthermore, inhibited by decreasing Ca2+ concentration and increasing Mg2+ concentration in Tyrode solution.This is therefore considered to be the response synaptically evoked by cholinergic fibers in the pelvic region.
Mechanical activities have been investigated on the same preparations by the Magnus method.Acetylcholine (10-7-10-4g/ml) produced a group of twitch responses which were antagonized by cholinergic blocking agents.The responsiveness of the preparations to acetylcholine was markedly decreased by removal of the pelvic region.
Cholinesterase activities in the calyx-pelvis and upper ureter have been estimated by the biochemical method.A preparation consisting of calyx-pelvis exhibited twice the enzyme activity as compared with the upper ureter.
These results suggested that there is a cholinergic innervation in the pelvic region of the guinea pig ureter which also takes part in control of the ureteric activity.View full abstractDownload PDF (1201K) -
Masahiro NOMOTO1980 Volume 30 Issue 3 Pages 427-442
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSSingle unit responses of the primary auditory cortex of unanesthetized cats were studied using three standard sets of sound stimuli, i.e., clicks, white noise bursts, and pure tone bursts.The units studied were classified into eight categories according to whether they responded to all three, two, one or none of the standard sets of stimuli; there were no units responding only to clicks.This suggests that excitation of some cortical neurons requires a special sound spectrum as well as temporal factors.Frequency-modulated (FM) sounds were usually more effective eliciting responses than the standard sets of stimuli.Responses to FM in bursts seemed to be classified into three groups, i.e., sharp monopeak post-stimulus time (PST) histograms, broad monopeak, and sharp multipeaks.The existence of the last group suggests a firm convergence from the lower auditory neurons.In some units, complex stimuli were more effective in evoking responses than simple FM sounds.These units responded only to sounds with complex temporal patterns. For example, a neuron did not respond to any FM sound with a constant modulation magnitude, but showed a transient response whenever the magnitude of FM varied from a continuous pure tone to a certain range of FM.These complex units often showed a response with hysteresis.View full abstractDownload PDF (1420K) -
Takeyasu YAMAMURA1980 Volume 30 Issue 3 Pages 443-454
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESS1.An orderly sequence in which the spontaneous electrical activity of the lateral geniculate nucleus (LGN) changes to a rhythmic one after intravenous administration of thiopental was studied in cats.
2.The response of LGN to barbiturate differed greatly from those of other thalamic specific nuclei.After administration of barbiturate, there appeared in the LGN a series of oscillatory potentials (barbiturate oscillatory potentials;BO potentials), the frequency of which changed sequentially from an initial 40Hz to 20, 10, 5, and finally, 2.5Hz.
3.Frequency changes of BO potentials in the LGN were observed only when the retinas were intact.Following destruction of bilateral retinas, the LGN responded to barbiturate with spindle activity as did other thalamic nuclei.
4.Depth potential analysis of the LGN activities showed that the BO potentials were generated in layers A and Al.By contrast, the spindle activity was recorded mainly from layer B.
5.Simultaneous recordings from the LGN and the optic nerve indicated that the BO potentials in the LGN were driven by retinal afferent discharges.View full abstractDownload PDF (1249K) -
Koon Ong LIM1980 Volume 30 Issue 3 Pages 455-464
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe mechanical properties and ultrastructure of normal human tricuspid valve chordae tendineae were examined. Mechanical studies showed that these chordae exhibited less extensibility than normal mitral valve chordae of comparable size.The non-linear stress-strain curve of the tricuspid chordae, however, can be attributed to their microstructure. Under scanning electron microscopy these chordae were found to consist of fairly straight collagen bundles that were made up of networks of collagen fibrils.Transmission electron microscopical studies showed that the distribution of collagen fibril size was bimodal with an average fibril diameter of 441 Å(S.E.=2Å) while the average fibril density was 198.4 (S.E.=8.4) per 10-8cm2.These data from the transmission electron micrographs were found to be different from those already reported for the mitral valve chordae.Thus, fine structural differences exist between chordae from both the mitral and tricuspid valves.These differences in fine structure could be due to the fact that these valves are under different in vivo mechanical stresses and they may account for the less extensible nature exhibited by the tricuspid chordae tendineae.View full abstractDownload PDF (2804K) -
Mamoru AOKI, Takeyasu YAMAMURA1980 Volume 30 Issue 3 Pages 465-471
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSNeural mechanisms of the reflex rebound of the hindlimb were studied in the high spinalized cat.After the animal had recovered from spinal shock, a light touch-pressure on the foot pad elicited a reboundextension reflex of the ipsilateral hindlimb.Excitability changes in hindlimb motor nuclei during the rebound phenomenon were examined by recording test monosynaptic reflexes (MSR).During touchpressure stimulation, flexors such as the biceps femoris and tibialis anterior were facilitated, while extensors such as the gastrocnemius and quadriceps femoris were inhibited.After cessation of a stimulus, extensor MSRs showed a rebound facilitation which lasted for a few seconds.The greater the preceding suppression of MSR, the greater the rebound facilitation.Membrane potential changes induced in extensor motoneurons by touch-pressure were investigated by intracellular recordings.In most of the motoneurons tested (21/24), a clear membrane hyperpolarization was observed during stimulation and was followed by a rebound firing on cessation of stimulation.Possible mechanisms underlying the rebound extension reflex were discussed.View full abstractDownload PDF (728K) -
Keisuke EGASHIRA1980 Volume 30 Issue 3 Pages 473-485
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSThe mechanism of hyperpolarization of the membrane caused by noradrenaline (NA) was investigated in guinea pig liver cells.The hyperpolarization produced by NA was accompanied by a reduction of membrane resistance.Both hyperpolarization and reduction of membrane resistance were suppressed by ouabain (5×10-6M).However, when the external Na+ was reduced to 38mm, the NA response reappeared even in the presence of ouabain.The hyperpolarizing NA response may be divided into two phases, an early phase and a late phase. In a Ca2+-free solution, the NA response gradually disappeared.However, the early phase of hyperpolarizing response was more resistant to a removal of external Ca2+than the late phase.Manganese ion also suppressed the late phase more strongly than the early phase.It was concluded that the hyperpolarization induced by noradrenaline is due to an increase in K+conductance and that this may be a result of an increase in intracellular Ca2+ concentration.The early phase of hyperpolarizing NA response is probably due to release of bound Ca2+ and the late phase to influx of Ca2+ from the external solution.Suppression of the NA response by ouabain may be explained by assuming that the Cat2+ activated K+conductance is blocked by an increase in intracellular Na+ concentration.View full abstractDownload PDF (1406K) -
Kazuo TODA, Atsushi IRIKI, Hiroyoshi TANAKA1980 Volume 30 Issue 3 Pages 487-490
Published: 1980
Released on J-STAGE: June 07, 2011
JOURNAL FREE ACCESSRat cortical evoked responses (CERs) of the somatosensory area I and II following tooth pulp stimulation were decreased in amplitude by electroacupuncture stimulation. Suppression was more marked with the contralateral CERs than with the ipsilateral ones. Onset latencies of somatosensory II CER of both sides were lengthened after electroacupuncture stimulation.View full abstractDownload PDF (424K)
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