This paper describes ERG's obtained from all rod retinas containing essentially only a-waves. Albino rats, treated with sodium glutamate, were used. The fractionated ERG's obtained from dark adapted rats were in response to stimuli of varying intensity, duration, and wave length. Others were taken during the recovery from light adaptation. A small b-wave was present whenever an a-wave was absent. In the presence of an a-wave, the b-wave appeared only as a very small positive deflection at the peak of the a-wave. The a-waves obtained in these experiments are compared with those obtained from untreated albino rats. The a-wave appears unaffected by the sodium glutamate treatment.

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1. Amphibians of three genera; Amphiuma, Necturus, and Triturus ventricular muscle fibers were studied. The shape of the heart action potential was not independent of the size of the tissue masses.
2. With the effect of tissue size on the shape of the heart action potential, the large tissue masses and small tissue masses yield plateau as well as spikes. The plateau-shaped action potential was mainly recorded from the larger tissue masses.
3. The hypertonic solution of NaCl, CaCl2, MgCl2, glucose and (NH4) 2Ac produced the conversion of plateau to spike, in such as a similar mode on the dissection effect.
4. The effect of a Ca-removal agent, of EDTA, Na2C2O4 and (NH4) 2C204, produced to convert from plateau to spike in large tissue masses, and convert from spike to long lasting plateau-shaped in sliced small tissue masses.
5. The resting membrane-resistance increased during the application of certain hypertonic solution, the value of relative membrane resistance depended upon the concentration of certain agents, such as, applying high concentration produced to result a high relative membrane resistance. These measured resistances might be lumped resistances.
6. The hypertonic solution would make injuries by a toxic effect of certain agents. The injured areas might depend upon the concentration of applying agents, so that the situation on the effect by agent might be the same as a dissection.
7. The plateau-shaped action potential could separate several complexes mostly as a spike and plateau complex. The result was interpreted: the long duration of the excited state was the result of the fusion of discrete discharges of short duration as a subspike electrotonic potential and or spike potential.
8. Increased stimulus strength induced from the subspike or spike potential to larger plateau-shaped action potential, this unusual phenomenon might only be explained by the increasing of the population of excited cells.

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1. Electrical and mechanical responses to catecholamines were studied in isolated ring muscle strips of the coronary artery of the dog.
2. Adrenaline and noradrenaline caused various responses of large coronary artery and relaxation of the small coronary artery. Isoprenaline caused relaxation of both large and small coronary artery.
3. Catecholamine-induced relaxation or contraction was blocked by beta or alpha adrenergic blockade respectively.
4. The mean, resting membrane potential of small coronary artery recorded intracellularly was -47 mV.
5. Adrenaline caused relaxation without changes in the membrane potential and in the absence of action potentials.
6. Increase in extracellular potassium initiated depolarization of cell membrane.
7. Dissociation in smooth muscle between relaxation and membrane potential change were discussed.

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From the viewpoint of the neurohumoral interaction in the control of body temperature, brain activity under extreme cold was studied by means of EEG observation and electrical stimulation, employing New Zealand white rabbits with chronically implanted bipolar electrodes in the several parts of the brain. During experiment, rabbits were free to move around on the observation table or in the cold box under constant illumination.
The results were as follows:
The EEG activity showed the following alterations during exposure to cold (at a temperature of 20°C below zero for a period of 12 hours).
1. Exposure to the extreme cold brought about an enhancement of EEG activity in the medial preoptic area, ventromedial nucleus of the hypothalamus, posterior hypothalamus, periventricular stratum, hippocampus, medial amygdala, lateral septum and central grey, and suppression of EEG activity in the lateral preoptic area, lateral hypothalamus, lateral amygdala and medial septum. EEG recorded from the arcuate nucleus and its adjacent region did not show any notable change resulting from cold exposure. To summarize the above results, EEG of the areas belonging to the so-called sympathetic zone showed elevated activity under extreme cold. At the same time, some areas belonging to the so-called parasympathetic zone and the limbic system also showed an activated pattern during cold exposure. EEGs were recorded from the brain of immature rabbits of 14 to 40 days of age. It was suggested that the amygdala was the earliest center to develop for the regulation of body temperature. In the later stages of development the hippocampus takes the place of the amygdala in the thermo-regulatory mechanism.
2. Repetitive cold exposure (20°C below zero for 12 hours per a day) and simultaneous EEG recording were carried out for a period of 7 or 10 days in summer. The change observed in the hippocampus, amygdala, medial preoptic area, periventricular stratum, ventromedial hypothalamus and posterior hypothalamus observed at the initial exposure gradually decreased, until the EEG activity in these areas was hardly influenced by the 5th or 10th exposure to cold. The activity of the limbic areas tended to lose reaction to cold exposure earlier than the latter.
3. In order to elucidate the relation of increased activity in various parts of the brain to body temperature, a stimulation experiment was performed. Stimulation consisted of monophasic square wave pulses delivered unilaterally for one hour, 60 sec. on and 60 sec. off, at 0.5 msec. duration, 60 cps. The stimulation on each part of the brain caused a rise in rectal temperature. The change was divided into immediate effect (Effect during stimulation) and delayed effect (effect after stimulation). Immediate effect (rise of rectal temperature by 0.3 to 0.8°C) was observed by the stimulation of regions included in the so-called sympathetic zone of the hypothalamus such as the medial preoptic area, ventromedial hypothalamus and posterior hypothalamus and some areas of limbic system such as the amygdala, lateral septum and central grey. On the other hand, delayed effect was observed by the stimulation of the medial preoptic area, ventromedial hypothalamus (so-called sympathetic zone), lateral hypothalamus, arcuate nucleus (so-called para sympathetic zone), hippocampus, amygdala, lateral septum and central grey (limbic area). It may be supposed that the immediate effect was caused by neural factors or by fast-acting substances like epinephrine, and that the latter was brought about by slow-acting factors such as ad renocortical hormones or thyroid hormone.
4. In order to clarify the significance of the delayed effect which might play an important role in the prolonged exposure to cold, electrical stimulation of the limbic area was carried out in adrenalectomized rabbits and thyroidectomized rabbits.

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By the methods of intracellular microelectrode technique and the bridge circuit for recording the mechanical activity, the effect of external calcium concentration of the cultured chick embryonic heart has been investigated. Trypsin-dispersed cells from the ventricle of 5 days old chick embryos were cultured. The cell clusters became attached to the bottom of cultured-dish. Then, results from trypsin-dispersed cells were compared with those of noncultured intact embryonic hearts. Spontaneous cells were compared with those of non-cultured intact embryonic hearts. Spontaneous cells were discarded and only quiescent cells were driven by electrical field stimulation.
1. The reduction of calcium in the external medium strikingly prolonged the duration of action potential in cultured cells, while the amplitude of mechanical activity was prominently decreased.
2. In the intact embryonic hearts, the configuration of action potential is not significantly affected by the calcium deficient solution. On the other hand, the effect of calcium deficiency on mechanical activity is more dramatic than that in cultured cells. These results suggest that the inward movement of calcium ion through the membrane plays a significant role in the initiation of contraction.
3. The reduced mechanical activity of cultured and intact cells due to calci um deficiency returns to its normal level by the application of g-strophanthin, but the recovery rate was larger in cultured cells.

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Functional properties of afferent discharges from compound, tandem and single muscle spindles in the ventral and dorsal parts of the semitendinosus muscle of the frog were compared. Six dorsal root filaments supplied intramuscular branches to two capsules which were arranged either in series along a bundle of intrafusal muscle fibers (tandem spindle) or in parallel along intrafusal bundles (compound spindle) and discharged spontaneously at frequencies from 1.1 to 4.7 impulses/sec at the in situ (+0mm) length of the muscle. The static sensitivity of the fibers during stretch of the muscle by 2mm at velocities from 1 to 10mm/sec was 12.0 impulses/sec/mm in the mean. The dynamic index increased steeply with increase of the initial length of the muscle, and also with increase in the velocity of stretch. Ten filaments supplying one capsule in tandem or compound spindles discharged spontaneously at 0.7 to 3.2 impulses/sec at +0mm length. The mean static sensitivity was 10.2 impulses/sec/mm. The dynamic indices depended upon stretch velocity and also upon initial length, but the rate of the dependence was lower than that of the fibers supplying two capsules. Twelve filaments supplying single spindles discharged spontaneously at 0.1-0.65 impulses/sec at +0mm. The mean static sensitivity was 5.1 impulses/sec/mm, and the dynamic indices were the smallest. These results suggest that the role of tandem and compound spindles may be to respond sensitively to minute changes of the muscle length.

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Effects of metabolic inhibitors (sodium cyanide, sodium azide and DNP) on taste response in the chorda tympani nerve of rats were studied, when they were applied on the tongue with or without taste solutions.
DNP depressed taste responses but not other inhibitors. When DNP was neutralized by NaOH, its depressive action disappeared. Similar depression of taste responses was observed by addition of HCl to taste solutions. Therefore, the depression by DNP was attributed to its low pH effect. It is concluded that taste responses are not affected by these metabolic inhibitors.
The enzyme hypothesis of taste receptor stimulation was discussed, based on the results of the present experiments.

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1. Sodium desoxycholate in a dose of 2.5×10^-4 gm/ml decreased the slope of phase 4 of the action potential of the sinoatrial nodal cells of the rabbit heart and also decreased the amplitude, duration and rate of rise of the action potential.
2. Its effect on the action potential of the sinoatrial nodal cells is not affected by atropine, but antagonized by norepinephrine.
3. It decreased the conduction velocity of the impulses from S-A node to atrial muscle fibers or to the His' bundle.
4. The sinoatrial cells are more sensitively depressed by sodium desoxycholate than the atrial muscle fibers.

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1. Effects of pH on chorda tympani nerve responses to NaCl, KCl, sucrose and quinine of varying concentration and of the optimum temperature were investigated in rats.
2. Magnitudes of responses to NaCl in concentrations of 0.1M or lower were decreased linearly with lowering of pH of test solutions below 4.0, whereas those for 0.3M and 1M NaCl were independent of pH at 30°C. Depression of responses to NaCl by low pH were greater at 10°C than at 30°C. Magnitudes of responses to 0.01M, 0.3M and 1M KCl were increased as pH of test solutions was decreased below 4.0, but those of responses to 0.03M and 0.1M were independent of pH. pH dependency of the response to KCl was in marked contrast with that of the response to NaCl.
3. Magnitudes of responses to sucrose of varying concentrations were almost independent of pH, but slight decrease in the response magnitude was seen below pH 4.0.
4. Magnitudes of responses to quinine of varying concentrations were monotonously increased as pH of test solutions was decreased from 4.5 to 3.0.
5. Km or Michaelis constant of taste reaction was obtained from Beidler's taste equation and pH dependency of Km was examined. Thus, depression of responses to NaCl was attributed to the ionization of the receptor for NaCl, whereas facilitation of the responses to quinine was ascribed to that of the quinine receptor-quinine complex.

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It was shown that the extreme susceptibility of adrenalectomized rabbits to hemorrhagic hypotension was mainly due to the absence of glucocorticoid.‘Take-up’ of shed blood in an elevated reservoir proceeded far earlier and more rapidly than in the non-adrenalectomized rabbit. This was accompanied by progressive diminution of pulse pressures, while the cardiac rate was reduced. At autopsy, no blood pooling was noticed except that due to acute right heart failure. Examination of right ventricular pressures revealed the presence of progressive secondary rise in systolic and diastolic pressures indicating an increase in the resistance of the pulmonary circuit. Pretreatment with physiological dose of Cortisone prevented these changes and inhibited the rapid progress of ‘take-up’. The significance of glucocorticoid therapy in hemorrhagic hypotension in rabbits which differed from that in dogs has been discussed.

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Effect of cold exposure on the storage and metabolism of serotonin in brown adipose tissue was investigated in order to elucidate its physiological significance in cold adaptation.
Acute cold exposure at 0°C for 30 min, 6 and 24 hours as well as chronic cold exposure at 5°C for 2 weeks failed to influence greatly the serotonin content in interscapular brown adipose tissue and brain of the rat.
Plasma levels of serotonin in the external jugular vein and venous drainage from brown adipose tissue did not show any significant variations in response to cold exposure at 0°Cfor 30 min.
Monoamine oxidase activity in rat brown adipose tissue was elevated by chronic cold exposure at 5°C for 2 weeks, but not by acute cold exposure at 0°C for 30 min. Its activity in the whole brain and hypothalamus remained stable either on acute or chronic exposure to cold.
Norepinephrine did not affect the serotonin content in rat brown adipose tissue.
Administration of L-tryptophan raised the serotonin content in the brain, but not in the brown adipose tissue.
Conversion of ¹⁴C-5-HTP to 5-HT and 5-HIAA was not modified by acute cold exposure at 3°C for 4 hours and chronic cold exposure at 5°C for 2 weeks.In vitro metabolism of serotonin was not greatly affected by the addition of norepinephrine.

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