1. Intracellular recording of spike potentials from single motoneurons in toad's spinal cord revealed that some motoneurons were excitable from two different ventral roots (mostly IXth and Xth roots).
2. Between these two antidromic pathways, differences were found in their latent times, slopes of initial part of the spikes and liability to blockade of antidromic conduction. Same conduction velocities were found in the extraspinal part of both routes, which indicated that, in both pathways, alpha fibers were concerned.
3. Action potentials were recorded from a few fibers in one ventral root upon stimulating the other ventral root.
4. Efferent discharges were detected in a small number of ventral root fibers in response to antidromic impulses backfired through the same ventral root.
5. In order to account for these findings, seven types of correlation between two pathways were presented and their possibilities were discussed. In conclusion, the most likely neuronal configuration is a double motoneuron with dendritic liaison, though ephaptic transmission between motoneurons cannot be exclubed to a certainty.

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1) For the purpose of clarifying the nature of the so-called cone action potential (S-potential), some electric properties of the membrane, from inside which this action potential was recorded, was investigated by means of doublebarrelled microelectrode technique.
2) Neither depolarizing nor hyperpolarizing current passage gave influence to the original response in its amplitude and configuration. In other words, S-potential did not have an equilibrium potential.
3) While the values of effective resistance were widely distributed in a range from below 200 KΩ to over 3 MΩ, there appeared to be some difference in their distribution between L-and RG-elements. The effective resistance was not changed during activity and was independent of the change in amplitude of the response produced by the change in the intensity of illumination.
4) Based on the above results, it was fully discussed whether the nature of S-potential is of intra-or extracellular.

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1. In the adult female, the electrical discharge of M. bulbocavernosus and M. transversus perinei superficialis showed a weak cyclic change with the menstruation cycle, decreasing or vanishing around the bleeding period and, restoring thereafter. With M. sphincter ani externus and M. triceps brachii, no such remarkable reduction was observed.
In male, such a cyclic change could not be detected.
2. The inhibitory action of progesterone, and human chorionic gonadotro. phin, and the enhancing action of estrogen and androgen were demonstrated on the tonus of M. transversus perinei superficialis and M. triceps brachii in the female subjects. The male subjects responsed with much lesser degree. With M. sphincter ani externus, effects were less marked than those on the other perineal muscles.
3. After the intravenous administration of 1 unit oxytocin, the perineal muscle group of female subjects showed diminished discharges or their disappearance regardless of the sexual cycle. On the other hand, those of male subjects showed slightly increased discharge with exception of the external spincter ani muscle which was hardly changed by oxytocin.
The brachial triceps muscle, both in female and male, on the other hand, showed increased discharge.
4. With progesterone and oxytocin, it was demonstrated that effects of the hormone on the muscular tone are different among various sorts of skeletal muscle. From this fact together with the authors' previous reports, it was presumed that the changes in electromyogram due to hormones may be the result of their combined effect upon the nervous system and the muscle itself. It was also emphasized that, effects of progesterone and oxytocin upon tonus of abdominal and perineal muscles are useful to promote gestation and parturition respectively.

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1.The effects ofγ-aminobutyric acid (GABA) on the isolated guinea pig ileum were investigated.
2. In the absence of other drugs GABA produces occasionally stimulation and also relaxation, which are abolished by atropine (1μg/ml.), LSD (0.01μg/ml.) and picrotoxin (10μg/ml.).
3. Effects of GABA on the dose-response curves of gut-stimulating drugs were examined and found that it has an antagonistic action to acetylcholine, nicotine and 5 HT, the anti-5 HT action being the highest and the anti-Ach one the lowest. But hardly any antagonism between GABA and histamine or BaCl₂ is observed.
4. The anti-5 HT and anti-nicotine actions of GABA are abolished or more or less depressed by LSD (0.0005μg/ml.), dibenzyline (0.001-0.1μg/ml.), atropine (1μg/ml.), and picrotoxin (10μg/ml.), but scarcely affected by pyribenzamine (10μg/ml.) and strychnine (100μg/ml.). The anti-nicotine action are also blocked by desensitization for 5 HT due to application of its high dose, while the anti-5 HT action is hardly influenced by high dose of hexamethonium (10-100μg/ml.) which is a sufficient dose to block the gut-stimulating action of nicotine.
5. The peristalsis of isolated guinea pig ileum, recorded by means of the method similar to that of Bülbring and Lin, is also blocked or depressed by 1-100 μg/ml. GABA, when applied outside, but barely affected by its inside application. This action was found to be blocked by LSD, dibenamine and picrotoxin. The peristalsis-inhibiting action of 5 HT is also blocked by LSD and dibenamine in their appropriate concentrations of not affecting the peristalsis, but picrotoxin has no such effect. When applied inside, GABA also depresses the peristalsis-promoting action of 5 HT applied inside.
6. Based on the results stated above and those obtained on the stretch receptors of crayfish or on the frog spinal reflex, it is suggested that the sites of action of GABA would have a close correlation with the tryptamine receptors.

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1. The action of ultrasound was studied on the sciatic nerve of a frog, the spinal cord of a toad, and the brain of a bullfrog tadpole and a frog. The results were compared with the effect of temperature.
2. The action potential of a myelinated nerve was enlarged by irradiation with ultrasound of about 16 W/cm.², but it was inhibited by irradiation with that of higher intensity.
3. The reflex discharges of the spinal cord were increased by irradiation with ultrasound of about 3 W/cm.². But they were inhibited at higher intensity (beyond 6.83 W/cm.²).
4. The brain wave was augmented by irradiation with weak ultrasound, but they were decreased by repeated irradiation.
5. It was concluded that ultrasound has a stimulative action at low intensity, but has an inhibitory action at high intensity on the nerve tissues and the muscle. However, when ultrasound with a stimulative action was repetitively applied, it eventually produced an inhibitory action.
6. Spontaneous discharges appeared on the spinal ventral root by ultrasonic irradiation. Up to a certain ultrasonic intensity, an inverse linear relation was found between the intensity and the latent period of the discharge.
7. The rise of temperature was measured in a frog muscle during and after ultrasonic irradiation. It was found to be less than 10°C. at the ultrasonic intensities which produced a stimulative action.
8. By raising the temperature of Ringer's solution, the effect of temperature was studied on the spinal reflex activity. The results were entirely different from the ultrasonic actions on the spinal cord. It was therefore presumed that the main role of the actions of ultrasound is not played by a rise of temperature, but by the other actions of ultrasound.

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The membrane constants of muscle fibres of toads, in normal and stretched states, were measured by square pulse analysis. A tendency for both C_m and 1/R_m to increase by the application of stretch was observed, but the difference of these constants between relaxed and stretched states is so small that it cannot be considered significant by taking into consideration various errors involved in measuring these constants. However, other kinds of experiments on muscle fibres would support the conclusion that C_m and 1/R_m increase, although this increase is only about 14%.

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Transport of Ca ions across the cornea was studied by the use of ⁴⁵Ca. The solution containing radioactive Ca was brought in contact with either side of the cornea. The transmission of the film which was exposed to radioactive Ca penetrated into the cornea was determined photoelectrically. The relative flux rate was thus determined.
It was found that flux ratio (outflux/influx) is far greater than the theoretical value estimated on the assumption that the transport is carried out by diffusion.
The outflux was depressed at low temperature. The metabolic inhibitors such as iodoacetic acid, DNP, NaF, KCN inhibited the outflux.
These results seem to indicate the existence of an active transport of Caions from the aqueous humor, across the endothelial cells, to the stromal fluid.

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The beginning and development of the spontaneous electric activity obtaining from the exposed cortex were examined in various young animals in the pre-and postnatal growth. The animals used were albino rats, guinea pigs, chicks, and pigeons. Guinea pigs and chicks present the spontaneous electric activity in an early embryonic stage as observed by the previous writers, while albino rats and pigeons do show this activity only in the postnatal life. In albino rats it is possible to initiate the spontaneous electric activity after the rats are 5 days old and in pigeons after the age of about 4 days.
The onset of the spontaneous electric activity seems to reflect ecologically the difference found between the animal classes which can stand and feed by themselves as soon as birth, and those which do not leave the nest for a while after birth. In all these animals the cortical electric response by afferent stimulation is elicitable for a certain period after the spontaneous electric activity appeared.
Cytological examination of the cortical cells in albino rats and pigeons reveals that the spontaneous electric activity will be initiated before nerve connection between the cortical and the subcortical regions is established. The appearance of the spontaneous electric activity seems to be timely correspondent with that of Nissl substance in the nerve cells.

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The conversion of thyroxine to tetraiodothyroacetic acid was studied employing rat kidney mitochondria as an enzyme source. The conversion was only slight without the addition of pyridoxal phosphate and α-ketoglutarate. The effect of these two cofactors of transaminases was much greater than that of any other compounds tested, such as DPN, succinate and malate. The enhancing effect of pyridoxal phosphate and amino acid acceptors (α-ketoglutarate, oxalacetate and pyruvate), only a slight influence of anaerobiosis, the lack of “dilution effect”, and a marked inhibitory effect of amino group donors (glutamate and aspartate) upon the conversion-all of these things indicated that the enzyme involved is of the nature of a transaminase rather than l-amino acid oxidase. The transaminase may be the main enzyme involved in the deaminative breaking down of thyroxine, even if other enzymes are present and active. The transaminase exists mainly within mitochondria and is inactivated by boiling for 20 minutes.

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