1) The attitudes of the spike activity and the so-called local response of a single node of Ranvier (Japanese toad) to urethane-Ringer's, low Na⁺-Ringer's, anisotonic solutions and to stimulating current of a long duration were investigated, to be compared with those to normal Ringer's solution and to short pulse stimulation, respectively.
2) The results obtained were never simple, but it is a fact that they react to those agents in different manners, although not clear whether the difference is essential or only apparent.
3) The spike was often observed to start from the falling phase of the maximal local response.
4) The significance of the ratio of spike height to maximal local response height was discussed.
5) Assuming that urethane is adsorbed by a nodal membrane after Freundlich's adsorption isotherm, it was concluded that the spike activity decreases and the maximal local response activity increases, and that both linearly in proportion to the amount of urethane adsorbed.

View full abstract

Minor tremor (MT), the phenomenon that the body surface of the warmblooded animal is constantly vibrating, was led with the special pickup. The present investigation was to elucidate the meaning of MT and its originating mechanism.
1) The rhythm of MT was principally 10 cycles per second, and its amplitude was 1-10 micron. MT was influenced by the resting, temperature and hyperventilation. All other possible origins of the rhythm were excluded.
2) The originating mechanism of MT was discussed and it was suggested that the spinal reflex, especially gamma motor system, may be responsible to the production of MT. The evidences are as follows:
a) relation between the pinna reflex and MT,
b) relation between the electrical stimulation of central nervous system and MT,
c) the effect of drugs on MT.
3) Application of MT to the diagnosis of certain diseases will be possible in future.

View full abstract

The changes in EEG and EP were investigated on the rat and the rabbit, in relation to the SP shift produced by DC application and repetitive brainstem stimulation.
1. EEG and EP changed correlatively very often, if not always, with the forced SP-shift generated by DC application.
2. In general, the cortical surface, in resting state, showed a slight positive steady potential relative to indifferent electrode placed on the nasal area. Therefore the application of slight negative DC was observed to supersede this positive steady potential. EP changed not only in amplitude, but also in polarity associated with the forced SP-shift, namely in positive direction by negative SP level and in negative direction by positive SP level.
3. The slow component in EEG and EP changed (mainly in amplitude) in many cases in proportion to the magnitude of SP-shift.
4. Repetitive stimulation of lower reticular formation caused sometimes the changes in SP, EEG and EP. However, there could not be found any consistent and regular correlation between them.
5. RF stimulation of very low frequency caused the arousal reaction in EEG, when it was very low or very high in intensity. When the stimulation was moderate in intensity, the arousal reaction could not be produced by lower frequency. However, with increase in intensity, even very low frequency showed the significant arousal effect on EEG.

View full abstract

Employing single myelinated nerve fibres which were dissected out of sciatic nerves of the toad, observations were made on various actions of weak narcotic and NaCl-deficiency upon the nodal activity. Results obtained are as follows:
1. The urethane concentration just critical for conduction block is certainly smaller than that for excitation block.
2. There is a small range of stimulus near the threshold, where the spike of a normal node appears graded. The range gets wider with larger narcotic concentration, and, at the same time, the spike height gets smaller until it vanishes finally, leaving the local response behind.
3. In advance to the range of graded spike mentioned above, there is another range of stimulus where the local response appears. The local response gets larger almost linearly with stronger stimuli, up to a certain maximal value, which gets larger in stronger narcotization.
4. Narcotic and NaCl-deficiency are co-operative in bringing forth conduction block.

View full abstract

It has been demonstrated that insulin suppresses and alloxanization potentiates the leucocytotic response to typhoid vaccine. In connection with the previous finding supposition was given that insulin stabilizes the vaccine effect which in the presence of glycocorticoids leads to the formation of endogenous “leucocytosis-inducing factor” directly responsible for the reaction.

View full abstract

1. The nature of action of some plateau forming chemical agents on toad's single myelinated nerve fibres was analyzed.
2. Among simple oxidizing agents, only hydrogen peroxide at very high concentrations (higher than 2%) produced plateau in the temporal course of action current. Its effect was mainly due to hypertonicity proper, but its oxidizing potency was somewhat favourable to plateau formation.
3. p-Quinone depolarized the Ranvier's node and delayed the repolarization phase at the same time. Although recovery with the addition of cysteine was not so good, its effect was essentially attributable to its oxidizing potency, for hydroquinone at high concentrations caused simply deterioration.
4. Some divalent metals, such as Fe, Co, Ni, Cu, Zn, Cd caused generally slight hyperpolarization of the Ranvier's node and produced a prominent plateau in the repolarization phase of action current or action potential. Theirplateau forming action reached quickly an equilibrium and remained constant for a few hours. Cysteine recovery was prompt and complete in all the cases.
5. The plateau forming strength varied only slightly between Fe, Cu, Zn and Cd. But, Co was about five-fold and Ni about eighteen-fold more powerful than the formers.
6. Within some limit, the duration of plateau was more prolonged with increasing the concentration of Cd, Co and Ni. However, beyond this limit, the plateau was rather curtailed. Their optimal concentration for plateau formation was about 10^-3 mole.
7. The plateau formation with divalent metals was competitively inhibited by p-chloromercuribenzoic acid which by itself affected hardly single nerve fibres.
8. Phenylmercuric acetate produced appreciable depolarization and sometimes plateau. Cysteine recovery in its plateau formation was partial.
9. All the plateau forming metals were found to belong to the transition element. Not all the heavy metals had a plateau forming action.
10. It is concluded that the repolarization phase of action potential can be delayed most effectively by the-S-Me-S-linkage (Me represents divalent transition metals) in the plasma membrane of the Ranvier's node. And, the possible mechanism in which the difference in the plateau forming strength between each transition metal may be brought about, is briefly discussed.

View full abstract

Distribution of the scattered light from the cornea has been determined, using a phototube of multiplier type.
A slight scattering occurs in the forward direction even in the transparent cornea. In the peripheral region of the cornea, the scattering in the direction right angles to the radial fibers is greater than that in the parallel direction. In the central region, no directional difference is found in the scattering characteristics.
As the cornea clouds, the scattering increases in the backward and lateral directions, though the greater parts of the scattering occur in the forward direction.
On drying the cornea, the transparency of the clouded or fresh cornea is recovered or even enhanced.
The transparency and clouding of the cornea are explained in terms of interference in the double lattice structure consisting of the fibers and the fibrils.
The changes in the microscopic lattice are revealed in the diffraction spectra and the polarization findings. On the other hand, the changes in the submicroscopic lattice are revealed in the angular intensity distribution of the scattered light.

View full abstract

1. The effect of stimulation of the midbrain upon the spinal motor activity was investigated by recording intracellular potentials from the spinal alpha motoneurons in lumbar segments of the cat. Indirect effects through the gamma fibers and spindle afferents were excluded by sectioning the ventral roots and the peroneal and tibial nerves.
2. The stimulation of the red nucleus produced EPSP's and consequent spike potential in the contralateral flexor motoneurons with a latency of 9 msec. and IPSP's in the contralateral extensor motoneurons with a latency of 11 msec.
3. The effect of stimulation of the decussations in the midbrain was similar to that of the rubrospinal tracts. It occurred bilaterally with latencies much shorter than from the red nucleus.
4. With the stimulation of the midbrain reticular formation, EPSP's and consequent spike potentials were recorded bilaterally from both flexor and extensor motoneurons with a latency of 6 msec. EPSP's in the extensor motoneurons were followed by slight IPSP's.
5. The central gray matter produced inconspicuous effects upon the spinal motoneurons. They partly resembled those of the reticular formation, the inhibitory effect being somewhat predominant.
6. The midbrain foci facilitated or inhibited the reflex firing of motoneurons as a result of algebraic summation of EPSP or IPSP centrally induced with EPSP induced from the dorsal root.
7. Some spinal interneurons were found responsive to the stimuli delivered to all of the midbrain foci and a dorsal root.
8. The stimulation of the midbrain foci brought about the ventral root slow potentials, which corresponded to the PSP's in single motoneurons and also to the facilitatory or inhibitory effects of the midbrain foci upon the monosynaptic spinal reflexes.We are indebted to Prof. T. Otani for advice and criticism

View full abstract

1. The electrical responses to olfactory stimulation were studied by a macroand a micro-electrode in the olfactory epithelium of six kinds of fishes, the Channa argus, eel, catfish, carp, mudfish and lamprey.
2. The averaged resting potentials of the olfactory epithelium of these fishes were found to be between 7.6 and 12.4 mV.
3. The shapes of the slow potentials produced in the olfactory epithelium by olfactory stimulation were different in different fishes. The potential in the Channa, carp and lamprey showed a steep rise and an exponential slow decline. The potential in the catfish and eel had a far steeper rise and decline and it had a short and constant duration in spite of the durations of stimulation.
4. Three types of responses, the on-, the on-off-and the off-responses were found in the olfactory epithelium of these fishes. The relative magnitudes of the on-and the off-responses were various and not consistent during repetitive stimulation.
5. By means of a micro-electrode spontaneous spike discharges were sometimes recorded in the olfactory epithelium. They increased in number in response to olfactory stimulation.
6. The colour of the olfactory epithelium, the duration of the slow potential and the keenness of olfaction were compared. It was presumed that the short duration of the slow potential is closely related with the olfactory sensitivity.
7. The olfactory responses of fish were compared with those of the frog and the toad. The origin of the three types of responses was considered.

View full abstract

The role of the upper brain upon the reflex response of the long ciliary nerve produced by stimulating the sciatic nerves was investigated, using the efferent impulses from a single or few active units of the long ciliary nerve in the cats.
1. In non-decerebrate cats a marked increased activity of the long ciliary nerve was elicited by stimulating the sciatic nerve centrally. Such a reflex activation was not affected with the removal of the cerebral cortex and the anterior half of the thalamus, whilst it was greatly reduced after the removal of the hypothalamus.
2. In decerebrate cats the responses in the sympathetic nerve to nociceptive stimuli were various; in some fibers a slightly increased activation was evoked, whereas in other fibers an inhibition of the spontaneous discharges was elicited irrespective of the frequency and strength of the stimuli. Such responses were also recognized in the medullary animal.
3. In spinal cats the excitatory response of the long ciliary nerve did not occur, whereas in some fibers inhibition of the spontaneous activity was produced with strong stimuli.
4. From these results it was highly probable that the interbrain particularly the hypothalamus, and the medulla oblongata played an important role for the development of the reflex activation of the long ciliary nerve. Furthermore, the reflex inhibition of the long ciliary nerve was discussed.

View full abstract

(1) Threshold strength-duration for transverse field stimulation of muscle in normal ringer is given by a relation with two time constants which are independent of temperature.
(2) Increase of latency relaxation with transverse field strength of stimulation in normal ringer (Goodall, 1958) is not due to synchronisation of stimulus.
(3) In choline ringer the amplitude of both latency relaxation and twitch height varies for low levels of stimulation as the sixth power of the field for pulses of constant duration.
(4) This amplitude depends linearly on duration after an apparent induction time.
(5) The induction time is temperature dependent and smaller than would be expected from the charging time of the membrane derived from (1).
(6) The amplitude for constant stimulation depends on resting potential, having a maximum somewhat below the normal resting potential.
(7) On replacing chloride by nitrate the amplitude is increased and this maximum shifted to a higher potential.
(8) Induction time increases with potassium concentration and is independent of calcium.
(9) Two pulse experiments show that activity following an undirectional pulse is localised to one side of the fibres.

View full abstract