The direct and indirect effects of the stimulus given to the thalamus were electrophysiologically studied by using rabbits. Describing the result of the experiment from the direct effect of stimulus, an appearance of a movement accompanied by a muscular discharge evoked thereby was noticed, in addition to a recruiting response and arousal reaction as the result of such an electrical stimulation of the thalamus. It was clarified that this muscular discharge is due to an excitation of the nervous system, which is different from the recruiting response or arousal reaction, and that such a phenomenon may be evoked both by 100 c/s stimulus and by 8 c/s stimulus. Then, regarding the effect of an indirect stimulus given to the efferent pathway, the evoked muscular discharge in the fore and hind limbs due to the stimulation given to the cerebral cortex and the sciatic nerve was examined. In this muscular discharge, the thalamus was seen to indicate both facilitating and inhibiting effects similarly to 8 c/s stimulus and to 100 c/s stimulus. A histological examination revealed that the region exerting a facilitating influence exists in the central part of nucl. ventralis anterior, and that the inhibiting tissue surrounds it. Furthemore, it was known that as to nucl. centrum medianum, on the contrary, the inhibiting system exists in the central part and the facilitating tissue is located in the outer peripheral part. In regard to the influence exerted by the stimuli given to the thalamus on the afferent evoked potential revealed by applying an average response computer, it was seen that the inhibiting effect was observed in all cases under 8 c/s stimulus and in almost all cases under 100 c/s stimulus. In the light of such experimental results about the afferent evoked potential, it was understood that, independently of the appearance of the shape of brain wave, the indirect facilitating or inhibiting effect may be influenced by the respective regional characteristics, in other words, that the inhibiting effect may appear in a region where more inhibitory tissues exist, and on the contrary in a region having more facilitating tissues, the facilitating effect may appear more prominently.
Concerning the spike and wave noticed in consequence of the 3 c/s stimulation of the rabbits' thalamus, a neurophysiological study was conducted. The results obtained in this study are as follows: In the first place, the effects of various drugs on the spike and wave were examined, and, as a result of it, it was discovered that in either of the spike or the wave or in both, the drugs in different combinations indicated either the action of facilitation or that of inhibition. In the next place, the effect of the 3 c/s stimulation of the thalamus on the efferent muscular discharge due to the stimulation of the cerebral cortex was examined. As a result of it, the actions of both facilitation and inhibition were observed. However, no coincidence was noticed between the above-mentioned result and the result of the nociceptively induced reflex discharge, which was simultaneously carried out. By using an average response computer, the influence of the spike and wave on the efferent pathway was examined, following a similar examination on the afferent pathway, and from this experiment it was made clear that the 3 c/s stimulation of the thalamus inhibits the afferent action potential. Furthermore, from the behavior of the action of various drugs upon the degrees of the inhibition of the spike and wave on the afferent action potential, it became clear, too, that the wave, besides the spike, also indicates an action of inhibition on the afferent pathway. From the histological examination of the regions of stimulation, it was known that the spike is well recognizable due to the stimulation of VA, and that the wave is noticeable by the stimulation of RET. The influence exerted by RET stimulation on the afferent action potential, unlike the result shown by CM and VA stimulation, was noticed more strongly even under a weak stimulation. In the light of the results obtained in this way, it may be reasonably concluded that the spike and the wave are caused by the excitation of the different system of nervous tissues, and that, of these two, the wave alone has something to do with the action of inhibition exerted on the sensation, and the spike is related to the appearance of movement.
The adrenalectomized rabbits were treated daily with compound F (CF), prednisolone (PD), β-methasone (BM), or DOCA. Some of them were treated with nitromin (NMO) combined with CF, or DOCA. The animals were examined as to their blood and bone marrow pictures. The results are as follows: 1) Erythrocytes: The administration of CF, PD, BM, or DOCA prevented anemia induced by adrenalectomy. The color indeces and reticulocyte counts showed no remarkable changes. In the bone marrow, too, CF and DOCA prevented hypoplasia of the erythroid system after adrenalectomy. 2) Diameter of erythroctes: The administration of CF or DOCA prevented the enlargement of the erythrocyte diameter after adrenalectomy. In general, the enlargement of the erythrocyte diameter ran parallel to the increase in the reticulocyte count. 3) Leucocytes: No remarkable change in W. B. C. count was observed in the untreated rabbits while those treated with CF and NMO showed decreases in the count. PD or BM were even, in dosages larger than those corresponding to CF (calculated by their antiinflammatory activity), found to be less potent than CF. The administration of DOCA showed no remarkable effect. 4) Pseudoeosinophils: The administration of NMO intensified the moderate decrease in pseudoeosinophil count brought on by adrenalectomy while the administration of CF increased the count even in those rabbits treated with NMO. In this respect PD and BM were found less potent than CF. DOCA reduced the fall in the pseudoeosinophil count. 5) Lymphocytes: Adrenalectomy by itself causes a slight increase in the lymphocyte count. The adrenalectomized rabbits treated with DOCA showed no change in the count; while the combined treatment with NMO caused a slight decrease. CF decreased the count considerably. In this respect, too, PD and BM were found less potent than CF. 6) Eosinophils: The eosinophil count, which had increased slightly after adrenalectomy, showed no change due to NMO administration. CF decreased the count both in the peripheral blood and in the bone marrow. The effect of DOCA was found inconsistent in the peripheral blood, but it seemed to cause a slight increase in the bone marrow. 7) Toxic granules in the pseudoeosinophils: The rate of the cells with toxic granules goes up after adrenalectomy in the peripheral blood as well as in the bone marrow. This effect was intensified by NMO administration, and lessened by CF or DOCA administration, CF being more potent than DOCA. 8) Body weight: The body weight loss, caused by adrenalectomy, was intensified by CF administration, while DOCA recovered it. NMO, in the dosage used in these experiments, caused no remarkable changes. The results obtained may suggest that, although CF and DOCA are similarly effective in preventing the anemia caused by adrenalectomy, their effects on the leucocyte systems, i. e. lymphocytes and granulocytes, are quite different.
I) Leucocyte mobility: 1) The wandering velocity of the pseudoeosinophils in the peripheral, blood is markedly supressed by adrenalectomy. 2) The in vitro addition of CF or PD was found to reduce this supression of the velocity. 3) The in vivo administration of CF (alone, combined with DOCA, or with DOCA + adrenalin) also reduced this supression, while DOCA or adrenalin by itself displayed no preventing effect. II) Phagocytic activity of the leucocytes: 1) The phagocytic activity, examined with India ink, of the pseudoeosinophils in the peripheral blood is markedly supressed by adrenalectomy. 2) The in vitro addition of CF or PD was found to reduce this supression of the activity. 3) The in vivo administration of CF (alone, combined with DOCA, or with DOCA + adrenalin) also reduced the supression, while that of DOCA or adrenalin, administered alone, did not. III) Growth rate of the bone marrow in the tissue culture: 1) The relative growth rate of the bone marrow is markedly supressed after adrenalectomy. 2) This supression of the growth rate was found to be reduced by CF or PD added in vitro. 3) In vivo administration of CF, DOCA, or adrenalin more or less subdued the suprepsion of the growth, CF being the most potent of the three hormones. CF +DOCA, with or without adrenalin combined completely prevented the supression caused by adrenalectomy. The above results show that leucocyte function and the growth rate of the bone marrow in vitro, are sapressed by adrenalectomy, and that the supressing effects of adrenalectomy are almost completely compensated by glucocorticoids, while the compensating potency of DOCA is quite insufficient, and that of adrenalin nearly null.