It was investigated by electron microscope that subcellular calcium is existed in specific sites in skeletal and uterine muscles.
Tissue was fixed with 2% osumium tetroxide after incubation for 5 minutes in the mixed solution containing 100 mM sodium tartaric acid, 100 mM sodium hydroxide and 10 mM sodium dihydroxytararate osazone.
Skeletal muscle: Calcium precipitate was consistently found densely concentrated in Z-band, myofilament and about triad, but sarcoplasmic reticulum had no precipitate at the muscle contraction.
At the muscle relaxation, on the other hand, precipitate was found about sarcoplasmic reticulum and lateral sac, but Z-band, myofilament, cell-interstitium and the inside of T-vesicle had no precipitate.
Uterine muscle: At the muscle contraction, calcium precipitate was present in myofilament and matrix of mitochondxia, but was not present in the inside of pinocytotic vesicle. At the muscle relaxation, precipitate was localized about pinocytotic vesicle and in cell-interstitium, but in myofilament it distinctly decreased.
We recognized that the mechanism of the contraction and relaxation in skeletal was different from that of uterine muscle.

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In experiments on dogs the influences of peristaltic contraction of the distal colon on blood flow through the colonic vein were studied. Blood flow was recorded continuously by electro-magnetic flow-meter.
The peristaltic contraction of the distal colon caused the periodicity on the flow-meter tracing of the colonic vein.
Three groups of the correlation between the peristaltic contraction and venous blood flow were observed. The first pattern is that the abrupt augmentation of the colonic blood flow was elicited during the contraction. The second pattern is that the diminution of colonic blood flow during the contractile phase was followed by the sustaining augmentation of the blood flow during the relaxation. The above mentioned two patterns being in combination is the third pattern. That is, the augmentation of the blood flow during the contraction was followed by the diminution of blood flow corresponding to the highest level of contraction and by the sustaining augmentation of blood flow during the relaxation. The third type was usually elicited by the stimulation of the pelvic nerve.
The initial augmentation of blood flow is due to propulsive action on the blood within the colonic vessels. The secondary augmentation of blood flow is depended on the vascular dilatation which is caused by the obstruction of blood flow through the colon during the prolonged contraction.

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The isolated guinea-pig ileum was heated at various temperatures (46-48°C) for various times (5-30 min) and the responses of the ileum to acetylcholine, histamine, potassium chloride and transmural stimulation were investigated.
The responses to acltylcholine, histamine and KCl were depressed by heating at the same degree while it was impossible to depress selectively those to acetylcholine and histamine. The responses which were decreased after heating under mild condition sometimes showed reversible recovery. These facts show that the resistance of both acetylcholine and histamine receptors to thermal alteration is similar to that of the muscle membrane.
Meanwhile, the contractions obtained with nicotine and transmural stimulation disappeared selectively under such the conditions of heating that the responses to acetylcholine, histamine and KCl were kept almost normal, namely, it means that nervous elements were damaged selectively by heating.

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This study was made to clarify chemical properties of a-receptor and acetylcholine receptor. The isolated was deferenses of rats and guinea pigs were heated in organ bath, and the receptor activity was examined.
1) The heat treatments of the was deferenses of a guinea pig (46°C or 47°C, 20 min) and of a rat (45°C or 46°C, 20min) produced no change in the response to K.C1. On the other hand, the responses to noradrenaline and acetylcholine were depressed significantly.
2) The reversible denaturations of the acetylcholine receptor of a guineas pig was deferens by heat treatment were observed.
3) In the guinea pig was deferens received heat treatment the response to acetylcholine was significantly larger than the responses to noradrenaline.
4) The a-receptor of the rat was deferens was heat-labile and the thermal alteration produced irreversible changes of the receptor activity.
5) In the rat was deferens, the heat treatment caused a decrease in the maximum response of the dose response curve of noradrenaline without the parallel shift.

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The developmental morphology of the neuro-muscular junction in the small intestine of the human fetuses from 8 weeks to 20 weeks has been studied with the electron microscope. In the 8th week embryos, neural processes from Auerbach's plexus were found to have extended to the surface of the muscle cells, which appeared as a thin layer on the inside of the plexus. The neural processes found on the surface of the muscle cells contained occasionally a numbr of small vesicles of irregular form and fine filaments. In the tenth and eleventh weeks, when the logitudinal muscle layer was formed on the outside of Auerbach's plexus, the neural processes were demonstrated to have extended into the circular muscle layer. They, hawever, were still free and did not form bundle with Schwann cell cytoplasm. In the muscle lyer of 14 weeks old fetus, many bundles of the nerve fibers were observed accompanying Schwann cell process and the cells with light cytoplasm. The latter cells may be considered as Cajal's interstitial cell. The neural processes which were terminated on the muscle cell surface appeared to have, whithing the processes, many small vesicles of 300 to 500 A in diameter and a number of cored vesicles of 1000 A in size. In 20 weeks old fetus, the nerve bundles in the muscle layer increased both in number and size. The neural processes which were terminated on the muscle cell surface contained many vesicles and cored vesicles. The small vesicles appeared sometimes in a cluster in the vicinity of the axoplasmic membrane. The thickening of the presynaptic membrane was found inconstantly in the present observation.

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Using the isolated dog ureter or kidney-ureter preparations, the effects of intraluminal perfusion pressure, and the possible influence of autonomic nervous system on the ureteral motility were examined.
Normal peristaltic activity was markedly changed in its rhythm, contraction force and conduction, by intraluminal pressure gradient and sometimes antiperistalsis was observed by moderate decrease in intraluminal pressure. Electrical stimulation on the renal hilus with which we attempted to stimulate nerve fibers, failed to find any change in peristaltic activity. Furthermore, TTX, both adrenergic and cholinergic blocking agents did not show any effect on the peristaltic activity and intraluminal pressure-peristalsis relationship.
By the histochemical examinations both adrenergic and cholinergic fibers in the ureter were observed to be extremely few comparing to that in was deferens, and ganglion cell could not be found.
From the results, it was concluded that dog ureteral peristalsis might be mainly regulated by hydrauric factor, especially gradient of intraluminal pressure, and might be scarcely regulated by autonomic nervous system.

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