The effects of ajmaline, cocaine, diphenylhydantoin, lidocaine, procainamide, propranolol, quinidine and trimetazidine on the contractility, functional refractory period and responsibility to electrical stimuli of rat isolated papillary muscle were studied and the following results were obtained: 1) Ajmaline, procainamide and trimetazidine decreased scarcely the contractile tension of the muscle in the concentration of 10-6,10-3 or 10-4 (g/ml) respectively, quinidine, propranolol, cocaine and diphenylhydantoin decreased remarkably it in the concentration of 10-6,10-8,10-6 or 5 ×10-6 (g/ml) respectively. However, lidocaine decreased the muscle tension in a concentration of 5 x10-5(g/ml), but did scarcely it in the lower concentration. 2) The func t ional refractory period of the muscle was increased by lidocaine, ajmaline, quinidine or procainamide in the concentration of 5 ×10-6,5 ×10-7,5 ×10-6 or 5 ×10-4(g/ml) respectively, The period was slightly increased by propranolol or diphenylhydaintoin in each concentration of 10-5(g/ml) and that was scarcely influenced by trimetazidine or cocaine in the concentration of 10-5 or 10-4(g/ml) respectively. 3) The response pattern of the muscle to electrical stimuli of 60 to 660 cycles per minute was studied and found to be influenced in the presence of lidocaine, ajmaline, quinidine or procainamide: these drugs, in the concentration of 10-6,10-7,10-6 or 4 × 10-4(g/ml) respectively, suppressed the muscle responses to electrical stimuli of low frequencies and this effect was seen remarkably in lidocaine and ajmaline. This kind of effect of propranolol was seen when the stimulation frequencies were low and it was characteristic in lower concentrations than 10-8(g/ml). Cocaine, trimetazidine and diphenylhydantoin, in any concentration, showed scarcely this effect when the stimulation frequencies were high or low. From these results it was assumed that ajmaline, lidocaine, procainamide and propranolol may act to depress the ectopic contractions of rat papillary muscle and that quinidine is the depressant of the papillary muscle of rat ventricle.
The effects of adrenaline, noradrenaline and isoproterenol on rabbit ear vessels and the influence of pipratecol on their effects were pharmacologically investigated and the following results were obtained: 1) Pipratecol decreased the perfusion drops of rabbit ear vessels when 0.1ml of the drug was perfused in a concentration of 10-4,10-6, or 10-8g/ml. 2) The perfusion drops decreased by 0.1ml of adrenal ine or noradrenaline 10-10g/ml was prevented by pipratecol 10-4or 10-6g/m1 with which the preparation was pretreated 60 minutes before the affection of the adrenaline or noradrenaline. But, this kind of effect of pipratecol was scarcely seen when the drug was applied in the concentration of 10-8g/ml. 3 ) The slight increase in the perfusion drops, appeared when 0.1ml of isoproterenol 10-10g/ml was applied on ear vessels, was scarcely influenced by the pretrea tment with pipratecol in any concentration. From these resul ts it was assumed that pipratecol acts on the a-adrenergic receptor of rabbit ear vessels.
The effect of pipratecol on isolated guinea-pig atria was investigated and the following results were obtained: 1) In a high concentration of 10-4g/ml, pipratecol increased the amplitude of atrial contractions while decreased the rate. But, in a low concentration of 10-8g/ml, the drug decrease the amplitude and increased the rate slightly. 2) These effects of pipratecol on atrial contractions were gradually reduced when similar affection of pipratecol was repeated on the same atria. 3) The effects of adrenaline and noradrenaline were suppressed by the preceding addition of pipratecol, while that of isoproterenol was scarcely. 4) The effect of pipratecol on atrial contractions wa s hardly influenced by reserrine with which the animal had been pretreated 24 hours before the sacrifice of animal. 5) The augmentative effect of nicotine on atrial contractions was slightly suppressed by the preceding addition of pipratecol. From these results, it was assumed that pipratecol has some affinity with the adrenergic receptor of atria.
Middle silk gland of the silkworm in embryonic stage (120 hours after blastokinesis)has been observed electron microscopically. Comparing with the posterior silk gland in the same stage, rough ER was much less developed in the middle silk gland cells and dilatation of the ER cavity was hardly observable. Golgi apparatus is also not well developed and the sericin globules were not found. It is suggested that synthesis and secretion of protein are slight at this stage of development. In nuclei, a number of nucleoli and chromatin blocks are observable. They are usually smaller in size than those in the posterior silk gland and are not attached to the inner nuclear envelope. These results suggest that there is some delay in the commencement of the synthesis and secretion of fibroin and sericin.
In the early embryonic stage the silk gland cells contain hardly any rough ER and ribosomes exist freely in the cytoplasm. A number of mitochondria are observed, some of which are probably in the process of fission. Since rough ER and Golgi apparatus are very poorly developed, it is suggested that secretory protein is not yet synthesized in the silk gland cells in this stage. In contrast to the arrangemen t of the glandular cells in regular two rows at 24 hours after the blastokinesis, a number of cells exist irregularly around the glandular lumen in the early embryonic stage.
The development of the inner limiting membrane, inner layer of the retina and hyaloid capillaries were studied by electron microscopy from 13 days of gestation until 3 6 days after birth. 1) On the 13th day of gestation, a complete basal lamina encloses the optic cup prior to the retinal development and remains constant in its feature until 36 days after birth. It reveals that the basal laminas of the Muller cells and the pigment epithelium are continuous with one another and derived from ectodermal tissues and it was concluded that the inner limiting membrane of the retina is the basal lamina of the Muller cell. 2) The hyaloid capillaries are ramified from the hyaloid vascular system and some of them extend along the optic cup to the periphery. Endothelial cells are nonfenestrated and contain many pinocytotic vesicles especially during the 16th day of gestation and the 2nd day after birth, which are thought to function in fluid transport across the capillary wall. Their continuous basal laminas are formed on the 20th day of gestation. 3) The marginal zone of the optic cup is occupied by the basal part of the immature Muller cells on the 13th day of gestation, which contain free ribosomes, mitochondria and rough surfaced endoplasmic reticulum. During the gestation, developing Milner cells appear less dence and contaiin less organelles as compare with the mature cells. The mature Muller cell shows characteristic feature containing typical smooth surfaced endoplasmic reticulum, a large number of filaments and mitochondria. It is thought that the maturity of the Muller cell is accomplished after the 7 th postnatal day.
In 1969 B. P. Gloor demonstrated that after photocoagulation of the rabbit retina wound healing occurred with a marked increase in mitosis not only in the choroid, pigment epithelium and retina where mainly Muller cells were proliferating but also in the cortical vitreous cells, the hyalocytes. The present paper reports morpholo gical changes of the hyalocytes after photocoagulation which were observed with an electronmicroscope. On the 3rd-5th day after mild photocoagulation the hyalocytes increased in number and numerous cytoplasmic granules and phagocytotic vesicles were observed in the cytoplasm of the hyalocytes. This finding may suggest an increased production of polymucosaccharide of the hyalocytes. Following a marked coagulation numerous phagocytotic vesicles appear in the cytoplasm of the cells in the early stage and cytoplasmic granules appear in the later stage. The author presume that phagocytotic activities of the hyalocytes appear first and an increased production of polymucosaccharide appear in the later stage following a maked photocoagulation.
Since it has been proved that a small amount of an amino acid, which is injected close to the cell bodies, is taken up and synthesized within the neurons and moves out inside their axons as the axoplasmic flow, the axoplasmic flow has been analysed by radioautography or by scintillation counting with the use of labelled amino acids. Two different rates are classified in the axoplasmic flow. The slow transport which was primarily identified by radioautography moves one to several milimeters per day and the fast transport which has been recently discovered moves as fast as several hundred milimeters per day. The following experiment was carried out to show the fast and the slow axoplasmic flows of the dorsal root and the peripheral nerve originating from the 7th lumbar dorsal root ganglion (L7 DRG). An emphasis was placed on the alteration of the peripheral axoplasmic flow, if any, as the result of the surgical intervention on the dorsal root in the same spinal segment.