The catalytic subunits of Na⁺, K⁺-ATPase were isolated from the kidney and brain of rats (α I and α II, respectively). The antisera raised against these subunits were used as probes to analyze the isoforms of catalytic subunits of Na⁺, K⁺-ATPase in various tissues of rats. The submandibular gland (SMG) contained a new α subunit isoform (designated α (S) in this report) in addition to α I identical to those found in the kidney and brain. The new α (S) strongly cross-reacted with anti-α I -antiserum. The α (S) had a molecular weight slightly less (approximately 90 kDa) than the kidney and brainα I. The author examined whether or not the α (S) is formed by proteolytic cleavage of α subunits and concluded that this is not the case. The α (S) reacted with [γ-³²P] ATP, resulting in the formation of radioactive α subunit which was stabilized by 2 mM ouabain but which was labile in the presence of 70mM potassium chloride. The author detected only a single species of mRNA for the α subunit in the rat SMG. The Ki value of the submandibular gland Na⁺, K⁺-ATPase on the ouabain was similar to that of the kidney. The N-terminal amino acid sequence of the α (S) corresponded with that of the α I. In conclusion, the author suggested that, at first the α I was synthesized with the α I mRNA, secondly the α (S) appeared after the C-terminal of the α I was processed in the rat SMG in vivo.

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Effects of dexamethasone, a representative of the steroidal anti-inflammatory drugs, and indomethacin, a non-steroidal anti-inflammatory drug, on the healing of wound holes made in the parietal bone of growing rats (4 weeks old) and on the growth of femurs were studied. Drugs were administered s. c., 0.5, 1, 2 mg/kg/day for 1, 2 and 4 weeks except Sunday. After the end of administration, the parietal bones and femurs were removed. The uncalcified area of the wound hole portion detected by alizarin red S staining was measured. New formation and rearrangement of blood vessels in the holes which were detected by India ink injection into the aorta, were also investigated. Femur length and width were measured from soft x-ray photographs, and changes in the degree of the film whitening of the femur image were determined with a microdensitometer. The results obtained were as follows: 1. Both dexamethasone and indomethacin delayed the reduction of the uncalcified area of the wound holes, and the effect of the former was stronger than that of the latter. 2. Administration of dexamethasone for one week resulted in a weak inhibition of new growth of blood vessels into the wound hole. However, the normal reduction of the amount of blood vessels seen without drug administration was more strongly inhibited by the second week of the drug treatment. These results suggest that dexamethasone inhibits bone wound healing by the retardation of mineralization, which is closedly linked to the inhibition of reconstruction of blood vessels in the wound hole. A similar result was obtained by indomethacin administration, but the effect was much weaker than that of dexamethasone. 3. The growth in length and width of the femur was greatly inhibited by dexamethasone administration, but the effect of indomethacin was weaker. And the normal time dependent increase in the film whitening of the femur image was cleary inhibited by both drugs. The result of microdensitometry of the soft x-ray films also showed stronger blackening of the film by dexamethasone administration for two weeks than one week admistration but not by indomethacin. These results suggest that the retardation effect of dexamethasone on bone wound healing and bone growth is stronger than that of indomethacin with some difference in action mechanism between the two drugs.

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The purpose of this study was to determine whether any definite change in the brain development could be produced by the difference amounts of mastication. All teeth in the unilateral mandible of Wistar rats were enucleated at 2 weeks after birth and histological changes in the brain were examined at 4 and 8 weeks after birth.
In 4 week old rats, the number of pyramidal cells in the contralateral cerebral cortex of the no teeth side were much less than those of the ipsilateral side. However in 8 week old rats, there was no difference. In Hebb and Williams' maze test, Wistar rats weaned at 20 days of age were divided into two groups. Group 1 was fed on pellets, while Group 2 was fed on powder. At 4 and 8 weeks after birth, both groups were used or a Hebb and Williams' maze test.
In 8 week old rats, the total error score of the pellet group was less than that in the powder group. However in 4 week old rats, there was no difference in the total error score between the groups. From these results, it is deduced oral afferent impulses may stimulate the development of the brain in the animals chewing on the hard diet.

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Fluorapatite crystals were formed, and enamel crystallinity by the incorporation of fluoride was improved, by applying a newly developed freeze-drying gelatin gel method to extracted tooth enamel surfaces (group I) and also the same method to extracted tooth enamel surfaces (group II) by the use of a tray, as an easy way of adapting the gel method for clinical applications, and on enamel surfaces and cross-sectioned surfaces, including those of non-treated teeth (group III). Morphological observations were made by scanning electron microscopy, qualitative analyses by X-ray diffraction of thin layer specimens and by microarea X-ray diffraction, elemental analyses by electron probe X-ray microanalysis, and observations on contact microradiographs as well as by polarised light microscopy micrograph.
As a result, it is suggested that an in vivo application by the use of a tray, the freeze-drying gelatin gel method would be as effective in forming fluorapatite and of improving enamel crystallinity as the gelatin gel method used at present.

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To examine the change in mechanical properties and ATPase activity of guinea pig masticatory muscles associated with bite opening, isometric tension, Ca2+-sensitivity, maximum shortening velocity and ATP consumption were measured using glycerinated muscles (3.0-4.5mm in length, 100-200 μn in diameter) obtained from control and bite-opened guinea pigs (3 days, 1 week). Ca2+-sensitivity of the contractile system for tension development was decreased with bite-opening both in the masseter and the digastric. However, the maximum tension increased significantly only in the masseter of the 1-week-bite-opened guinea pigs, and the shortening velocity was increased significantly only in the 1-week-bite-opend digastric muscle. ATPase activity was always increased with an increase in tension development. However, the tension cost (ATPase activity/tension) was significantly decreased only in the masseter of animals receiving 1-week of bite opening. These results suggest that biteopening changes the mechanical property and tension cost of the masseter and the digastric differently. Greater tension was produced in the masseter by consuming ATP more economically after 1-week of bite-opening. Also the digastric decreased Ca2+-sensitivity and increased the shortening velocity, but the amount of ATP consumption was not changed after 1-week of bite-opening.

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Stoichiometric and crystalline strontium and barium hydroxyapatite (SrHA and BaHA) were examined for their solubility in organic acids.
The solubility of SrHA was increased with decrease of pH, and was about twice in comparison with CaHA within the range of pH studied. The solubility is represented as a fundamental relationship equation between the concentration of Sr²⁺, PO₄^3- and H⁺ in the solution and strontium ion complexes with the organic acid. However, based on Sr/P ratio which was calculated by using the equation, it is assumed that the surface of SrHA crystals are covered with complexes having a smallar Sr/P ratio.
The dissolution of BaHA was different from SrHA and CaHA. BaHA was unstable in the range of pH 4 to 7 and became changed to barium hydrogen phosphate.

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In order to investigate the reflex regulation of the infrahyoid muscle activities induced by sensory signals (chemical and mechanical) from the tongue in the frog, excitatory and inhibitory reflex responses in the infrahyoid muscles (sternohyoid muscle-SH muscle, omohyoid muscle-OH muscle) by both chemical and mechanical stimulation of the tongue were studied using electromyography (EMG) recordings in bullfrogs, Rana catesbeiana. The chemical stimulations (1 mM quinine-HCl, 0.5-1.5 M NaCl) evoked no reflex response in either the SH or the OH muscles, and this result suggested that the infrahyoid muscle activities may not be reflexly regulated by chemical signals from the tongue in the bullfrog. Both the mechanical stimulation of the tongue and the electrical stimulation of the glossopharyngeal nerve evoked excitatory responses in the SH and the OH muscles, bilaterally and contralaterally, respectively. The electrical stimulation of the glossopharyngeal nerve evoked no inhibitory response in the SH, while the stimulation evoked the inhibitory response in the ipsilateral OH. These differences may be related to a difference in the role of these muscles during tongue movement in the bullfrog.

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Membrane phospholipid compositions of a secretory granule-rich fraction (SG) from rat parotid glands were analyzed and compared with those of a microsomal fraction (Ms) and homogenates. Remarkable differences were concentrated in their phospholipid composition rather than their side-chain composition. SG had significantly higher levels of lysophospholipids (lyso-PL, 8.3 %) and phosphatidylethanolamine (PE, 30.5 %), whereas it had lower levels of phosphatidylcholine (PC. 40.3%) and phosphatidylserine (PS, 2.4%) than those of Ms. Although these phospholipids showed a characteristic side-chain composition depending on each phospholipid class, few differences among the three fractions were found in individual phospholipid side-chain compositions. Only PE from SG was relatively poor in the alkenyl chain, especially the octadec-1'-enyl chain, and concomitantly rich in octadecanoyl chain compared with PE from Ms. The side-chain compositions of total phospholipids from SG, Ms and homogenates were nearly similar to one another. Furthermore, ESR analysis demonstrated that fluidity of hydrophilic region of liposomes prepared by the phospholipids which were extracted from individual fractions, increase in the order of Ms<homogenates<SG. On the contrary, there were no differences in the fluidity of their hydrophobic regions.
These results suggest that the granular membranes have a characteristic phospholipid profile, which affects the physical property of granular membranes.

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