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M Takeda

Publications and source records attributed to M Takeda.

At least 1,081 records · Page 60Linked to original sources
PubMed1976

Nucleoside triphosphate and cation requirement for dopamine uptake by plain synaptic vesicles isolated from rat cerebrums.

Plain synaptic vesicles were partially purified from rat cerebrums and their [3H]dopamine uptake was investigated. The addition of MgCl2 plus ATP and of CaCl2 plus ATP increased the uptake 16 times and 5.5 times, respectively, higher than the control level, whereas the separate addition of these agents augmented the level at most 2.5 times. GTP stimulated the uptake as well as ATP, whereas UTP was one-third as effective and CTP, ADP, and AMP were all ineffective. Adenylyl imidodiphosphate was not only ineffective, but strongly reduced the ATP-dependent uptake. The half-maximal level of the ATP-dependent uptake was reached within 1.5 min after the start of incubation at 25 degrees C. The incorporation peaked at 5-10 min, then gradually declined to half-maximum at 45 min. This decline was prevented by the further addition of small amounts of CaCl2. There was no uptake at 0 degrees C, and the incorporation rate was at least 2 times faster at 37 degrees C than it was at 25 degrees C. The apparent Michaelis constant for [3H] dopamine was 1.6 muM. The half maximal inhibition of uptake was obtained at 0.1 muM reserpine; neither colchicine nor ouabain showed significant inhibition. The ATP-dependent uptake was not affected by K+, Na+, and Cl-, but was drastically decreased by isotonic phosphate buffer.

Adenosine Triphosphate↗
PubMed1976

Effect of guanosine 3' : 5'-monophosphate on glucose oxidation and epinephrine-stimulated lipolysis in isolated rat epididymal fat cells.

The guanosine 3': 5'-monophosphate (cyclic GMP) level in isolated rat epididymal fat cells increased more than doubled 10 min after addition to the cells of carbamylcholine (10(-6) M) in the presence or absence of epinephrine (5 X 10(-7) M). Addition of carbamylcholine, cyclic GMP or dibutyryl cyclic GMP (10(-9) to 10(-5) M) did not affect glucose oxidation or epinephrine-stimulated lipolysis of the cells. No significant change in the cyclic GMP level was detected 2 min or 10 min after addition of insulin (1 mU/ml) to the cells, when glucose oxidation was stimulated and lipolysis induced by epinephrine was inhibited. These results indicate that the transient increase in the cyclic GMP level in the cells on treatment with carbamylcholine is not sufficient for expression of the effects of insulin.

Adipose Tissue↗
PubMed1976

Characterization of ATPases of plain synaptic vesicle and coated vesicle fractions isolated from rat brains.

The plain synaptic vesicle and the ocated vesicle fractions were isolated from rat brains, and the ATPase [EC 3.6.1.3] activities were characterized in terms of ionic effects, drug effects, and protein components. Coated vesicle fraction contained three times as much actomysin-like proteins as plain vesicle fraction, although both fractions had an identical ratio of actin-like protein to myosin-like protein. The ATPases of these two fractions were activated by both Mg2+ and Ca2+, and, in the presence of either of the cations, were inhibited by KCl. Reserpine activated plain vesicle ATPase only in the presence of Cl-. Colchicine and vinblastine inhibited coated vesicle ATPase only. The results are consistent with the view that actomyosin-like proteins are involved in the synaptic retrieval process.

Actins↗
PubMed1976

Comparison of local anesthetic activities between cis and trans isomers of DL-1-benzoyloxy-2-dimethylamino-1,2,3,4-tetrahydronaphthalene.

The local anesthetic activities of cis- and trans- dl-1-benzoyloxy-2-dimethylamino-1,2,3,4-tetrahydronaphthalene were compared using several methods with guinea-pigs. The cis compound (YAU-17) was 2.9 to 6 times as potent as its trans isomer and exceeded procaine, lidocaine and cocaine in potencies of corneal anesthesia, intracutaneous anesthesia and sciatic nerve block. In another experiment on isolated frog sartorius muscle, all of the local anesthetics suppressed the twitch contractions elicited by stimulation of the sciatic nerve. The neuromuscular blocking activity of the cis compound was more pronounced than that of the trans form. Supersensitivity to noradrenaline was produced by both of the stereoisomers in isolated vas deferens of guinea-pigs although there was no difference in the activity. The sensitizing action was also demonstrable with cocaine and lidocaine but not with procaine. When injected intravenously into mice, the cis compound was twice as toxic as its isomer. It is postulated that stereoselectivity is to some extent involved in the mechanisms of action of the local anesthetic agents.

Anesthetics, Local↗
PubMed1976

Comparison of local anesthetic activities between optical isomers of cis-1-benzoyloxy-2-dimethylamino-1,2,3,4-tetrahydronaphthalene.

The optical isomers of cis-1-benzoyloxy-2-dimethylamino-1,2,3,4-tetrahydronaphthalene (YAU-17) were compared for their local anesthetic activity, acute toxicity, spasmolytic activity, and partition coefficient between chloroform and phosphate buffer. 1-YAU-17 was more active than d-YAU-17 in blocking the conduction of action potentials in isolated frog sciatic nerves. The difference in local anesthetic activities between the optical isomers was further substantiated by in vivo tests for corneal anesthesia, intracutaneous anesthesia and sciatic nerve block in quinea-pigs. Similarly, the i.v. injection to mice revealed a higher toxicity for 1-YAU-17 as compared to its d-isomer. In these tests, the potency ratios of the enantiomers ranged from 2 to 4, and the racemate had an intermediate potency. On the contrary, no difference among the compounds was found in their liposolubility, partition coefficient, and spasmolytic activity examined with isolated guinea-pig ileum. These results indicate that the steric factors play an important role in the production of different local anesthetic activities between the optical isomers of YAU-17, and their local anesthetic potency tends to be correlated to their intravenous acute toxicity but not to their spasmolytic activity.

Action Potentials↗
PubMed1976

An electron microscopic study on the innervation in the taste buds of the mouse circumvallate papillae.

Taste buds of the mouse circumvallate papillae were studied by electron microscopy to elucidate the innervation involving the adrenergic nerve supply. Typical afferent synaptic contacts, with increased density of the membranes and aggregations of synaptic vesicles in the cytoplasm adjacent to the nerve endings, were demonstrated between the type III cells and the nerve endings. Along the regions of contact between the type II cells and the nerve endings, cisternae of endoplasmic reticulum were often seen beneath the cell membrane, and the nerve endings contained relatively many synaptic-sized vesicles. Such an innervation seems to be efferent in nature. For the detection of the adrenergic nerve supply, 5-hydroxydopamine (5-OH-DA) was injected after pretreatment with L-DOPA and nialamide. The mice showed numerous adrenergic nerve fibers in the connective tissue underlying the taste buds. On very few occasions, the adrenergic nerves penetrated the basal lamina of the taste buds and came into contact with the bud cells. Some adrenergic nerves were distributed among the epithelial cells around the taste buds. The reaction product from acetylcholine esterase activity was found around the adrenergic nerve fibers labeled with 5-OH-DA.

Acetylcholinesterase↗
PubMed1976

Gas-liquid chromatographic determination of chloramphenicol in agricultural crops.

A method is presented for the gas-liquid chromatographic determination of chloramphenicol in agricultural crops. Chloramphenicol is extracted with ethyl acetate, cleaned up by silicic acid column chromatography, acetylated with acetic anhydride and pyridine, and then measured by gas-liquid chromatography with electron capture detection. Two stationary phases, DEGS + phosphoric acid and Reoplex 400, were used. The sensitivity was ca 8 ng (40% full scale deflection). The efficicency of the analytical method was evaluated by analyzing crops fortified with chloramphenicol. The average recovery ranged from 72% in unpolished rice to 86% in Chinese radishes.

Acetylation↗