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Biomedical subjects

C Inagaki

Publications and source records attributed to C Inagaki.

At least 109 records · Page 6Linked to original sources
PubMed1982

The activities of noradrenergic and dopaminergic neuron systems in experimental hydrocephalus.

Experimental hydrocephalus was induced in rabbits by intracisternal injection of kaolin suspension, and the concentration of noradrenaline (NA), dopamine (DA), and their metabolites was determined in several brain regions. The NA concentration had decreased in the cerebellum, hypothalamus, and pons plus medulla oblongata, and increased in the caudate nucleus at 2 days after kaolin injection (the stage of early intracranial hypertension). At 1 week (the stage of progressive hydrocephalus), the NA content had returned to control levels in all brain regions studied, and it decreased again at 4 weeks (the stage of chronic hydrocephalus) in the pons plus medulla oblongata. The DA level was unchanged throughout the 4-week period after kaolin injection. The concentration of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MOPEG-SO4), the major metabolite of NA, was elevated in all brian regions except the caudate nucleus at all stages after kaolin injection. An increase in MOPEG-SO4 in the caudate nucleus was also observed 1 week after kaolin injection. The content of homovanillic acid (HVA), the major metabolite of DA in the rabbit brain, was decreased in the cerebral cortex at 2 days and at 1 week after kaolin injection, and in the caudate nucleus at 2 days and at 1 week, and 4 weeks. The level of HVA was increased in the hypothalamus at 2 days, in the cerebellum at 2 days and at 1 week, in the pons plus medulla oblongata at 2 days, 1 week, and 4 weeks, and in the midbrain at 4 weeks. These data suggest that, in experimental hydrocephalus in the rabbit, NA release is increased throughout the brain, while DA release is decreased in the cerebral cortex and caudate nucleus, and increased in the cerebellum, hypothalamus, midbrain, and pons plus medulla oblongata.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1981

Possible mechanisms of the triphasic effects of neurotensin on the rat blood pressure.

Neurotensin administered intravenously in a dose of 1 nmole/kg produced triphasic blood pressure responses in anesthetized rats: the first depressor, second pressor and third depressor responses. The first depressor response was significantly suppressed by treatment of animals with a mixture of diphenhydramine and metiamide or chronic administration of compound 48/80, but was not modified by treatment with atropine, phentolamine, yohimbine, propranolol, sulpiride and adrenalectomy. The second pressor response was abolished by phentolamine, yohimbine and adrenalectomy. The second phase response was also markedly reduced by diphenhydramine in reserpinized rats and chronic administration of compound 48/80. The third depressor response was blocked by treatment of animals with diphenhydramine or chronic administration of compound 48/80. These results suggest that neurotensin may produce an immediate depressor response (the first phase) partly through a histamine-mediated process, and the second pressor response is produced by catecholamines released from the adrenal medulla through a histamine-mediated process. The third depressor response appears to be mediated mainly by histamine. The participation of mast cells as an origin of histamine which mediates these processes is suggested.

Adrenalectomy↗
PubMed1981

Separative determination of ascorbic acid and erythorbic acid by high-performance liquid chromatography.

High-performance liquid chromatography (HPLC) was applied to the determination of ascorbic acid (AsA) and erythorbic acid (ErA). The apparatus was a Shimadzu model LC-2P Liquid Chromatograph equipped with a UV detector set at 254 nm. The separation was achieved on a LiChrosorb-NH2 column which was pre-treated with 0.1 M ammonium monophosphate solution using a mixture of acetonitrile, acetic acid and water (87:2:11, v/v) as an eluant. The HPLC method has the following advantages: AsA and ErA are quantitated after being distinctly separated, analysis time per one sample is short, and AsA or ErA levels as low as 1.0 X 10(-2) microgram are detectable. Recovery experiments with dehydro-AsA and dehydro-ErA, involving reduction with H2S, give satisfactory results.

Antioxidants↗
PubMed1981

Separative determination of ascorbic acid and erythorbic acid in animal tissues by high-performance liquid chromatography.

A method for the separation and determination of ascorbic acid (AsA) and erythorbic acid (ErA) in animal tissues is described. It employs high-performance liquid chromatography on a LiChrosorb-NH2 column in conjunction with a mixture of acetonitrile, acetic acid and water as an eluant. Application of the method, which is sensitive, rapid and simple, to the analyses of AsA and ErA in animal tissues such as liver, adrenals, spleen, kidneys and heart gave satisfactory results. Dehydro-AsA and dehydro-ErA in rat liver could be determined after reduction with H2S. The method was shown to be useful for the routine analyses.

Adrenal Glands↗
PubMed1980

Na,K-, Mg- and HCO3-adenosine triphosphatases in the rabbit brain choroid plexus.

Properties of adenosine triphosphatases (ATPases) in the choroid plexus of rabbit cerebral ventricles were investigated using tissue homogenates and subcellular fractions. Na,K-ATPase or HCO3-ATPase activity of choroid plexus was significantly lower than that of the brain or the kidney, respectively. Among the homogenates of choroid plexus from the lateral, third and fourth ventricles, there were no differences in the activities of Na,K-, Mg- and HCO3-ATPases. In the choroid plexus, Na,K-ATPase activity was demonstrated to be highest in 10,000 X g fraction, while the highest Mg- and HCO3-ATPase activities were observed in 8,000 X g fraction, the so-called mitochondrial fraction. Ion requirement, pH optimum and ouabain sensitivity of Na,K-ATPase in 10,000 X g fraction of choroid plexus were similar to findings in erythrocytes, brain and kidney. However, properties of Mg- and HCO3-ATPases in 8,000 X g fraction were considerably different from those found in the brain and gastric mucosa. In the choroid plexus, thiocyanate ion inhibited Mg-ATPase as well as HCO3-ATPase. These results indicate that characteristics of ATPase systems in the choroid plexus are to some extent different from those in tissues such as brain, kidney and gastric mucosa.

Adenosine Triphosphatases↗
PubMed1978

Enzymatic decarboxylation of L-threo-3,4-dihydroxyphenylserine in rat heart.

Decarboxylation of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) by the higher speed supernatant of the rat heart homogenate and the regional distribution of L-threo-DOPS decarboxylase activity were examined. Decarboxylation was demonstrated to occur specifically with L-isomer but not with D-isomer. Addition of pyrogallol was necessary for maximal recovery of norepinephrine. The optimal condition for decarboxylation of L-threo-DOPS by the rat heart enzyme was similar to conditions required with the enzymes from brain and kidney. Under the optimal conditions, Km and Vmax for L-threo-DOPS were 2.1 mM and 6.4 nmoles/mg protein/15 min, respectively. Decarboxylation of L-threo-DOPS was markedly inhibited by D-threo-DOPS and D-DOPA. The L-aromatic amino acid decarboxylase activity was highest in the right auricle followed by the atrial body, the left auricle, the right ventricle and the left ventricle.

Animals↗
PubMed1976

[Inhibition of harmaline induced tremor by L-threo-3, 4-dihydroxyphenylserine, an L-norepinephrine precursor].

Effect of 3, 4-dihydroxyphenylserine (DOPS), a norepinephrine precurosr, on harmaline tremor was investigated in mice to elucidate the role of norepinephrine in the genesis of tremor. 1) Spontaneous motor activity was inhibited by L-threo-DOPS (200 mg/kg i.p.). 2) Tremor induced by harmaline (5 and 7 mg/kg i.p.) was enhanced by alpha-methyl-p-tyrosone (200 mg/kg i.p.). 3) The development and duration of tremor induced by harmaline (10 mg/kg i.p.) were inhibited significantly in a dose dependent manner by L-threo-DOPS (50, 70, 100, 150 and 200 mg/kg i.p.), but neither by D-threo-DOPS (200 mg/kg i.p.) nor DL-erythro-DOPS (200 mg/kg i.p.). 4) L-threo-DOPS (200 mg/kg i.-.) had no effect on the development of tremor induced by tremorine (5 and 10 mg/kg i.p.), while lacrimation and diarrhea caused by tremorine was markedly inhibited. 5) Administration of harmaline (10 mg/kg i.p.) produced an increase in brain 5-hydroxytryptamine content but not in that of norepinephrine. Administration of L-threo-DOPS (100 mg/kg i.p.) increased the norepinephrine content but not the 5-hydroxytryptamine content in the brain. Inhibition of harmaline tremor induced by L-threo-DOPS is attributed to the L-norepinephrine converted from L-threo-DOPS and the involvement of a noradrenergic mechanism in harmaline tremor has to be considered.

Alkaloids↗