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Volume 108, Issue 1
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Hisashi MORI, Masayoshi MISHINA1996 Volume 108 Issue 1 Pages 1-12
Published: 1996
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSMolecular cloning has elucidated the molecular diversity of the N-methyl-D-aspartate (NMDA)-receptor channel and has provided a solid basis for extensive studies of the structure and function of the NMDA-receptor channel. Mutational analyses have assigned functional domains and the transmembrane topology of the channel subunits. Identification of the multiple subunits with distinct distribution, properties, and regulation has suggested that NMDA-receptor channels are distinct in molecular architecture and functional characteristics in various brain regions at different developmental stages. The physiological significance of the NMDA-receptor channel diversity is presently under investigation by various techniques including gene targeting.View full abstractDownload PDF (10408K) -
Yukito HIGUCHI, Kimihiro YAMASHITA, Kotaro TANIYAMA, Motoyoshi SATAKE, ...1996 Volume 108 Issue 1 Pages 13-22
Published: 1996
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSShichimotsu-koka-to, a Chinese herb, is a medicine prescribed to treat patients with hypertension. We investigated the effects of Shichimotsu-koka-to on the lesions of stroke-prone spontaneously hypertensive rats (SHRSP). The SHRSP were given 1% or 2% Shichimotsu-koka-to solution (1 g /kg/day or 2 g/kg/day) instead of drinking water from 8 to 42 weeks of age. When the 2 g/kg/ day Shichimotsu-koka-to was chronically administered to the SHRSP, their life span was significantly prolonged by prevention of stroke, but there was no effect on blood pressure. The Shichimotsu-koka-to treatment decreased superoxide dismutase (SOD) activities in the cytosol of the cerebral cortex and increased SOD activities in the cytosol of the brain stem. The treatment with 2 g/kg/day Shichimotsu-koka-to decreased xanthine oxidase (XOD) activities in the cytosol of the cerebral cortex, and Shichimotsu-koka-to quenched superoxide anion (O2-) as determined by electron spin resonance analysis in vitro. In addition, SOD activities in the cytosol of the cerebral cortex of SHRSP not administered Shichimotsu-koka-to were increased by the drug in vitro. XOD activities in the cytosol of the cerebral cortex of SHRSP not administered Shichimotsu-koka-to were inhibited by this herb in vitro. These results suggest that these preventive effects of Shichimotsu-koka-to on the stroke in SHRSP are due its ability to scavenge O2- and to inhibit O2- production by the hypoxanthine-XOD system in the cytosol of the cerebral cortex.View full abstractDownload PDF (7559K) -
Osamu ISHIZUKA, Akira FUJITA, Etsuko KANBE, Mitsue NOGUCHI, Makoto HOS ...1996 Volume 108 Issue 1 Pages 23-30
Published: 1996
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSEffects of prolonged noradrenaline infusion on the density of cardiac β-adrenoceptors, phosphodiesterase (PDE) and adenylate cyclase (AC) activities, and the ability of NKH477, 6-(3-dimethylaminopropionyl) forskolin hydrochloride, to increase tension development and heart rate were studied in rat cardiac preparations. Noradrenaline infusion (400μg/kg/hr, s.c.) for 7 days significantly decreased cardiac β-adrenoceptor density (Bmax), whereas the binding affinity (Kd) of the ligand was unchanged. The basal cardiac PDE activity was increased in treated rats, whereas there was no difference in the basal cardiac AC activity between treated and untreated rats. Significant decreases in basal developed tension and heart rate were observed in the left and right atrial muscles from treated rats, respectively. The positive inotropic and chronotropic potencies of NKH477 were unaffected by noradrenaline infusion, whereas the positive inotropic potencies of isoproterenol and 3-isobutyl-l-methylxanthine were significantly reduced. Thus, NKH477 appears to be superior to β-adrenoceptor agonists or PDE inhibitors as a cardiotonic drug in the treatment of heart failure accompanied by β-adrenoceptor downregulation.View full abstractDownload PDF (6247K)
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