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151 results on '"Yokokawa, Koji"'

1. Phosphoinositide turnover signaling stimulated by ET-3 in endothelial cells from spontaneously hypertensive rats

Author

Yokokawa, Koji, Johnson, Joy, Kohno, Masakazu, Mandal, Anil K., Yanagisawa, Masashi, Horio, Takeshi, Yasunari, Kenichi, and Takeda, Tadanao

Subjects
Rats -- Physiological aspects, Endothelin -- Physiological aspects, Phosphoinositides -- Physiological aspects, Biological sciences
Abstract

Comparative studies of the role of endothelin (ET) B-type receptor in the phosphoinositide turnover signaling in cultured aortic endothelial cells of the Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) strains of hypertensive rat models reveal that ET receptor-mediated signal transduction is higher in the SHR strain than in the WKY strain. The mobilization of Ca(2+) from intracellular stores stimulation of protein kinase C is higher in SHR-based cells than in WKY-based cells after ET-3 addition.

Published
1994

2. Dopamine DA1 receptors on vascular smooth muscle cells are regulated by glucocorticoid and sodium chloride

Author

Yasunari, Kenichi, Kohno, Masakazu, Yokokawa, Koji, Horio, Takeshi, and Takeda, Tadanao

Subjects
Vascular smooth muscle -- Research, Dopamine receptors -- Physiological aspects, Corticosteroids -- Physiological aspects, Biological sciences
Abstract

Adenylate cyclase assays, tissue cultures and cAMP measurements in the vascular smooth muscle cells of rats show that sodium chloride and glucocorticoid regulate the dopamine DA1 receptors through different mechanisms and cause low adenylate cyclase function and low receptor affinity, and high cyclase activity and receptor activity. Glucocorticoid elevates cAMP response to dopamine to increase receptor activity and adenylate cyclase affinity. Glucocorticoid antagonist or cyloheximide inhibit the glucocorticoid's effect on the DA1 receptors.

Published
1994

3. Endothelin modulates the mitogenic effect of PDGF on glomerular mesangial cells

Author

Kohno, Masakazu, Horio, Takeshi, Yokokawa, Koji, Yasunari, Kenichi, Kurihara, Naotsugu, and Takeda, Tadanao

Subjects
Endothelin -- Physiological aspects, Platelet-derived growth factor -- Research, Biological sciences
Abstract

Endothelin regulates the mitogenic effect of platelet-derived growth factor (PDGF) on glomerular mesangial cells. The PDGF isoforms, AB and BB, activate endothelin-1 (ET-1) secretion in mesangial cells through PDGF beta-receptors. Endogenously-produced ET-1 regulates the mitogenic effect of PDGF AB and BB through A-type endothelin (ETa) receptors in cells. Treatment of rats with ETa receptors decreases renal mass limited glomerular damage and inhibits renal function impairment.

Published
1994

4. Cardiac hypertrophy and brain natriuretic peptide in experimental hypertension

Author

Kohno, Masakazu, Fukui, Toshiki, Horio, Takeshi, Yokokawa, Koji, Yasunari, Kenichi, Yoshiyama, Minoru, Kurihara, Naotsugu, and Takeda, Tadanao

Subjects
Natriuretic peptides -- Research, Malignant hypertension -- Analysis, Corticosterone -- Analysis, Hydralazine -- Analysis, Biological sciences
Abstract

Chronic treatment with enalapril and MK-954 decreases the ventricular weight and systolic blood pressure in deoxycorticosterone acetate salt-induced spontaneously hypertensive rats. The plasma concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are reduced, but not to the levels seen in Wistar-Kyoto rats. Hydralazine causes enhanced ANP and BNP plasma concentrations when compared to enalapril and MK-954.

Published
1994

5. Natriuretic peptides inhibit mesangial cell production of endothelin induced by arginine vasopressin

Author

Kohno, Masakazu, Horio, Takeshi, Ikeda, Miwako, Yokokawa, Koji, Fukui, Toshiki, Yasunari, Kenichi, Murakawa, Koh-Ichi, Kurihara, Naotsugu, and Takeda, Tadanao

Subjects
Natriuretic peptides -- Physiological aspects, Cell proliferation -- Physiological aspects, Arginine -- Physiological aspects, Endothelin -- Physiological aspects, Peptides -- Physiological aspects, Biological sciences
Abstract

The effects of natriuretic peptides (NP) on the secretion of endothelin-1 (E-1) was studied in the mesangial cells of rat kidney glomerulus. Atrial NP and brain NP inhibits excessive excretion of E1 on contraction of mesangial cells and glomerular microcirculation by induction of ET-1 secretion by arginine vasopressin. C-type NP also inhibited EP-1 secretion to a lesser degree compared to ANP and BNP.

Published
1993

6. Interaction between a phorbol ester and dopamine DA(sub 1) receptors on vascular smooth muscle

Author

Yasunari, Kenichi, Kohno, Masakazu, Murakawa, Koh-Ichi, Yokokawa, Koji, Horio, Takeshi, and Takeda, Tadanao

Subjects
Blood pressure -- Regulation, Dopamine receptors -- Physiological aspects, Protein kinases -- Physiological aspects, Phorbol esters -- Physiological aspects, Vascular smooth muscle -- Physiological aspects, Vasoconstriction -- Research, Biological sciences
Abstract

The roles of protein kinase C, dopamine DA-1 receptors and cyclic adenylic acid (cAMP) in vasodilation and blood pressure regulation were investigated. The study protocol involved examination of the interaction between a phorbol ester and DA-1 receptors in rat vascular smooth muscle cells. The results indicate that protein kinase C induces an increase in the expression of DA-1 receptors, thus enhancing receptor-coupled generation of cAMP.

Published
1993

11. Brain natriuretic peptide as a cardiac hormone in essential hypertension

Author

Kohno, Masakazu, Horio, Takeshi, Yokokawa, Koji, Murakawa, Koh-Ichi, Yasunari, Kenichi, Akioka, Kaname, Tahara, Akira, Toda, Iku, Takeuchi, Kazuhide, Kurihara, Naotsugu, and Takeda, Tadanao

Subjects
Cardiomyopathy, Hypertrophic -- Complications, Hypertension -- Diagnosis, Neuropeptides, Health, Health care industry
Abstract

PURPOSE: A natriuretic peptide, brain natriuretic peptide (BNP), has been isolated from porcine hearts. We performed this study to determine if BNP is secreted from the heart and to identify changes, if any, in the plasma BNP concentration in essential hypertension. PATIENTS AND METHODS: We measured the immunoreactive (ir) BNP concentration at intracardiac sites including the coronary sinus of five patients with heart disease during cardiac catheterization. We examined plasma ir-BNP in 48 hypertensive patients, 15 borderline hypertensive patients, and 25 normotensive subjects. RESULTS: Plasma ir-BNP in the coronary sinus was greater than at other cardiac sites. The concentration was significantly higher in hypertensive subjects than in borderline hypertensive or normotensive subjects. Hypertensive patients with left ventricular hypertrophy (LVH) established by echocardiography had higher plasma ir-BNP levels than those without LVH. In the hypertensive group, plasma ir-BNP was closely correlated with the LV mass index. In these patients, BNP levels were correlated with mean arterial pressure and inversely correlated with the LV ejection fraction, although these correlations were weak. Reverse-phase high-pressure liquid chromatography showed that the major component of circulating ir-BNP in the hypertensive and normotensive subjects corresponded to authentic human BNP-32. CONCLUSIONS: Human BNP-32 was secreted through the coronary sinus from the heart and may act as a cardiac hormone. Plasma BNP was increased in many of the hypertensive subjects with LVH. The increase in BNP seemed to be related to LVH or the cardiac overload associated with LVH.

Published
1992

48. Vascular Dopamine-I Receptors

Author

Yasunari, Kenichi, primary, Kohno, Masakazu, additional, Yokokawa, Koji, additional, Horio, Takeshi, additional, Kano, Hiroaki, additional, and Takeda, Tadanao, additional

Published
1995
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