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Mitsuaki Nakamaru

Bio: Mitsuaki Nakamaru is an academic researcher from Osaka University. The author has contributed to research in topics: Renin–angiotensin system & Angiotensin II. The author has an hindex of 17, co-authored 61 publications receiving 1406 citations.


Papers
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Journal ArticleDOI
TL;DR: It is suggested that endothelin contributes to endothelium-dependent vasoconstriction by hypoxia in mesenteric artery and may play an important role in the local peripheral vascular tone.

205 citations

Journal ArticleDOI
TL;DR: The blood pressure of patients with essential hypertension has a seasonal variation with higher pressures in the winter than in the summer, and an increased load of sodium presented to the kidney for excretion may be contributing factors in the rise in blood pressure in winter.
Abstract: We examined the role of dietary electrolytes and humoral factors in causing seasonal changes in blood pressure. Normal subjects had no seasonal difference in blood pressure, although urinary sodium and norepinephrine were significantly higher in winter than in summer. In patients with essential hypertension blood pressure, urinary sodium and norepinephrine excretion and plasma norepinephrine concentration were significantly higher in winter. Plasma renin activity, plasma and urinary aldosterone and urinary kallikrein excretion were not significantly different between the two seasons in both normal subjects and hypertensive patients. In conclusions, the blood pressure of patients with essential hypertension has a seasonal variation with higher pressures in the winter than in the summer. Increased sympathetic nervous activity and an increased load of sodium presented to the kidney for excretion may be contributing factors in the rise in blood pressure in winter in patients with essential hypertension.

167 citations

Journal ArticleDOI
Hiromi Rakugi1, Mitsuaki Nakamaru1, Hiroshi Saito1, Jitsuo Higaki1, Ogihara T1 
TL;DR: The results suggest that endothelin inhibits renin release via a calcium entry mechanism and increases intracellular calcium.

163 citations

Journal ArticleDOI
TL;DR: It is suggested that endothelin enhances the responsiveness of alpha-adrenergic receptors to catecholamines probably through the increase in calcium influx, and may interact with sympathetic nerve activity in addition to having a direct vasoconstrictor action in peripheral vascular tissue.

130 citations

Journal ArticleDOI
TL;DR: It is suggested that cardiac tissue angiotensin II, rather than circulating angioten II, may account for the pathophysiology of left ventricular hypertrophy in SHR.
Abstract: To examine the role of the tissue renin-angiotensin system in left ventricular hypertrophy, converting enzyme inhibitors were administered orally to 12-week-old male spontaneously hypertensive rats (SHR) for 4 weeks, and cardiac tissue angiotensin II was measured. Treatment with enalapril (10 mg/kg per day) and trandolapril (1 mg/kg per day) lowered systolic blood pressure, left ventricular weight and left ventricular angiotensin II content. Plasma angiotensin II concentration was increased by the treatment with enalapril whereas trandolapril did not cause any change. There was significantly positive correlation between left ventricular weight and angiotensin II content. Because angiotensin II promotes cell proliferation, these results suggest that cardiac tissue angiotensin II, rather than circulating angiotensin II, may account for the pathophysiology of left ventricular hypertrophy in SHR.

103 citations


Cited by
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Journal ArticleDOI
TL;DR: Three distinct human endothelin-related genes were cloned by screening a genomic DNA library under a low hybridization stringency with a synthetic oligonucleotide probe encoding a portion of the endotheli sequence, suggesting the possible existence of endothelins receptor subtypes.
Abstract: Three distinct human endothelin-related genes were cloned by screening a genomic DNA library under a low hybridization stringency with a synthetic oligonucleotide probe encoding a portion of the endothelin sequence. Genomic Southern blot analysis with the same oligonucleotide probe showed three corresponding chromosomal loci not only in the human genome but also in porcine and rat genomes. The nucleotide sequences of the three human genes were highly conserved within the regions encoding the 21-residue (mature) endothelins, in spite of the fact that the immediately upstream exon sequences, which encode a part of the propeptides, retained little similarity. Moreover, each of the human genes predicted a putative 21-residue peptide, similar to but distinct from each other: (i) the "classical" endothelin (ET-1), (ii) [Trp6,Leu7]endothelin (ET-2), and (iii) [Thr2,Phe4,Thr5,Tyr6, Lys7,Tyr14]endothelin (ET-3). Synthetic ET-1, ET-2, and ET-3 were prepared according to the deduced amino acid sequences, and the biological activities were assayed by contraction of isolated porcine coronary artery strips and by intravenous injection to anesthetized rats. All these synthetic peptides produced strong vasoconstrictor and pressor responses. However, the quantitative profiles of the pharmacological activities were considerably different among the three isopeptides, suggesting the possible existence of endothelin receptor subtypes.

2,548 citations

Journal ArticleDOI
TL;DR: The vascular endothelium, which envelops the circulating blood in a continuous monolayer, is mainly responsible for this function, but over the past 20 years numerous other important functions have been discovered.
Abstract: William harvey, when studying the circulation of the blood, must have recognized that "In sound and living vessels the blood remains fluid, but it coagulates in dead ones" (Ernst Brucke, 1857). Joseph Lister (1909) provided further evidence for an active role of blood vessels in maintaining the liquidity of blood. The vascular endothelium, which envelops the circulating blood in a continuous monolayer, is mainly responsible for this function. Over the past 20 years numerous other important functions have been discovered. For instance, the outer surface of the endothelial cell contains angiotensin-converting enzyme, which catalyzes the formation of the vasoconstrictor angiotensin . . .

1,969 citations

Journal ArticleDOI
TL;DR: The primary function of the corpus luteum is secretion of the hormone progesterone, which is required for maintenance of normal pregnancy in mammals, although growth hormone, prolactin, and estradiol also play a role in several species.
Abstract: The primary function of the corpus luteum is secretion of the hormone progesterone, which is required for maintenance of normal pregnancy in mammals. The corpus luteum develops from residual follic...

1,001 citations

Journal ArticleDOI
21 Apr 1994-Nature
TL;DR: It is suggested that ET-1 is essential for normal mouse development and may also play a physiological role in cardiovascular homeostasis.
Abstract: The endothelin-1 (ET-1) gene was disrupted in mouse embryonic stem cells by homologous recombination to generate mice deficient in ET-1. These ET-1-/- homozygous mice die of respiratory failure at birth and have morphological abnormalities of the pharyngeal-arch-derived craniofacial tissues and organs. ET-1+/- heterozygous mice, which produce lower levels of ET-1 than wild-type mice, develop elevated blood pressure. These results suggest that ET-1 is essential for normal mouse development and may also play a physiological role in cardiovascular homeostasis.

995 citations

Journal ArticleDOI
TL;DR: Ongoing studies will elucidate the effect of ACE inhibitor on cardiovascular mortality in essential hypertension, the role of ACE inhibitors in patients without ventricular dysfunction after myocardial infarction, and the roleof ACE inhibitors compared with newly available angiotensin AT1 receptor antagonists.
Abstract: ACE inhibitors have achieved widespread usage in the treatment of cardiovascular and renal disease. ACE inhibitors alter the balance between the vasoconstrictive, salt-retentive, and hypertrophic properties of angiotensin II (Ang II) and the vasodilatory and natriuretic properties of bradykinin and alter the metabolism of a number of other vasoactive substances. ACE inhibitors differ in the chemical structure of their active moieties, in potency, in bioavailability, in plasma half-life, in route of elimination, in their distribution and affinity for tissue-bound ACE, and in whether they are administered as prodrugs. Thus, the side effects of ACE inhibitors can be divided into those that are class specific and those that relate to specific agents. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have proved effective in the treatment of hypertension, they decrease mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction, and they delay the progression of diabetic nephropathy. Ongoing studies will elucidate the effect of ACE inhibitors on cardiovascular mortality in essential hypertension, the role of ACE inhibitors in patients without ventricular dysfunction after myocardial infarction, and the role of ACE inhibitors compared with newly available angiotensin AT1 receptor antagonists.

910 citations