本態性高血圧患者の昇圧機構に関わる血小板交感神経α_2受容体の意義 : norepinephrine昇圧反応性との関連 The Significance of Platelet Alpha_2-Adrenoceptor and Sympathetic Nerve Activity in The Hypertensive Mechanism under Essential Hypertension : With Special Reference to Pressor Response to Norepinephrine

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著者

    • 澤井 仁郎 SAWAI Niro
    • 札幌医科大学医学部内科学第二講座 Second Department of Internal Medicine, Sapporo Medical University School of Medicine
    • 島本 和明 SHIMAMOTO Kazuaki
    • 札幌医科大学医学部内科学第二講座 Second Department of Internal Medicine, Sapporo Medical University School of Medicine
    • 宮本 篤 MIYAMOTO Atushi
    • 札幌医科大学医学部内科学薬理学講座 Department of Pharmacology, Sapporo Medical University School of Medicine
    • 飯村 攻 IIMURA Osamu
    • 札幌医科大学医学部第二講座 Second Department of Internal Medicine, Sapporo Medical University School of Medicine

抄録

Although many studies have examined the metabolism of catecholamines and cardiovascular responsiveness to norepinephrine in essential and various experimental hypertension, the role of sympathetic nervous system in the pathogenesis of hypertension has not been elucidated. In this study, therefore, the role of sympathetic nerve activity related to platelet alpha<SUB>2</SUB>-adrenoceptor was investigated to clarify the mechanism in which sympathetic nervous system augments the blood pressure elevation in patients with essential hypertension (EHT).<BR>Tritiated yohimbine binding was used to estimate platelet membrane alpha2-adrenoceptor characteristics in 27 hospitalized patients with mild to moderate EHT and 27 normotensive subjects (NT) receiving a regular diet containing 120mEq/day of sodium and 75mEq/day of potassium.<BR>In this study, mean arterial pressure (MAP) and plasma norepinephrine concentration (pNE) was significantly higher in EHT than those in NT. Total binding sites (Bmax) and dissociation constant (Kd) for <SUP>3</SUP>H-yoshimbine in EHT was also significantly higher than those in NT.<BR>There was a significant positive correlation between Bmax and age in NT, but not in EHT. A significant positive correlation was observed between the pressor response to infused norepinephrine (NE-R:increments in MAP induced by i.v. infused 0.2μg/kg/min of NE) and Bmax both in NT and EHT. On the other hand, no significant correlation was found between NE-R and Kd in NT and EHT. In addition, Bmax was correlated inversely with PNE in both NT and EHT.<BR>These findings suggest that down-regulation mechanism exists in platelet alpha<SUB>2</SUB>-adrenoceptor number responded to PNE levels. Moreover, the increased density of alpha-adrenoceptor might have something to do with the augmented NE-R in EHT, indicating an important pathophysiological role of this receptor in the hypertensive mechanisms in EHT.

収録刊行物

  • 日本内分泌学会雑誌

    日本内分泌学会雑誌 71(7), 1075-1088, 1995-07-01

    The Japan Endocrine Society

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