1987 Fiscal Year Final Research Report Summary
Changes in somatic exercise reflex originating from chemosenditive muscle afferents and cardiac responses to increased sympathetic activity during exercise in patients with chronic heart failure.
| Project/Area Number |
61480207
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Osaka University |
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Principal Investigator |
TAKEDA Hiroshi Osaka University Hospital, 医学部附属病院, 助教授 (20127252)
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| Co-Investigator(Kenkyū-buntansha) |
尾崎 仁 大阪大学, 医学部附属病院, 医員
MATSUYAMA Taizo Osaka University Hospital, 医学部附属病院, 医員
SATO Hideyuki Osaka University Hospital, 医学部附属病院, 医員 (70167435)
INOUE Michitoshi Osaka University Hospital, 医学部附属病院, 教授 (30028401)
OZAKI Hitoshi Osaka University Hospital
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| Project Period (FY) |
1986 – 1987
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| Keywords | Exercise / Sympathetic activity / Muscle hypoxia / Heart failure / Chronotropic response / Inotropic response / Plasma norepinephrine / 混合静脈血酸素分圧 |
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| Research Abstract |
To investigate changes in exercise refrex mediated by chemosensitive muscle afferents and cardiac responses to increased sympathetic activity during exercise in patients with chronic heart failure, we analyzed plasma norepinephrine(NE) response to graded muscle hypoxia assessed by mixed venous oxygen tension (PV02) (study 1),and heart rate (HR) and contractile responses to increased plasma NE (study 2) during leg bicycle exercise in normal subjects and patients with chronic heart failure. Study 1: An inverse correlation was observed between log PV02 and log NE in each subject(r=-0.75 to -0.99, mean -0.93). The slope of log PV02-log NE line showed no significant difference between normal subjicts and patients with heart failure. To enhance a degree of muscle hypoxia, we administrated 40 mg metoprolol in heart failure group and perfomed re-exercise study. Metoprolol increased plasma NE with a decrease in PV02. The quantitative relationship between PV02 and plasma NE was not affected by metoprolol (before: log NE=15.7-3.01og PV02,after: log NE=15.1-2.8 log PV02). Study 2: Close linear correlations of HR and contractility to plasma NE were observed in each subject(HR-log NE: r=0.89 to 0.99, mean 0.96 ; contractility-log NE: r=0.68 to 0.99, mean 0.92). The slope of regression lines decreased significantly along with the severity of heat failure. these results suggest that 1) the degree of muscle hypoxia plays an important role in regulation of sympathetic activity during exercise,2) the somatic exercise refrex arc mediated by chemosensitive muscle afferents remains intact in patients with heart failure and 3) the decreased chronotropic and inotropic responses to sympathetic activity are responsible for the exercise intolerance in patients with heart failure.
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