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Captopril attenuates reflex adrenergic response in essential hypertension
1Department of Medicine, Wakayama Medical College, Japan.
Life Sciences
|January 1, 1991
Summary
Captopril, an angiotensin-converting enzyme inhibitor, reduced blood pressure without reflex tachycardia. This suggests diminished adrenergic activity, unlike nifedipine, which caused reflex tachycardia in essential hypertension.
Area of Science:
- Cardiovascular Pharmacology
- Hypertension Research
Background:
- Essential hypertension management often involves addressing sympathetic nervous system activity.
- Angiotensin II plays a key role in blood pressure regulation and sympathetic tone.
Purpose of the Study:
- To evaluate the effect of inhibiting endogenous angiotensin II formation on adrenergic activity.
- To compare the impact of captopril versus nifedipine on plasma norepinephrine levels and reflex tachycardia in essential hypertension.
Main Methods:
- Single oral administration of captopril and nifedipine in patients with essential hypertension.
- Measurement of mean arterial pressure, heart rate, plasma renin activity, and plasma norepinephrine concentration.
Main Results:
- Both captopril and nifedipine similarly reduced mean arterial pressure.
- Nifedipine induced significant reflex tachycardia, whereas captopril did not.
- Plasma norepinephrine concentration increased significantly less after captopril compared to nifedipine.
Conclusions:
- Inhibition of angiotensin II formation by captopril attenuates adrenergic activity.
- Diminished adrenergic activity likely explains the absence of reflex tachycardia with captopril in essential hypertension.