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beta-Receptors and contractile reserve in left ventricular hypertrophy
Hypertension (Dallas, Tex. : 1979)
|March 1, 1983
Summary
Hypertension with left ventricular hypertrophy (LVH) diminishes the heart's response to adrenergic stimulation. This is linked to reduced beta-receptor numbers in the heart, potentially contributing to heart failure progression.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
Background:
- Hypertension often leads to left ventricular hypertrophy (LVH).
- Adrenergic stimulation plays a crucial role in cardiac contractility.
Purpose of the Study:
- To investigate the impact of renovascular hypertension-induced LVH on cardiac inotropic responsiveness to adrenergic stimulation.
- To determine the role of beta-adrenergic receptors in this diminished responsiveness.
Main Methods:
- Comparison of isolated hearts from renal hypertensive rats (RHR) and normotensive controls (NR).
- Assessment of inotropic responses to isoproterenol, calcium ions, and scillaren.
- Quantification of left ventricular beta-adrenergic receptor density and affinity.
Main Results:
- Isoproterenol-induced inotropic responses were significantly lower in RHR compared to NR.
- Responsiveness to calcium ions and scillaren remained unaffected.
- Left ventricular beta-receptor density was significantly reduced in RHR, with no change in affinity.
Conclusions:
- LVH associated with renovascular hypertension impairs inotropic responsiveness to beta-adrenergic stimulation.
- Reduced ventricular beta-receptor concentration is a key factor in this impairment.
- This blunted response may contribute to the progression from LVH to heart failure.