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[Myocardial beta-adrenergic receptors and left ventricular hypertrophy induced by pressure overload in man]
M Galinier1, J M Sénard, G Dréan
1Laboratoire de pharmacologie médicale et clinique, INSERM U317, faculté de médecine, Toulouse.
Insights
Left ventricular hypertrophy (LVH) in humans does not alter total beta-adrenoceptors. However, pressure overload associated with LVH selectively decreases left ventricular beta 1-adrenoceptors.
Area of Science:
- Cardiology
- Molecular Pharmacology
Context:
- Beta-adrenoceptor characteristics in left ventricular hypertrophy (LVH) from pressure overload are controversial in experimental models.
- Limited data exist in human subjects.
Purpose:
- To investigate the characteristics of right auricular (RA) and left ventricular (LV) beta-adrenoceptors in humans with and without LVH due to pressure overload.
Summary:
- This study compared beta-adrenoceptor characteristics using 125I-cyanopindolol binding in 12 patients with mitral stenosis (control, no LVH) and 13 patients with aortic stenosis (LVH).
- Results indicate that LVH due to pressure overload in humans does not change the total number of beta-adrenoceptors.
- A selective decrease in left ventricular beta 1-adrenoceptors was observed in patients with LVH.
Impact:
- Provides the first human data on beta-adrenoceptor characteristics in pressure-overload-induced LVH.
- Suggests a selective alteration of beta 1-adrenoceptors in the human hypertrophied left ventricle.
- Contributes to understanding the pathophysiology of cardiac remodeling and adrenergic signaling in hypertensive heart disease.
Abstract:
In experimental models, the characteristics of beta-adrenoceptors in left ventricular hypertrophy (LVH) due to pressure overload remain controversial and no data are still available in man. We investigated right auricular (RA) and left ventricular (LV) beta-adrenoceptors characteristics (125 I cyanopindolol binding) in two groups of patients undergoing valve replacement without heart failure (LV ejection fraction > 55%). Height patients with mitral stenosis (mean age: 64 +/- 4 years) and without LVH (LV mass index < 120 g/m2) constituted the control group and 13 patients with aortic stenosis (mean age: 66 +/- 4 years) and LVH (LV mass index > 150 g/m2) the study group. The results are: [table: see text] These results show that, in man, LVH due to pressure overload does not induce variation of total number beta-adrenoceptors, but is associated with a selective decrease in left ventricular beta 1-adrenoceptors.