Cardiovasc Res. 1990 Jan;24(1):65-71. doi: 10.1093/cvr/24.1.65.

Alterations in the regional beta adrenergic system in experimental left ventricular hypertrophy.

Cardiovascular research

P M Scholz, M E Upsher, D Eliades, J Kedem, H R Weiss

PMID: 2158400 DOI: 10.1093/cvr/24.1.65

Abstract

STUDY OBJECTIVE - The aim of the study was to determine the changes in the beta adrenergic system induced by cardiac hypertrophy due to valvular aortic stenosis. DESIGN - Density of beta adrenoceptors, cardiac tissue noradrenalime concentrations, coronary blood flow (using radioactive microspheres), and haemodynamic variables were compared in a model of experimental aortic valve stenosis of 6 month's duration and in sham operated controls. SUBJECTS - 14 mongrel dogs with aortic stenosis and eight sham operated litter mates were used in the studies. MEASUREMENTS and RESULTS - Heart weight to body weight ratio was 33% greater in dogs with aortic valve stenosis than in controls. There were no haemodynamic differences except for a left ventricular to aortic systolic pressure gradient of 38 (SD 22) mm Hg in the aortic stenosis group. Response of left ventricular dP/dtmax to dopamine was similar in the two groups, as was coronary flow. Density of beta adrenoceptors (Bmax) as measured by (125I)-iodopindolol binding was reduced in ventricles from the aortic stenosis group compared to control: 41.2(13.3) v 59.1(8.1) fmol.mg-1 protein, p less than 0.005. Affinity of receptor for ligand (Kd) was not affected by cardiac hypertrophy. Tissue noradrenaline concentration was reduced in the hypertrophy group: 1108(402) (control) v 438(13) ng.g-1 initial wet weight (aortic stenosis), p less than 0.05. There were no significant subepicardial v subendocardial differences in any variable. CONCLUSIONS - Cardiac hypertrophy induced by aortic valve stenosis over a 6 month period is accompanied by a decrease in the density of ventricular beta adrenoceptors per gram and a decrease in ventricular noradrenaline concentration, though responsiveness of the whole heart is maintained.

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Substances

• Receptors, Adrenergic, beta
• Norepinephrine

MeSH terms

• Animals
• Aortic Valve Stenosis / complications
• Aortic Valve Stenosis / metabolism
• Cardiomegaly / etiology
• Cardiomegaly / metabolism
• Cardiomegaly / physiopathology
• Disease Models, Animal
• Dogs
• Heart / anatomy & histology
• Heart Ventricles / analysis
• Norepinephrine / analysis
• Organ Size / physiology
• Receptors, Adrenergic, beta / analysis
• Sympathetic Nervous System / physiopathology

Publication Types

• Comparative Study
• Journal Article
• Research Support, Non-U.S. Gov't
• Research Support, U.S. Gov't, P.H.S.

Grant support

• HL 26919/HL/NHLBI NIH HHS/United States
• HL 40320/HL/NHLBI NIH HHS/United States

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