Repeated Immobilization Stress Increases Expression of Beta(3)-Adrenoceptor in the Left Ventricle and Atrium of the Rat Heart
Abstract
Stress is a contributor of many cardiovascular diseases. Positive inotropic and chronotropic effects of catecholamines are regulated via Beta-adrenergic receptors (ARs).
Many reports exist concerning changes of cardiac Beta1 - and Beta2 -ARs in stress, but only a few deal with modulation of cardiac Beta3 -AR. Our aim was to analyze the expression and binding sites of Beta1 -, Beta2 - and Beta3 -ARs and adenylyl cyclase activity in the left ventricle, and Beta3 -AR expression and binding in the left atrium of rats exposed to acute and chronic immobilization stress (IMO).
The concentration of noradrenaline in the ventricle decreased, while adrenaline increased, especially after repeated IMO. The mRNA and protein levels, and binding sites of Beta3 -subtype significantly rose following chronic IMO, while all parameters for Beta2 -AR dropped after single and repeated exposure.