Role of β-Adrenergic Receptors in Stress-Induced Cardiac Injury.

Stress-induced cardiac injury (SICI) was modeled on female Wistar rats using a 24-h immobilization. SICI was quantified by 99mTc-pyrophosphate accumulation in the myocardium. Blockade of β1- and β2-adrenergic receptors (AR) led to a decrease in SICI. β1-AR antagonists nebivolol and atenolol almost completely prevented SICI. The selective β2-AR antagonist ICI 118,551 increased SICI, while the selective β3-AR antagonist L-748337 did not affect heart damage. The selective β2-AR agonist formoterol increased cardiac tolerance to stress. These findings suggest that β1-AR play a key role in the pathogenesis of SICI. Stimulation of β2-AR enhances cardiac tolerance to stress. β3-AR are not involved in the pathogenesis of SICI.