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.