Fig. 1. Schematic diagram illustrating the experimental protocol. Desflurane and sevoflurane were given at a dose of 1.0 MAC. Esmolol, an ultrashort-acting selective β¹-adrenergic receptor blocker, was given intravenously at a dose of 30.0 mg · kg⁻¹· h⁻¹. H-89, a selective protein kinase A inhibitor, was administered into the left ventricle at a dose of 250 μg/kg.