Fig. 1. Schematic diagram illustrating the experimental protocol. CON = control; DES = 1.0 minimum alveolar concentration (MAC) desflurane; DES + KN-93 = desflurane + KN-93; DES + METO = 1.0 MAC desflurane + 0.2, 1.0, 1.75, or 2.5 mg/kg metoprolol; KN-93 = 300 μg/kg KN-93; METO = 0.2, 1.0, 1.75, or 2.5 mg/kg metoprolol. n = 10 per group, except for KN-93 and DES + KN-93 (n = 6 per group).