Fig. 1. Contractions in the fura-2–nonloaded strips produced by consecutive applications of either halothane (HAL), enflurane (ENF), isoflurane (ISO), or sevoflurane (SEV) and caffeine in the Ca²⁺-free solution (n = 4). (A ) Examples. (Left ) Control caffeine contractions (CONT). (Right ) Anesthetic effects. Arrows indicate the time points when the extracellular Ca²⁺was removed after the Ca²⁺load. (B  and C ) Concentration–response data for the consecutive applications of each anesthetic (B ) and caffeine (C ). The contractions induced by each anesthetic or caffeine were normalized to the control caffeine contraction (100%). The EC⁵⁰values for the halothane and enflurane contractions were 1.20 and 3.88%, respectively. * P < 0.05 versus  control within each group. #P < 0.05 between halothane and enflurane groups at each concentration.