Different effects of inhalation anesthetics on calcium homeostasis in the cardiac muscle of isolated working rat hearts

The aims of the study were to evaluate whether inhalation anesthetics have the same mechanisms of negative inotropic action, and to compare the relationship between the calcium homeostasis and cardiac depression for each anesthetic. The effects of inhalation anesthetics on left ventricular contraction, calcium content of the sarcoplasmic reticulum (SR; as measured by caffeine-induced calcium release), and calcium content of the left ventricular muscle (as measured by atomic absorption spectroscopy) were evaluated in the isolated perfused rat heart. Inhalation anesthetics (i.e., halothane, enflurane, isoflurane, and sevoflurane) reduced both left ventricular contraction and calcium content of the SR. For all four drugs, there was a relationship between the negative inotropic effect and the decrease in calcium content of the SR. Sevoflurane maintained the calcium content of both the SR and the left ventricular muscle at a significantly higher level as compared with other anesthetics. These data suggest that, although inhalation anesthetics increase the calcium permeability of cardiac SR, their mechanisms of myocardial contractile depression are different.