Volatile anesthetic action on muscle Ca2+ homeostasis

It is proposed that volatile anesthetics act through the modification of Ca 2+ homeostasis in excitable cells. To test this hypothesis, cardiac and ske letal muscles were used as models to examine Ca2+ response, and Ca2+ regula tory and delivery mechanisms. I found that halothane did not alter Ca2+ bin ding to cardiac troponin C. However, halothane and isoflurane reversibly de creased the Ca2+ affinity of calmodulin at low anesthetic concentration, an d irreversibly increased the Ca2+ affinity of calmodulin at high anesthetic concentration. The volatile anesthetics also increased the permeability of light fraction of sarcoplasmic reticulum (SR) to Ca2+. I conclude that vol atile anesthetics alter calcium homeostasis in cardiac and skeletal muscles . This work was in part performed in collaboration with Giovanni Salviati a nd the author benefited from Salviati's work in similar areas.