Effects of Volatile Anesthetics on Cardiac Sarcoplasmic Reticulum as Determined in Intact Cells

Abstract

While it is generally agreed that the volatile anesthetics halothane, enflurane and isoflurane act at both the sarcoplasmic reticulum (SR) and sarcolemma (SL) in cardiac cells, it is less clear whether all three agents have the same qualitative effects at these sites. In many preparations, it has been demonstrated that isoflurane has a less potent negative inotropic effect than halothane or enflurane.^1–5 It has recently been demonstrated that at equi-anesthetic concentrations the agents produce a similar degree of depression of peak second inward current.^6–8 The effect of these agents at the SR is less readily measured, and evidence exists that there is a major difference between halothane’s and isoflurane’s action there.⁹ Since it appeared that the differences in negative inotropic potency among these agents are a consequence of their actions at the SR, we sought to document differences in effect at the SR for all three commonly used agents.