T Akata1, M Nakashima, K Izumi. 1. Department of Anesthesiology and Critical Care Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan. akata@kuaccm.med.kyushu-u.ac.jp
Abstract
BACKGROUND: Volatile anesthetic actions on intracellular Ca2+ stores (ie., sarcoplasmic reticulum [SR]) of vascular smooth muscle have not been fully elucidated. METHODS: Using isometric force recording method and fura-2 fluorometry, the actions of four volatile anesthetics on SR were studied in isolated endothellum-denuded rat mesenteric arteries. RESULTS: Halothane (> or = 3%) and enflurane (> or = 3%), but not isoflurane and sevoflurane, increased the intracellular Ca2+ concentration ([Ca2+]i) in Ca2+-free solution. These Ca2+-releasing actions were eliminated by procaine. When each anesthetic was applied during Ca2+ loading, halothane (> or = 3%) and enflurane (5%), but not isoflurane and sevoflurane, decreased the amount of Ca2+ in the SR. However, if halothane or enflurane was applied with procaine during Ca2+ loading, both anesthetics increased the amount of Ca2+ in the SR. The caffeine-induced increase in [Ca2+], was enhanced in the presence of halothane (> or = 1%), enflurane (> or = 1%), and isoflurane (> or = 3%) but was attenuated in the presence of sevoflurane (> or = 3%). The norepinephrine-induced increase in [Ca2+], was enhanced only in the presence of sevoflurane (> or = 3%). Not all of these anesthetic effects on the [Ca2+]i were parallel with the simultaneously observed anesthetic effects on the force. CONCLUSIONS: In systemic resistance arteries, the halothane, enflurane, isoflurane, and sevoflurane differentially influence the SR functions. Both halothane and enflurane cause Ca2+ release from the caffeine-sensitive SR. In addition, both anesthetics appear to have a stimulating action on Ca2+ uptake in addition to the Ca2+-releasing action. Halothane, enflurane, and isoflurane all enhance, while sevoflurane attenuates, the Ca2+-induced Ca2+-release mechanism. However, only sevoflurane stimulates the inositol 1,4,5-triphosphate-induced Ca2+ release mechanism. Isoflurane and sevoflurane do not stimulate Ca2+ release or influence Ca2+ uptake.
BACKGROUND: Volatile anesthetic actions on intracellular Ca2+ stores (ie., sarcoplasmic reticulum [SR]) of vascular smooth muscle have not been fully elucidated. METHODS: Using isometric force recording method and fura-2 fluorometry, the actions of four volatile anesthetics on SR were studied in isolated endothellum-denuded rat mesenteric arteries. RESULTS:Halothane (> or = 3%) and enflurane (> or = 3%), but not isoflurane and sevoflurane, increased the intracellular Ca2+ concentration ([Ca2+]i) in Ca2+-free solution. These Ca2+-releasing actions were eliminated by procaine. When each anesthetic was applied during Ca2+ loading, halothane (> or = 3%) and enflurane (5%), but not isoflurane and sevoflurane, decreased the amount of Ca2+ in the SR. However, if halothane or enflurane was applied with procaine during Ca2+ loading, both anesthetics increased the amount of Ca2+ in the SR. The caffeine-induced increase in [Ca2+], was enhanced in the presence of halothane (> or = 1%), enflurane (> or = 1%), and isoflurane (> or = 3%) but was attenuated in the presence of sevoflurane (> or = 3%). The norepinephrine-induced increase in [Ca2+], was enhanced only in the presence of sevoflurane (> or = 3%). Not all of these anesthetic effects on the [Ca2+]i were parallel with the simultaneously observed anesthetic effects on the force. CONCLUSIONS: In systemic resistance arteries, the halothane, enflurane, isoflurane, and sevoflurane differentially influence the SR functions. Both halothane and enflurane cause Ca2+ release from the caffeine-sensitive SR. In addition, both anesthetics appear to have a stimulating action on Ca2+ uptake in addition to the Ca2+-releasing action. Halothane, enflurane, and isoflurane all enhance, while sevoflurane attenuates, the Ca2+-induced Ca2+-release mechanism. However, only sevoflurane stimulates the inositol 1,4,5-triphosphate-induced Ca2+ release mechanism. Isoflurane and sevoflurane do not stimulate Ca2+ release or influence Ca2+ uptake.
Authors: Shuying Gao; David J Sandstrom; Harold E Smith; Brigit High; Jon W Marsh; Howard A Nash Journal: Anesthesiology Date: 2013-03 Impact factor: 7.892