Klip A, Mills G B, Britt B A, Elliott M E
Department of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.
Am J Physiol. 1990 Mar;258(3 Pt 1):C495-503. doi: 10.1152/ajpcell.1990.258.3.C495.
The concentration of ionized cytosolic calcium [( Ca2+]i) was determined in peripheral blood mononuclear cells from normal and malignant hyperthermia (MH)-susceptible humans and pigs, using the fluorescent Ca2+ indicator indo-1. [Ca2+]i was slightly but significantly elevated in cells from MH human cells relative to normal cells (198 +/- 18 nM, n = 15, and 146 +/- 14 nM, n = 11, respectively, P less than 0.05). Anesthetic concentrations of halothane in the cell suspension resulted in a rapid increase in [Ca2+]i in cells from both normal and MH humans or pigs. The increases (delta) were more pronounced in cells from MH subjects than from normal individuals (delta at 5.7 mM halothane: 245 +/- 53 vs. 57 +/- 11 nM, respectively) and from MH than from normal pigs (delta of 241 +/- 63 vs. 53 +/- 27 nM, respectively). Removal of extracellular Ca2+ obliterated the delta[Ca2+]i caused by halothane in cells from normal humans or pigs but only decreased by about half the delta[Ca2+]i in cells from MH humans or pigs. In 1,2-bis-(aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)-loaded cells, in the absence of extracellular Ca2+, halothane failed to increase [Ca2+]i. This suggests that buffering Cai2+ with BAPTA precludes detection of release of Ca2+ from intracellular stores, explaining the previous observations made with quin2, a highly chelating Ca2+ indicator. It is concluded that clinical concentrations of halothane allow influx of Ca2+ in cells from both normal and MH-susceptible individuals but release Ca2+ from intracellular stores selectively in cells from the latter group.(ABSTRACT TRUNCATED AT 250 WORDS)
利用荧光钙指示剂indo-1，测定了正常人和恶性高热（MH）易感的人和猪外周血单个核细胞中游离胞质钙浓度[（Ca2+]i）。与正常细胞相比，MH人细胞中的[Ca2+]i略有升高，但差异显著（分别为198±18 nM，n = 15，和146±14 nM，n = 11，P<0.05）。细胞悬液中麻醉浓度的氟烷导致正常人和MH人或猪细胞中的[Ca2+]i迅速升高。MH受试者细胞中的升高幅度（δ）比正常个体更明显（在5.7 mM氟烷时的δ：分别为245±53和57±11 nM），且MH猪细胞中的升高幅度比正常猪更明显（分别为241±63和53±27 nM）。去除细胞外Ca2+消除了氟烷在正常人和猪细胞中引起的δ[Ca2+]i，但仅使MH人和猪细胞中的δ[Ca2+]i降低约一半。在加载1,2-双（氨基苯氧基）乙烷-N,N,N',N'-四乙酸（BAPTA）的细胞中，在没有细胞外Ca2+的情况下，氟烷未能升高[Ca2+]i。这表明用BAPTA缓冲Ca2+会妨碍检测细胞内钙库中Ca2+的释放，解释了先前使用高度螯合钙指示剂quin2时的观察结果。得出结论，临床浓度的氟烷允许Ca2+流入正常人和MH易感个体的细胞，但仅在后一组个体的细胞中选择性地从细胞内钙库释放Ca2+。（摘要截短至250字）
