The action of halothane on spontaneous contractile waves and stimulated contractions in isolated rat and dog heart cells.
The action of halothane on spontaneous contractile waves and stimulated contractions in isolated rat and dog heart cells.
复制标题
氟烷对自发收缩波的作用并刺激离体大鼠和狗心脏细胞的收缩。
DOI：
10.1097/00000542-199005000-00022
复制
发表时间：
1990
期刊：
影响因子：
8.8
通讯作者：
Lakatta,EG
中科院分区：
文献类型：
--
作者：
Wheeler,DM;Rice,RT;Lakatta,EG
为确定氟烷负性肌力作用的细胞机制，在氟烷溶液中对单个、分离的大鼠和狗的心脏细胞长度进行了监测。反映静息状态下大鼠心肌细胞肌浆网(SR)自发钙释放的自发收缩波，在氟烷浓度为0.27 mM(0.9%)和0.55 mm(1.7%)时，频率显著增加，幅度显著降低。电刺激犬和大鼠心肌细胞突然暴露于氟烷(0.47-0.55 mM或1.5-1.7Vol%)后，其抽动幅度出现一过性增加(与对照组有显著差异)。随着氟烷暴露的继续，抽动幅度随后下降到明显低于对照组的值。在以每分钟60次跳动跳动的大鼠细胞和狗细胞中，这种抽动的减少达到了对照组的42+/-13%(平均+/-SD)和50+/-14%。在犬细胞中，快搏动频率下的短暂性收缩幅度增加幅度大于低跳动频率下的短暂性增加幅度(P<0.01)，且对维拉帕米不敏感。氟烷0.55 mM(1.7%Vol%)对静息(负阶梯)后刺激的大鼠细胞连续搏动幅度的下降速度也有显著的促进作用。关于自发收缩波的研究结果表明，氟烷对静息细胞的SR有直接影响，其发生与慢内向电流的任何变化无关。氟烷引起的跳动细胞的变化可以解释为促进了SR的钙释放，最终减少了SR的钙库。
The cell length of single, isolated rat and dog heart cells was monitored during exposure to halothane-containing solution to define the cellular mechanism of halothane's negative inotropic effect. Spontaneous contractile waves, which reflect spontaneous Ca release from the sarcoplasmic reticulum (SR) in resting rat heart cells, exhibited a significant increase in frequency and a decrease in amplitude in the presence of halothane 0.27 mM (0.9 vol%) and 0.55 mM (1.7 vol%). Electrically stimulated dog and rat heart cells abruptly exposed to halothane (0.47-0.55 mM or 1.5-1.7 vol%) revealed a transient increase in twitch amplitude (significantly different from control). Twitch amplitude then declined to values significantly below control as halothane exposure continued. This decrease in twitch reached 42+/-13%(mean+/-SD) of control in rat cells and 50+/-14% in dog cells beating at 60 beats per min. In dog cells the magnitude of the transient increase in twitch amplitude was greater at faster beating rates compared with lower rates in the same cells (P less than 0.01) and the transient increase was insensitive to verapamil. Halothane 0.55 mM (1.7 vol%) also significantly accelerated the rate of decline in the twitch amplitude of successive beats in rat cells stimulated after a rest interval (negative staircase). The findings regarding spontaneous contractile waves indicate a direct effect of halothane at the SR in resting cells, occurring independently of any changes in the slow inward current. The halothane-induced changes in beating cells can be explained by an enhancement of Ca release from the SR with an eventual reduction of SR Ca stores.