CA2+ EFFLUX MECHANISMS FOLLOWING DEPOLARIZATION EVOKED CALCIUM TRANSIENTS IN CULTURED RAT SENSORY NEURONS
CA2+ EFFLUX MECHANISMS FOLLOWING DEPOLARIZATION EVOKED CALCIUM TRANSIENTS IN CULTURED RAT SENSORY NEURONS
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DOI：
10.1113/jphysiol.1992.sp019316
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发表时间：
1992-09-01
影响因子：
5.5
通讯作者：
MCBAIN, CJ
中科院分区：
文献类型：
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作者：
BENHAM, CD;EVANS, ML;MCBAIN, CJ
1.我们采用显微荧光和膜片钳技术相结合的方法研究了生理性钙负荷对培养的大鼠背根神经节神经元胞浆内钙缓冲的影响.在负载Indo-1 AM的细胞中，使用高电阻微电极启动和记录动作电位，单个动作电位与[Ca 2 +]i的可测量升高相关。动作电位短列车诱发[Ca 2 +]i瞬变与单指数恢复率与时间常数约为5秒。在全细胞记录模式下用膜片钳移液管灌注的细胞中观察到类似的Ca 2+缓冲特性，这表明缓慢（秒）的Ca 2+缓冲特性没有受到记录技术的严重干扰。在电压钳下的细胞中，Na+-Ca 2+交换器驱动力的逆转对Ca 2+清除速率有很小但显著的影响.增加细胞外的pH值或加入钒酸盐（200 μ m）的内部解决方案显着减缓了复苏的速度。向移液管溶液中加入钙咪达唑鎓也产生了显著但不太显著的Ca 2+流出减缓。结果表明，质膜Ca 2 +-ATP酶的活性是重要的去除体细胞Ca 2+负载的幅度相似的那些所产生的一些动作电位的发射。
1. We have used a combination of microfluorimetry and patch-clamp techniques to investigate cytoplasmic Ca2+ ([Ca2+]i) buffering in response to physiological Ca2+ loads in neurones cultured from the dorsal root ganglia of the rat.2. In cells loaded with Indo-1 AM and using high resistance microelectrodes to initiate and record action potentials, single action potentials were associated with a measurable rise in [Ca2+]i. Short trains of action potentials evoked [Ca2+]i transients with monoexponential recovery rates with time constants of around 5 s.3. Similar Ca2+ buffering properties were seen in cells perfused with patch-clamp pipettes in the whole-cell recording mode suggesting that the slow (seconds) Ca2+ buffering properties were not seriously perturbed by the recording technique.4. In cells held under voltage clamp, reversal of the Na+-Ca2+ exchanger driving force had a small but significant effect on the rate of Ca2+ removal.5. Increasing extracellular pH or adding vanadate (200-mu-m) to the internal solution dramatically slowed the rate of recovery. Addition of calmidazolium to the pipette solution also produced a significant but much less dramatic slowing of Ca2+ efflux.6. The results demonstrate that the activity of a plasmalemmal Ca2+-ATPase is important for the removal of somatic Ca2+ loads of a similar amplitude to those generated by the firing of a few action potentials.