Effects of propofol and pentobarbital on calcium concentration in presynaptic boutons on a rat hippocampal neuron
Effects of propofol and pentobarbital on calcium concentration in presynaptic boutons on a rat hippocampal neuron
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DOI：
10.1007/s00540-011-1186-4
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发表时间：
2011-07
影响因子：
2.8
通讯作者：
Shinichi Ito;H. Sugiyama;S. Kitahara;Y. Ikemoto;T. Yokoyama
中科院分区：
文献类型：
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作者：
Shinichi Ito;H. Sugiyama;S. Kitahara;Y. Ikemoto;T. Yokoyama
目的大量研究表明静脉注射麻醉药影响中枢神经系统的突触后事件。然而，关于全身麻醉药如何影响突触前过程的证据很少。突触前钙离子浓度（[Ca 2 +]pre）调节神经递质的释放。在这项研究中，我们探讨了麻醉剂异丙酚IV和巴比妥酸戊巴比妥钠对神经递质释放的影响，通过测量[Ca 2 +]prein突触前神经末梢（扣）上分离的单个海马大鼠neurons.MethodsSprague-Dawley大鼠10-14日龄断头戊巴比妥钠麻醉下，脑切片制备。用水平振动的火抛光玻璃吸管接触海马CA 1区，沿着附着的突触前终扣分离神经元。用FM 1 -43染料染色后，在激光共聚焦显微镜下观察突触前终扣，用Fluo-3的乙酰氧基甲酯（Fluo-3 AM）测定突触前[Ca 2 +]蛋白。而异丙酚（10 μM）和戊巴比妥（300 μM）抑制高K+（60 mM）诱导的连接到树突的终扣中[Ca 2 +]前蛋白的增加，它们不影响连接到索马或树突基底的终扣中[Ca 2 +]前蛋白。由于大多数兴奋性突触都位于树突棘上，这些药物可能会影响兴奋性突触前神经终末的Ca 2+动员。结论异丙酚和戊巴比妥可能会影响兴奋性突触前神经末梢的神经递质释放，由于抑制[Ca 2 +]前。
PurposeNumerous reports suggest that intravenously administered (IV) anesthetics affect postsynaptic events in the central nervous system. However, there is little evidence about how general anesthetics influence the presynaptic processes. The level of presynaptic calcium (Ca2+) concentration ([Ca2+]pre) regulates neurotransmitter release. In this study, we investigated the effects of anesthetic propofol IV and the barbiturate pentobarbital on neurotransmitter release by measuring [Ca2+]prein the presynaptic nerve terminals (boutons) on a dissociated single hippocampal rat neuron.MethodsSprague-Dawley rats 10–14 days old were decapitated under pentobarbital anesthesia, and brain slices were prepared. The hippocampal CA1 area was touched with a fire-polished glass pipette, which vibrated horizontally, and neurons were dissociated, along with the attached presynaptic boutons. The presynaptic boutons were visualized under a confocal laser-scanning microscope after staining with FM1-43 dye, and [Ca2+]prewas measured with acetoxymethyl ester of fluo-3 (fluo-3 AM).ResultsHigh potassium (K+) (15–90 mM) increased the [Ca2+]prein the Ca2+-containing solution in a concentration-dependent manner. Whereas propofol (10 μM) and pentobarbital (300 μM) suppressed the high K+(60 mM)-induced increase in [Ca2+]prein the boutons attached to the dendrite, they did not affect [Ca2+]prein the boutons attached to the soma or dendrite base. As a large majority of excitatory synapses are located on dendritic spines, these agents may affect Ca2+mobilization in the excitatory presynaptic boutons.ConclusionsPropofol and pentobarbital may affect neurotransmitter release from the excitatory presynaptic nerve terminals due to inhibition of increase in [Ca2+]pre.