IMPROVED STABILITY OF DROSOPHILA LARVAL NEUROMUSCULAR PREPARATIONS IN HEMOLYMPH-LIKE PHYSIOLOGICAL SOLUTIONS
IMPROVED STABILITY OF DROSOPHILA LARVAL NEUROMUSCULAR PREPARATIONS IN HEMOLYMPH-LIKE PHYSIOLOGICAL SOLUTIONS
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DOI：
10.1007/bf00215114
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发表时间：
1994-08-01
期刊：
影响因子：
--
通讯作者：
WU, CF
中科院分区：
文献类型：
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作者：
STEWART, BA;ATWOOD, HL;WU, CF
来自果蝇第三龄幼虫的神经肌肉制剂在常用的生理溶液中不能得到很好的维持：在肌纤维中形成空泡，并且膜电位下降。这些问题可能是由于这些生理溶液的Na:K比和总二价阳离子含量与血淋巴的Na:K比和总二价阳离子含量有很大不同所致。因此，基于主要阳离子的离子测量，开发并测试了类血淋巴溶液。类血淋巴溶液使膜电位保持在相对恒定的水平，延长了制剂的生理寿命。突触传递在血淋巴样溶液中得到良好维持，但与标准果蝇溶液相比，兴奋性突触电位的时程较慢，并且通过重复刺激更有效地累加。电压钳实验表明，这些效应与标准溶液中肌纤维膜电导的更明显激活有关，而不是与被动肌膜特性的差异或突触后受体通道动力学的变化有关。在标准溶液和类血淋巴溶液中，递质释放的钙依赖性都很大，但在血淋巴样溶液中，对于给定的释放水平，需要更高的外部钙浓度。因此，类血淋巴溶液可以长时间、稳定地记录突触传递。
Neuromuscular preparations from third instar larvae of Drosophila are not well-maintained in commonly used physiological solutions: vacuoles form in the muscle fibers, and membrane potential declines. These problems may result from the Na:K ratio and total divalent cation content of these physiological solutions being quite different from those of haemolymph. Accordingly haemolymph-like solutions, based upon ion measurements of major cations, were developed and tested. Haemolymph-like solutions maintained the membrane potential at a relatively constant level, and prolonged the physiological life of the preparations. Synaptic transmission was well-maintained in haemolymph-like solutions, but the excitatory synaptic potentials had a slower time course and summated more effectively with repetitive stimulation, than in standard Drosophila solutions. Voltage-clamp experiments suggest that these effects are linked to more pronounced activation of muscle fiber membrane conductances in standard solutions, rather than to differences in passive muscle membrane properties or changes in postsynaptic receptor channel kinetics. Calcium dependence of transmitter release was steep in both standard and haemolymph-like solutions, but higher external calcium concentrations were required for a given level of release in haemolymph-like solutions. Thus, haemolymph-like solutions allow for prolonged, stable recording of synaptic transmission.