Light scattering in rat neocortical slices differs during spreading depression and ischemia.
Light scattering in rat neocortical slices differs during spreading depression and ischemia.
复制标题
大鼠新皮质切片中的光散射在扩散抑郁和缺血期间有所不同。
DOI：
10.1016/s0006-8993(02)03254-7
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发表时间：
2002
期刊：
影响因子：
2.9
通讯作者：
Nicholson,Charles
中科院分区：
文献类型：
--
作者：
Tao,Lian;Masri,Daniel;Hrabetová,Sabina;Nicholson,Charles
扩散性抑制（SD）和缺血是不同的病理生理事件，但具有相似的特征。本研究探讨是否存在相似的光散射（LS）的性质在SD和缺血大鼠新皮层切片。采用K+诱导SD模型，同时采用去氧去糖法模拟缺血模型。LS与细胞外直流（DC）电位和细胞外间隙（ECS）容积的变化同步记录。使用光子计数光纤系统测量LS，并且通过测量四甲基铵（TMA+）的ECS浓度来确定ECS体积变化。正常人工脑脊液（ACSF）中的切片在SD期间表现出一致的LS增加，但在6分钟的缺血期间表现出两种不同的LS行为。在8个切片中，LS降低，并保持如此，直到缺血性挑战结束。在另外10个切片中，LS最初减少，但在2分钟后，突然逆转的迹象，伴随着细胞外DC电位的快速负移。当ACSF中50%或91%的Cl-被膜渗透性丙酸盐取代时，LS在SD期间保持其增加，但在缺血期间总是显示突然的LS逆转。相比之下，当Cl−被膜不渗透的硫酸甲酯取代时，SD诱导的LS增加被LS减少所取代，并且在缺血期间不存在突然的LS逆转。在SD和缺血时，LS信号表现出不同的特征，但DC电位总是负移，ECS体积总是表现出类似的减少。这些结果表明，LS信号的极性是由至少两个因素的竞争：细胞肿胀和阴离子流入。
Spreading depression (SD) and ischemia are different pathophysiological events but have similar characteristics. This study investigated whether similarity exists in the light scattering (LS) properties during SD and ischemia in rat neocortical slices. SD was induced by injection of K+while ischemia was simulated by removing oxygen and glucose. LS was simultaneously recorded with changes in extracellular direct current (DC) potential and extracellular space (ECS) volume. LS was measured using a photon counting fiber optic system and the ECS volume change was determined by measuring the ECS concentration of tetramethylammonium (TMA+). Slices maintained in normal artificial cerebrospinal fluid (ACSF) showed a consistent LS increase during SD, but exhibited two different LS behaviors during 6 min of ischemia. In eight slices, LS decreased and remained so until the end of the ischemic challenge. In another 10 slices, LS diminished initially but, after 2 min, suddenly reversed sign, accompanied by a rapid negative shift in extracellular DC potential. When 50 or 91% of Cl−in the ACSF was replaced by membrane-permeable propionate, LS retained its increase during SD, but always showed the sudden LS reversal during ischemia. In contrast, when Cl−was substituted with membrane-impermeant methylsulfate, the SD-induced LS increase was replaced by an LS decrease, and the sudden LS reversal during ischemia was absent. While the LS signal showed different characteristics during SD and ischemia, the DC potential always presented negative shifts and the ECS volume always exhibited similar decreases. These results suggest that the polarity of the LS signal is determined by the competition of at least two factors: cell swelling and anion influx.