Balestrino M, Aitken P G, Somjen G G
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710.
Brain Res. 1989 Sep 11;497(1):102-7. doi: 10.1016/0006-8993(89)90975-x.
Hippocampal tissue slices were made hypoxic for 4-10 min and then reoxygenated for 60-120 min. Postsynaptic evoked potentials were recorded and extracellular DC potential was monitored continuously in stratum (st.) pyramidale of CA1 and st. granulosum of fascia dentata (FD). In some preparations extracellular potassium ([K+]o) and calcium ([Ca2+]o) were also recorded in both regions. Postsynaptic responses disappeared sooner during hypoxia and were less likely to recover upon reoxygenation in CA1 than in FD. The CA1 region exhibited a spreading depression (SD)-like response to hypoxia more often than did FD. When both regions showed SD-like depolarization, voltage shift and elevation of [K+]o were of greater magnitude and shorter latency in CA1. The probability of posthypoxic recovery of synaptic transmission was inversely related to the time spent in the SD-like state in both CA1 and FD. We conclude that the selective vulnerability of CA1 neurons to hypoxic and ischemic damage may be due, at least in part, to the region's propensity to undergo prolonged and severe SD-like depolarization.
海马组织切片缺氧4 - 10分钟，然后再给氧60 - 120分钟。记录突触后诱发电位，并在CA1区的锥体层和齿状回颗粒层连续监测细胞外直流电位。在一些标本中，还记录了这两个区域的细胞外钾离子（[K+]o）和钙离子（[Ca2+]o）。与齿状回相比，CA1区的突触后反应在缺氧期间消失得更快，再给氧时恢复的可能性更小。CA1区比齿状回更常出现类似扩散性抑制（SD）的缺氧反应。当两个区域都出现类似SD的去极化时，CA1区的电压变化和[K+]o升高的幅度更大，潜伏期更短。CA1区和齿状回突触传递缺氧后恢复的概率与类似SD状态下所持续的时间呈负相关。我们得出结论，CA1神经元对缺氧和缺血损伤的选择性易损性，至少部分可能是由于该区域倾向于经历长时间的严重类似SD的去极化。
