摘要
刺激Schaffer侧支,记录大鼠海马脑片CA_1区的突触前排放(presynaptic volley,PV)和突触后群锋电位(population spikes,PS),观察缺氧后PS和PV的变化及复氧30min后脑片PS的恢复,缺氧持续到PV消失1,2,3或4min,复氧后脑片恢复率分别为100％,11.5％,0％,0％。可见,缺氧后 PV 消失2min为损伤的关键时刻。提前1min终止缺氧,全部脑片的PS可以恢复,延迟1min终止缺氧,则全部脑片的PS不能恢复。这种方法是根据每个脑片的电反应确定其总的缺氧时间,故每个脑片的缺氧时间略有变动。与每次采用相同缺氧时间的传统方法相比,此方法脑片恢复率的稳定性与重复性均较好。用此方法发现美西律10和100μmol/L能增加复氧后PS恢复率,对突触功能的缺氧损伤具有保护作用。
Evoked population spikes (PS) and presynaptic fiber volleys (PV) were recorded from CA1 region in rat hippocampal slices while the Schaffer collaterals were stimulated. Changes of PS and PV during hypoxia and recovery of PS after 30 minutes reoxygenation were monitored. When hypoxia lasted 1, 2, 3 or 4 minutes after the disappearance of PV, the recovery rate was 100%, 11.5%, 0% and 0% respectively. Thus the second minute after the disappearance of PV seems to be a critical time point. When hypoxia ended 1 minutes before that point, synaptic transmission could recover. However, synaptic transmission was damaged irreversibly if hypoxia lasted 1 min beyond that point. Because the hypoxia time was controlled according to the electrical response of the individual slices, the total duration of hypoxia for each slice changed slightly. The results were more stable and reproducible than those using the conventional method, in which the hypoxia time was identical for any slice. Using this method we found that mexiletine at 10 to 100μmol/ L increased the recovery rate of PS and protected synaptic function from hypoxic damage.
出处
《中国应用生理学杂志》
CAS
CSCD
1992年第4期313-317,共5页
Chinese Journal of Applied Physiology
关键词
海马脑片
缺氧
突触前排放
hippocampal slice
population spike
hypoxia
mexiletine
presynaptic fiber volleys
