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首页> 外文学位 >Real-time glutamate release into, and removal from, the extracellular space in low flow states, and a novel eleven-vessel occlusion model, of rat forebrain ischemia: Correlation with EEG spectral analysis.
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Real-time glutamate release into, and removal from, the extracellular space in low flow states, and a novel eleven-vessel occlusion model, of rat forebrain ischemia: Correlation with EEG spectral analysis.

机译：谷氨酸在低流量状态下向细胞外空间的释放和清除，以及新型的11血管闭塞模型，与大鼠前脑缺血的关系：与EEG光谱分析的相关性。

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摘要

There remains controversy over the damaging effects of residual blood flow to the ischemic brain. In order to study the effects of a low flow state of cerebral ischemia, a novel eleven-vessel occlusion (11VO) rat model was devised, to more closely simulate complete forebrain ischemia, and compared to the four-vessel occlusion model (4VO), without exsanguination, and carotid transection (CT). Real time glutamate levels, in the extracellular space, were measured by microdialysis electrode, during control, ischemia and the early reperfusion phase in all animals. Finally, the EEG obtained during control, and ischemic periods, was compared by EEG spectral analysis. Ten-min periods of ischemia were tested.; Results show that the elapsed time, from the onset of ischemia to the ischemic plateau, is faster during 11VO (12–16 sec) than 4VO (72–155 sec). Cerebral blood flow falls to a lower mean level during 11VO (4–5%) than during 4VO (13–15%). Concomitantly, the peak interstitial glutamate concentration rises less during 11VO (138 μM, as opposed to 4VO (257 μM). Peak glutamate levels after CT (137 μM) are also significantly lower than during 4VO. There are no significant differences in glutamate release during 11VO and 10-min after CT. During the first 90-sec of reperfusion, glutamate levels rise to a second higher peak (315 μM) in 7 of 12 animals. Elapsed time to the normalization of glutamate following the onset of reperfusion is faster following 11VO (157 sec) than 4VO (547 sec). Finally, EEG spectral analysis reveals that the relative powers of δ1, [δ 1 + δ1], and [δ1 + δ2 + &thetas;] are significantly lower during ischemia in 11VO, than in 4VO animals (δ1 = 40% vs 74%; [δ1 + δ2] = 47% vs 82%; [δ1 + δ2 + &thetas;] = 51% vs 84%.; In conclusion, 11VO attains a level of profound, reversible ischemia, faster, than during 4VO. The 4VO model, without exsanguination, creates a low flow state (13–15% of control) of cerebral ischemia. The dialysis electrode provides real time evidence that glutamate levels in the interstitial space are enhanced during a low flow state of cerebral ischemia. Glutamate transients are seen to occur during the first 90 sec of reperfusion, and, the glutamate levels recorded, during ischemia, are the highest in the literature. A low flow state also requires a longer period of reperfusion, for glutamate normalization, than following 11VO. Finally, 4VO yields a greater power of slow waves, as determined by fast Fourier transform, than 11VO. Therefore, a low flow state of rat cerebral ischemia (13–15%) may be more damaging to the rat's brain than no flow at all.
机译：残余血流对缺血性脑的破坏作用仍存在争议。为了研究低流量状态的脑缺血的影响，设计了一种新型的11血管闭塞（11VO）大鼠模型，以更紧密地模拟完全前脑缺血，并与四血管闭塞模型（4VO）进行了比较，无需放血和颈动脉横切术（CT）。在所有动物的对照，局部缺血和早期再灌注阶段，通过微透析电极测量细胞外空间中的实时谷氨酸水平。最后，通过脑电波频谱分析比较在对照和缺血期获得的脑电图。测试了十分钟的局部缺血。结果表明，从缺血发作到缺血高原所经历的时间在11VO（12-16秒）期间比4VO（72-155秒）更快。 11VO（4–5％）期间的脑血流平均水平低于4VO（13–15％）期间的平均血流水平。同时，11VO（138μM，4VO（257μM）期间，组织间谷氨酸的峰值浓度升高幅度较小，CT（137μM）后的谷氨酸峰值水平也明显低于4VO。 CT后11VO和10分钟，在再灌注的前90秒内，在12只动物中的7只中，谷氨酸水平上升到第二个更高的峰值（315μM），在再灌注后谷氨酸恢复正常所需的时间更快11VO（157 sec）比4VO（547 sec）。最后，脑电波频谱分析显示δ 1 ，[δ 1 +δ 1 < / sub>]和11VO的[δ 1 +δ 2 +θ]显着低于4VO动物（δ 1 = 40％vs 74％; [δ 1 +δ 2 ] = 47％vs 82％; [δ 1 +δ< sub> 2 +＆thetas;] = 51％vs 84％.；总而言之，11VO达到的深度，可逆性缺血水平要快于du响4VO。 4VO模型，无需放血，可产生脑缺血的低血流状态（占对照的13-15％）。透析电极提供实时证据，证明在脑缺血的低流量状态下，组织间隙中的谷氨酸水平升高。谷氨酸瞬变在再灌注的前90秒内发生，并且在缺血期间记录的谷氨酸水平是文献中最高的。与11VO相比，低流量状态的谷氨酸标准化还需要更长的再灌注时间。最后，由快速傅里叶变换确定的4VO比11VO产生更大的慢波功率。因此，大鼠脑缺血的低流量状态（13–15％）可能比完全没有流量对大鼠的大脑更大。

著录项

  • 作者

    Caragine, Louis Phillip, Jr.;

  • 作者单位

    Wayne State University.;

  • 授予单位 Wayne State University.;
  • 学科 Biology Neuroscience.; Health Sciences Pathology.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 167 p.
  • 总页数 167
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 神经科学;病理学;
  • 关键词

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