Thaminy S, Bellissant E, Maginn M, Decombe R, Allain H, Bentué-Ferrer D
Laboratoire de Pharmacologie, Faculté de Médecine, Rennes, France.
J Neurosci Methods. 1996 Dec 28;70(2):185-93. doi: 10.1016/s0165-0270(96)00117-3.
The effect of repeated transient global ischemia and microdialysis on changes in aminergic neurotransmitter release was investigated using the rat four-vessel occlusion model of global ischemia. To examine the possible transient or permanent changes in neurotransmitter release, ischemia was induced at varying time points in 5 groups of rats. The first ischemia occurred either 24 h (groups I, II, IV, V) or 96 h (group III) following vertebral artery electro-coagulation and guide probe implantation(s), and the second ischemia was induced either 48 h (groups I, IV, V) or 72 h (group II) following the first ischemia. To assess the consequence of repeated microdialysis on the results, one group of rats (group IV) was not dialysed during the first ischemia and another group (group V) was bilaterally dialysed during the second ischemia. Finally, amphetamine-induced neurotransmitter release was also studied in rats submitted to ischemia and compared with that in normal rats. In each case, dopamine, serotonin and their main metabolites were measured by HPLC with electrochemical detection. Monoamine release was inhibited during the second episode of transient ischemia; this non-release was linked to the repeated microdialysis and not to the repeated ischemia. Although the results of chronic studies using brain microdialysis have been widely recognized as valid, the findings presented here indicate that combined with ischemia, probe reinsertion modifies the level of neurotransmitter release.
利用大鼠全脑缺血四血管闭塞模型，研究了反复短暂性全脑缺血和微透析对胺能神经递质释放变化的影响。为了检测神经递质释放可能出现的短暂或永久性变化，在5组大鼠的不同时间点诱导缺血。第一次缺血发生在椎动脉电凝和引导探针植入后24小时（I、II、IV、V组）或96小时（III组），第二次缺血在第一次缺血后48小时（I、IV、V组）或72小时（II组）诱导。为了评估反复微透析对结果的影响，一组大鼠（IV组）在第一次缺血期间未进行透析，另一组大鼠（V组）在第二次缺血期间进行双侧透析。最后，还研究了缺血大鼠中苯丙胺诱导的神经递质释放，并与正常大鼠进行比较。在每种情况下，通过高效液相色谱电化学检测法测量多巴胺、5-羟色胺及其主要代谢产物。在短暂性缺血的第二次发作期间，单胺释放受到抑制；这种无释放与反复微透析有关，而与反复缺血无关。尽管使用脑微透析的慢性研究结果已被广泛认为是有效的，但此处呈现的研究结果表明，与缺血相结合，探针重新插入会改变神经递质释放水平。
