脑缺血再灌注时鼠脑纹状体区细胞外液半胱氨酸含量变化及丹…

目的动态观察脑缺血再灌注时鼠脑纹状体区细胞外液半胱氨酸（Ｃｙｓ）含量变化及丹参的影响，探讨Ｃｙｓ对缺血性神经元的损害作用，方法 应用脑内微透析技术，采用高灵敏度的液相色谱－电化学检测手段，动态观察沙土鼠前脑缺血３０分钟再灌注１２０分钟时，纹状体区细胞外液Ｃｙｓ的变化。结果前脑缺血３０分钟时，细胞外液Ｃｙｓ浓度迅速升高，达缺血前的１８倍。再灌注３０、６０分钟时，分别为缺血前的５倍和２倍，９０分钟时基     

脑缺血再灌注时鼠脑纹状体区细胞外液半胱氨酸含量变化及丹参的影响

目的动态观察脑缺血再灌注时鼠脑纹状体区细胞外液半胱氨酸（Ｃｙｓ）含量变化及丹参的影响，探讨Ｃｙｓ对缺血性神经元的损害作用。方法应用脑内微透析技术，采用高灵敏度的高压液相色谱－电化学检测手段，动态观察沙土鼠前脑缺血３０分钟再灌注１２０分钟时，纹状体区细胞外液Ｃｙｓ的变化。结果前脑缺血３０分钟时，细胞外液Ｃｙｓ浓度迅速升高，达缺血前的１８倍。再灌注３０、６０分钟时，分别为缺血前的５倍和２倍，９０分钟时基本恢复到缺血前的水平。丹参治疗组脑缺血时细胞外液Ｃｙｓ的含量较对照组低。结论Ｃｙｓ参与了脑缺血再灌注引起的损伤，而丹参可降低Ｃｙｓ水平，从而对缺血脑组织起到保护作用。     

巴曲酶对脑缺血再灌注细胞外液单胺类及其代谢产物的影响——微透析研究

目的巴曲酶对脑缺血再灌流损伤的保护机理。方法采用脑内微透析技术结合高灵敏度的高压液相色谱－电化学检测手段（ＨＰＬＣ－ＥＤ），测定前脑缺血３０ｍｉｎ再灌注１２０ｍｉｎ时的纹状体细胞外液（ＥＣＦ）的ＤＡ、５－ＨＴ和ＮＥ及其代谢产物（５－ＨＩＡＡ）和ＨＶＡ的变化和巴曲酶的影响。结果显示脑缺血时，ＥＣＦＤＡ、ＮＥ及５－ＨＴ明显升高，巴曲酶能显著地降低脑缺血时ＥＣＦＤＡ及再灌注时ＥＣＦＨＶＡ和５－ＨＩＡＡ的水平。结论巴曲酶影响单胺神经递质是对脑缺血再灌注损伤起保护作用的机理之一     

脑缺血再灌注脑内纹状体区细胞外液谷胱甘肽的动态变化及丹参的影响

采用脑内微透析技术，应用高压液相色谱电化学检测方法（ＨＰＬＣ－ＥＤ），活体动态观察沙土鼠全脑缺血３０分钟，再灌注１２０分钟的细胞外液中的谷胱甘肽（Ｇｌｕｔａｔｈｉｏｎｅ，ＧＳＨ）的变化及丹参对它的影响。结果显示：全脑缺血后，细胞外液ＧＳＨ水平迅速升高（Ｐ＜０．０１），缺血３０分钟达高峰为缺血前的５。８２倍。再灌注后ＧＳＨ水平明显降低，于３０分钟趋于正常。脑缺血前３０分钟给予丹参注射液不影响细胞外液ＧＳＨ水平。表明脑缺血及再灌注期，ＧＳＨ反应性增高。ＧＳＨ作为内源性抗氧化剂及ＮＭＤＡ受体拮抗剂在脑缺血损伤中起重要作用。     

巴曲酶对脑缺血再灌注细胞外液单胺类及其代谢产物的影响 …

目的 巴曲酶对脑缺血再灌流损伤的保护机理。方法 采用脑内微透析技术结合高灵敏度的高压液相色谱－电化学检测手段（ＨＰＬＣ－ＥＤ），测定前脑缺血３０ｍｉｎ再灌注１２０ｍｉｎ时的纹状体细胞外液（ＥＣＦ）的ＤＡ、５－ＨＴ和ＮＥ及其代谢产物（５－ＨＩＡＡ）和ＨＶＡ的变化和巴曲酶的影响。结果 显示脑缺血时，ＥＣＦ ＤＡ、ＮＥ及５－ＨＴ明显升高，巴曲酶能显著地降低脑缺血时ＥＣＦ ＤＡ及再灌注时ＥＣＦ ＨＶＡ和５     

脑缺血纹状体细胞外液单胺类介质及其代谢物的微透析研究

目的观察脑缺血再灌注时鼠脑纹状体区细胞外液（ＥＣＦ）多巴胺（ＤＡ）、去甲肾上腺素（ＮＥ）、５－羟色胺（５－ＨＴ）及其代谢产物高香草酸（ＨＶＡ）和５－羟吲哚乙酸（５－ＨＩＡＡ）的动态变化。方法采用脑内微透析技术，用高压液相色谱测定了前脑缺血３０ｍｉｎ、再灌注１２０ｍｉｎ时ＥＣＦＤＡ、ＮＥ和５－ＨＴ的变化。结果脑缺血１０ｍｉｎ时ＥＣＦＤＡ、ＮＥ迅速升高为缺血前的２８２和９１４倍，持续整个缺血期，再灌注后迅速下降达缺血前水平。脑缺血期ＨＶＡ、５－ＨＩＡＡ迅速下降，在缺血３０ｍｉｎ时达缺血前的４５％和５２％，再灌注后升高并在再灌注后６０ｍｉｎ，９０ｍｉｎ达缺血前的１５０％、１１３％。结论单胺类介质代谢紊乱参与了缺血性神经元损害     

巴曲酶对大鼠大脑缺血及缺血再灌注ET1基因表达的影响

本实验采用大鼠急性脑缺血及缺血再灌注模型，研究巴曲酶对脑缺血及脑缺血再灌注时内皮素（ET1）基因表达的影响。用中大脑动脉（MCA）线检法大鼠模型，共12只，分为缺血组及缺血再灌注组（每组各6只），每组又分为巴曲酶组及盐水组（对照组）。缺血组在缺血后24h，再灌注组则在缺血1．5h及再灌注24h后用原位杂交，并采用IBHS图像分析系统研究ET1基因表达。发现巴曲酶组或对照组手术侧大脑皮质及尾壳核ET1mRNA表达均显著高于对侧（非手术侧）。但是巴曲酶组手术侧的ET1mRNA表达显著低于对照组。结果提示，巴曲酸可使缺血及缺血再灌注ET1基因表达下调。这可能是巴曲酶对缺血再灌注的脑保护作用机理之一。     

脑缺血再灌注脑内纹状体区细胞外液浴胱甘肽的动态变化及丹参的…

采用脑内微透析技术，应用高压液相色谱电化学检测方法（ＨＰＬＣ－ＥＤ），活体动态观察沙土鼠全脑缺血３０分钟，再灌注１２０分钟的细胞外液中谷胱甘肽（Ｇｌｕｔａｔｈｉｏｎｅ，ＧＳＨ）的变化及丹参对它的影响，结果显示：全脑缺血后，细胞外液ＧＳＨ水平迅速升高（Ｐ〈０．０１），缺知３０分钟达高峰为缺血前的５。８２倍，再灌注后ＧＳＨ水平明显降低，于３０分钟趋于正常，脑缺血前３０分钟给予丹参注射液不影响细胞外液Ｇ     

鼠脑反复缺血时纹状体单胺类递质的变化

目的研究反复缺血再灌注鼠脑纹状体单胺类递质变化规律。方法用４血管夹闭的方法制成ＳＤ大鼠脑反复缺血模型，利用右侧纹状体活体透析和高压液相电化学方法检测单胺类递质及其代谢产物。结果缺血期间细胞外液多巴胺（ＤＡ）含量增加１００倍，５羟色胺（５ＨＴ）增高３０倍，它们的代谢产物３，４－二羟苯乙酸、高香草酸、５羟吲哚乙酸分别降为基础值的９％、２０％和５％。灌注１２０分钟时，ＤＡ、５ＨＴ及其代谢产物均恢复到基础值水平。灌注２４小时，ＤＡ、５ＨＴ及其酸性代谢产物仍稳定在基础值水平。灌注３５小时，ＤＡ和５ＨＴ再次出现高峰，ＤＡ增加１２０倍，５ＨＴ增加３６倍，而它们的酸性代谢产物却降至最低点。灌注３８小时，ＤＡ、５ＨＴ及其代谢产物都恢复到基础值水平。结论脑缺血再灌注，在缺血即刻和再灌注３５小时ＤＡ和５ＨＴ两次过量释放，引发ｃＡＭＰ瀑布反应，激发自由基产生，与兴奋性氨基酸共同作用，是导致纹状体神经元缺血死亡的重要原因     

大鼠脑缺血后脑组织中一氧化氮的变化

本文采用荧光法测定了完全性脑缺血大鼠部分脑区一氧化氮（ＮＯ）代谢产物亚硝酸盐的变化。结果发现，脑缺血后，在大脑皮层、海马及纹状体，均有亚硝酸盐含量的明显升高，以缺血后１０分钟最高，３０分钟时已开始下降，６０分钟时降至正常水平；进一步证实在脑缺血早期具有ＮＯ的急剧升高，其病理生理意义值得进一步研究。     

巴曲酶的神经保护作用—缺血再灌注后不同时程热休克蛋白70及病理组织学变化的相关性研究

本文研究目的为巴曲酶是否影响热休克蛋白起到神经保护作用。用中大脑动脉(MCA)线栓法缺血再灌注大鼠模型。Wistar大鼠共51只。发现:在再灌注1h、2h、3h对照组与巴曲酶组(8BU/kg ip)HSP70均呈轻度表达,从再灌注12h起表达显著,至再灌注后24h达高峰,至再灌注后6d仅见于坏死灶周围,至再灌注后14d恢复至假手术组水平。巴曲酶组的HSP70表达变化在时程上与对照组一致,但在再灌注12h起至6d较对照组显著,同时相应时间点的MCA血供区皮层神经细胞有缺血变性者巴曲酶组少而轻。本文结果提示巴曲酶的神经保护作用,可能与它能影响HSP70蛋白合成的调控机制有关。     

电刺激一侧颈上神经节后家兔海马CA1区腺苷及其代谢物含量的变化

脑缺血由电刺激家兔一侧颈上神经节诱发。腺苷（Adenosine,Ado）及其代谢物在两侧海马CA1区细胞外的含量采用在体微透析技术结合高效液相色谱法（HPLC）监测。伴随着电刺激，在与刺激同侧的海马CA1区细胞外，腺苷、肌苷（Inosine，Ino）和次黄嘌吟（Hypoxanthine,Hyp）的含量分别显著性地提高了6．5倍(Ado）、4．5倍（Ino）和2．3倍（Hyp）（P＜0．05），而黄嘌呤（Xanthine,Xan）的含量在刺激期间没有改变，但停止刺激后暂时性地上升了3.3倍（P＜0．05）。这些结果与我们先前报道的电生理学及病理学结果相一致。本结果表明，腺苷可能是在脑缺血的早期起神经保护作用，而伴随黄嘌呤形成过程所产生的有害自由基离子，可能对这一不完全脑缺血模型缺血后脑损伤的形成是重要的。     

Adenosine release and changes in pial arteriolar diameter during transient cerebral ischemia and reperfusion

We utilized the closed cranial window technique in the anesthetized rat to determine changes in CSF concentrations of adenosine, inosine, and hypoxanthine and pial arteriolar diameter during transient (20 min) forebrain ischemia and reperfusion. After mock CSF under the cranial window was allowed to equilibrate with cerebral interstitial fluid, endogenous adenosine concentration was found to be 0.16 +/- 0.05 microM, while inosine and hypoxanthine were 0.35 +/- 0.17 and 1.23 +/- 0.47 microM, respectively. The concentration of adenosine in CSF increased 4.2-fold during ischemia and 13.8-fold during the first 5 min of reperfusion. Inosine and hypoxanthine concentrations were also significantly increased during ischemia and reperfusion. After 1 h of reperfusion, CSF adenosine and inosine levels had decreased from peak value but remained significantly above preischemic values. In contrast, hypoxanthine remained at peak concentrations even after 60 min of reperfusion. Preischemic arteriolar diameter was 42.6 +/- 11.3 microns and was not significantly changed after 20 min of ischemia. However, during the first 5 min of reperfusion, arteriolar diameter increased significantly (p less than 0.05), coincident with peak adenosine concentrations. By 60 min of reperfusion, arteriolar diameter had returned to baseline. These results indicate that during the postischemic period, adenine nucleosides and hypoxanthine in CSF are elevated and could affect reperfusion.     

Extracellular increase of hypoxanthine and xanthine in the cortex and basal ganglia of fetal lambs during hypoxia-ischemia

A microdialysis procedure was used to sample purine catabolites from the extracellular compartment of two areas of the fetal brain, the cerebral cortex and the striatum region. Seven exteriorized, anesthetized fetal sheep were studied during conditions of normal oxygenation and during asphyxia induced by stepwise lowering of maternal placental perfusion pressure. Fetal cerebral blood flow (CBF) was measured with the 133Xe washout method. Somatosensory evoked potentials were recorded during tactile stimulation of the fetal snout. The purine catabolites hypoxanthine (HX), xanthine (Xan), guanosine (Gua), inosine (Ino) and adenosine (Ade) were measured in arterial and venous plasma and in the dialysate by a HPLC method. During gradually increasing asphyxia HX increased 4-6-fold both in cerebral tissue and in arterial plasma, while Xan rose 1.5-3 times in cerebral tissue and arterial plasma. Gua did not change in either tissue or blood and Ino did not rise until at the most extreme degree of asphyxia it rose 2-4-fold. Ade concentrations remained unaltered during moderate asphyxia (when CBF rose 3-fold), but demonstrated a significant (2-3-fold) augmentation at the most extreme degrees of asphyxia. The results thus suggests a significant accumulation of oxypurines, especially HX, in the interstitium of the fetal brain during asphyxia. The rise in xanthine concentration demonstrates the presence of an activity of xanthine oxidase in brain tissue. A discrepancy between the elevation of CBF and of the tissue concentration of Ade does not support a direct role of Ade in the asphyctic cerebral vasodilation in the fetus.     

Effect of dipyridamole on cerebral extracellular adenosine level in vivo

The effect of dipyridamole, an adenosine transport inhibitor, on cerebral extracellular adenosine concentration remains to be determined. To examine this issue, bilateral brain dialysis samples were obtained from piglet frontal cortex before, during, and after 5 min of cerebral ischemia; 10(-4) M dipyridamole was administered through one dialysis probe. On the control side, dialysate adenosine concentration increased 5.7-fold during ischemia and 15-fold during the first 5 min of reperfusion; it returned to control levels after 15 min of reperfusion. Relative to the control side, dipyridamole caused a twofold increase in basal dialysate adenosine concentration and increased dialysate adenosine concentration at 10 and 15 min of reperfusion, but no increase in dialysate adenosine occurred during and immediately after ischemia. The results indicate that, in the piglet brain, cerebral ischemia markedly elevates intracerebral extracellular adenosine concentration and that dipyridamole increases extracellular adenosine levels.     

Effects of hyperglycemia on the time course of changes in energy metabolism and pH during global cerebral ischemia and reperfusion in rats: correlation of 1H and 31P NMR spectroscopy with fatty acid and excitatory amino acid levels.

The effects of hyperglycemia on the time course of changes in cerebral energy metabolite concentrations and intracellular pH were measured by nuclear magnetic resonance (NMR) spectroscopy in rats subjected to temporary complete brain ischemia. Interleaved 31P and 1H NMR spectra were obtained every 5 min before, during, and for 2 h after a 30-min bilateral carotid occlusion preceded by permanent occlusion of the basilar artery. The findings were compared with free fatty acid and excitatory amino acid levels as well as with cations and water content in funnel-frozen brain specimens. One hour before occlusion, nine rats received 50% glucose (12 ml/kg i.p.) and five received 7% saline (12 ml/kg i.p.). Before ischemia, there were no differences in cerebral metabolite levels or pH between hyperglycemic rats and controls. During the carotid occlusion, the lactate/N-acetylaspartate (Lac/NAA) peak ratio was higher (0.73-1.48 vs. 0.56-0.82; p less than 0.05) and pH was lower (less than 6.0 vs. 6.45 +/- 0.05; p less than 0.05) in the hyperglycemic rats than in the controls. Phosphocreatine and adenosine triphosphate were totally depleted in both groups. Within 5-15 min after the onset of reperfusion, the Lac/NAA peak ratio increased further in all rats; however, only in extremely hyperglycemic rats (serum glucose greater than 960 mg/dl) did the lactic acidosis progress rather than recover later during reperfusion. Total free fatty acid and excitatory amino acid levels, but not cation concentration or water content, in brain correlated with serum glucose levels during and after ischemia and with NMR findings after 2 h of reperfusion. Although profound hyperglycemia (serum glucose of 970-1,650 mg/dl) appears to be associated with progression of anaerobic glycolysis and failure of cerebral energy metabolism to recover after temporary complete brain ischemia and with postischemic excitotoxic and lipolytic reactions thought to participate in delayed cellular injury, severe hyperglycemia (490-720 mg/dl) was associated with recovery of energy metabolism.     

Intracerebral adenosine infusion improves neurological outcome after transient focal ischemia in rats

Second Institute of New Drug Research, Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan In order to elucidate the role of adenosine in brain ischemia, the possible protective effects of adenosine on ischemic brain injury were investigated in a rat model of brain ischemia both in vitro and in vivo. Exogenous adenosine dose-dependently rescued cortical neuronal cells from injury after glucose deprivation in vitro. Adenosine (1 mM) also significantly reduced hypoglycemia/hypoxia-induced glutamate release from the hippocampal slice. In a rat model of transient middle cerebral artery occlusion (MCAO), extracellular adenosine concentration was increased immediately after occlusion, and then returned to the baseline by 30 min after reperfusion. Adenosine infusion through a microdialysis probe into the ipsilateral striatum (1 mM adenosine, 2 microl min(-1), total 4.5 h from the occlusion to 3 h after reperfusion) showed a significant improvement in the neurological outcome, and about 25% reduction of infarct volume, although the effect did not reach statistical significance, compared with the vehicle-treated group at 20 h after 90 min of MCAO. These results demonstrated the neuroprotective effect of adenosine against ischemic brain injury both in vitro and in vivo, suggesting the possible therapeutic application of adenosine regulating agents, which inhibit adenosine uptake or metabolism to enhance or maintain extracellular endogenous adenosine levels, for stroke treatment.