新生大鼠缺血缺氧性脑病时脑微循环血流及一氧化氮的变化

目的：探讨脑微循环血流及一氧化氮（NO）在新生大鼠缺血缺氧性脑病（HIE）时的变化。方法：结扎新生大鼠右侧颈总动脉，观察脑微循环血流量、脑组织含水量、NO、丙二醛（MDA）含量的变化。结果：新生大鼠HIE动物有明显的左侧偏瘫等行为障碍，肉眼观察脑组织变白，脑微循环血流量（2 h、第2 d、第4 d）明显低于对照组（P<0.01）；脑组织含水量（2 h、第2 d）明显高于对照组（P<0.01）；NO及MDA含量（2 h、第2 d、第4 d）明显多于对照组（P<0.01或P<0.05）。结论：新生大鼠HIE时脑微循环血流量减少、NO含量及脂质过氧化的代谢产物MDA含量增高。     

葛根素对小鼠脑微循环血流量的影响

为了观察静脉注射葛根素对小鼠脑微循环的影响，应用ＪＩ ２００型激光微循环动态分析仪直接记录脑微循环血流量的变化。结果表明，正常小鼠静脉注射葛根素（０．２ｍｇ／ｋｇ）３ｍｉｎ后，脑微循环血流量显著增加（Ｐ＜０．０５），且持续３０ｍｉｎ；提高葛根素剂量（２ｍｇ／ｋｇ），其效应加强且持续６０ｍｉｎ。高分子右旋糖酐所致脑微循环障碍小鼠静脉注射葛根素后，脑微循环血流量有改善，但作用较弱。结果提示，葛根素可增加正常小鼠脑微循环血流量，改善脑微循环     

针刺对家兔脑微循环血流量的影响

采用颅骨开窗法，应用激光多普勒微循环血流仪观察了针刺家兔足三里、曲池、人中和内关穴对脑微循环血流量的影响。结果表明：针刺足三里、曲池穴可使正常家兔脑微循环血流量显著增加，足三里穴效应较强。提示针刺治疗缺血性脑血管疾病的机理之一是通过增加脑微循环血流量，改善脑微循环，从而加快缺血脑组织功能的恢复     

葛根素、川芎嗪、丹参注射液对大脑中动脉阻断大鼠脑微循环血流量的影响

目的应用闭合式颅骨开窗法，应用激光多普勒微循环血流仪，观察葛根素、川芎嗪、丹参注射液对脑微循环的影响。方法 Ｗｉｓｔａｒ大鼠 ５０只，腹腔注射 １％戊巴比妥钠 ４０ｍｇ／ｋｇ麻醉，将动物固定于大鼠立体定位仪上，于右侧领顶部用牙科钻钻开一直径为 ６×８ｍｍ大小的颅窗，彻底止血后，小心剪开硬脑膜，暴露软脑膜，玻璃及牙科水泥覆盖密闭，将激光多普勒微循环血流计的激光探头固定于颅窗上。之后动物取侧卧位固定，将右侧颈总动脉提起，结扎近心端，小心剪开颈总动脉，将一直径约０．３ｍｍ的尼龙线，穿入动脉，并同时观察激光多普勒微循环血流分析仪所显示的脑微循环血流量，穿到大脑中动脉时可出现微循环灌流量的突然下降，出现微循环血流量下降后，再向内穿入约１ｍｍ，然后将切口的远心端及动脉内的丝线牢固结扎，剪去多余丝线。实验结束后，查看尼龙线是否阻塞大脑中动脉的起始部，未阻塞动脉者实验数据作废。大鼠随机分为葛根素组、丹参注射液组、川芎嗪组、生理盐水组、空白对照组。结果阻断大脑中动脉后，供血区（额顶叶）脑微循环血流量迅速下降，并维持一较低水平，至阻断后５０ｍｉｎ脑微循环血流量才有所增加，但增加幅度较低．说明此ＭＣＡＯ模型是成功的。各用药组用药后脑微     

化学因素对脑微循环调节研究的若干进展

在生理和病理条件下，脑微循环受神经因素和化学因素调节脑微血管紧张度，控制脑微血管血流量，共同维持脑微循环内环境稳态。下面就影响脑微循环化学因素的国外若干研究进展综述如下。     

大鼠蛛网膜下腔出血脑微区血流量与血清一氧化氮变化

目的探讨蛛网膜下腔出血（ＳＡＨ）后继发性脑缺血损害及其一氧化氮（ＮＯ）的作用。方法应用非开颅性方法建立大鼠ＳＡＨ模型,检测２４ｈ内脑微区血流量和颅内血清ＮＯ的动态改变,并测量基底动脉（ＢＡ）管径。结果ＳＡＨ后脑微区血流量迅速降低,１ｈ达最低值,２４ｈ内无明显恢复趋势（Ｐ＜ ０．０１）。ＳＡＨ后１ｈ血清ＮＯ开始减低,井持续２４ｈ（Ｐ＜０．０１）。ＢＡ管径于ＳＡＨ后明显缩小（Ｐ＜０．０１）。结论ＳＡＨ时脑灌注压降低、脑血管痉挛及微循环异常均可能与脑血流量降低有关。ＮＯ减少是脑血管 痉挛和微循环异常发生的重要因素之一。     

大鼠脑慢性低灌注模型的研究进展

研究表明大鼠脑的低灌注模型可模拟人类脑血管疾病并作相关研究，而脑局部血流量的变化与脑血管疾病密切相关，本文阐述了慢性脑低灌注与脑局部血流变化的关系，总结了慢性脑低灌注模型和脑局部血流量检测方法的研究进展，探讨了大鼠脑慢性低灌注模型检测局部血流量变化的意义和应用前景。     

活体动物脑微循环实验研究方法

<正> 以往的脑微循环研究工作表明,人及其他哺乳动物脑实质内血管管径都在100μm以下,因此,测量脑内血流量以及脑内血管反应性的技术主要用于脑微血管床的研究。人们已经开发了研究脑微循环的许多技术和方法,如:N_2O法、氢清除法、放射自显影法、标记微球法及SPECT方法等。这些技术各有优点,但它们有着共同的不足,那就是无法直接观察脑微血管的行为(如:脑微血管管径、微血流速度、微血流量、微血管运动振幅、频率等)变化。     

肢体火器伤时脑微循环变化的特点

通过观察犬肢体火器伤时脑微循环的变化特点，发现肢体火器伤后脑微循环发生明显改变，犬脑组织血流量明显减少，脑微血管扩张，管径增大，导致脑组织缺血缺氧，从而引起脑组织水肿、颅内压增高等症状。因此，对肢体火器伤时，除对局部组织损伤的处理外，同时应注重远隔器官—脑的损伤。     

脑缺血大鼠脑血流量和微血管形态的定量分析

用生物微球法和图象分析法分别测量了大鼠脑缺血三小时和重灌流30分钟的脑血流量和脑微血管某些形态学参数。实验结果表明,重灌流后脑血流量只恢复到缺血前的80%,脑微血管壁增厚、管腔面积缩小。提示缺血后重灌流时脑微血管的这些变化是脑血流量不能完全恢复的一个原因。     

蝮蛇抗栓酶治疗缺血性脑血管病的甲襞微循环及血液流变性观察

对使用蝮蛇抗栓酶、维脑路通的缺血性脑血管病患者各５０例进行甲襞微循环和血液流变指标的检测。结果表明：蝮蛇抗栓酶组用药后，微循环和血液流变各项异常指标显著下降（Ｐ＜０．０１～０．０５）。而维脑路通对脑血栓的微循环障碍、血液粘度、β－脂蛋白、甘油三酯、血小板聚集等异常指标改善不大（Ｐ＞０．０５）。提示：蝮蛇抗栓酶是优于维脑路通的降粘药物。     

通塞益脑液治疗急性缺血性中风的微循环作用

对自制中药──＂通塞益脑液＂治疗急性缺血性中风２５例前后行甲襞微循环观察，并与低分子右旋糖酐加维脑路通治疗的同类患者２５例进行比较。结果发现：所有患者用药后，微循环均有明显改善，临床症状明显减轻（Ｐ＜０．０５），二组结果相似（Ｐ＞０．０５）。提示：该中药制剂与低分子右旋糖酐、维脑路通一样，均能有效治疗缺血性脑血管病。     

The Role of Adenosine in Regulation of Cerebral Blood Flow During Hypoxia in the Near-Term Fetal Sheep

The aim of this study was to determine in the near-term ovine fetus the role of adenosine in the basal regulation of cerebral blood flow and in the increases in cerebral blood flow in response to acute hypoxic insult. We measured cerebral blood flow in chronically instrumented fetal sheep (127-135 days gestation, term ≈145 days) using laser Doppler flowmetry probes implanted in the parietal cortices. Hypoxia was administered for 30 min by lowering the ewe's inspired oxygen to 10–12 % during an infusion of either saline or theophylline, a non-specific adenosine receptor antagonist. The theophylline infusion was begun 30 min prior to and ended 30 min after the completion of the hypoxic insult. The administration of theophylline had no significant effect on cerebral blood flow during the baseline period. During control hypoxic periods, cerebral blood flow increased by ≈45 %. During theophylline experiments, however, there was no significant increase in cerebral blood flow during hypoxia. In the control experiments, cerebral blood flow returned to baseline levels during the recovery period, while in the theophylline experiments cerebral blood flow fell below baseline levels. We conclude that, in the near-term ovine fetus, adenosine plays a minimal role in the regulation of basal cerebral blood flow. However, these data are strong evidence for the involvement of adenosine in increased fetal cerebral blood flow during an acute hypoxic insult. Finally, adenosine may also play an important role in the maintenance of fetal cerebral blood flow immediately following hypoxic insult.     

高压氧对脑缺血动物脑微循环及脑皮质血流量的影响

高压氧对脑缺血动物脑微循环及脑皮质血流量的影响１蔺世龙２刘景昌２冶建宏２近年来，国内外学者在缺血性脑损伤的研究方面进行了不少探讨，其中临床使用高压氧治疗缺血性脑损伤已经取得明显疗效［１］，同时对缺血性脑损伤机理的研究亦取得了有意义的结果［１～６］。本...     

Deficient adjustment of cerebral blood flow to cognitive activity due to chronically low blood pressure

The present study aimed to investigate aberrances in the adjustment of cerebral blood flow to cognitive activity due to chronically low blood pressure. By means of transcranial Doppler sonography blood flow velocities in both middle cerebral arteries (MCA) were recorded during the execution of a serial subtraction task in 40 subjects with constitutional hypotension and 40 normotensive control persons. Additionally, blood pressure was continuously monitored. As a main result significant correlations between the task-induced changes in blood pressure and those in MCA blood flow velocities were found in hypotensives, but not in control subjects. The dependence of the regulation of cerebral blood flow on blood pressure points towards deficits in cerebral autoregulation in hypotension. Over the total sample the extent of the task-induced MCA flow velocity increase was positively related to cognitive performance. This underlines the importance of the adjustment of cerebral blood flow to current demands for optimal cognitive functioning.     

Cerebral circulation: effect of stimulation and blockade of dopamine receptors.

The effects of stimulation and blockade of dopaminergic receptors on cerebral blood flow and metabolism were investigated in 15 anesthetized baboons. The intravenous administration of apomorphine resulted in immediate, dose-dependent increases in cerebral blood flow (increased by 58% following 0.1 mg/kg apomorphine) which were always accompanied by increases in cerebral oxygen consumption (increased by 36% with 0.1 mg/kg) and glucose uptake (increased by 72% with 0.1 mg/kg). It is suggested that the primary action of apomorphine is on cerebral metabolism and secondarily on cerebral blood flow rather than directly on cerebral vascular smooth muscle. Pimozide, at doses that totally blocked apomorphine-induced increases, was without effect on cerebral blood flow and metabolism. The dilatatory response of the cerebral circulation to hypercapnia was preserved during dopamine-receptor blockade. The basal level of overall cerebral metabolism and hemispheric cerebral blood flow does not appear to be dependent to any large extent on the activity of the dopaminergic pathways in the central nervous system.     

Cerebral Blood Flow and Oxygen Consumption in Rat,Measured with Microspheres or Xenon

The cerebral blood flow and, in some rats, the cerebral rate of oxygen consumption were measured in three groups of male rats. Fractionation of radioisotope-labeled microspheres was used to measure regional cerebral blood flow in four parts of the rat brain. The arterial and cerebral venous concentrations of radioactive xenon during desaturation were used to measure the blood flow and oxygen consumption of cortex when venous blood was collected from the superior sagittal sinus, or of whole brain when the transverse sinus was sampled. The regional cerebral blood flow measured with microspheres had a large standard error reflecting the technical difficulty of this method. The cerebral blood flow measured with xenon was higher when venous blood was sampled from the superior sagittal sinus than when sampled from the transverse sinus, but cerebral oxygen consumption rates were similar. The difference reflects the greater trauma involved in the superior sagittal approach and possible extracerebral contamination present in the transverse sinus approach.     

Measurement of cerebral blood flow in the fetal lamb with a note on the flow-distribution.

The cerebral blood flow was measured in the acutely exteriorized fetal lamb by 133Xenon washout and microsphere distribution techniques. The measurements were performed at different blood gas levels. Regional cerebral blood flow was calculated from the microsphere distribution for five different parts of the brain. This gave estimates for blood flow in both the grey and white matter of the hemispheres, which were in close agreement with the cerebral blood flow estimated by the 133Xe washout technique. The microsphere distribution shows that the fetal cerebral hemisphere has a low blood flow compared to the basel parts of the brain and that this difference is increased during hypoxia and hypercarbia.     

Cerebral blood flow and oxygen consumption in rat, measured with microspheres or xenon.

The cerebral blood flow and, in some rats, the cerebral rate of oxygen consumption were measured in three groups of male rats. Fractionation of radioisotope-labeled microspheres was used to measure regional cerebral blood flow in four parts of the rat brain. The arterial and cerebral venous concentrations of radioactive xenon during desaturation were used to measure the blood flow and oxygen consumption of cortex when venous blood was collected from the superior sagittal sinus, or of whole brain when the transverse sinus was sampled. The regional cerebral flow measured with microspheres had a large standard error reflecting the technical difficulty of this method. The cerebral blood flow measured with xenon was higher when venous blood was sampled from the superior sagittal sinus than when sampled from the transverse sinus, but cerebral oxygen consumption rates were similar. The difference reflects the greater trauma involved in the superior sagittal approach and possible extracerebral contamination present in the transverse sinus approach.     

急进高原人群脑血流量测定对急性高原病易感人群预测的临床与实验观察

本文对三级急进高原人群资料回顾分析了急进高海拔区（＞4500M）人群脑皿流量测定的临床意义。结果表明急进高原人群脑血流量较在低海拔区明显增高，有显著性差异；而急进高原人群中的急性高原反应和急性高原病患者脑血流量又显著高于高原适应人群。采用药物和吸氧治疗急进高原人群中急性高原反应人群，脑血流量明显降低，急进高原人群的高原反应程度和急性高原病的发病率亦相应降低。因此监测急进高原人群的脑血流量，不仅可以早期发现急性高原反应及急性高原病患者，更可以预测急性高原易感者，可为急性高原病的早期治疗和预防，扩大高原适应人群提供重要的理论依据。