吡拉西坦抗短暂性局灶性脑缺血作用观察

目的 观察吡拉西坦的抗局灶性脑缺血作用。方法采用动脉腔内插线大鼠局灶性脑缺血模型及激光多普勒血流计测定半暗带脑血流、湿重-干重法测定缺血半球水含量、3％伊文氏蓝染色结合图像分析测定血脑屏障(BBB)的破坏、HE染色结合图像分析测定缺血后21h的梗死体积。结果100mg／kg体重吡拉西坦对半暗带脑血流无明显影响，200mg／kg体重吡拉西坦可明显升高再灌注期间半暗带脑血流；100mg／kg和200mg/kg体重的吡拉西坦均可明显降低局灶性脑缺血后缺血半球的水含量及BBB的损伤，缩小梗死体积。结论吡拉西坦具有明确的抗局灶性脑缺血作用，它可改善半暗带脑血流、减轻脑组织水肿和BBB的损伤、缩小梗死体积。     

大鼠脑出血后脑血流和脑水分含量变化的研究

研究大鼠脑出血后局部脑血流量（ｒＣＢＦ）与脑水分变化的规律及影响因素。用立体定向法自体血回注建立大鼠脑尾状核出血模型，分别在２４ｈ内不同时限用氢清除法测定ｒＣＢＦ，干湿重法测定脑水分含量，发现出血后１０ｍｉｎ同侧ｒＣＢＦ即下降，１ｈ达最低水平，出血量大时对侧半球也有明显下降；双侧脑水分含量均明显增加，其高峰期晚于ｒＣＢＦ的下降。说明脑出血后迅速出现广泛的低灌注和脑水肿     

去骨瓣减压术对大鼠局灶性脑缺血后脑水肿、血脑屏障、脑血流变化的影响

目的:观察去骨瓣减压术对局灶性脑缺血大鼠脑水肿、血脑屏障(BBB)及脑血流(CBF)的影响,探讨该手术对缺血性脑损害的保护机制。方法:改良Koizumi′s法制作脑缺血大鼠动物模型,脑缺血后6h行去骨瓣减压术,分别在术后3和7d观察脑水肿和血脑屏障的变化,另持续观察缺血1h 去骨瓣减压2h的CBF变化。结果:去骨瓣减压术后半暗区CBF增加更加持久和有效,在术后第3天时BBB破坏范围明显缩小,术后第7天时脑水含量明显降低。结论:去骨瓣减压术对局灶性脑缺血的保护作用可能与增加半暗区CBF、改善BBB破坏和减轻脑水肿有关。     

Influence of various agents on the development of brain edema in the rat following microembolism. Protective effect of gamma-butyrolactone

Brain edema was induced in rats by injecting 50 mu microspheres, labelled with 85Sr, into the internal carotid artery. The use of radioactive microspheres as embolic agents enabled the number of microspheres to be determined in each cerebral hemisphere. Edema was assessed 12 or 24 h after embolization by measuring brain water content and, in some experiments, sodium and potassium. Pretreatments with dexamethasone, parachlorophenylalanine (an inhibitor of 5-hydroxytryptamine synthesis), mepyramine and metiamide (H1 and H2 histamine receptor antagonists) or aminophylline did not influence significantly the development of brain edema evaluated 24 h after embolization. Aminophylline treatment (100 mg/kg) markedly increased mortality following embolization. Gamma-butyrolactone (300 mg/kg, every 2 h) inhibited significantly the development of brain edema evaluated 12 hours after embolization. Increases in water and sodium in the embolized cerebral hemisphere were reduced by about 50%. This protective effect may be related to the known depressant action on brain metabolism.     

Regional cerebral blood flow during spreading cortical depression in conscious rats

Spreading cortical depression (SCD) of EEG activity was induced in one cerebral hemisphere of conscious restrained rats by direct current stimulation of the lateral frontal cortex. Regional CBF was measured using [14C]iodoantipyrine and brain dissection. An early phase of increased CBF was not measured in conscious rats, but an early relative hyperperfusion was measured if the resting CBF was first reduced by treatment with pentobarbital or indomethacin. A long-lasting reduction in CBF was measured in conscious rats following the passage of SCD. This flow reduction resolved after 3 h. In conscious rats, CBF decreased in the striatum and thalamus ipsilateral to the SCD, paralleling the CBF changes occurring in the cortex. The CBF change in these deep structures was abolished by pentobarbital. An early transient increase in regional CBF was measured in the cerebral cortex contralateral to the hemisphere involved with SCD in conscious rats. This early contralateral hyperperfusion was also abolished by pentobarbital or indomethacin but not by atropine or propranolol. The vascular response to SCD in conscious rats differs from that which occurs in anesthetized rats.     

Impaired cerebral autoregulation 24 h after induction of transient unilateral focal ischaemia in the rat

Cerebral blood flow (CBF) and cerebral autoregulation have been investigated 24 h after transient focal ischaemia in the rat. Cerebral blood flow was measured autoradiographically before and during a moderate hypotensive challenge, to test autoregulatory responses, using two CBF tracers, (99m)Tc-d,l-hexamethylproyleneamine oxide and 14C-iodoantipyrine. Prior to induced hypotension, CBF was significantly reduced within areas of infarction; cortex (28 +/- 20 compared with 109 +/- 23 mL/100 g/min contralateral to ischaemic focus, P = 0.001) and caudate (57 +/- 31 compared with 141 +/- 32 mL/100 g/min contralaterally, P = 0.005). The hypotensive challenge (mean arterial pressure reduced to 60 mmHg by increasing halothane concentration) did not compromise grey matter autoregulation in the contralateral hemisphere; CBF data were not significantly different at normotension and during hypotension. However, in the ipsilateral hemisphere, a significant volume of cortex adjacent to the infarct, which exhibited normal flow at normotension, became oligaemic during the hypotensive challenge (e.g. frontal parietal cortex 109 +/- 15% to 65 +/- 15% of cerebellar flow, P < 0.01). This resulted in a 2.5-fold increase in the volume of cortex which fell below 50% cerebellar flow (39 +/- 34 to 97 +/- 46 mm3, P = 0.003). Moderate hypotension induced a significant reduction in CBF in both ipsilateral and contralateral subcortical white matter (P < 0.01). In peri-infarct caudate tissue, CBF was not significantly affected by hypotension. In conclusion, a significant volume of histologically normal cortex within the middle cerebral artery territory was found to have essentially normal levels of CBF but impaired autoregulatory function at 24 h post-ischaemia.     

Comparison of the effects of hypertonic glycerol and urea on brain edema, energy metabolism and blood flow following cerebral microembolism in the rat. Deleterious effect of glycerol treatment

Cerebral microembolism was performed in rats by injecting radioactive calibrated 50 mu microspheres into the left internal carotid artery. The use of radioactive microspheres as embolic agents enabled the number of microspheres to be determined in each cerebral hemisphere. Edema was assessed 24 h after embolization by measuring brain water, sodium, and potassium content. Equiosmolal doses (40 mmol/kg) of glycerol or urea were injected i.p. at various times before sacrifice. Both treatments caused similar changes in water and electrolyte content, brain dehydration being maximal 30 min after urea and 2 h after glycerol injection. Cerebral energy metabolism and regional blood flow were evaluated at the times of maximal brain dehydration. Urea treatment resulted in an improvement of the cerebral circulation whereas glycerol treatment led to a deterioration of cerebral blood flow which cannot be explained by failure to reduce edema and the consequent microcirculatory impairment. Urea treatment had no marked effect on cerebral energy metabolism whereas glycerol injection resulted in an important increase in brain lactate level which may be relevant to the impairment of cerebral reperfusion. These results point out that administration of a metabolized solute like glycerol may exert deleterious effects on the ischemic brain.     

Magnetic resonance imaging of regional hemodynamic and cerebrovascular recovery after lateral fluid-percussion brain injury in rats

Hemodynamic and cerebrovascular factors are crucially involved in secondary damage after traumatic brain injury (TBI). With magnetic resonance imaging, this study aimed to quantify regional cerebral blood flow (CBF) by arterial spin labeling and cerebral blood volume by using an intravascular contrast agent, during 14 days after lateral fluid-percussion injury (LFPI) in rats. Immunohistochemical analysis of vessel density was used to evaluate the contribution of vascular damage. Results show widespread ipsilateral and contralateral hypoperfusion, including both the cortex and the hippocampus bilaterally, as well as the ipsilateral thalamus. Hemodynamic unrest may partly be explained by an increase in blood vessel density over a period of 2 weeks in the ipsilateral hippocampus and perilesional cortex. Furthermore, three phases of perilesional alterations in CBF, progressing from hypoperfusion to normal and back to hypoperfusion within 2 weeks were shown for the first time in a rat TBI model. These three phases were similar to hemodynamic fluctuations reported in TBI patients. This makes it feasible to use LFPI in rats to study mechanisms behind hemodynamic changes and to explore novel therapeutic approaches for secondary brain damage after TBI.     

Catecholamine levels and turnover during brain ischemia in the rat

Summary Unilateral brain ischemia was induced in the rat by injecting radioactive microspheres into the left internal carotid artery. The microspheres were mainly distributed in the left cerebral hemisphere which contained 8 to 10 times more microspheres than the contralateral hemisphere. Embolization caused dopamine (DA) and noradrenaline (NA) depletion only in the left hemisphere. NA levels were already reduced 2 hours after injury while DA was still unaltered after 6 hours. A 30–40% depletion was observed for the two amines after 24 hours. Catecholamine turnover was estimated by measuring the amine depletion after synthesis inhibition with-methyl-p-tyrosine. During the first 2 hours following embolization, DA and NA depletions were slightly increased only in the left hemisphere, indicating an increase in Catecholamine efflux. At time 24 hours, an important retardation in amine disappearance after synthesis inhibition was found for DA and NA in the left hemisphere and to a lesser extent for DA in the right hemisphere, suggesting a reduction of the physiological activity of catecholaminergic neurons. These biochemical alterations can be related to the post-stroke behavioural changes of the embolized animals which exhibited an initially increased motor activity followed by a lethargic state.     

Chronic hyperperfusion and angiogenesis follow subacute hypoperfusion in the thalamus of rats with focal cerebral ischemia

Cerebral blood flow (CBF) is disrupted after focal ischemia in rats. We examined long-term hemodynamic and cerebrovascular changes in the rat thalamus after focal cerebral ischemia. Cerebral blood flow quantified by arterial spin labeling magnetic resonance imaging was decreased in the ipsilateral and contralateral thalamus 2 days after cerebral ischemia. Partial thalamic CBF recovery occurred by day 7, then the ipsilateral thalamus was chronically hyperperfused at 30 days and 3 months compared with its contralateral side. This contrasted with permanent hypoperfusion in the ipsilateral cortex. Angiogenesis was indicated by endothelial cell (RECA-1) immunohistochemistry that showed increased blood vessel branching in the ipsilateral thalamus at the end of the 3-month follow-up. Only transient thalamic IgG extravasation was observed, indicating that the blood–brain barrier was intact after day 2. Angiogenesis was preceded by transiently altered expression levels of cadherin family adhesion molecules, cadherin-7, protocadherin-1, and protocadherin-17. In conclusion, thalamic pathology after focal cerebral ischemia involved long-term hemodynamic changes and angiogenesis preceded by altered expression of vascular adhesion factors. Postischemic angiogenesis in the thalamus represents a novel type of remote plasticity, which may support removal of necrotic brain tissue and aid functional recovery.     

实验性脑出血血肿周围血流量变化的研究

目的　建立实验性脑出血的动物模型 ,探讨血肿周围的脑血流量变化。方法　采用犬脑内缓慢注入非肝素化自体血的方法建立实验性脑出血动物模型。用 1 4C- iodoantipyrine微示踪技术测定实验性脑出血 6 h、2 4 h、72 h血肿周围皮质、白质及对侧相应部位的脑血流量。结果　注血 6 h组、2 4 h组血肿周围白质的 CBF与对照组相比有所下降 ,但无统计学差异 ;而注血 72 h组血肿周围白质的 CBF较对照组降低了 19.8% (P<0 .0 5 ) ;注血 72 h组血肿对侧相应部位白质的 CBF较对照组升高了 14 .8% (P<0 .0 5 )。结论　犬脑内缓慢注入非肝素化自体血可建立可靠、重复性好的实验性 ICH动物模型 ,脑出血后 72 h,血肿周围白质的血流量下降 ,脑出血早期的脑损伤非缺血所致。     

Herpes zoster ophthalmicus with cerebral angiitis and reduced cerebral blood flow

Two patients with herpes zoster ophthalmicus (HZO) who experienced a delayed contralateral hemiparesis, the so-called crossed zoster syndrome, are described. Particular emphasis is paid to the cerebral blood flow (CBF) findings studied with the Xenon-133 inhalation technique using single photon emission computed tomography (SPECT). In a 40-year-old female with right-sided hemiparesis, angiography showed multiple segmental narrowings of the intracerebral arteries. Cerebral computer tomography (CT) scans were normal. The CBF studied 11 months after the HZO showed a generalized reduction of flow which, however, was more pronounced in the left hemisphere. On re-examination 8 months later both the mean hemispheric flow and regional CBF (rCBF) had increased to normal values. In a 66-year-old male with dysphasia and right-sided hemiparesis, cerebral CT scans demonstrated two small deep left-sided infarcts. CBF examination showed a generalized reduction of flow in the left hemisphere. The flow was slightly increased on re-examination 12 months later. These findings suggest that the Xenon-133 inhalation method represents a useful way to demonstrate the CBF pattern in this group of patients.     

Quantitative EEG alterations after isovolemic-hemodilutional augmentation of cerebral perfusion in stroke patients

Eleven patients with ischemic neurologic deficits in the middle cerebral arterial (MCA) territory and ipsilateral slowing on initial EEG underwent venesection and equal volume replacement with intravenous 5% human serum albumin. As the mean hematocrit was reduced by 19%, the mean cerebral blood flow (CBF) in the MCA territory of the affected and contralateral hemisphere determined by the 133Xenon inhalation technique increased 18 and 21%, respectively. Similarly, CBF in the contralateral occipital region increased 17%. The percentage total slow-wave EEG activity (fractional sum of theta and delta activity, 1.0 to 7.5 Hz) determined by fourier analysis was reduced significantly in the affected MCA territory and in the contralateral occipital region within 1 to 2 hours after isovolemic hemodilution. Using quantitative EEG analysis, rapid improvement in background EEG activity can be demonstrated following the diffuse elevation in CBF by hemodilution.     

Effect of the NMDA antagonist MK-801 on local cerebral blood flow in focal cerebral ischaemia in the rat

The effects of MK-801 upon local CBF after permanent middle cerebral artery (MCA) occlusion have been examined using [14C]iodoantipyrine autoradiography in halothane-anaesthetised rats. MK-801 (0.5 mg kg-1 i.v.) or saline was administered 30 min before MCA occlusion and CBF measured approximately 40 min after occlusion. In the hemisphere contralateral to the occluded MCA, MK-801 significantly reduced local CBF in 19 of the 22 regions examined from the levels in saline-treated rats. In the contralateral hemisphere, after treatment with MK-801, blood flow was reduced by an average of 37% with little variation in the magnitude of the reductions in different regions. In the hemisphere ipsilateral to MCA occlusion, MK-801 reduced CBF in almost every region located outside the territory of the occluded MCA. Within the territory of the occluded MCA, blood flow in the MK-801-treated rat did not significantly differ from values in vehicle-treated rats in any of the five cortical areas examined, although in the caudate nucleus there was a tendency for CBF to be lower in rats pretreated with MK-801. MK-801 had no effect on the amount of hypoperfused cerebral tissue (CBF less than 30 ml 100 g-1 min-1) in the ipsilateral hemisphere at any coronal plane examined; e.g., at coronal plane anterior 7.2 mm, 51 +/- 5% of the hemisphere displayed CBF of less than 30 ml 100 g-1 min-1 in saline-treated rats with MCA occlusion compared with 52 +/- 8% of the hemisphere in rats treated with MK-801 prior to MCA occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regional cerebral blood flow during hypoxia-ischemia in immature rats

Immature rats subjected to a combination of unilateral common carotid artery ligation and hypoxia sustain brain damage confined largely to the ipsilateral cerebral hemisphere. To ascertain the extent and distribution of ischemic alterations in the brains of these small animals, we modified the Sakurada technique to measure regional cerebral blood flow using carbon-14 autoradiography. Seven-day-old rats underwent right common carotid artery ligation following which they were rendered hypoxic with 8% O2 at 37 degrees C. Before and during hypoxia, the rat pups received an injection of iodo[14C]antipyrine for determination of regional cerebral blood flow. Blood flows to individual structures of the ipsilateral cerebral hemisphere were not influenced by arterial occlusion alone; flows to the contralateral hemisphere and to the brainstem and cerebellum actually increased by 25-50%. Hypoxia-ischemia was associated with decreases in regional cerebral blood flow of the ipsilateral hemisphere such that by 2 hours, flows to subcortical white matter, neocortex, striatum, and thalamus were 15, 17, 34, and 41% of control, respectively. The hierarchy of the blood flow reductions correlated closely with the distribution and extent of ischemic neuronal necrosis. However, unlike the pathologic pattern of this model, the degree of ischemia appeared homogeneous within each brain region. Blood flows to contralateral cerebral hemispheric structures were relatively unchanged from prehypoxic values, whereas flows to the brainstem and cerebellum nearly doubled and tripled, respectively. Thus, ischemia is the predominant factor that determines the topography of tissue injury to major regions of immature rat brain, whereas metabolic factors (intrinsic vulnerability) may influence the heterogeneous pattern of damage seen within individual structures.     

Effect of the kappa-1 opioid agonist CI-977 on ischemic brain damage and cerebral blood flow after middle cerebral artery occlusion in the rat

The effects of the kappa-1 opioid agonist CI-977 upon the volume of ischemic brain damage (defined using quantitative neuropathology) and local cerebral blood flow (CBF) (defined using quantitative [¹⁴C]iodoantipyrine autoradiography) have been examined at 4 h and 30 min, respectively, after permanent middle cerebral artery (MCA) occlusion in halothane-anesthetised rats. Treatment with CI-977 (0.3 mg/kg, s.c.) 30 min before and 30 min after occlusion of the MCA reduced the volume of infarction in the cerebral hemisphere (reduced by 27% when compared to vehicle;P<0.05) and cerebral cortex (reduced by 32%;P<0.05), despite a marked and sustained hypotension, with only minimal effect on damage in the caudate nucleus. In the hemisphere contralateral to the occluded MCA, treatment with CI-977 (0.3 mg/kg, s.c.) 30 min prior to the induction of ischemia failed to demonstrate any significant effect on either the level of local CBF in any of the 25 regions examined or on the volume of low CBF determined by frequency distribution analysis. In the hemisphere ipsilateral to MCA occlusion, CI-977 failed to produce statistically significant alterations in either the level of local CBF in 23 of the 25 regions or on the volume of low CBF, but areas of hyperemia were observed in both the medial caudate nucleus and lateral thalamus (local CBF increased by 65% and 86%, respectively, when compared to vehicle). The results of the present study indicate that the kappa-1 opioid agonist CI-977 is neuroprotective in a rat model of focal cerebral ischemia where key physiological variables have been assessed throughout the entire post-ischemic period, and fail to demonstrate that the neuroprotective effects of CI-977 in this model are due to improved blood flow to ischemic tissue.     

MRI assessment of cerebral blood flow after experimental traumatic brain injury combined with hemorrhagic shock in mice

Secondary insults such as hypotension or hemorrhagic shock (HS) can greatly worsen outcome after traumatic brain injury (TBI). We recently developed a mouse combined injury model of TBI and HS using a controlled cortical impact (CCI) model and showed that 90 minutes of HS can exacerbate neuronal death in hippocampus beneath the contusion. This combined injury model has three clinically relevant phases, a shock, pre hospital, and definitive care phases. Mice were randomly assigned to four groups, shams as well as a CCI only, an HS only, and a CCI+HS groups. The CCI and HS reduced cerebral blood flow (CBF) in multiple regions of interest (ROIs) in the hemisphere ipsilateral and contralateral to injury. Hemorrhagic shock to a level of ∼30 mm Hg exacerbated the CCI-induced CBF reductions in multiple ROIs ipsilateral to injury (hemisphere and thalamus) and in the hemisphere contralateral to injury (hemisphere, thalamus, hippocampus, and cortex, all P<0.05 versus CCI only, HS only or both). An important effect of HS duration was also seen after CCI with maximal CBF reduction seen at 90 minutes (P<0.0001 group-time effect in ipsilateral hippocampus). Given that neuronal death in hippocampus is exacerbated by 90 minutes of HS in this model, our data suggest an important role for exacerbation of posttraumatic ischemia in mediating the secondary injury in CCI plus HS. In conclusion, the serial, non invasive assessment of CBF using ASL-MRI (magnetic resonance imaging with arterial spin labeling) is feasible in mice even in the complex setting of combined CCI+HS. The impact of resuscitation therapies and various mutant mouse strains on CBF and other outcomes merits investigation in this model.     

Thrombolysis with tissue plasminogen activator alters adhesion molecule expression in the ischemic rat brain

BACKGROUND AND PURPOSE: We tested the hypothesis that treatment of embolic stroke with recombinant human tissue plasminogen activator (rhtPA) alters cerebral expression of adhesion molecules. METHODS: Male Wistar rats were subjected to middle cerebral artery occlusion by a single fibrin-rich clot. P-selectin, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) immunoreactivity was measured at 6 or 24 hours after embolic stroke in control rats and in rats treated with rhtPA at 1 or 4 hours after stroke. To examine the therapeutic efficacy of combined rhtPA and anti-ICAM-1 antibody treatment at 4 hours after embolization, ischemic lesion volumes were measured in rats treated with rhtPA alone, rats treated with rhtPA and anti-ICAM-1 antibody, and nontreated rats. RESULTS: Administration of rhtPA at 1 hour after embolization resulted in a significant reduction of adhesion molecule vascular immunoreactivity after embolization in the ipsilateral hemisphere compared with corresponding control rats. However, when rhtPA was administered to rats at 4 hours after embolization, significant increases of adhesion molecule immunoreactivity in the ipsilateral hemisphere were detected. A significant increase of ICAM-1 immunoreactivity was also detected in the contralateral hemisphere at 24 hours after ischemia. A significant reduction in lesion volume was found in rats treated with the combination of rhtPA and anti-ICAM-1 antibody compared with rats treated only with rhtPA. CONCLUSIONS: The present study suggests that the time of initiation of thrombolytic therapy alters vascular immunoreactivity of inflammatory adhesion molecules in the ischemic brain and that therapeutic benefit can be obtained by combining rhtPA and anti-ICAM-1 antibody treatment 4 hours after stroke.     

Streptokinase treatment versus calcium overload blockade in experimental thromboembolic stroke

Thromboembolic brain ischemia was produced in dogs using an autologous blood clot model. The effect of postembolic treatment with flunarizine and streptokinase on hemispheric cerebral metabolic rate for oxygen (CMRO2), oxygen extraction ratio (OER), and cerebral blood flow (CBF) was studied by positron emission tomography (oxygen-15 technique) 24 hours after the insult. We studied five groups of experimental dogs and compared them with a control group of nonembolized dogs. Group I received no treatment, Group II was treated locally with 500,000 IU streptokinase starting 30 minutes after the insult, Group III received streptokinase locally 30 minutes after the insult and 0.1 mg/kg i.v. flunarizine immediately after the insult and 2 hours later, Group IV received flunarizine as Group III, and Group V was orally pretreated with 0.5 mg/kg/day flunarizine during 2 weeks preceding embolization. Compared with the contralateral hemisphere, in the embolized hemisphere a significant reduction of CMRO2 (-25% to -40%) and CBF in normocapnia (-35%) and hypercapnia (-50%) was observed in Groups I, II, and V. In Groups III and IV, CMRO2, OER, and CBF of the embolized hemisphere were within the normal range during normocapnia and hypercapnia; the extent of the ischemic lesions was markedly less than in the other groups of experimental dogs. We conclude that flunarizine treatment after experimental thromboembolic stroke had a favorable influence on brain tissue. Chronic preventive flunarizine treatment failed to have a beneficial effect.     

Effects of prostacyclin analogue iloprost on the regional cerebral blood flow in transplanted rat brain tumour

Abstract

We studied the effect of intracarotid administration of prostacyclin analogue iloprost on the regional cerebral blood flow in transplanted rat C6 glioma by the hydrogen clearance method. Iloprost at doses of 0.1 and 0.5 μg/kg/min produced a selective increase of the regional cerebral blood flow in the tumour (17.8 ± 5.6%, p < 0.05 and 27.3 ± 10.3%, p < 0.05, respectively) without significant change of the regional cerebral blood flow in the ipsilateral hemisphere and the systemic arterial pressure. At a dose of 1 μg/kg/min, iloprost produced a significant reduction of a systemic blood pressure, but did not change the regional cerebral blood flow significantly both in the tumour and the ipsilateral hemisphere. These results indicated that brain tumour vessels could respond to iloprost in a different fashion from the normal brain capillaries. The selective action of iloprost to the tumour vessels might contribute to the drug-delivery in malignant brain tumour. [Neurol Res 1993; 15: 401-404]