RESUMEN
Sigma-1 receptor (S1R) is detected in different cell types and can regulate intracellular signaling pathways. S1R plays a role in the pathomechanism of diseases and the regulation of neurotransmitters. Fluvoxamine can bind to S1R and reduce the serotonin uptake of neurons and platelets. We therefore hypothesized that platelets express S1R, which can modify platelet function. The expression of the SIGMAR1 gene in rat platelets was examined with a reverse transcription polymerase chain reaction and a quantitative polymerase chain reaction. The receptor was also visualized by immunostaining and confocal laser scanning microscopy. The effect of S1R agonist PRE-084 on the eicosanoid synthesis of isolated rat platelets and ADP- and AA-induced platelet aggregation was examined. S1R was detected in rat platelets both at gene and protein levels. Pretreatment with PRE-084 of resting platelets induced elevation of eicosanoid synthesis. The rate of elevation in thromboxane B2 and prostaglandin D2 synthesis was similar, but the production of prostaglandin E2 was higher. The concentration-response curve showed a sigmoidal form. The most effective concentration of the agonist was 2 µM. PRE-084 increased the quantity of cyclooxygenase-1 as detected by ELISA. PRE-084 also elevated the ADP- and AA-induced platelet aggregation. S1R of platelets might regulate physiological or pathological functions.
Asunto(s)
Plaquetas , Agregación Plaquetaria , Adenosina Difosfato/farmacología , Animales , Plaquetas/metabolismo , Eicosanoides/metabolismo , Eicosanoides/farmacología , Humanos , Prostaglandinas/metabolismo , Prostaglandinas/farmacología , RatasRESUMEN
PURPOSE: Depleted uranium (DU) has several civilian and military applications. The effects of this emerging environmental pollutant on human health raise some concerns. Previous experimental studies have shown that uranium (U) exposure can disturb the central nervous system. A small quantity of U reaches the brain via the blood, but the effects on the blood-brain barrier (BBB) remain unclear. MATERIALS AND METHODS: In the present work, two cell culture models were exposed to DU for different times to study its cytotoxicity, paracellular permeability and extracellular concentration of U. The well-known immortalized human cerebral microvascular endothelial cells, hCMEC/D3, were cultured on the filter in the first model. In the second model, human primary cells of pericytes were cultured under the filter to understand the influence of cell environment after U exposure. RESULTS: The results show that U is not cytotoxic to hCMEC/D3 cells or pericytes until 500 µM (1.6 Bq.L-1). In addition, acute or chronic low-dose exposure of U did not disturb permeability and was conserved in both cell culture models. However, U is able to reach the brain compartment. During the first hours of exposure, the passage of U to the abluminal compartment was significantly reduced in the presence of pericytes. Electronic microscopy studies evidenced the formation of needlelike structures, like urchin-shaped precipitates, from 1 h of exposure. Analytical microscopy confirmed the U composition of these precipitates. Interestingly, precipitated U was detected only in endothelial cells and not in pericytes. U was localized in multilamellar or multivesicular bodies along the endo-lysosomal pathway, suggesting the involvement of these traffic vesicles in U sequestration and/or elimination. CONCLUSIONS: We show for the first time the in vitro passage of U across a human cerebral microvascular endothelial cells, and the intracellular localization of U precipitates without any cytotoxicity or modification of paracellular permeability. The difference between the results obtained with monolayers and co-culture models with pericytes illustrates the need to use complex in vitro models in order to mimic the neurovascular unit. Further in vivo studies should be performed to better understand the passage of U across the blood-brain barrier potentially involved in behavioral consequences.
Asunto(s)
Encéfalo/irrigación sanguínea , Células Endoteliales/metabolismo , Microvasos/citología , Uranio/metabolismo , Barrera Hematoencefálica/metabolismo , Línea Celular , Técnicas de Cocultivo , Células Endoteliales/efectos de la radiación , Espacio Extracelular/metabolismo , Espacio Extracelular/efectos de la radiación , Humanos , Permeabilidad , Factores de TiempoRESUMEN
BACKGROUND AND PURPOSE: The blood-brain barrier (BBB) restricts drug penetration to the brain preventing effective treatment of patients suffering from brain tumours. Intra-arterial injection of short-chain alkylglycerols (AGs) opens the BBB and increases delivery of molecules to rodent brain parenchyma in vivo. The mechanism underlying AG-mediated modification of BBB permeability is still unknown. Here, we have tested the effects of AGs on barrier properties of cultured brain microvascular endothelial cells. EXPERIMENTAL APPROACH: The effects of two AGs, 1-O-pentylglycerol and 2-O-hexyldiglycerol were examined using an in vitroâ BBB model consisting of primary cultures of rat brain endothelial cells, co-cultured with rat cerebral glial cells. Integrity of the paracellular, tight junction-based, permeation route was analysed by functional assays, immunostaining for junctional proteins, freeze-fracture electron microscopy, and analysis of claudin-claudin trans-interactions. KEY RESULTS: AG treatment (5 min) reversibly reduced transendothelial electrical resistance and increased BBB permeability for fluorescein accompanied by changes in cell morphology and immunostaining for claudin-5 and ß-catenin. These short-term changes were not accompanied by alterations of inter-endothelial tight junction strand complexity or the trans-interaction of claudin-5. CONCLUSION AND IMPLICATIONS: AG-mediated increase in brain endothelial paracellular permeability was short, reversible and did not affect tight junction strand complexity. Redistribution of junctional proteins and alterations in the cell shape indicate the involvement of the cytoskeleton in the action of AGs. These data confirm the results from in vivo studies in rodents characterizing AGs as adjuvants that transiently open the BBB.
Asunto(s)
Barrera Hematoencefálica/fisiología , Encéfalo/metabolismo , Claudina-5/farmacología , Células Endoteliales/metabolismo , Glicerol/análogos & derivados , Glicerol/farmacología , Uniones Estrechas/efectos de los fármacos , Animales , Barrera Hematoencefálica/ultraestructura , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Citoesqueleto , Células Endoteliales/efectos de los fármacos , Glicerol/farmacocinética , Células HEK293 , Humanos , Microscopía Electrónica de Transmisión , Permeabilidad/efectos de los fármacos , Ratas , Ratas WistarRESUMEN
One of the main difficulties with primary rat brain endothelial cell (RBEC) cultures is obtaining pure cultures. The variation in purity limits the achievement of in vitro models of the rat blood-brain barrier. As P-glycoprotein expression is known to be much higher in RBECs than in any contaminating cells, we have tested the effect of five P-glycoprotein substrates (vincristine, vinblastine, colchicine, puromycin and doxorubicin) on RBEC cultures, assuming that RBECs would resist the treatment with these toxic compounds whereas contaminating cells would not. Treatment with either 4 microg/mL puromycin for the first 2 days of culture or 3 microg/mL puromycin for the first 3 days showed the best results without causing toxicity to the cells. Transendothelial electrical resistance was significantly increased in cell monolayers treated with puromycin compared with untreated cell monolayers. When cocultured with astrocytes in the presence of cAMP, the puromycin-treated RBEC monolayer showed a highly reduced permeability to sodium fluorescein (down to 0.75 x 10(-6) cm/s) and a high electrical resistance (up to 500 Omega x cm(2)). In conclusion, this method of RBEC purification will allow the production of in vitro models of the rat blood-brain barrier for cellular and molecular biology studies as well as pharmacological investigations.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Endotelio Vascular/citología , Endotelio Vascular/efectos de los fármacos , Puromicina/farmacología , Animales , Barrera Hematoencefálica/citología , Barrera Hematoencefálica/metabolismo , Permeabilidad Capilar/efectos de los fármacos , Permeabilidad Capilar/fisiología , Técnicas de Cultivo de Célula/métodos , Separación Celular/métodos , Células Cultivadas , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Técnicas de Cocultivo/métodos , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Especificidad de Órganos/efectos de los fármacos , Especificidad de Órganos/fisiología , Puromicina/metabolismo , Ratas , Ratas WistarRESUMEN
Tight junctions (TJs) of the cerebral endothelial cells play a crucial role in the regulation of BBB permeability under physiological, as well as pathological conditions. The regulation of the junctional proteins is under a complex control. In these regulatory processes signalling molecules, some of them localized to the TJ, play an important role. Among the best characterized second messengers which regulate TJ function are the cyclic nucleotides, which, as shown in our experiments, as well, decrease paracellular permeability. Another important signalling molecule involved in TJ regulation is protein kinase C, which may affect differently the formation of TJ and the function of mature TJ. Further signalling molecules known to regulate paracellular permeability are G-proteins, both conventional and small G-proteins, MAP kinases and other protein kinases. Much of our knowledge concerning second messenger regulation of TJ arises fon the study of epithelial cells of different origin, mostly from kidney, therefore the specific regulation of the junctional complex of the BBB still remains to be elucidated.
Asunto(s)
Barrera Hematoencefálica/metabolismo , Transducción de Señal/fisiología , Uniones Estrechas/metabolismo , Animales , AMP Cíclico/metabolismo , Humanos , Óxido Nítrico/metabolismo , PermeabilidadAsunto(s)
Compuestos de Bencidrilo/farmacología , Permeabilidad de la Membrana Celular/efectos de los fármacos , Células Endoteliales/efectos de los fármacos , Etilaminas/farmacología , Albúminas , Algoritmos , Animales , Células Cultivadas , Impedancia Eléctrica , Fluoresceínas , Colorantes Fluorescentes , Ratones , Microcirculación , Éteres FenílicosRESUMEN
Necrotizing enterocolitis (NEC) is the most common acquired gastrointestinal emergency in neonates. We have developed an animal model of NEC in asphyxiated newborn pigs and investigated the effects of asphyxia on blood flow in superior mesenteric artery and abdominal aorta, cardiovascular data, arterial acid-base and blood gas parameters, and endothelial cytoskeletal structure in mesenteric microvasculature. Anesthetized, mechanically ventilated newborn pigs were included in two groups: piglets underwent severe asphyxia, and sham-operated control animals. A cardiovascular and metabolic failure developed in asphyxiated piglets approximately 1 h after the induction: severe hypotension and bradyarrhythmia were seen and significant reductions of the blood flow were measured in the superior mesenteric artery and abdominal aorta during the critical phase. Rearrangement of cytoskeletal actin structure corresponding to enhanced vascular permeability was seen with bodipy phallacidin in mesenterial endothelium of asphyxiated piglets after a 24-h recovery period. In conclusion, severe vasomotor changes during asphyxia may result in mesenteric endothelial dysfunction implicated in increased vascular permeability, edema formation, and development of NEC in asphyxiated piglets.
Asunto(s)
Asfixia/complicaciones , Enterocolitis Necrotizante/fisiopatología , Intestinos/irrigación sanguínea , Isquemia , Circulación Esplácnica/fisiología , Animales , Animales Recién Nacidos , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/fisiopatología , Enterocolitis Necrotizante/etiología , Femenino , Intestinos/patología , Masculino , Modelos Animales , PorcinosRESUMEN
We previously found that the production of adrenomedullin (AM) is one magnitude higher in cerebral endothelial cells (CECs) than in the peripheral endothelium and the AM concentration in the cerebral circulation is significantly higher than in other tested parts of the circulation. We also showed that CECs express AM receptors, and AM as an autocrine hormone is important to regulate the intracellular cAMP level in CECs. Further we reported that acute AM treatment has cAMP-like effects on specific BBB functions: AM decreased endothelial fluid phase endocytosis, activated the P-glycoprotein, increased transendothelial electrical resistance (TEER) and reduced endothelial permeability for sodium fluorescein, which suggests a tightening of intercellular junctions. In the present study, we found chronic AM exposure also increased TEER. In contrast, we could not detect significant effect of AM on the expression of tight junction proteins (claudin-1, occludin and zonula occludens-1). While not affecting expression of tight junction proteins, chronic AM treatment may influence the localization of these proteins which has been reported to correlate with functional changes of the BBB without a change in protein expression.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Encéfalo/metabolismo , Proteínas de la Membrana/metabolismo , Péptidos/administración & dosificación , Uniones Estrechas/metabolismo , Adrenomedulina , Animales , Células Cultivadas , Circulación Cerebrovascular , Claudina-1 , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Impedancia Eléctrica , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Ocludina , Fosfoproteínas/metabolismo , Ratas , Ratas Wistar , Proteína de la Zonula Occludens-1RESUMEN
Adrenomedullin is a peptide hormone with multifunctional biological properties. Its most characteristic effects are the regulation of circulation and the control of fluid and electrolyte homeostasis through peripheral and central nervous system actions. Although adrenomedullin is a vasodilator of cerebral vasculature, and it may be implicated in the pathomechanism of cerebrovascular diseases, the source of adrenomedullin in the cerebral circulation has not been investigated thus far. We measured the secretion of adrenomedullin by radioimmunoassay and detected adrenomedullin mRNA expression by Northern blot analysis in primary cultures of rat cerebral endothelial cells (RCECs), pericytes and astrocytes. We also investigated the expression of specific adrenomedullin receptor components by reverse transcriptase-polymerase chain reaction and intracellular cAMP concentrations in RCECs and pericytes. RCECs had approximately one magnitude higher adrenomedullin production (135 +/- 13 fmol/10(5) cells per 12 h; mean +/- SD, n = 10) compared to that previously reported for other cell types. RCECs secreted adrenomedullin mostly at their luminal cell membrane. Adrenomedullin production was not increased by thrombin, lipopolysaccharide or cytokines, which are known inducers of adrenomedullin release in peripheral endothelial cells, although it was stimulated by astrocyte-derived factors. Pericytes had moderate, while astrocytes had very low basal adrenomedullin secretion. In vivo experiments showed that adrenomedullin plasma concentration in the jugular vein of rats was approximately 50% higher than that in the carotid artery or in the vena cava. Both RCECs and pericytes, which are potential targets of adrenomedullin in cerebral microcirculation, expressed adrenomedullin receptor components, and exhibited a dose-dependent increase in intracellular cAMP concentrations after exogenous adrenomedullin administration. Antisense oligonucleotide treatment significantly reduced adrenomedullin production by RCECs and tended to decrease intraendothelial cAMP concentrations. These findings may suggest an important autocrine and paracrine role for adrenomedullin in the regulation of cerebral circulation and blood-brain barrier functions. Cerebral endothelial cells are a potential source of adrenomedullin in the central nervous system, where adrenomedullin can also be involved in the regulation of neuroendocrine functions.
Asunto(s)
Barrera Hematoencefálica/fisiología , Encéfalo/citología , Endotelio/citología , Endotelio/metabolismo , Péptidos/genética , Adrenomedulina , Animales , Encéfalo/irrigación sanguínea , Encéfalo/metabolismo , AMP Cíclico/metabolismo , Expresión Génica , Oligonucleótidos Antisentido/farmacología , Péptidos/sangre , Pericitos/metabolismo , ARN Mensajero/análisis , Radioinmunoensayo , Ratas , Ratas Wistar , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Adrenomedullin (AM) is an important vasodilator in cerebral circulation, and cerebral endothelial cells are a major source of AM. This in vitro study aimed to determine the AM-induced changes in blood-brain barrier (BBB) functions. AM administration increased, whereas AM antisense oligonucleotide treatment decreased transendothelial electrical resistance. AM incubation decreased BBB permeability for sodium fluorescein (mol. wt 376 Da) but not for Evan's blue albumin (mol. wt 67 kDa), and it also attenuated fluid-phase endocytosis. AM treatment resulted in functional activation of P-glycoprotein efflux pump in vitro. Our results indicate that AM as an autocrine mediator plays an important role in the regulation of BBB properties of the cerebral endothelial cells.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Péptidos/metabolismo , Vasodilatadores/farmacología , Adrenomedulina , Albúminas/farmacocinética , Animales , Comunicación Autocrina/fisiología , Barrera Hematoencefálica/fisiología , Colorantes/farmacocinética , Impedancia Eléctrica , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/metabolismo , Azul de Evans/farmacocinética , Colorantes Fluorescentes/farmacocinética , Técnicas In Vitro , Ratas , Ratas Wistar , Rodamina 123/farmacocinéticaRESUMEN
Asphyxia and reperfusion induced changes in the plasma and cerebrospinal fluid (CSF) concentrations of alpha-melanocyte-stimulating hormone (alpha-MSH) were studied in newborn pigs using a specific radioimmunoassay technique. Cardiovascular and metabolic failure induced by neonatal asphyxia resulted in a 3-fold, significant (P < 0.05) increase in plasma alpha-MSH levels, whereas the hormone concentration in CSF was significantly (P < 0.05) reduced by 50% during postasphyxial reperfusion. Our data indicate an asphyxia-induced release of alpha-MSH, and suggest a discordant regulation of plasma and CSF concentrations in newborn pigs.
Asunto(s)
Asfixia , alfa-MSH/farmacología , Animales , Animales Recién Nacidos , Neumotórax , Radioinmunoensayo , Reperfusión , Porcinos , Factores de Tiempo , alfa-MSH/sangre , alfa-MSH/líquido cefalorraquídeoRESUMEN
Tissue plasminogen activator (0.01-30 microgram/ml) dose-dependently inhibited the functional activity of P-glycoprotein, assessed by rhodamine 123 accumulation in GP8 immortalized rat brain endothelial cells, but this effect was unrelated to its proteolytic activity. Elevation of intra-endothelial cyclic AMP concentration and stimulation of protein kinase C increased P-glycoprotein activity in GP8 cells and also attenuated the tissue plasminogen activator-induced inhibition.
Asunto(s)
Subfamilia B de Transportador de Casetes de Unión a ATP/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Activador de Tejido Plasminógeno/farmacología , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Animales , Barrera Hematoencefálica , Encéfalo/citología , Encéfalo/metabolismo , Línea Celular Transformada , Relación Dosis-Respuesta a Droga , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Rodamina 123/metabolismoRESUMEN
The central nervous system requires an effective autoregulation of cerebral circulation in order to meet the critical and unusual demands of the brain. In addition, cerebral microvessels has a unique feature, the formation of the blood-brain barrier, which contributes to the stability of the brain parenchymal microenvironment. Many factors are known to be involved in the regulation of cerebral circulation and blood-brain barrier functions. In the last few years a new potential candidate, adrenomedullin, a hypotensive peptide was added to this list. Adrenomedullin has a potent vasodilator effect on the cerebral vasculature, and it may be implicated in the pathologic mechanism of cerebrovascular diseases. In this review, we describe current knowledge about the origin and possible role of adrenomedullin in the regulation of cerebral circulation and blood-brain barrier functions.
Asunto(s)
Circulación Cerebrovascular/fisiología , Péptidos/fisiología , Adrenomedulina , Animales , Barrera Hematoencefálica , Trastornos Cerebrovasculares/metabolismo , Trastornos Cerebrovasculares/patología , Humanos , Péptidos/sangre , Receptores de Adrenomedulina , Receptores de Péptidos/fisiologíaRESUMEN
A hydrophobic, fibrillogenic peptide fragment of human prion protein (PrP106-126) had in vitro toxicity to neurons expressing cellular prion protein (PrP(C)). In this study, we proved that primary cultures of mouse cerebral endothelial cells (MCEC) express PrP(C). Incubation of MCEC with PrP106-126 (25-200 microM) caused a dose-dependent toxicity assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase release, bis-benzimide staining for nuclear morphology, and trypan blue exclusion test. Pentosan polysulphate (50-100 microg/ml), a drug effective in scrapie prophylaxis, dose-dependently attenuated the injury. MCEC cultures from mice homogenous for the disrupted PrP gene were resistant to the toxicity of PrP106-126. In conclusion, cerebral endothelium expressing PrP(C) may be directly damaged during spongiform encephalopathies.
Asunto(s)
Encéfalo/citología , Endotelio/citología , Fragmentos de Péptidos/toxicidad , Priones , Priones/toxicidad , Secuencia de Aminoácidos , Animales , Western Blotting , Encéfalo/enzimología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Endotelio/enzimología , Inhibidores Enzimáticos/farmacología , Colorantes Fluorescentes , L-Lactato Deshidrogenasa/metabolismo , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Poliéster Pentosan Sulfúrico/farmacología , Fragmentos de Péptidos/antagonistas & inhibidores , Priones/antagonistas & inhibidores , Sales de Tetrazolio , TiazolesRESUMEN
1. Effects of pentosan polysulfate (PPS) and the structurally related sulfated polyanions dextran sulfate, fucoidan, and heparin on the scavenger receptor-mediated and fluidphase endocytosis in GP8 immortalized rat brain endothelial cells were investigated. 2. Using 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarboxyamine perchlorate-labeled acetylated low-density lipoprotein (DiI-AcLDL), we found a binding site with high affinity and low binding capacity, and another one with low affinity and high binding capacity. Increasing ligand concentrations could not saturate DiI-AcLDL uptake. DiI-AcLDL uptake, but not binding, was sensitive to pretreatment with filipin, an inhibitor of caveola formation. 3. PPS (20-200 microg/ml) significantly reduced the binding of DiI-AcLDL after coincubation for 3 hr, though this effect was less expressed after 18 hr. Among other polyanions, only fucoidan decreased the DiI-AcLDL binding after 3 hr, whereas dextran sulfate significantly increased it after 18 hr. PPS treatment induced an increase in DiI-AcLDL uptake, whereas other polysulfated compounds caused a significant reduction. 4. Fluid-phase endocytosis determined by the accumulation of Lucifer yellow was concentration and time dependent in GP8 cells. Coincubation with PPS or other sulfated polyanions could not significantly alter the rate of Lucifer yellow uptake. 5. In conclusion. PPS decreased the binding and increased the uptake of DiI-AcLDL in cerebral endothelial cells, an effect not mimicked by the other polyanions investigated.
Asunto(s)
Endocitosis/fisiología , Endotelio Vascular/fisiología , Proteínas de la Membrana , Poliéster Pentosan Sulfúrico/farmacología , Receptores Inmunológicos/fisiología , Receptores de Lipoproteína , Animales , Transporte Biológico , Línea Celular Transformada , Circulación Cerebrovascular , Endocitosis/efectos de los fármacos , Endotelio Vascular/citología , Endotelio Vascular/efectos de los fármacos , Isoquinolinas/farmacocinética , Cinética , Metilaminas/farmacocinética , Ratas , Receptores Inmunológicos/efectos de los fármacos , Receptores Depuradores , Receptores Depuradores de Clase BRESUMEN
Histamine plays a role in the regulation of the blood-brain barrier function. In this study, effects of N, N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine (DPPE), an intracellular histamine binding site antagonist on the cerebrovascular permeability were investigated in control and post-ischemic male Wistar rats. Intravenous administration of DPPE, in a dose of 1 and 5 mg/kg, was not followed by any major clinical change, but 20 mg/kg proved to be toxic. A significantly (P<0.05) increased permeability for sodium fluorescein (MW=376) was seen in hippocampus, striatum, and cerebellum, but not in parietal cortex, of rats 2 h after the injection of 5 mg/kg DPPE, whereas no increase was measured later. There was a more intense (5- to 12-fold) and prolonged elevation in Evan's blue-labeled albumin (MW=67,000) extravasation 2, 4, and 8 h after 5 mg/kg DPPE administration in each brain region. In parietal cortex, a dose-dependent increase in albumin extravasation developed 4 h after intravenous injection of 1, 5, and 20 mg/kg DPPE, but doses applied resulted in no significant change in sodium fluorescein permeability. Cerebral ischemia-reperfusion evoked by four-vessel occlusion caused a significant (P<0.05) increase in the permeability for albumin in each region, but few changes in that of sodium fluorescein. DPPE treatment failed to prevent the ischemia-reperfusion-induced changes in the blood-brain barrier permeability. In conclusion, DPPE induced an increased permeability in the rat, which supports a role for histamine, as an intracellular messenger, in the regulation of the blood-brain barrier characteristics.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Permeabilidad Capilar/efectos de los fármacos , Antagonistas de los Receptores Histamínicos/farmacología , Éteres Fenílicos/farmacología , Animales , Barrera Hematoencefálica/fisiología , Isquemia Encefálica/fisiopatología , Cuerpo Estriado/irrigación sanguínea , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Relación Dosis-Respuesta a Droga , Azul de Evans/farmacocinética , Extravasación de Materiales Terapéuticos y Diagnósticos , Fluoresceína/farmacocinética , Inyecciones Intravenosas , Masculino , Lóbulo Parietal/irrigación sanguínea , Lóbulo Parietal/efectos de los fármacos , Lóbulo Parietal/metabolismo , Ratas , Ratas Wistar , Daño por Reperfusión/fisiopatología , Albúmina Sérica/farmacocinéticaRESUMEN
The effect of serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF) was investigated on the prevention of tumor-necrosis-factor-alpha (TNF-alpha)-induced blood-brain barrier opening. TNF-alpha (10,000 IU) was injected intracarotidly to newborn pigs pretreated with 0, 2.4, 4.8, 9.6 and 19.2 mg/kg AEBSF (n = 6 in each group). AEBSF dose-dependently inhibited the TNF-alpha-induced increase in the blood-brain barrier permeability for sodium fluorescein (MW = 376) in all of the five brain regions examined, while only 19.2 mg/kg AEBSF could significantly (P < 0.05) decrease the change in Evan's blue-albumin (MW = 67,000) transport in two regions. In conclusion, AEBSF attenuates vasogenic brain edema formation.
Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Edema Encefálico/prevención & control , Inhibidores de Serina Proteinasa/farmacología , Sulfonas/farmacología , Factor de Necrosis Tumoral alfa/farmacología , Animales , Animales Recién Nacidos , Barrera Hematoencefálica/fisiología , Encéfalo/metabolismo , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Azul de Evans/farmacocinética , Femenino , Fluoresceína/farmacocinética , Masculino , PorcinosAsunto(s)
Antiinflamatorios no Esteroideos/farmacocinética , Poliéster Pentosan Sulfúrico/farmacocinética , Enfermedades por Prión/metabolismo , Animales , Antiinflamatorios no Esteroideos/uso terapéutico , Ratones , Poliéster Pentosan Sulfúrico/uso terapéutico , Enfermedades por Prión/tratamiento farmacológico , Distribución TisularRESUMEN
The vasoactive substances synthesized by primary cultures of rat brain endothelial cells were investigated and compared to those from two, immortalized cell lines, RBE4 and GP8. The vasoactivity of endothelium-derived substances was measured on isolated canine coronary artery. Vascular tone was significantly decreased by both primary and GP8, but not by RBE4 cells. Indomethacin pretreatment of primary and GP8 cells turned vasorelaxation into contraction while N(omega)-nitro-L-arginine pretreatment decreased the vasorelaxation induced by primary, but not by GP8 cells. Eicosanoid production was determined after incubation with [14C]arachidonic acid. The predominant vasoactive eicosanoid was prostaglandin E2 in both primary and GP8 cells. RBE4 cells synthetized mainly prostaglandin E2 and thromboxane B2 and significantly less prostaglandin E2 than did either primary or GP8 cells. The capacity of cerebral endothelium to regulate vascular tone by production of dilator and constrictor substances can be preserved under certain circumstances in immortalized cell lines.