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BACKGROUND: Alcoholism is one of the risk factors for cerebrovascular diseases. Our previous study demonstrated that acute alcohol intoxication enhances brain injury and neurological impairment in rats suffering from intracerebral hemorrhage (ICH). We plan to investigate the effect of chronic alcohol consumption (CAC) in rats with ICH by magnetic resonance imaging (MRI). METHODS: Sixteen Sprague-Dawley male rats were divided into 2 groups: CAC group (fed with 10% alcohol drinking water for 4 weeks, nâ¯=â¯8), and Control group (plain drinking water, nâ¯=â¯8). ICH was induced by collagenase infusion into the right striata of all rats. Coronal T1-weighted imaging, T2-weighted imaging, T2*-weighted imaging, and diffusion-weighted imaging were generated with a 3.0T MRI scanner to investigate the changes of hemorrhagic volume and edema throughout the injury and recovery stages of ICH in rats. RESULTS: T2-weighted imaging is ideal for monitoring hematoma volume in rats. The hematoma volume was larger in the CAC group than in the control group (P < .001), however, did not correlate to post-ICH progressive edema formation (P > .7), and neurological impairment (P > .28) between the 2 groups, respectively. DISCUSSION: Although our findings indicate that CAC induces larger hematoma in rats with ICH, the underlying mechanism should be studied in the future.
Assuntos
Alcoolismo/complicações , Alcoolismo/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/etiologia , Imageamento por Ressonância Magnética , Consumo de Bebidas Alcoólicas , Animais , Encéfalo/efeitos dos fármacos , Edema Encefálico/diagnóstico por imagem , Edema Encefálico/etiologia , Modelos Animais de Doenças , Imageamento por Ressonância Magnética/métodos , Masculino , Distribuição Aleatória , Ratos Sprague-DawleyRESUMO
OBJECTIVE: Spontaneous intracerebral hemorrhage (ICH) accounts for 10%-15% of all strokes and causes high mortality and morbidity. In the previous study, we demonstrated that ethanol could aggravate the severity of brain injury after ICH by increasing neuroinflammation and oxidative stress. In this study, we further investigate the acute effects of ethanol on brain injury within 24 h after ICH. MATERIALS AND METHODS: Totally, 66 male Sprague-Dawley rats were assigned randomly into two groups: saline pretreatment before ICH (saline + ICH), and ethanol pretreatment before ICH (ethanol + ICH). Normal saline (10 mL/kg) or ethanol (3 g/kg, in 10 mL/kg normal saline) was administered intraperitoneally 1 h before induction of experimental ICH. Bacterial collagenase VII-S (0.23 U in 1.0 µL sterile saline) was injected into the right striatum to induce ICH in the rats. We evaluated the hematoma expansion, hemodynamic parameters (heart rate and blood pressure), activated partial thromboplastin time (aPTT), prothrombin time (PT), and striatal matrix metallopeptidase 9 (MMP-9) expressions at 3, 6, 9, and 24 h after ICH. RESULTS: The ethanol + ICH group exhibited decreased hematoma at 3 h after ICH; nevertheless, there was a larger hematoma compared with the saline + ICH group at 9 and 24 h after ICH. The ethanol + ICH group had lower blood pressure at 3, 6, and 9 h post-ICH, but both groups maintained similar heart rates after ICH. There was no significant difference in the aPTT and PT between the two groups. Incremental ethanol concentrations had no influence on collagenase VII-S activity at 120 min in vitro. MMP-9 expression was upregulated in the right striata of the ethanol + ICH group, especially at 3 and 9 h after ICH. CONCLUSION: Ethanol delayed hematoma formation in the first 3 h due to a hypotensive effect; however, the accelerated growth of hematomas after 9 h may be a sequela of ethanol-induced MMP-9 activation.
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Basal ganglia hemorrhage accounts for approximately 50% of all hemorrhagic strokes. A good rat model that produces severe intrastriatal hemorrhage (ISH) mimicking human severe ISH is lacking. The present study compared the intra-striatal injection of 0.2 U with that of 0.6 U of collagenase in inducing severe ISH in rats. Three-Tesla (3T) magnetic resonance imaging (MRI) was used to evaluate brain injuries in terms of hematoma size (volume), midline shift (MLS), and brain edema. This evaluation was further substantiated by determination of behavior and neurologic functions and mortality over 56 h. The 0.2 U collagenase caused hematoma volume increases for 10.3 to 30.1 mm³, while the 0.6 U caused 36.4 to 114.8 mm³, at post-ISH 1 h to 56 h. The 0.6 U collagenase significantly increased MLS to 1.5-3.0 times greater than the 0.2 U did at all post-intracerebral hemorrhage (ICH) time points. The MLS increased dependently with hematoma expansion with high correlation coefficients, yet no mortality occurred. These two dosages, nevertheless, caused the same pattern and severity in relative apparent diffusion coefficient (rADC) changes for three regions of interest (ROIs). Both ISH models induced consistent behavior deficits. The larger dosage produced severe brain injuries as well as neurological deficits, more closely mimicking severe human ISH. Hematoma volume and MLS can be the most useful parameters for evaluating the ISH severity in the present experimental model. The larger dosage, therefore, would be useful for investigating the pathophysiology of the severer ISH in the striatum. This may be applied for evaluating potential therapeutic strategies and outcomes in the future.
Assuntos
Hemorragia Cerebral/etiologia , Colagenases/farmacologia , Corpo Estriado , Modelos Animais de Doenças , Envelhecimento , Animais , Humanos , Imageamento por Ressonância Magnética , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: Alcohol intoxication is associated with worse intracerebral hemorrhage (ICH) outcome, indicating the important role of alcohol in ICH pathogenesis. We intended to investigate the effects of ethanol pretreatment on the severity of ICH-induced brain injury in rats. METHODS: At 1 hour after intraperitoneal injection of ethanol (3 g/kg), 0.2 U bacterial collagenase was infused into the striatum of male Sprague-Dawley rats to induce ICH. Accumulative mortality rate, body weight changes, and motorsensory and neurological abnormalities were evaluated. The hemorrhagic volume, hematoma expansion, and water content were measured by Drabkin's method, morphometric assay, and dry/wet method, respectively. Blood-brain barrier disruption was assessed using Evans blue assay. Oxidative stress was evaluated by the enzymatic activity of glutathione peroxidase, oxidation of hydroethidine, and the production of malondialdehyde. Cerebral blood flow perfusion volume and hypo-/hyperperfusion neuroimaging were examined by magnetic resonance imaging. RESULTS: Ethanol pretreatment aggravates the hematoma hemolysis, hemorrhagic volume, hematoma expansion, brain edema, blood-brain barrier disruption, microglial activation, elevated oxidative stress, and neuroinflammation in the hemorrhagic striatum. The summation effect of these consequences is the major cause of marked neurological impairment and higher mortality rate (64%) in ethanol-pretreated rats with ICH. CONCLUSION: This is a novel model to evaluate the effects of high-dose alcohol administration on experimental ICH rats. IMPLICATIONS: The present study may provide clues for making novel strategies in the management of patients with ICH who overconsume alcoholic drinks before the attack.
Assuntos
Intoxicação Alcoólica/complicações , Dano Encefálico Crônico/etiologia , Hemorragia Cerebral/complicações , Corpo Estriado/patologia , Intoxicação Alcoólica/fisiopatologia , Animais , Barreira Hematoencefálica , Dano Encefálico Crônico/patologia , Edema Encefálico/etiologia , Hemorragia Cerebral/fisiopatologia , Circulação Cerebrovascular , Modelos Animais de Doenças , Etanol/administração & dosagem , Etanol/toxicidade , Hematoma/etiologia , Inflamação , Injeções Intraperitoneais , Imageamento por Ressonância Magnética , Masculino , Microglia/patologia , Estresse Oxidativo , Imagem de Perfusão , Pré-Medicação , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Teste de Desempenho do Rota-RodRESUMO
Granulocyte-colony stimulating factor (G-CSF) protects brain from ischemic/reperfusion (I/R) injury, and inhibition of nitric oxide (NO) synthases partially reduces G-CSF protection. We thus further investigated the effects of G-CSF on ischemia-induced NO production and its consequence on regional cerebral blood flow (rCBF) and neurological deficit. Endothelin-1 (ET-1) microinfused above middle cerebral artery caused a rapid reduction of rCBF (ischemia) which lasted for 30 minutes and was followed by a gradual recovery of blood flow (reperfusion) within the striatal region. Regional NO concentration increased rapidly (NO surge) during ischemia and recovered soon to the baseline. G-CSF increased rCBF resulting in shorter ischemic duration and an earlier onset of reperfusion. The enhancement of the ischemia-induced NO by G-CSF accompanied by elevation of phospho-Akt and phospho-eNOS was noted, suggesting an activation of Akt/eNOS. I/R-induced infarct volume and neurological deficits were also reduced by G-CSF treatment. Inhibition of NO synthesis by L-N(G)-Nitroarginine Methyl Ester (L-NAME) significantly reduced the effects of G-CSF on rCBF, NO surge, infarct volume, and neurological deficits. We conclude that G-CSF increases rCBF through a NO surge mediated by Akt/eNOS, which partially contributes to the beneficial effect of G-CSF on brain I/R injury.
Assuntos
Isquemia Encefálica/metabolismo , Circulação Cerebrovascular/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/farmacologia , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Animais , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Modelos Animais de Doenças , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Fármacos Neuroprotetores/farmacologia , Ratos , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/fisiopatologiaRESUMO
Urocortin exerts neuroprotective effects in intracerebral hemorrhage (ICH) of rats. For pre-clinical trial, we intended to study the neuroprotective efficacy of human UCN (hUCN)-1, -2 and -3 in treating ICH rats. ICH was induced by infusing bacterial collagenase VII (0.23 U in sterile saline) to the striatum. The hUCN-1, -2, and -3 were administrated (2.5µg/kg, i.p.) at 1h after ICH insult, respectively. Neurological deficits were evaluated by modified Neurological Severity Scores. Brain edema and hematoma expansion was evaluated by coronal T2-WI and DWI magnetic resonance imaging on 1, 3, 6, 24, and 56h after ICH insult. Blood-brain barrier permeability was evaluated by Evans blue assay on day 3 after ICH. Brain lesion volume was evaluated by morphormetric measurement on day 7 after ICH. Our results demonstrated that the hUCN-1 significantly reduced hematoma, blood-brain barrier disruption and neurological deficits on day 3, and brain lesion volume on day 7 after ICH insult. The prediction of secondary structure of the hUCNs clarifies that the percentage of alpha-helix, random coil and extended strand between rat-UCN (rUCN)-1 and hUCN-1 are the same. The structure similarity between human- and rat-UCN-1 may be one of the reasons that both can exert similar therapeutic potential in ICH rats.
Assuntos
Hemorragia Cerebral/prevenção & controle , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Hormônio Liberador da Corticotropina/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Urocortinas/administração & dosagem , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Hemorragia Cerebral/induzido quimicamente , Hormônio Liberador da Corticotropina/uso terapêutico , Humanos , Masculino , Colagenase Microbiana , Fármacos Neuroprotetores/uso terapêutico , Ratos , Ratos Sprague-Dawley , Urocortinas/uso terapêuticoRESUMO
Granulocyte-colony stimulating factor (G-CSF) induced regeneration of dopaminergic neurons and improved behavior deficit in moderate Parkinson's disease (PD) model mice. Post treatment of G-CSF in severe PD model has not been addressed. A very severe PD model in rats was induced by a high dose 6-hydroxydopamine (6-OHDA) injected into the right medial forebrain bundle to evaluate therapeutic effects of G-CSF. G-CSF (50 microg/kg/day for five days) was given on the 9th day after the 6-OHDA injection. Rotational behavior was examined on the 9th and 28th days. Rats were killed on the 28th day and survival dopaminergic neurons in the substantia nigra, dopaminergic axons and dopaminergic receptor 2 in the striatum were examined. We, for the first time, demonstrated that post treatment with G-CSF reduced abnormal rotational behavior and increased the lesion to non-lesion ratio of dopaminergic fibers in the striatum, but the treatment promoted neither the increase in survival dopaminergic neurons nor the increase in dopaminergic receptor 2 expression. We conclude that post treatment with G-CSF can reduce the abnormal rotational behavior of severe PD rats primarily through relative increases in dopaminergic fibers of the lesion side in the striatum. Results of our study suggest therapeutic potentials of G-CSF for treating severe PD patients.
Assuntos
Neurônios Dopaminérgicos/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Regeneração Nervosa/efeitos dos fármacos , Transtornos Parkinsonianos/tratamento farmacológico , Animais , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Fator Estimulador de Colônias de Granulócitos/farmacologia , Masculino , Oxidopamina/administração & dosagem , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D2/metabolismo , Simpatolíticos/administração & dosagemRESUMO
The common carotid artery (CCA) supplies intra- and extra-cranial vascular beds. An area in the medulla controlling CCA blood flow is defined as the dorsal facial area (DFA) by Kuo et al. in 1987. In the DFA, presynaptic nitrergic and/or glutamatergic fibers innervate preganglionic nitrergic and/or cholinergic neurons which give rise to the preganglionic fibers of the parasympathetic 7th and 9th cranial nerves. Released glutamate from presynaptic nitrergic and/or glutamatergic fibers can activate N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors on preganglionic nitrergic and/or cholinergic neurons. By modulating this glutamate release, several neurochemicals including serotonin, arginine, nitric oxide, nicotine, choline and ATP in the DFA regulate CCA blood flow. Understanding the neurochemical regulatory mechanisms can provide important insights of the physiological roles of the DFA, and may help develop therapeutic strategies for diseases involving CCA blood flow, such as migraine, hypertensive disease, Alzheimer's disease and cerebral ischemic stroke.
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The mortality in septic patients with myocardial dysfunction is higher than those without it. Beneficial effects of flavonoid oroxylin A (Oro-A) on endotoxemic hearts were evaluated and compared with that of arginine vasopressin (AVP) which is used to reverse hypotension in septic patients. Endotoxemia in rats was induced by one-injection of lipopolysaccharides (LPS, 10 mg/kg, i.p.), and hearts were isolated 5-hrs or 16-hrs later. Isolated hearts with constant-pressure or constant-flow mode were examined by Langendorff technique. Rate and force of contractions of isolated atrial and ventricular strips were examined by tissue myography. Isolated endotoxemic hearts were characterized by decreased or increased coronary flow (CF) in LPS-treated-for-5hr and LPS-treated-for-16-hr groups, respectively, with decreased inotropy in both groups. Oro-A-perfusion ameliorated while AVP-perfusion worsened the decreased CF and inotropy in both preparations. Oro-A and AVP, however, did not affect diminished force or rate of contraction of atrial and ventricular strips of endotoxemic hearts. Oro-A-induced CF increase was not affected following coronary endothelium-denudation with saponin. These results suggest that Oro-A ameliorates LPS-depressed cardiac functions by increasing CF, leading to positive inotropy. In contrast, AVP aggravates cardiac dysfunction by decreasing CF. Oro-A is a potentially useful candidate for treating endotoxemia complicated with myocardial dysfunction.
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During cortical development, cell proliferation and cell cycle exit are carefully regulated to ensure that the appropriate numbers of cells are produced. Urocortin (UCN) is a member of the corticotrophin releasing hormone (CRH) family of neuropeptides that regulates stress responses. UCN is widely distributed in adult rat brain. However, the expression and function of UCN in embryonic brain is, as yet, unclear. Here, we show that UCN is endogenously expressed in proliferative zones of the developing cerebral cortex and its receptors are exhibited in neural stem cells (NSCs), thus implicating the neuropeptide in cell cycle regulation. Treatment of cultured NSCs or organotypic slice cultures with UCN markedly reduced cell proliferation. Furthermore, blocking of endogenous UCN/CRHRs system either by treatment with CRHRs antagonists or by neutralization of secreted UCN with anti-UCN antibody increased NSCs proliferation. Cell cycle kinetics analysis demonstrated that UCN lengthened the total cell cycle duration via increasing the G1 phase and accelerated cell cycle exit. UCN directly inhibited the histone deacetylase (HDAC) activity and induced a robust increase in histone H3 acetylation levels. Using pharmacological and RNA interference approaches, we further demonstrated that antiproliferative action of UCN appeared to be mediated through a HDAC inhibition-induced p21 upregulation. Moreover, UCN treatment in vitro and in vivo led to an increase in neuronal differentiation of NSCs. These findings suggest that UCN might contribute to regulate NSCs proliferation and differentiation during cortical neurogenesis.
Assuntos
Inibidores de Histona Desacetilases/farmacologia , Células-Tronco Neurais/citologia , Neurônios/citologia , Urocortinas/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/fisiologia , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Feminino , Neocórtex/citologia , Neocórtex/embriologia , Neocórtex/metabolismo , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Técnicas de Cultura de Órgãos , Fosforilação/efeitos dos fármacos , Gravidez , Ratos , Receptores de Hormônio Liberador da Corticotropina/biossíntese , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Fase de Repouso do Ciclo Celular/fisiologia , Fase S/efeitos dos fármacos , Fase S/fisiologia , Transfecção , Regulação para Cima , Urocortinas/biossíntese , Urocortinas/farmacologiaRESUMO
Memantine, an NMDA receptor antagonist used for treatment of Alzheimer's disease (AD), is known to block the nicotinic acetylcholine receptors (nAChRs) in the central nervous system (CNS). In the present study, we examined by wire myography if memantine inhibited α3ß2-nAChRs located on cerebral perivascular sympathetic nerve terminals originating in the superior cervical ganglion (SCG), thus, leading to inhibition of nicotine-induced nitrergic neurogenic dilation of isolated porcine basilar arteries. Memantine concentration-dependently blocked nicotine-induced neurogenic dilation of endothelium-denuded basilar arteries without affecting that induced by transmural nerve stimulation, sodium nitroprusside, or isoproterenol. Furthermore, memantine significantly inhibited nicotine-elicited inward currents in Xenopous oocytes expressing α3ß2-, α7- or α4ß2-nAChR, and nicotine-induced calcium influx in cultured rat SCG neurons. These results suggest that memantine is a non-specific antagonist for nAChR. By directly inhibiting α3ß2-nAChRs located on the sympathetic nerve terminals, memantine blocks nicotine-induced neurogenic vasodilation of the porcine basilar arteries. This effect of memantine is expected to reduce the blood supply to the brain stem and possibly other brain regions, thus, decreasing its clinical efficacy in the treatment of Alzheimer's disease.
Assuntos
Artéria Basilar/efeitos dos fármacos , Memantina/farmacologia , Antagonistas Nicotínicos/farmacologia , Vasodilatação/efeitos dos fármacos , Animais , Artéria Basilar/fisiologia , Sinalização do Cálcio , Técnicas In Vitro , Isoproterenol/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Nicotina/farmacologia , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Oócitos/fisiologia , Técnicas de Patch-Clamp , Cloreto de Potássio/farmacologia , Ratos , Receptores Nicotínicos/metabolismo , Gânglio Cervical Superior/efeitos dos fármacos , Gânglio Cervical Superior/metabolismo , Suínos , Xenopus laevis , Receptor Nicotínico de Acetilcolina alfa7RESUMO
The close apposition between sympathetic and parasympathetic nerve terminals in the adventitia of cerebral arteries provides morphological evidence that sympathetic nerve activation causes parasympathetic nitrergic vasodilation via a sympathetic-parasympathetic interaction mechanism. The decreased parasympathetic nerve terminals in basilar arteries (BA) of spontaneously hypertensive rat (SHR) and renovascular hypertensive rats (RHR) compared with Wistar-Kyoto rats (WKY), therefore, would diminish this axo-axonal interaction-mediated neurogenic vasodilation in hypertension. Increased basilar arterial blood flow (BABF) via axo-axonal interaction during sympathetic activation was, therefore, examined in anesthetized rats by laser-Doppler flowmetry. Electrical stimulation (ES) of sympathetic nerves originating in superior cervical ganglion (SCG) and topical nicotine (10-30 µM) onto BA of WKY significantly increased BABF. Both increases were inhibited by tetrodotoxin, 7-nitroindazole (neuronal nitric oxide synthase inhibitor), and ICI-118,551 (ß(2)-adrenoceptor antagonist), but not by atenolol (ß(1)-adrenoceptor antagonist). Topical norepinephrine onto BA also increased BABF, which was abolished by atenolol combined with 7-nitroindazole or ICI-118,551. Similar results were found in prehypertensive SHR. However, in adult SHR and RHR, ES of sympathetic nerves or topical nicotine caused minimum or no increase of BABF. It is concluded that excitation of sympathetic nerves to BA in WKY causes parasympathetic nitrergic vasodilation with increased BABF. This finding indicates an endowed functional neurogenic mechanism for increasing the BABF or brain stem blood flow in coping with increased local sympathetic activities in acutely stressful situations such as the "fight-or-flight response." This increased blood flow in defensive mechanism diminishes in genetic and nongenetic hypertensive rats due most likely to decreased parasympathetic nitrergic nerve terminals.
Assuntos
Artéria Basilar/efeitos dos fármacos , Ponte/irrigação sanguínea , Ponte/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Animais , Atenolol/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Estimulação Elétrica , Inibidores Enzimáticos/farmacologia , Estimulantes Ganglionares/farmacologia , Indazóis/farmacologia , Fluxometria por Laser-Doppler , Masculino , Nicotina/farmacocinética , Norepinefrina/farmacologia , Propanolaminas/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Fluxo Sanguíneo Regional/efeitos dos fármacos , Fluxo Sanguíneo Regional/fisiologia , Gânglio Cervical Superior/efeitos dos fármacos , Gânglio Cervical Superior/fisiologia , Sistema Nervoso Simpático/fisiologia , Tetrodotoxina/farmacologiaRESUMO
BACKGROUND: Intracerebral hemorrhage (ICH) remains a serious clinical problem lacking effective treatment. Urocortin (UCN), a novel anti-inflammatory neuropeptide, protects injured cardiomyocytes and dopaminergic neurons. Our preliminary studies indicate UCN alleviates ICH-induced brain injury when administered intracerebroventricularly (ICV). The present study examines the therapeutic effect of UCN on ICH-induced neurological deficits and neuroinflammation when administered by the more convenient intraperitoneal (i.p.) route. METHODS: ICH was induced in male Sprague-Dawley rats by intrastriatal infusion of bacterial collagenase VII-S or autologous blood. UCN (2.5 or 25 µg/kg) was administered i.p. at 60 minutes post-ICH. Penetration of i.p. administered fluorescently labeled UCN into the striatum was examined by fluorescence microscopy. Neurological deficits were evaluated by modified neurological severity score (mNSS). Brain edema was assessed using the dry/wet method. Blood-brain barrier (BBB) disruption was assessed using the Evans blue assay. Hemorrhagic volume and lesion volume were assessed by Drabkin's method and morphometric assay, respectively. Pro-inflammatory cytokine (TNF-α, IL-1ß, and IL-6) expression was evaluated by enzyme-linked immunosorbent assay (ELISA). Microglial activation and neuronal loss were evaluated by immunohistochemistry. RESULTS: Administration of UCN reduced neurological deficits from 1 to 7 days post-ICH. Surprisingly, although a higher dose (25 µg/kg, i.p.) also reduced the functional deficits associated with ICH, it is significantly less effective than the lower dose (2.5 µg/kg, i.p.). Beneficial results with the low dose of UCN included a reduction in neurological deficits from 1 to 7 days post-ICH, as well as a reduction in brain edema, BBB disruption, lesion volume, microglial activation and neuronal loss 3 days post-ICH, and suppression of TNF-α, IL-1ß, and IL-6 production 1, 3 and 7 days post-ICH. CONCLUSION: Systemic post-ICH treatment with UCN reduces striatal injury and neurological deficits, likely via suppression of microglial activation and inflammatory cytokine production. The low dose of UCN necessary and the clinically amenable peripheral route make UCN a potential candidate for development into a clinical treatment regimen.
Assuntos
Hemorragia Cerebral/complicações , Encefalite/etiologia , Doenças do Sistema Nervoso/etiologia , Fármacos Neuroprotetores/administração & dosagem , Urocortinas/administração & dosagem , Análise de Variância , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Barreira Hematoaquosa/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Edema Encefálico/tratamento farmacológico , Edema Encefálico/etiologia , Antígeno CD11b/metabolismo , Contagem de Células , Hemorragia Cerebral/classificação , Hemorragia Cerebral/etiologia , Hemorragia Cerebral/patologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Ectodisplasinas/metabolismo , Injeções Intraventriculares , Fluxometria por Laser-Doppler , Masculino , Fosfopiruvato Hidratase/metabolismo , Ratos , Ratos Sprague-Dawley , Índice de Gravidade de Doença , Fatores de TempoRESUMO
OBJECT: Intracerebral hemorrhage (ICH) accounts for about 15% of all deaths due to stroke. It frequently causes brain edema, leading to an expansion of brain volume that exerts a negative impact on ICH outcomes. The ICH-induced brain edema involves inflammatory mechanisms. The authors' in vitro study shows that urocortin (UCN) exhibits antiinflammatory and neuroprotective effects. Therefore, the neuroprotective effect of UCN on ICH in rats was investigated. METHODS: Intracerebral hemorrhage was induced by an infusion of bacteria collagenase type VII-S or autologous blood into the unilateral striatum of anesthetized rats. At 1 hour after the induction of ICH, UCN (0.05, 0.5, and 5 µg) was infused into the lateral ventricle on the ipsilateral side. The authors examined the injury area, brain water content, blood-brain barrier permeability, and neurological function. RESULTS: The UCN, administered in the ipsilateral lateral ventricle, was able to penetrate into the injured striatum. Posttreatment with UCN reduced the injury area, brain edema, and blood-brain barrier permeability and improved neurological deficits of rats with ICH. CONCLUSIONS: Posttreatment with UCN through improving neurological deficits of rats with ICH dose dependently provided a potential therapeutic agent for patients with ICH or other brain injuries.
Assuntos
Edema Encefálico/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Hemorragia Cerebral/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Urocortinas/uso terapêutico , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Barreira Hematoencefálica/fisiopatologia , Encéfalo/fisiopatologia , Edema Encefálico/patologia , Edema Encefálico/fisiopatologia , Hemorragia Cerebral/patologia , Hemorragia Cerebral/fisiopatologia , Modelos Animais de Doenças , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento , Urocortinas/farmacologiaRESUMO
BACKGROUND: Perivascular adipose tissue (PVAT)-derived relaxing factor (PVATRF) significantly regulates vascular tone. Its chemical nature remains unknown. We determined whether palmitic acid methyl ester (PAME) was the PVATRF and whether its release and/or vasorelaxing activity decreased in hypertension. METHODS AND RESULTS: Using superfusion bioassay cascade technique, tissue bath myography, and gas chromatography/mass spectrometry, we determined PVATRF and PAME release from aortic PVAT preparations of Wistar Kyoto rats and spontaneously hypertensive rats. The PVAT of Wistar Kyoto rats spontaneously and calcium dependently released PVATRF and PAME. Both induced aortic vasorelaxations, which were inhibited by 4-aminopyridine (2 mmol/L) and tetraethylammonium 5 and 10 mmol/L but were not affected by tetraethylammonium 1 or 3 mmol/L, glibenclamide (3 µmol/L), or iberiotoxin (100 nmol/L). Aortic vasorelaxations induced by PVATRF- and PAME-containing Krebs solutions were not affected after heating at 70°C but were equally attenuated after hexane extractions. Culture mediums of differentiated adipocytes, but not those of fibroblasts, contained significant PAME and caused aortic vasorelaxation. The PVAT of spontaneously hypertensive rats released significantly less PVATRF and PAME with an increased release of angiotensin II. In addition, PAME-induced relaxation of spontaneously hypertensive rats aortic smooth muscle diminished drastically, which was ameliorated significantly by losartan. CONCLUSIONS: We found that PAME is the PVATRF, causing vasorelaxation by opening voltage-dependent K+ channels on smooth muscle cells. Diminished PAME release and its vasorelaxing activity and increased release of angiotensin II in the PVAT suggest a noble role of PVAT in pathogenesis of hypertension. The antihypertensive effect of losartan is attributed partly to its reversing diminished PAME-induced vasorelaxation.
Assuntos
Tecido Adiposo/metabolismo , Hipertensão/metabolismo , Palmitatos/metabolismo , Vasodilatadores/metabolismo , 4-Aminopiridina/farmacologia , Adipócitos/metabolismo , Tecido Adiposo/efeitos dos fármacos , Angiotensina II/metabolismo , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Cálcio/metabolismo , Células Cultivadas , Endotélio Vascular/efeitos dos fármacos , Fibroblastos/metabolismo , Glibureto/farmacologia , Hipertensão/tratamento farmacológico , Losartan/farmacologia , Masculino , Peptídeos/farmacologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Tetraetilamônio/farmacologia , Vasodilatação/efeitos dos fármacosRESUMO
The α(7)-nicotinic ACh receptor (α(7)-nAChR) on sympathetic neurons innervating basilar arteries of pigs crossed bred between Landrace and Yorkshire (LY) is known to mediate nicotine-induced, ß-amyloid (Aß)-sensitive nitrergic neurogenic vasodilation. Preliminary studies, however, demonstrated that nicotine-induced cerebral vasodilation in pigs crossbred among Landrace, Yorkshire, and Duroc (LYD) was insensitive to Aß and α-bungarotoxin (α-BGTX). We investigated nAChR subtype on sympathetic neurons innervating LYD basilar arteries. Nicotine-induced relaxation of porcine isolated basilar arteries was examined by tissue bath myography, inward currents on nAChR-expressing oocytes by two-electrode voltage recording, and mRNA and protein expression in the superior cervical ganglion (SCG) and middle cervical ganglion (MCG) by reverse transcription PCR and Western blotting. Nicotine-induced basilar arterial relaxation was not affected by Aß, α-BGTX, and α-conotoxin IMI (α(7)-nAChR antagonists), or α-conotoxin AuIB (α(3)ß(4)-nAChR antagonist) but was inhibited by tropinone and tropane (α(3)-containing nAChR antagonists) and α-conotoxin MII (selective α(3)ß(2)-nAChR antagonist). Nicotine-induced inward currents in α(3)ß(2)-nAChR-expressing oocytes were inhibited by α-conotoxin MII but not by α-BGTX, Aß, or α-conotoxin AuIB. mRNAs of α(3)-, α(7)-, ß(2)-, and ß(4)-subunits were expressed in both SCGs and MCGs with significantly higher mRNAs of α(3)-, ß(2)-, and ß(4)-subunits than that of α(7)-subunit. The Aß-insensitive sympathetic α(3)ß(2)-nAChR mediates nicotine-induced cerebral nitrergic neurogenic vasodilation in LYD pigs. The different finding from Aß-sensitive α(7)-nAChR in basilar arteries of LY pigs may offer a partial explanation for different sensitivities of individuals to Aß in causing diminished cerebral nitrergic vasodilation in diseases involving Aß.
Assuntos
Artéria Basilar/inervação , Neurônios Nitrérgicos/metabolismo , Receptores Nicotínicos/metabolismo , Gânglio Cervical Superior/metabolismo , Vasodilatação , Peptídeos beta-Amiloides/metabolismo , Animais , Artéria Basilar/efeitos dos fármacos , Western Blotting , Relação Dose-Resposta a Droga , Estimulação Elétrica , Feminino , Humanos , Masculino , Potenciais da Membrana , Miografia , Agonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/farmacologia , Neurônios Nitrérgicos/efeitos dos fármacos , Oócitos , Técnicas de Patch-Clamp , RNA Mensageiro/metabolismo , Receptores Nicotínicos/efeitos dos fármacos , Receptores Nicotínicos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Gânglio Cervical Superior/efeitos dos fármacos , Suínos , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , XenopusRESUMO
Urocortin (UCN) is a member of the corticotropin-releasing hormone (CRH) family of neuropeptides that regulates stress responses. Although UCN is principally expressed in dopaminergic neurons in rat substantia nigra (SN), the function of UCN in modulating dopaminergic neuronal survival remains unclear. Using primary mesencephalic cultures, we demonstrated that dopaminergic neurons underwent spontaneous cell death when their age increased in culture. Treatment of mesencephalic cultures with UCN markedly prolonged the survival of dopaminergic neurons, whereas neutralization of UCN with anti-UCN antibody accelerated dopaminergic neurons degeneration. UCN increased intracellular cAMP levels followed by phosphorylating glycogen synthase kinase-3ß (GSK-3ß) on Ser9. Moreover, UCN directly inhibited the histone deacetylase (HDAC) activity and induced a robust increase in histone H3 acetylation levels. Using pharmacological approaches, we further demonstrated that inhibition of GSK-3ß and HDAC contributes to UCN-mediated neuroprotection. These results suggest that dopaminergic neuron-derived UCN might be involved in an autocrine protective signaling mechanism.
Assuntos
Dopamina/fisiologia , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Histona Desacetilase 1/antagonistas & inibidores , Neurônios/metabolismo , Substância Negra/metabolismo , Urocortinas/fisiologia , Animais , Comunicação Autócrina/fisiologia , Morte Celular/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Hormônio Liberador da Corticotropina/fisiologia , Quinase 3 da Glicogênio Sintase/fisiologia , Glicogênio Sintase Quinase 3 beta , Histona Desacetilase 1/fisiologia , Humanos , Camundongos , Neurônios/enzimologia , Neurônios/fisiologia , Doença de Parkinson/enzimologia , Doença de Parkinson/metabolismo , Doença de Parkinson/terapia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia , Substância Negra/citologia , Substância Negra/enzimologiaRESUMO
Individual activation of nicotinic acetylcholine receptor (nAChR) or nitric oxide (NO) synthase in the dorsal facial area (DFA) increases blood flow of common carotid artery (CCA) supplying intra- and extra-cranial tissues. We investigated whether the activation of nAChR initiated the activation of NO synthase and guanylyl cyclase to increase CCA blood flow in anesthetized cats. Microinjections of nicotine (a non-selective nAChR agonist), or choline (a selective α7-nAChR agonist) in the DFA produced increases in CCA blood flow ipsilaterally. These increases were significantly reduced by pretreatment with NG-nitro-arginine methyl ester (l-NAME, a non-specific NO synthase inhibitor), 7-nitroindazole (7-NI, a relatively selective neuronal NO synthase inhibitor) or methylene blue (MB, a guanylyl cyclase inhibitor) but not by that with N5-(1-iminoethyl)-l-ornithine (l-NIO, a potent endothelial NO synthase inhibitor). Control microinjection with d-NAME (an isomer of l-NAME), artificial cerebrospinal fluid or DMSO (a solvent for 7-NI) did not affect resting CCA blood flow, nor did they affect nicotine- or choline-induced response. In conclusion, activation of nAChR, at least α7-nAChR, led to the activation of neuronal NO synthase and guanylyl cyclase in the DFA, which induced an increase in CCA blood flow.
Assuntos
Artéria Carótida Primitiva/fisiologia , Circulação Cerebrovascular/efeitos dos fármacos , Circulação Cerebrovascular/fisiologia , Guanilato Ciclase/metabolismo , Bulbo/enzimologia , Neurônios/enzimologia , Nicotina/farmacologia , Óxido Nítrico Sintase Tipo I/metabolismo , Animais , Artéria Carótida Primitiva/efeitos dos fármacos , Gatos , Ativação Enzimática/efeitos dos fármacos , Feminino , Masculino , Bulbo/irrigação sanguínea , Bulbo/efeitos dos fármacos , Microinjeções/métodos , Neurônios/efeitos dos fármacos , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/fisiologia , Receptor Nicotínico de Acetilcolina alfa7RESUMO
PURPOSE: To determine whether palmitic acid methyl ester (PAME) or methyl palmitate is the retina-derived relaxing factor (RRF). METHODS: A superfusion bioassay cascade technique was used with rat isolated retina as donor tissue and rat aortic ring as detector tissue. The superfusate was analyzed with gas chromatography/mass spectrometry (GC/MS). The biochemical and pharmacologic characteristics of RRF and PAME were compared. RESULTS: The authors demonstrated that the retina on superfusion with Krebs solution spontaneously released RRF (indicated by aortic ring relaxation) and PAME (measured by GC/MS). The release of RRF and PAME was calcium dependent because the release was abolished when the retinas were superfused with calcium-free Krebs solution. Furthermore, aortic relaxations induced by RRF and PAME were not affected after heating their solutions at 70 degrees C for 1 hour, suggesting that both are heat stable. Exogenous PAME concentration dependently induced aortic relaxation with EC50 of 0.82+/-0.75 pM. The aortic relaxations induced by RRF and exogenous PAME were inhibited by 4-aminopyridine (2 mM) and tetraethylammonium (TEA, 10 mM) but were not affected by TEA at 1 mM or 3 mM, glibenclamide (3 microM), or iberiotoxin (100 nM). The vasodilator activity of Krebs solution containing RRF or exogenous PAME was greatly attenuated after hexane extraction. CONCLUSIONS: RRF and PAME share similar biochemical properties and react similarly to all pharmacologic inhibitors examined. Both act primarily on the voltage-dependent K+ (Kv) channel of aortic smooth muscle cells, causing aortic relaxation. These results suggest that PAME is the hydrophobic RRF.
Assuntos
Aorta/fisiologia , Palmitatos/metabolismo , Retina/metabolismo , Vasos Retinianos/fisiologia , Vasodilatação/fisiologia , 4-Aminopiridina/farmacologia , Animais , Bioensaio , Cálcio/metabolismo , Cálcio/farmacologia , Inibidores Enzimáticos/farmacologia , Hexanos , Soluções Isotônicas/metabolismo , Soluções Isotônicas/farmacologia , Masculino , Miconazol/farmacologia , Nitroarginina/farmacologia , Palmitatos/isolamento & purificação , Peptídeos/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Proadifeno/farmacologia , Ratos , Ratos Sprague-Dawley , Solventes , Tetraetilamônio/farmacologia , Vasodilatação/efeitos dos fármacosRESUMO
Microinjection of nicotine or glutamate into the dorsal facial area (DFA) of the medulla increases blood flow of common carotid artery (CCA). Whether there is a causal relationship between these two events is not known. Various agonists and antagonists for the nicotinic and glutamatergic receptors were microinjected through a four-barrel tubing into the DFA of anesthetized cats. Microinjections of nicotine [a non-selective nicotinic acetylcholine receptor (nAChR) agonist], choline (a selective alpha7-nAChR agonist), glutamate or KCl induced a modest increase in CCA blood flow. The nicotine- and choline-induced increases were reduced by alpha-bungarotoxin (an alpha7-nAChR antagonist) as well as MK-801 (a non-competitive NMDA receptor antagonist) or glutamate diethylester (a competitive AMPA/kainate receptor antagonist). The glutamate or KCl-induced increases were blocked by MK-801 and glutamate diethylester, but not by alpha-bungarotoxin. In conclusion, activation of nAChRs primarily via alpha7-nAChR caused a release of glutamate, which in turn activated NMDA and AMPA receptors, while cholinergic substance was not released into the DFA to activate the nicotinic receptor.