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Gholizadeh R, Abdolmaleki Z, Bahremand T, Ghasemi M, Gharghabi M, Dehpour AR. Involvement of N-Methyl-D-Aspartate Receptors in the Anticonvulsive Effects of Licofelone on Pentylenetetrazole-Induced Clonic Seizure in Mice. J Epilepsy Res 2021; 11:14-21. [PMID: 34395219 PMCID: PMC8357553 DOI: 10.14581/jer.21003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/03/2021] [Accepted: 06/06/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Licofelone is a dual 5-lipoxygenase/cyclooxygenase inhibitor, with well-documented anti-inflammatory and analgesic effects, which is used for treatment of osteoarthritis. Recent preclinical studies have also suggested neuroprotective and anti-oxidative properties of this drug in some neurological conditions such as seizure and epilepsy. We have recently demonstrated a role for nitric oxide (NO) signaling in the anti-epileptic activity of licofelone in two seizure models in rodents. Given the important role of N-methyl-D-aspartate receptors (NMDARs) activation in the NO production and its function in the nervous system, in the present study, we further investigated the involvement of NMDAR in the effects of licofelone (1, 3, 5, 10, and 20 mg/kg, intraperitoneal [i.p.]) in an in vivo model of seizure in mice. METHODS Clonic seizures were induced in male NMRI mice by intravenous administration of pentylenetetrazol (PTZ). RESULTS Acute administration of licofelone exerted anticonvulsant effects at 10 (p<0.01) and 20 mg/kg (p<0.001). A combined treatment with sub-effective doses of the selective NMDAR antagonist MK-801 (0.05 mg/kg, i.p.) and licofelone (5 mg/kg, i.p.) significantly (p<0.001) exerted an anticonvulsant effect on the PTZ-induced clonic seizures in mice. Notably, pre-treatment with the NMDAR co-agonist D-serine (30 mg/kg, i.p.) partially hindered the anticonvulsant effects of licofelone (20 mg/kg). CONCLUSIONS Our data suggest a possible role for the NMDAR in the anticonvulsant effects of licofelone on the clonic seizures induced by PTZ in mice.
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Affiliation(s)
- Ramtin Gholizadeh
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, College of Veterinary Medicine, Islamic Azad University, Karaj, Iran
| | - Zohreh Abdolmaleki
- Department of Pharmacology, College of Veterinary Medicine, Islamic Azad University, Karaj, Iran
| | - Taraneh Bahremand
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Mehdi Gharghabi
- Department of Cancer Biology and Genetics, Comprehensive Cancer Center, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ahmad Reza Dehpour
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Rawat C, Kukal S, Dahiya UR, Kukreti R. Cyclooxygenase-2 (COX-2) inhibitors: future therapeutic strategies for epilepsy management. J Neuroinflammation 2019; 16:197. [PMID: 31666079 PMCID: PMC6822425 DOI: 10.1186/s12974-019-1592-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 09/23/2019] [Indexed: 01/15/2023] Open
Abstract
Epilepsy, a common multifactorial neurological disease, affects about 69 million people worldwide constituting nearly 1% of the world population. Despite decades of extensive research on understanding its underlying mechanism and developing the pharmacological treatment, very little is known about the biological alterations leading to epileptogenesis. Due to this gap, the currently available antiepileptic drug therapy is symptomatic in nature and is ineffective in 30% of the cases. Mounting evidences revealed the pathophysiological role of neuroinflammation in epilepsy which has shifted the focus of epilepsy researchers towards the development of neuroinflammation-targeted therapeutics for epilepsy management. Markedly increased expression of key inflammatory mediators in the brain and blood-brain barrier may affect neuronal function and excitability and thus may increase seizure susceptibility in preclinical and clinical settings. Cyclooxygenase-2 (COX-2), an enzyme synthesizing the proinflammatory mediators, prostaglandins, has widely been reported to be induced during seizures and is considered to be a potential neurotherapeutic target for epilepsy management. However, the efficacy of such therapy involving COX-2 inhibition depends on various factors viz., therapeutic dose, time of administration, treatment duration, and selectivity of COX-2 inhibitors. This article reviews the preclinical and clinical evidences supporting the role of COX-2 in seizure-associated neuroinflammation in epilepsy and the potential clinical use of COX-2 inhibitors as a future strategy for epilepsy treatment.
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Affiliation(s)
- Chitra Rawat
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi, 110007, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), Delhi, India
| | - Samiksha Kukal
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi, 110007, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), Delhi, India
| | - Ujjwal Ranjan Dahiya
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi, 110007, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), Delhi, India
| | - Ritushree Kukreti
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi, 110007, India. .,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR), Delhi, India.
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Hussein UK, Hassan NEHY, Elhalwagy MEA, Zaki AR, Abubakr HO, Nagulapalli Venkata KC, Jang KY, Bishayee A. Ginger and Propolis Exert Neuroprotective Effects against Monosodium Glutamate-Induced Neurotoxicity in Rats. Molecules 2017; 22:E1928. [PMID: 29117134 PMCID: PMC6150236 DOI: 10.3390/molecules22111928] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/19/2022] Open
Abstract
Central nervous system cytotoxicity is linked to neurodegenerative disorders. The objective of the study was to investigate whether monosodium glutamate (MSG) neurotoxicity can be reversed by natural products, such as ginger or propolis, in male rats. Four different groups of Wistar rats were utilized in the study. Group A served as a normal control, whereas group B was orally administered with MSG (100 mg/kg body weight, via oral gavage). Two additional groups, C and D, were given MSG as group B along with oral dose (500 mg/kg body weight) of either ginger or propolis (600 mg/kg body weight) once a day for two months. At the end, the rats were sacrificed, and the brain tissue was excised and levels of neurotransmitters, ß-amyloid, and DNA oxidative marker 8-OHdG were estimated in the brain homogenates. Further, formalin-fixed and paraffin-embedded brain sections were used for histopathological evaluation. The results showed that MSG increased lipid peroxidation, nitric oxide, neurotransmitters, and 8-OHdG as well as registered an accumulation of ß-amyloid peptides compared to normal control rats. Moreover, significant depletions of glutathione, superoxide dismutase, and catalase as well as histopathological alterations in the brain tissue of MSG-treated rats were noticed in comparison with the normal control. In contrast, treatment with ginger greatly attenuated the neurotoxic effects of MSG through suppression of 8-OHdG and β-amyloid accumulation as well as alteration of neurotransmitter levels. Further improvements were also noticed based on histological alterations and reduction of neurodegeneration in the brain tissue. A modest inhibition of the neurodegenerative markers was observed by propolis. The study clearly indicates a neuroprotective effect of ginger and propolis against MSG-induced neurodegenerative disorders and these beneficial effects could be attributed to the polyphenolic compounds present in these natural products.
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Affiliation(s)
- Usama K Hussein
- Zoology Department, Faculty of Science, Beni-Suef University, Beni Suef 62511, Egypt.
- Department of Pathology, Chonbuk National University Medical School, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University, Hospital and Research Institute for Endocrine Sciences, Jeonju 54896, Korea.
| | - Nour El-Houda Y Hassan
- Department of Toxicology and Forensic Medicine, Faculty of Veterinary Medicine, Beni-Suef University, Beni Suef 62511, Egypt.
| | - Manal E A Elhalwagy
- Faculty of Science, Al Faisaliah Campus, King Abdulaziz University, Jeddah 21453, Saudi Arabia.
| | - Amr R Zaki
- Department of Forensic Medicine and Clinical Toxicology, Faculty of Medicine, Beni-Suef University, Beni Suef 62511, Egypt.
| | - Huda O Abubakr
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Cairo University, Giza 12613, Egypt.
| | | | - Kyu Yun Jang
- Department of Pathology, Chonbuk National University Medical School, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University, Hospital and Research Institute for Endocrine Sciences, Jeonju 54896, Korea.
| | - Anupam Bishayee
- Department of Pharmaceutical Sciences, College of Pharmacy, Larkin University, Miami, FL 33169, USA.
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Deng S, Liu H, Qiu K, You H, Lei Q, Lu W. Role of the Golgi Apparatus in the Blood-Brain Barrier: Golgi Protection May Be a Targeted Therapy for Neurological Diseases. Mol Neurobiol 2017; 55:4788-4801. [PMID: 28730529 DOI: 10.1007/s12035-017-0691-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 07/13/2017] [Indexed: 12/17/2022]
Abstract
The blood-brain barrier (BBB) protects the brain from toxic material in the blood, provides nutrients for brain tissues, and screens harmful substances from the brain. The specific brain microvascular endothelial cells (BMVECs), tight junction between endothelial cells, and astrocytes ensure proper function of the central nervous system (CNS). Pathological factors disrupt the integrity of the BBB by destroying the normal function of endothelial cells and decreasing the production of tight junction proteins or the expression of proteins specifically localized on astrocytes. Interestingly, fragmentation of the Golgi apparatus is observed in neurological diseases and is involved in the destruction of the BBB function. The Golgi acts as a processing center in which proteins are transported after being processed in the endoplasmic reticulum. Besides reprocessing, classifying, and packaging proteins, the Golgi apparatus (GA) also acts as a signaling platform and calcium pool. In this review, we summarized the current literature on the potential relationship between the Golgi and endothelial cells, tight junction, and astrocytes. The normal function of the BBB is maintained as long as the normal function and morphology of the GA are not disturbed. Furthermore, we speculate that protecting the Golgi may be a novel therapeutic approach to protect the BBB and treat neurological diseases due to BBB dysfunction.
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Affiliation(s)
- Shuwen Deng
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China
| | - Hui Liu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China
| | - Ke Qiu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China
| | - Hong You
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China
| | - Qiang Lei
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China
| | - Wei Lu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, 410011, People's Republic of China.
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Park JC, Baik SH, Han SH, Cho HJ, Choi H, Kim HJ, Choi H, Lee W, Kim DK, Mook-Jung I. Annexin A1 restores Aβ 1-42 -induced blood-brain barrier disruption through the inhibition of RhoA-ROCK signaling pathway. Aging Cell 2017; 16:149-161. [PMID: 27633771 PMCID: PMC5242298 DOI: 10.1111/acel.12530] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2016] [Indexed: 12/15/2022] Open
Abstract
The blood–brain barrier (BBB) is composed of brain capillary endothelial cells and has an important role in maintaining homeostasis of the brain separating the blood from the parenchyma of the central nervous system (CNS). It is widely known that disruption of the BBB occurs in various neurodegenerative diseases, including Alzheimer's disease (AD). Annexin A1 (ANXA1), an anti‐inflammatory messenger, is expressed in brain endothelial cells and regulates the BBB integrity. However, its role and mechanism for protecting BBB in AD have not been identified. We found that β‐Amyloid 1‐42 (Aβ42)‐induced BBB disruption was rescued by human recombinant ANXA1 (hrANXA1) in the murine brain endothelial cell line bEnd.3. Also, ANXA1 was decreased in the bEnd.3 cells, the capillaries of 5XFAD mice, and the human serum of patients with AD. To find out the mechanism by which ANXA1 recovers the BBB integrity in AD, the RhoA‐ROCK signaling pathway was examined in both Aβ42‐treated bEnd.3 cells and the capillaries of 5XFAD mice as RhoA was activated in both cases. RhoA inhibitors alleviated Aβ42‐induced BBB disruption and constitutively overexpressed RhoA‐GTP (active form of RhoA) attenuated the protective effect of ANXA1. When pericytes were cocultured with bEnd.3 cells, Aβ42‐induced RhoA activation of bEnd.3 cells was inhibited by the secretion of ANXA1 from pericytes. Taken together, our results suggest that ANXA1 restores Aβ42‐induced BBB disruption through inhibition of RhoA‐ROCK signaling pathway and we propose ANXA1 as a therapeutic reagent, protecting against the breakdown of the BBB in AD.
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Affiliation(s)
- Jong-Chan Park
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Sung Hoon Baik
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Sun-Ho Han
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Hyun Jin Cho
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Hyunjung Choi
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Haeng Jun Kim
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Heesun Choi
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Wonik Lee
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Dong Kyu Kim
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences; College of Medicine; Seoul National University; Seoul 110-799 Korea
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Imer M, Omay B, Uzunkol A, Erdem T, Sabanci PA, Karasu A, Albayrak SB, Sencer A, Hepgul K, Kaya M. Effect of magnesium, MK-801 and combination of magnesium and MK-801 on blood–brain barrier permeability and brain edema after experimental traumatic diffuse brain injury. Neurol Res 2013; 31:977-81. [DOI: 10.1179/174313209x385617] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Bolton C. Neurovascular damage in experimental allergic encephalomyelitis: a target for pharmacological control. Mediators Inflamm 2012; 6:295-302. [PMID: 18472862 PMCID: PMC2365877 DOI: 10.1080/09629359791415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The blood-brain barrier (BBB) is composed of a continuous endothelial layer with pericytes and astrocytes in close proximity to offer homeostatic control to the neurovasculature. The human demyelinating disease multiple sclerosis and the animal counterpart experimental allergic encephalomyelitis (EAE) are characterized by enhanced permeability of the BBB facilitating oedema formation and recruitment of systemically derived inflammatory-type cells into target tissues to mediate eventual myelin loss and neuronal dysfunction. EAE is considered a useful model for examining the pathology which culminates in loss of BBB integrity and the disease is now proving valuable in assessing compounds for efficacy in limiting damage at neurovascular sites. The precise mechanisms culminating in EAE-induced BBB breakdown are unclear although several potentially disruptive mediators have been implicated and have been previously identified as potent effectors of cerebrovascular damage in non-disease related conditions of the central nervous system. The review considers evidence that common mechanisms may mediate cerebrovascular permeability changes irrespective of the initial insult and discusses therapeutic approaches for the control of BBB leakage in the demyelinating diseases.
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Affiliation(s)
- C Bolton
- Pharmacology Group, School of Pharmacy and Pharmacology, University of Bath, Bath, BA2 7AY UK.
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Chi OZ, Barsoum S, Grayson J, Hunter C, Liu X, Weiss HR. Effects of Cannabinoid Receptor Agonist WIN 55,212-2 on Blood-Brain Barrier Disruption in Focal Cerebral Ischemia in Rats. Pharmacology 2012; 89:333-8. [DOI: 10.1159/000338755] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 03/16/2012] [Indexed: 11/19/2022]
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Potschka H. Modulating P-glycoprotein regulation: future perspectives for pharmacoresistant epilepsies? Epilepsia 2010; 51:1333-47. [PMID: 20477844 DOI: 10.1111/j.1528-1167.2010.02585.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Enhanced brain efflux of antiepileptic drugs by the blood-brain barrier transporter P-glycoprotein is discussed as one mechanism contributing to pharmacoresistance of epilepsies. P-glycoprotein overexpression has been proven to occur as a consequence of seizure activity. Therefore, blocking respective signaling events should help to improve brain penetration and efficacy of P-glycoprotein substrates. A series of recent studies revealed key signaling factors involved in seizure-associated transcriptional activation of P-glycoprotein. These data suggested several interesting targets, including the N-methyl-d-aspartate (NMDA) receptor, the inflammatory enzyme cyclooxygenase-2, and the prostaglandin E2 EP1 receptor. These targets have been further evaluated in rodent models, demonstrating that targeting these factors can control P-glycoprotein expression, improve antiepileptic drug brain penetration, and help to overcome pharmacoresistance. In general, the approach offers particular advantages over transporter inhibition as it preserves basal transporter function. In this review the different strategies for blocking P-glycoprotein upregulation, including their therapeutic promise and drawbacks are discussed. Moreover, pros and cons of the approach are compared to those of alternative strategies to overcome transporter-associated resistance. Regarding future perspectives of the novel approach, there is an obvious need to more clearly define the clinical relevance of transporter overexpression. In this context current efforts are discussed, including the development of imaging tools that allow an evaluation of P-glycoprotein function in individual patients.
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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Reijerkerk A, Kooij G, van der Pol SMA, Leyen T, Lakeman K, van het Hof B, Vivien D, de Vries HE. The NR1 subunit of NMDA receptor regulates monocyte transmigration through the brain endothelial cell barrier. J Neurochem 2010; 113:447-53. [DOI: 10.1111/j.1471-4159.2010.06598.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Liu X, Hunter C, Weiss HR, Chi OZ. Effects of blockade of ionotropic glutamate receptors on blood-brain barrier disruption in focal cerebral ischemia. Neurol Sci 2010; 31:699-703. [PMID: 20217443 DOI: 10.1007/s10072-010-0241-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
Abstract
To determine whether blockade of ionotropic glutamate receptors such as NMDA or AMPA receptors would attenuate blood-brain barrier (BBB) disruption in focal cerebral ischemia, 15 min before middle cerebral artery (MCA) occlusion, CGS-19755 or NBQX was injected intraperitoneally in rats. At 1 h after MCA occlusion, BBB permeability was determined by measuring the transfer coefficient (K(i)) of (14)C-α-aminoisobutyric acid and the volume of dextran distribution. With MCA occlusion, K(i) was increased in the ischemic cortex (IC) (316%). CGS-19755 attenuated the increase in K(i) in the IC (-46%), but NBQX did not significantly decrease it. The difference in the volume of dextran distribution between the IC and the contralateral cortex became insignificant with the blockade of NMDA or AMPA receptors. Our data demonstrated that blockade of NMDA or AMPA receptors could attenuate the BBB disruption in focal cerebral ischemia and suggest that ionotropic glutamate receptors are involved in part in BBB disruption.
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Affiliation(s)
- Xia Liu
- Department of Anesthesia, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Suite 3100, New Brunswick, NJ 08901-1977, USA
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Effects of exogenous excitatory amino acid neurotransmitters on blood-brain barrier disruption in focal cerebral ischemia. Neurochem Res 2009; 34:1249-54. [PMID: 19127429 DOI: 10.1007/s11064-008-9902-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2008] [Indexed: 10/21/2022]
Abstract
This study was performed to determine whether exogenous N-methyl-D: -aspartate (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) would aggravate blood-brain barrier (BBB) disruption in focal cerebral ischemia in rats. Forty-five minutes after middle cerebral artery (MCA) occlusion, one of the following patches was applied to the exposed ischemic cerebral cortex of each rat: normal saline (control), 10(-5) M AMPA, 10(-4) M AMPA, 10(-5) M NMDA, or 10(-4) M NMDA. At 1 h after MCA occlusion, BBB permeability was determined by measuring the transfer coefficient (Ki) of (14)C-alpha-aminoisobutyric acid ((14)C-AIB). In all experimental groups, the Ki of the ischemic cortex (IC) was higher than that of the corresponding contralateral cortex (CC). The Ki of the IC of the animals treated with 10(-4) M AMPA or 10(-4) M NMDA was higher (+41%: P < 0.05 and +33%: P < 0.05, respectively) than that of the control animals. Our data demonstrated that exogenous NMDA or AMPA could further aggravate the BBB disruption in focal cerebral ischemia. Any insult increasing the release of excitatory neurotransmitters could further aggravate BBB disruption and brain edema during the ischemic period.
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Minagar A, Steven Alexander J, Kelley RE, Harper M, Jennings MH. Proteomic Analysis of Human Cerebral Endothelial Cells Activated by Glutamate/MK-801: Significance in Ischemic Stroke Injury. J Mol Neurosci 2008; 38:182-92. [DOI: 10.1007/s12031-008-9149-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 08/29/2008] [Indexed: 01/28/2023]
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Shi F, Cavitt J, Bailey CA, Malick AW, Audus KL. Characterization of Dextromethorphan and Dextrorphan Uptake by a Putative Glutamic Acid Carrier and Passive Diffusion across Brain Microvessel Endothelium. Drug Deliv 2008. [DOI: 10.3109/10717549309022764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Domoki F, Kis B, Gáspár T, Bari F, Busija DW. Cerebromicrovascular endothelial cells are resistant to L-glutamate. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1099-108. [PMID: 18667711 DOI: 10.1152/ajpregu.90430.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral microvascular endothelial cells (CMVECs) have recently been implicated as targets of excitotoxic injury by l-glutamate (l-glut) or N-methyl-d-aspartate (NMDA) in vitro. However, high levels of l-glut do not compromise the function of the blood-brain barrier in vivo. We sought to determine whether primary cultures of rat and piglet CMVECs or cerebral microvascular pericytes (CMVPCs) are indeed sensitive to l-glut or NMDA. Viability was unaffected by 8-h exposure to 1-10 mM l-glut or NMDA in CMVECs or CMVPCs isolated from both species. Furthermore, neither 1 mM l-glut nor NMDA augmented cell death induced by 12-h oxygen-glucose deprivation in rat CMVECs or by 8-h medium withdrawal in CMVPCs. Additionally, transendothelial electrical resistance of rat CMVEC-astrocyte cocultures or piglet CMVEC cultures were not compromised by up to 24-h exposure to 1 mM l-glut or NMDA. The Ca(2+) ionophore calcimycin (5 microM), but not l-glut (1 mM), increased intracellular Ca(2+) levels in rat CMVECs and CMVPCs assessed with fluo-4 AM fluorescence and confocal microscopy. CMVEC-dependent pial arteriolar vasodilation to hypercapnia and bradykinin was unaffected by intracarotid infusion of l-glut in anesthetized piglets by closed cranial window/intravital microscopy. We conclude that cerebral microvascular cells are insensitive and resistant to glutamatergic stimuli in accordance with their in vivo role as regulators of potentially neurotoxic amino acids across the blood-brain barrier.
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Affiliation(s)
- Ferenc Domoki
- Dept. of Physiology and Pharmacology, Wake Forest Univ. Health Sciences, Medical Center Blvd, Hanes Bldg 1052, Winston-Salem, NC 27157-1010, USA.
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Abstract
The constitutive isoform of heme oxygenase, HO-2, is highly expressed in the brain and in cerebral vessels. HO-2 functions in the brain have been evaluated using pharmacological inhibitors of the enzyme and HO-2 gene deletion in in vivo animal models and in cultured cells (neurons, astrocytes, cerebral vascular endothelial cells). Rapid activation of HO-2 via post-translational modifications without upregulation of HO-2 expression or HO-1 induction coincides with the increase in cerebral blood flow aimed at maintaining brain homeostasis and neuronal survival during seizures, hypoxia, and hypotension. Pharmacological inhibition or gene deletion of brain HO-2 exacerbates oxidative stress induced by seizures, glutamate, and inflammatory cytokines, and causes cerebral vascular injury. Carbon monoxide (CO) and bilirubin, the end products of HO-catalyzed heme degradation, have distinct cytoprotective functions. CO, by binding to a heme prosthetic group, regulates the key components of cell signaling, including BK(Ca) channels, guanylyl cyclase, NADPH oxidase, and the mitochondria respiratory chain. Cerebral vasodilator effects of CO are mediated via activation of BK(Ca) channels and guanylyl cyclase. CO, by inhibiting the major components of endogenous oxidant-generating machinery, NADPH oxidase and the cytochrome C oxidase of the mitochondrial respiratory chain, blocks formation of reactive oxygen species. Bilirubin, via redox cycling with biliverdin, is a potent oxidant scavenger that removes preformed oxidants. Overall, HO-2 has dual housekeeping cerebroprotective functions by maintaining autoregulation of cerebral blood flow aimed at improving neuronal survival in a changing environment, and by providing an effective defense mechanism that blocks oxidant formation and prevents cell death caused by oxidative stress.
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Affiliation(s)
- Helena Parfenova
- Laboratory for Research in Neonatal Physiology, Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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17
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Titova E, Ostrowski RP, Sowers LC, Zhang JH, Tang J. Effects of apocynin and ethanol on intracerebral haemorrhage-induced brain injury in rats. Clin Exp Pharmacol Physiol 2007; 34:845-50. [PMID: 17645627 DOI: 10.1111/j.1440-1681.2007.04664.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. In the present study, we investigated whether the administration of apocynin, an NADPH oxidase inhibitor, provided brain protection in a rat model of intracerebral haemorrhage (ICH). 2. Rats were divided into sham, ICH untreated, ICH treated with vehicle (ethanol) and ICH treated with apocynin groups. Intracerebral haemorrhage was induced by collagenase injection. Neurological function, haemorrhage volume and brain oedema were measured 24 h after ICH. 3. Intracerebral haemorrhage caused significant neurological deficit associated with brain oedema. Apocynin (3, 10 and 30 mg/kg) failed to reduce brain injury after ICH. Low dose ethanol (0.2 g/kg) improved neurological function and reduced brain oedema (ICH-vehicle vs ICH-untreated, P < 0.05). 4. In conclusion, apocynin has no neuroprotective effect when administered intraperitoneally after ICH.
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Affiliation(s)
- Elena Titova
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, California 92354, USA
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18
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Abstract
Multiple sclerosis (MS) is a chronic demyelinating disease of the
human central nervous system (CNS). The condition predominantly
affects young adults and is characterised by immunological and
inflammatory changes in the periphery and CNS that contribute to
neurovascular disruption, haemopoietic cell invasion of target
tissues, and demyelination of nerve fibres which culminate in
neurological deficits that relapse and remit or are progressive.
The main features of MS can be reproduced in the inducible animal
counterpart, experimental autoimmune encephalomyelitis (EAE). The
search for new MS treatments invariably employs EAE to determine
drug activity and provide a rationale for exploring clinical
efficacy. The preclinical development of compounds for MS has
generally followed a conventional, immunotherapeutic route.
However, over the past decade, a group of compounds that suppress
EAE but have no apparent immunomodulatory activity have emerged.
These drugs interact with the N-methyl-D-aspartate (NMDA) and
α-amino-3-hydroxy-5-isoxazolepropionic acid (AMPA)/kainate
family of glutamate receptors reported to control neurovascular
permeability, inflammatory mediator synthesis, and resident glial
cell functions including CNS myelination. The review considers the
importance of the glutamate receptors in EAE and MS pathogenesis.
The use of receptor antagonists to control EAE is also discussed
together with the possibility of therapeutic application in
demyelinating disease.
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Affiliation(s)
- Christopher Bolton
- Centre for Biochemical Pharmacology and Experimental Pathology, John Vane Science
Centre, St Bartholomew's Hospital Medical School, Charterhouse Square, London EC1M 6BQ, UK
- *Christopher Bolton:
| | - Carolyn Paul
- Faculty of Applied Sciences, University of the West of England, Frenchay Campus,
Coldharbour Lane, Bristol BS16 1QY, UK
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19
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Xiao F, Pardue S, Arnold TC, Monroe J, Alexander JS, Carden DL, Turnage R, Conrad SA. Ifenprodil treatment is associated with a down-regulation of brain aquaporin 4 following cardiac arrest in rats. ACTA NEUROCHIRURGICA. SUPPLEMENT 2006; 95:415-9. [PMID: 16463893 DOI: 10.1007/3-211-32318-x_85] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
OBJECTIVES Ifenprodil, a NMDA receptor polyamine site antagonist, reduces experimental cardiac arrest (CA)-elicited brain edema, which is associated with an up-regulation of aquaporin 4 (AQP4), a brain water-selective channel. However, the interacting roles of NMDA receptors and AQP4 in CA-elicited brain edema are unknown. The objective of this study was to test our hypothesis that ifenprodil treatment is associated with a down-regulation of brain AQP4. METHODS Twenty-five rats were assigned to normal controls (group 1, n = 6) or subjected to eight minutes of asphyxial CA treated with placebo (group 2, n = 9) or ifenprodil (group 3, n = 10). Ifenprodil at 10 mg/kg or normal saline of equal volume was given intraperitoneally, 5 minutes before CA. The density of AQP4 protein and actin bands was scanned and expressed as the ratios of the optical density of AQP4 relative to that of actin. The ANOVA analysis was used to compare the group differences. RESULTS The ratios of the optical density of AQP4 to that of actin were 0.88 +/- 0.06 in group 1, 1.11 +/- 0.08 in group 2 (p < 0.05 vs. group 1), and 0.78 +/- 0.04 in group 3 (p < 0.01 vs. group 2; NS vs. group 1). CONCLUSION Ifenprodil given before CA is associated with a downregulation of brain AQP4 in rats.
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Affiliation(s)
- F Xiao
- Department of Emergency Medicine, Louisiana State University Health Science Center, Shreveport 71130, USA.
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20
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de Lange ECM, Ravenstijn PGM, Groenendaal D, van Steeg TJ. Toward the prediction of CNS drug-effect profiles in physiological and pathological conditions using microdialysis and mechanism-based pharmacokinetic-pharmacodynamic modeling. AAPS JOURNAL 2005; 7:E532-43. [PMID: 16353931 PMCID: PMC2751256 DOI: 10.1208/aapsj070354] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Our ultimate goal is to develop mechanism-based pharmacokinetic (PK)-pharmacodynamic (PD) models to characterize and to predict CNS drug responses in both physiologic and pathologic conditions. To this end, it is essential to have information on the biophase pharmacokinetics, because these may significantly differ from plasma pharmacokinetics. It is anticipated that biophase kinetics of CNS drugs are strongly influenced by transport across the blood-brain barrier (BBB). The special role of microdialysis in PK/PD modeling of CNS drugs lies in the fact that it enables the determination of free-drug concentrations as a function of time in plasma and in extracellular fluid of the brain, thereby providing important data to determine BBB transport characteristics of drugs. Also, the concentrations of (potential) extracellular biomarkers of drug effects or disease can be monitored with this technique. Here we describe our studies including microdialysis on the following: (1) the evaluation of the free drug hypothesis; (2) the role of BBB transport on the central effects of opioids; (3) changes in BBB transport and biophase equilibration of anti-epileptic drugs; and (4) the relation among neurodegeneration, BBB transport, and drug effects in Parkinson's disease progression.
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Affiliation(s)
- Elizabeth C M de Lange
- Leiden/Amsterdam Center for Drug Research, Division of Pharmacology, Gorlaeus Laboratories, 2300 RA, Leiden University, Leiden, The Netherlands.
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21
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Banks WA, Kumar VB, Franko MW, Bess JW, Arthur LO. Evidence that the species barrier of human immunodeficiency virus-1 does not extend to uptake by the blood--brain barrier: comparison of mouse and human brain microvessels. Life Sci 2005; 77:2361-8. [PMID: 15946698 DOI: 10.1016/j.lfs.2004.11.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Accepted: 11/17/2004] [Indexed: 11/15/2022]
Abstract
HIV-1 within the CNS produces a neuroAIDS syndrome and may act as a reservoir for reinfection of the peripheral tissues. Study of how HIV-1 crosses the blood-brain barrier (BBB) has been hampered by the lack of nonprimate animal models. However, BBB transport of HIV-1 does not involve any of the known steps conferring species specificity, including binding to CD4 receptors. In vivo and in vitro studies show that HIV-1 and its glycoprotein coat, gp120, are taken up and transported across the BBB of the mouse. Here, we compared the ability of gp120 and HIV-1 to be taken up by isolated brain microvessels (IBM) freshly isolated from mice, from post-mortem human brain, and from mice that had been treated in a manner analogous to the human material (mouse post-mortem). Freshly isolated mouse IBM took up more gp120 and HIV-1 than the human or mouse post-mortem cells. We found no difference between the ability of mouse post-mortem and human IBM to take up either gp120 or HIV-1. Wheatgerm agglutinin has been previously shown to stimulate gp120 and HIV-1 uptake by the BBB; here, it stimulated the uptake of gp120 and of HIV-1 by both mouse post-mortem and human IBM, although stimulated uptake was greatest for fresh mouse IBM. These results show that the mouse can be used to study the initial phases of HIV-1 uptake by the BBB.
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Affiliation(s)
- William A Banks
- GRECC, Veterans Affairs Medical Center--St. Louis and Saint Louis University School of Medicine, Division of Geriatrics, Department of Internal Medicine, St. Louis, MO 63106, USA.
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22
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St'astný F, Lisý V, Mares V, Lisá V, Balcar VJ, Santamaría A. Quinolinic acid induces NMDA receptor-mediated lipid peroxidation in rat brain microvessels. Redox Rep 2005; 9:229-33. [PMID: 15479567 DOI: 10.1179/135100004225006001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Quinolinic acid increased the generation of lipid peroxidation products by isolated rat brain microvessels in vitro. The effect was inhibited both by a specific NMDA receptor antagonist D-2-amino-5-phosphonovaleric acid and by reduced glutathione (GSH). Furthermore, quinolinic acid displaced specific binding of [(3)H]-L-glutamate by cerebral microvessel membranes, particularly in the presence of NMDA receptor co-agonist (glycine) and modulator (spermidine). We conclude that quinolinic acid can cause potentially cytotoxic lipid peroxidation in brain microvessels via an NMDA receptor mediated mechanism.
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Affiliation(s)
- Frantisek St'astný
- Prague Psychiatric Centre affiliated with Charles University 3rd Faculty of Medicine, Prague, Czech Republic
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23
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Liu X, Chi OZ, Weiss HR. Effects of metabotropic glutamate receptor stimulation on blood-brain barrier permeability during focal cerebral ischemia. Neurochem Res 2005; 29:1857-62. [PMID: 15532541 DOI: 10.1023/b:nere.0000042212.14137.6f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This investigation was performed to evaluate whether ACPD [(1S, 3R)-1-aminocyclopentane-1, 3-dicarboxylic acid], a metabotropic glutamate receptor agonist, would enhance the degree of increase in blood-brain barrier (BBB) permeability caused by focal cerebral ischemia. In this study, male Wistar rats were placed in control (n = 7) and ACPD (n = 7) groups under isoflurane anesthesia. Twenty minutes after middle cerebral artery (MCA) occlusion, patches of 10(-5) M ACPD or normal saline were placed on the ischemic cortex (IC) for a period of 40 min. Patches were changed every 10 min. One hour after MCA occlusion, BBB permeability was determined by measuring the transfer coefficient (Ki) of [alpha-14C] aminoisobutyric acid. There were no statistical differences in systemic blood pressures and heart rates between these groups. Blood gases were within normal limits. In the control group, the Ki of ischemic cortex (IC) was 2.1 times that of the contralateral cortex (CC) (3.7+/-0.9 vs. 1.8+/-0.3 microl/g/min). In the ACPD group, the Ki of the IC was 3.3 times that of the CC (5.0+/-0.7 vs. 1.5+/-0.4 microl/g/min). The increase in Ki of the ACPD group in the ischemic cortex was significantly greater than that in the control group. There was no significant difference in the Ki of the CC between these groups. Our data suggest that activation metabotropic glutamate receptors in the cortex can further augment the increase in BBB permeability caused by focal ischemia.
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Affiliation(s)
- Xia Liu
- Department of Physiology & Biophysics and Anesthesiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA
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24
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Banks WA, Robinson SM, Wolf KM, Bess JW, Arthur LO. Binding, internalization, and membrane incorporation of human immunodeficiency virus-1 at the blood-brain barrier is differentially regulated. Neuroscience 2004; 128:143-53. [PMID: 15450361 DOI: 10.1016/j.neuroscience.2004.06.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2004] [Indexed: 11/24/2022]
Abstract
Human immunodeficiency virus (HIV)-1 within the CNS induces neuro-acquired immunodeficiency syndrome and acts as a reservoir for reinfection of peripheral tissues. HIV-1 crosses the blood-brain barrier (BBB) within infected immune cells and as cell-free virus by a CD4-independent mechanism. Which proteins control free virus transport across the BBB are unknown, but work with wheatgerm agglutinin (WGA) and heparin suggests that heparan sulfate proteoglycans, sialic acid, and N-acetyl-beta-D-glucosaminyl acid bind HIV-1. Here, we found that an HIV-1 T-tropic virus was taken up by mouse brain endothelial cells in vitro and crossed the BBB in vivo and could be effluxed as intact virus. Uptake was stimulated by WGA and protamine sulfate (PS) and inhibited by heparin. BBB uptake of virus involved four distinguishable binding sites: i) reversible cell surface binding involving gp120 and sensitive to PS/heparin but insensitive to WGA; internalization with a ii) WGA-sensitive site binding gp120 and iii) a PS/heparin-sensitive site not involving gp120; iv) membrane incorporation not affected by WGA, heparin, or PS. In conclusion, binding, internalization, and membrane incorporation are separately regulated steps likely determining whether HIV-1 is incorporated into brain endothelial cells, transported across them, or returned to the circulation.
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Affiliation(s)
- W A Banks
- GRECC, Veterans Affairs Medical Center-St. Louis and St. Louis University School of Medicine, Division of Geriatrics, Department of Internal Medicine, St. Louis, MO 63106, USA.
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25
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Xiao F, Pardue S, Arnold T, Carden D, Alexander JS, Monroe J, Sharp CD, Turnage R, Conrad S. Effect of ifenprodil, a polyamine site NMDA receptor antagonist, on brain edema formation following asphyxial cardiac arrest in rats. Resuscitation 2004; 61:209-19. [PMID: 15135198 DOI: 10.1016/j.resuscitation.2003.12.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 12/18/2003] [Accepted: 12/18/2003] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Brain edema occurs in experimental and clinical cardiac arrest (CA) and is predictive of a poor neurological outcome. N-Methyl--aspartate (NMDA) receptors contribute to brain edema elicited by focal cerebral ischemia/reperfusion (I/R). Ifenprodil, a NMDA receptor antagonist, attenuates brain edema and injury size in rats after focal cerebral I/R. We assessed the hypothesis that ifenprodil reduces CA-elicited brain edema. METHODS Eighteen male Sprague-Dawley rats were assigned to group 1 (normal control, n=6), group 2 (placebo-treated CA, n=6), or group 3 (ifenprodil-treated CA, n=6). CA was induced by 8 min of asphyxiation and the animals were resuscitated with cardiopulmonary resuscitation (CPR), ventilation, epinephrine (adrenaline), and sodium bicarbonate (NaHCO3). Ifenprodil of 10 mg/kg or a placebo vehicle was given intraperitoneally 5 min before CA. Brain edema was determined by brain wet-to-dry weight ratio at 1 h after resuscitation. RESULTS There were no differences between groups 2 and 3 in all physiological variables at baseline. Time from asphyxiation to CA was 201.5 +/- 7.5 s in group 2 and 160.7 +/- 10.4 s in group 3 (P<0.001). Resuscitation time was 68.2 +/- 13.3 s in group 2 and 92.8 +/- 18.2 s in group 3 (P<0.05). Ifenprodil decreased mean arterial pressure (MAP) before asphyxiation, from 128 +/- 7 in group 2 to 82 +/- 15 mmHg in group 3 (P<0.001), and negated immediate post-resuscitation hypertension. Brain wet-to-dry weight ratio was 5.64 +/- 0.44 in group 1, 7.34 +/- 0.95 in group 2 (P<0.01 versus group 1), and 5.93 +/- 0.40 in group 3 (P<0.05 versus group 2). CONCLUSIONS Ifenprodil reduces CA-elicited brain edema. In addition, we observed significant hemodynamic changes caused by ifenprodil.
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Affiliation(s)
- Feng Xiao
- Department of Emergency Medicine, Louisiana State University Health Sciences Center in Shreveport, 1501 Kings Highway, Shreveport, LA 71130, USA.
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26
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Zhu HJ, Liu GQ. Glutamate up-regulates P-glycoprotein expression in rat brain microvessel endothelial cells by an NMDA receptor-mediated mechanism. Life Sci 2004; 75:1313-22. [PMID: 15234189 DOI: 10.1016/j.lfs.2004.02.027] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Accepted: 02/09/2004] [Indexed: 11/23/2022]
Abstract
The accumulation of glutamate in the extracellular space in the central nervous system (CNS) plays a major part in ischemic and anoxic damage. In this study, we examined the effect of glutamate on the expression and activity of P-glycoprotein (P-gp) in rat brain microvessel endothelial cells (RBMECs) making up the blood-brain barrier (BBB). The level of P-gp expression significantly increased in RBMECs after the treatment of 100 microM glutamate. At this concentration, glutamate also enhanced rat mdr1a and mdr1b mRNA levels determined by RT-PCR analysis. Flow cytometry was used to study P-gp activity by analysis of intracellular rhodamine123 (Rh123) accumulation. Overexpression of P-gp resulted in a decreased intracellular accumulation of Rh123 in RBMECs. Glutamate-induced increase of intracellular reactive oxygen species (ROS) was observed by using the 2',7'-dichlorofluorescein (2',7'-DCF) assay. MK-801, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, and ROS scavenger N-acetylcysteine obviously blocked ROS generation and attenuated the changes of both expression and activity of P-gp induced by glutamate in RBMECs. These data suggested that glutamate up-regulated P-gp expression in RBMECs by an NMDA receptor-mediated mechanism and that glutamate-induced generation of ROS was linked to the regulation of P-gp expression. Therefore, transport of P-gp substrates in BBB appears to be affected during ischemic and anoxic injury.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Blood-Brain Barrier/drug effects
- Blood-Brain Barrier/metabolism
- Cell Survival/drug effects
- Cells, Cultured
- Cerebral Cortex/blood supply
- Dizocilpine Maleate/pharmacology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Glutamic Acid/pharmacology
- Microcirculation/drug effects
- Microcirculation/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Reactive Oxygen Species/antagonists & inhibitors
- Reactive Oxygen Species/metabolism
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Up-Regulation
- ATP-Binding Cassette Sub-Family B Member 4
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Affiliation(s)
- Hao-Jie Zhu
- Department of Pharmacology, China Pharmaceutical University, Nanjing, Jiangsu 210009, PR China.
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27
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Wang X, Lee SR, Arai K, Lee SR, Tsuji K, Rebeck GW, Lo EH. Lipoprotein receptor-mediated induction of matrix metalloproteinase by tissue plasminogen activator. Nat Med 2003; 9:1313-7. [PMID: 12960961 DOI: 10.1038/nm926] [Citation(s) in RCA: 375] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2003] [Accepted: 08/04/2003] [Indexed: 02/07/2023]
Abstract
Although thrombolysis with tissue plasminogen activator (tPA) is a stroke therapy approved by the US Food and Drug Administration, its efficacy may be limited by neurotoxic side effects. Recently, proteolytic damage involving matrix metalloproteinases (MMPs) have been implicated. In experimental embolic stroke models, MMP inhibitors decreased cerebral hemorrhage and injury after treatment with tPA. MMPs comprise a family of zinc endopeptidases that can modify several components of the extracellular matrix. In particular, the gelatinases MMP-2 and MMP-9 can degrade neurovascular matrix integrity. MMP-9 promotes neuronal death by disrupting cell-matrix interactions, and MMP-9 knockout mice have reduced blood-brain barrier leakage and infarction after cerebral ischemia. Hence it is possible that tPA upregulates MMPs in the brain, and that subsequent matrix degradation causes brain injury. Here we show that tPA upregulates MMP-9 in cell culture and in vivo. MMP-9 levels were lower in tPA knockouts compared with wild-type mice after focal cerebral ischemia. In human cerebral microvascular endothelial cells, MMP-9 was upregulated when recombinant tPA was added. RNA interference (RNAi) suggested that this response was mediated by the low-density lipoprotein receptor-related protein (LRP), which avidly binds tPA and possesses signaling properties. Targeting the tPA-LRP signaling pathway in brain may offer new approaches for decreasing neurotoxicity and improving stroke therapy.
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Affiliation(s)
- Xiaoying Wang
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Charlestown, and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA.
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28
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Leffler CW, Balabanova L, Fedinec AL, Waters CM, Parfenova H. Mechanism of glutamate stimulation of CO production in cerebral microvessels. Am J Physiol Heart Circ Physiol 2003; 285:H74-80. [PMID: 12623781 DOI: 10.1152/ajpheart.01081.2002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dilation of piglet pial arterioles to glutamate involves carbon monoxide (CO) produced from heme by heme oxygenase-2 (HO-2). Piglet cerebral microvessels and endothelial and smooth muscle cells grown on microcarrier beads were used to address the hypothesis that glutamate increases endothelial CO production by increasing HO-2 catalytic activity. CO was measured by gas chromatography/mass spectrometry. Glutamate increased CO production from endogenous heme by cerebral microvessels, endothelial cells, and smooth muscle cells. Glutamate increased the conversion of exogenous heme to CO. Protein tyrosine kinase inhibition blocked glutamate stimulation of CO production. Inhibition of protein tyrosine phosphatases stimulated CO production. Conversely, neither phorbol myristate acetate nor H-7 changed glutamate stimulation of CO production. The mechanism of HO-2 stimulation by glutamate appears to be independent of cytosolic Ca, because stimulation of CO production by glutamate was the same in Careplete medium, Ca-free medium with ionomycin, and Careplete medium with ionomycin. Therefore, glutamate appears to increase HO-2 catalytic activity in cerebral microvessels via a tyrosine kinase mediated pathway.
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MESH Headings
- Animals
- Blood Vessels/drug effects
- Blood Vessels/enzymology
- Blood Vessels/metabolism
- Brain Chemistry/drug effects
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Capillaries/drug effects
- Capillaries/enzymology
- Capillaries/metabolism
- Carbon Monoxide/metabolism
- Cells, Cultured
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Enzyme Inhibitors/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- Gas Chromatography-Mass Spectrometry
- Glutamic Acid/pharmacology
- Heme Oxygenase (Decyclizing)/metabolism
- Microspheres
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Protein Tyrosine Phosphatases/antagonists & inhibitors
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Swine
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Affiliation(s)
- Charles W Leffler
- Department of Physiology, University of Tennessee, Memphis, TN 38163, USA.
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29
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Abstract
Experimental autoimmune encephalomyelitis reproduces in rodents the features of multiple sclerosis, an immune-mediated, disabling disorder of the human nervous system. No adequate therapy is available for multiple sclerosis, despite anti-inflammatory, immunosuppressive, and immunomodulatory measures. Increasingly glutamate is implicated in the pathogenesis of neurodegenerative diseases. Here we (1) review changes in the glutamatergic system in multiple sclerosis and (2) reveal the effects of glutamate AMPA antagonists in acute and chronic rodent models of multiple sclerosis. Administration of structurally diverse competitive and non-competitive AMPA antagonists reduces neurologic disability in rodents subjected to acute experimental autoimmune encephalomyelitis. In addition, AMPA antagonists are active in both the adoptive transfer and in chronic models of experimental autoimmune encephalomyelitis in rats and mice and affect both the acute and chronic relapsing phases. Moreover, short-term therapy with AMPA antagonists leads to sustained benefit well into the progressive phases. These results imply that therapeutic strategies for multiple sclerosis should be complemented by glutamate AMPA antagonists to reduce neurologic disability.
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MESH Headings
- Animals
- Brain Stem/immunology
- Brain Stem/pathology
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/etiology
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Excitatory Amino Acid Antagonists/immunology
- Excitatory Amino Acid Antagonists/pharmacology
- Excitatory Amino Acid Antagonists/therapeutic use
- Glutamic Acid/metabolism
- Humans
- Mice
- Mice, Inbred Strains
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/etiology
- Multiple Sclerosis/physiopathology
- Nootropic Agents/pharmacology
- Nootropic Agents/therapeutic use
- Pyrrolidinones/pharmacology
- Pyrrolidinones/therapeutic use
- Quinoxalines/immunology
- Quinoxalines/pharmacology
- Quinoxalines/therapeutic use
- Rats
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Spinal Cord/immunology
- Spinal Cord/pathology
- Spinal Cord/ultrastructure
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Affiliation(s)
- Anthony J Groom
- Eisai London Research Laboratories, University College London, Bernard Katz Building, Gower Street, United Kingdom
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30
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Ter Minassian A. [Treatment of cerebral oedema]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2003; 22:336-48. [PMID: 12818327 DOI: 10.1016/s0750-7658(03)00056-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Progress in brain imaging, monitoring and physiopathology allows the identification of brain oedema from brain swelling, determination of its interstitial or intracellular nature, as well as blood-brain barrier permeability and the evaluation of the impact on cerebral haemodynamic. Common treatment of all types of cerebral oedema is based on prevention of self-sustained disorders due to increased intracranial pressure resulting in ischemic cerebral oedema. The specific treatment of each type of cerebral oedema is reviewed. Optimization of conventional anti-oedematous strategies is based on the precise determination of the nature of the cerebral oedema and of the blood-brain barrier status.
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Affiliation(s)
- A Ter Minassian
- Département d'anesthésie-réanimation, CHU d'Angers, 4, rue Larrey, 49033 cedex, Angers, France
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31
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Parfenova H, Fedinec A, Leffler CW. Ionotropic glutamate receptors in cerebral microvascular endothelium are functionally linked to heme oxygenase. J Cereb Blood Flow Metab 2003; 23:190-7. [PMID: 12571450 DOI: 10.1097/01.wcb.000004823561824.c4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Vasodilator effects of glutamate in the cerebral circulation are, in part, mediated by carbon monoxide (CO), which is formed from heme via the heme oxygenase (HO) pathway. The hypothesis addressed was that glutamate receptors (GluRs) in cerebral microvascular endothelium are functionally linked to HO. Using a radioligand binding and immunoblotting, GluRs were characterized in cerebral microvascular endothelial cells (CMVEC) from newborn pigs. High-affinity (80 nmol/L) reversible binding of [3H]glutamate ([ 3H]Glu) was detected in CMVEC membranes. The -methyl-d-aspartate (NMDA) receptor ligands-NMDA, quinolinic acid, (+/-)1-aminocyclopentane- -1,3-dicarboxylic acid ( ACPD), AP5, 4C3HPG, and CPP-and the (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate receptor ligands-AMPA, kainic acid, quisqualic acid, DNQX, and CNQX-displaced 20% to 30% of bound [3H]Glu in CMVEC membranes. Metabotropic GluRs antagonists (4CPG, PHCC, and CPPG) did not displace bound [3H]Glu. l-Aspartate, an agonist of GluRs and glutamate transporters, displaced 80% or more of bound [3H]Glu. Ionotropic (NR1 and GluR1) and metabotropic (mGluR1alpha) GluRs were detected in CMVEC by immunoblotting. Glutamate, aspartate, ACPD, AMPA, (RS)-2-amino-(3-hydroxy-5- -butylisoxazol-4-yl)propanoic acid (ATPA), and kainate (10(-5) mol/L) increased HO-directed CO formation by isolated cerebral microvessels and by cultured CMVEC. These data in newborn pigs suggest that CMVEC express ionotropic GluRs that are functionally linked to HO. GluR-mediated increases in CO formation by vascular endothelium may result in increase in cerebral blood flow.
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Affiliation(s)
- Helena Parfenova
- Laboratory for Research in Neonatal Physiology, Department of Physiology, University of Tennesse Health Science Center, Memphis, Tennessee 38163, USA.
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Jara-Prado A, Ortega-Vazquez A, Martinez-Ruano L, Rios C, Santamaria A. Homocysteine-induced brain lipid peroxidation: effects of NMDA receptor blockade, antioxidant treatment, and nitric oxide synthase inhibition. Neurotox Res 2003; 5:237-43. [PMID: 12835115 DOI: 10.1007/bf03033381] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of homocysteine (HCY) on lipid peroxidation (LP), a current mechanism of oxidative neurotoxicity, was investigated in rat brain synaptosomes. LP was assessed by measuring the amount of thiobarbituric acid-reactive substances (TBARS) formed from synaptosomal fractions following HCY treatment. Increasing HCY concentrations (5-1000 micro M) enhanced the TBARS formation in brain synaptosomes in a concentration-dependent manner. When compared at equimolar concentrations (100 micro M), the oxidative potency of HCY was lower than that of the oxidant ferrous sulfate, similar to that produced by glutamate (Glu) and the mitochondrial toxin 3-nitropropionic acid, and higher than that of the Glu agonists, kainate and quinolinate. The N-methyl-D-aspartate receptor (NMDAr) antagonist dizocilpine (MK-801) completely blocked the HCY-induced LP at concentrations between 5 to 1000 micro M, whereas the well-known antioxidant N-acetylcysteine (NAC) was less effective, but still protective against the HCY oxidative toxicity at higher concentrations (400 and 1000 micro M). Three nitric oxide synthase (NOS) inhibitors, 7-nitroindazole (7-NI), Nomega-nitro-L-arginine (L-NARG) and Nomega-nitro-L-arginine methyl ester (L-NAME), were also tested on HCY-induced LP at increasing concentrations. Both nonspecific NOS inhibitors (L-NARG and L-NAME) decreased more effectively the HCY-induced LP than did the selective neuronal NOS inhibitor, 7-NI. These results show that submillimolar concentrations of HCY can induce oxidative injury to nerve terminals, and this effect involves NMDAr stimulation, NOS activation, and associated free radicals formation.
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Affiliation(s)
- Aurelio Jara-Prado
- Departamento de Genetica, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, S.S.A. Insurgentes Sur # 3877, México D.F., 14269, México
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Kinoshita K, Chatzipanteli K, Alonso OF, Howard M, Dietrich WD. The effect of brain temperature on hemoglobin extravasation after traumatic brain injury. J Neurosurg 2002; 97:945-53. [PMID: 12405386 DOI: 10.3171/jns.2002.97.4.0945] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Although the benefits of posttraumatic hypothermia have been reported in experimental studies, the potential for therapeutic hypothermia to increase intracerebral hemorrhage remains a clinical concern. The purpose of this study was to quantify the amount of extravasated hemoglobin after traumatic brain injury (TBI) and to assess the changes in intracerebral hemoglobin concentrations under posttraumatic hypothermic and hyperthermic conditions. METHODS Intubated and anesthetized rats were subjected to fluid-percussion injury (FPI). In the first experiment, rats were divided into moderate (1.8-2.2 atm) and severe (2.4-2.7 atm) TBI groups. In the second experiment, the effects of 3 hours of posttraumatic hypothermia (33 or 30 degrees C), hyperthermia (39 degrees C), or normothermia (37 degrees C) on hemoglobin levels following moderate trauma were assessed. The rats were perfused with saline at 24 hours postinjury, and then the traumatized and contralateral hemispheres, including the cerebellum, were dissected from whole brain. The hemoglobin level in each brain was quantified using a spectrophotometric hemoglobin assay. The results of these assays indicate that moderate and severe FPI induce increased levels of hemoglobin in the ipsilateral hemisphere (p < 0.0001). After severe TBI, the hemoglobin concentration was also significantly increased in the contralateral hemisphere (p < 0.05) and cerebellum (p < 0.005). Posttraumatic hypothermia (30 degrees C) attenuated hemoglobin levels (p < 0.005) in the ipsilateral hemisphere, whereas hyperthermia had a marked adverse effect on the hemoglobin concentration in the contralateral hemisphere (p < 0.05) and cerebellum (p < 0.005). CONCLUSIONS Injury severity is an important determinant of the degree of hemoglobin extravasation after TBI. Posttraumatic hypothermia reduced hemoglobin extravasation, whereas hyperthermia increased hemoglobin levels compared with normothermia. These findings are consistent with previous data reporting that posttraumatic temperature manipulations alter the cerebrovascular and inflammatory consequences of TBI.
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Affiliation(s)
- Kosaku Kinoshita
- Department of Neurological Surgery, The Neurotrauma Research Center and The Miami Project to Cure Paralysis, University of Miami School of Medicine, Florida 33101, USA
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Paul C, Bolton C. Modulation of blood-brain barrier dysfunction and neurological deficits during acute experimental allergic encephalomyelitis by the N-methyl-D-aspartate receptor antagonist memantine. J Pharmacol Exp Ther 2002; 302:50-7. [PMID: 12065699 DOI: 10.1124/jpet.302.1.50] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies by us have strongly indicated a role for the N-methyl-D-aspartate (NMDA) receptor in the pathogenesis of experimental allergic encephalomyelitis (EAE) and, moreover, the loss of blood-brain barrier (BBB) integrity implicit in the disease. The current investigation has used the NMDA receptor antagonist memantine to modify the neurological course of EAE and, in particular, prevent BBB breakdown. Memantine was administered orally either semiprophylactically, from day 7 postinoculation (PI), or therapeutically, 10 to 11 days PI. Semiprophylactic administration of drug at 60 mg/kg b.wt. significantly restored BBB integrity, reduced symptoms, and limited inflammatory lesions (p < 0.05), when assessed 12 days PI. Higher concentrations of memantine did not notably advance disease improvements observed at 60 mg/kg b.wt., and 40-mg/kg b.wt. doses only reduced histological scores (p < 0.05). Therapeutic application of memantine was found to be as effective as semiprophylactic dosing. Administration of drug at 60 mg/kg b.wt. was demonstrated as the optimum dose, significantly reducing disease, BBB permeability, and lesions (p < 0.01). Extended studies revealed that, after cessation of memantine treatment using either dosing regime, any subsequent appearance of disease was suppressed in severity and duration. We have provided further strong evidence in support of a role for the NMDA receptor in the development of EAE and, in particular, the loss of BBB function and recruitment of inflammatory cells. Moreover, memantine is therapeutically efficacious, suggesting the NMDA receptor as a viable pharmacological target for future treatment of human neurological conditions such as multiple sclerosis.
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Affiliation(s)
- Carolyn Paul
- Department of Pharmacy and Pharmacology, University of Bath, Bath, UK.
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Madrigal JLM, Moro MA, Lizasoain I, Lorenzo P, Leza JC. Stress-induced increase in extracellular sucrose space in rats is mediated by nitric oxide. Brain Res 2002; 938:87-91. [PMID: 12031539 DOI: 10.1016/s0006-8993(02)02467-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Exposure to physical or psychological stress causes brain damage ranging from minimal behavioural alterations to neurodegeneration. One of the proposed mechanisms for stress-induced neurodegeneration is the overproduction of nitric oxide (NO) and related oxidative-nitrosative compounds via expression of the inducible NO synthase (iNOS). In the present investigation, the effect of acute or chronic immobilisation on blood-brain barrier (BBB) permeability and the possible role of iNOS were studied in adult male Wistar rats. Stress-induced [(14)C]-sucrose uptake by brain tissue correlates with the production of the stable NO metabolites nitrite and nitrate in both peripheral (plasma) and central (brain) compartments. Injection of the specific iNOS inhibitor 1400W (2 mg/kg, i.p.) prevents the stress-induced increase in BBB permeability. Taken together, these findings indicate that iNOS expression mediates stress-induced increase in BBB permeability and support a possible neuroprotective role for specific iNOS inhibitors in this situation.
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Affiliation(s)
- José L M Madrigal
- Departmento de Farmacología, Facultad de Medicina, Universidad Complutense, Madrid 28040, Spain
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St'astný F, Schwendt M, Lisý V, Jezová D. Main subunits of ionotropic glutamate receptors are expressed in isolated rat brain microvessels. Neurol Res 2002; 24:93-6. [PMID: 11783759 DOI: 10.1179/016164102101199468] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Excitatory amino acids are known to modulate blood-brain barrier (BBB) permeability, however, the information on glutamate receptors in cerebral capillaries is inconsistent. In the present study, freshly isolated microvessels obtained from saline-perfused rat brains were used. Gene expression of the main N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) receptor subunits NMDAR1 and GLUR1, respectively, were investigated by reverse transcription-polymerase chain reaction (RT-PCR). The results confirmed the presence of both NMDAR1 and GLUR1 mRNAs in microvessels of seven brain regions studied. Moreover, specific binding of [3H]glutamate to capillary membranes and its displacement by AMPA, NMDA and metabotropic, but not kainate receptor agonists were observed. These results suggest that rat brain capillaries and/or albuminally adhering astrocyte processes possess functional glutamate receptors. Thus, the effects of glutamate agonists and antagonists in modulation of BBB function might be mediated directly by cerebral microvessels.
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Affiliation(s)
- Frantisek St'astný
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague
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Bested AC, Saunders PR, Logan AC. Chronic fatigue syndrome: neurological findings may be related to blood--brain barrier permeability. Med Hypotheses 2001; 57:231-7. [PMID: 11461179 DOI: 10.1054/mehy.2001.1306] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite volumes of international research, the etiology of chronic fatigue syndrome (CFS) remains elusive. There is, however, considerable evidence that CFS is a disorder involving the central nervous system (CNS). It is our hypothesis that altered permeability of the blood-brain barrier (BBB) may contribute to ongoing signs and symptoms found in CFS. To support this hypothesis we have examined agents that can increase the blood-brain barrier permeability (BBBP) and those that may be involved in CFS. The factors which can compromise the normal BBBP in CFS include viruses, cytokines, 5-hydroxytryptamine, peroxynitrite, nitric oxide, stress, glutathione depletion, essential fatty acid deficiency, and N-methyl-D-aspartate overactivity. It is possible that breakdown of normal BBBP leads to CNS cellular dysfunction and disruptions of neuronal transmission in CFS. Abnormal changes in BBBP have been linked to a number of disorders involving the CNS; based on review of the literature we conclude that the BBB integrity in CFS warrants investigation.
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Affiliation(s)
- A C Bested
- Environmental Health Clinic, Sunnybrook and Women's College, Health Sciences Centre, Toronto, Canada
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Sakaeda T, Tada Y, Sugawara T, Ryu T, Hirose F, Yoshikawa T, Hirano K, Kupczyk-Subotkowska L, Siahaan TJ, Audus KL, Stella VJ. Conjugation with L-Glutamate for in vivo brain drug delivery. J Drug Target 2001; 9:23-37. [PMID: 11378521 DOI: 10.3109/10611860108995630] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In vitro studies have shown that conjugation of a model compound [p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD)] with L-Glu can improve D-MOD permeation through the bovine brain microvessel endothelial cell monolayers (Sakaeda et al., 2000). The transport of this D-MOD-L-Glu conjugate is facilitated by the L-Glu transport system. In this paper, we evaluate the in vivo brain delivery of model compounds (i.e. D-MOD, p-nitro-D-phenylalanine (p-nitro-D-Phe), 5,7-dichlorokynurenic acid (DCKA) and D-kyotorphin) and their L-Glu conjugates. DCKA was also conjugated with L-Asp and L-Gln amino acids. The analgesic activities of D-kyotorphin and its L-Glu conjugate were also evaluated. The results showed that the brain-to-plasma concentration ratio of D-MOD-L-Glu was higher than the D-MOD alone; however, the plasma concentration of both compounds were the same. The plasma concentration of p-nitro-D-Phe-L-Glu conjugate was higher than the parent p-nitro-D-Phe; however, the brain-to-plasma concentration ratio of p-nitro-D-Phe was higher than its conjugate. On the other hand, both DCKA and DCKA conjugates have a low brain-to-plasma concentration ratio due to their inability to cross the blood-brain barrier (BBB). The L-Asp and L-Glu conjugates of DCKA have elevated plasma concentrations relative to DCKA; however, the DCKA-L-Gln conjugate has the same plasma concentration as DCKA. For D-kyotorphin, both the parent and the L-Glu conjugate showed similar analgesic activity. In conclusion, conjugation of a non-permeable drug with L-Glu may improve the drug's brain delivery; however, this improvement may depend on the physicochemical and receptor binding properties of the conjugate.
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Affiliation(s)
- T Sakaeda
- Shionogi Research Laboratories, Shionogi & Co., Ltd., 5-12-4, Sagisu Fukushima-ku, Osaka, 553-0002, Japan
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Banks WA, Freed EO, Wolf KM, Robinson SM, Franko M, Kumar VB. Transport of human immunodeficiency virus type 1 pseudoviruses across the blood-brain barrier: role of envelope proteins and adsorptive endocytosis. J Virol 2001; 75:4681-91. [PMID: 11312339 PMCID: PMC114222 DOI: 10.1128/jvi.75.10.4681-4691.2001] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Blood-borne human immunodeficiency virus type 1 (HIV-1) crosses the blood-brain barrier (BBB) to induce brain dysfunction. How HIV-1 crosses the BBB is unclear. Most work has focused on the ability of infected immune cells to cross the BBB, with less attention devoted to the study of free virus. Since the HIV-1 coat glycoprotein gp120 can cross the BBB, we postulated that gp120 might be key in determining whether free virus can cross the BBB. We used radioactive virions which do (Env+) or do not (Env-) bear the envelope proteins to characterize the ability of HIV-1 to be taken up by the murine BBB. In vivo and in vitro studies showed that the envelope proteins are key to the uptake of free virus and that uptake was enhanced by wheat germ agglutinin, strongly suggesting that the envelope proteins induce viral adsorptive endocytosis and transcytosis in brain endothelia. Capillary depletion showed that Env+ virus completely crossed the vascular BBB to enter the parenchyma of the brain. Virus also entered the cerebrospinal fluid, suggesting passage across the choroid plexus as well. About 0.22% of the intravenously injected dose was taken up per g of brain. In vitro studies showed that postinternalization membrane cohesion (membrane binding not reversed with acid wash or cell lysis) was a regulated event. Intact virus was recovered from the brain endothelial cytosol and was effluxed from the endothelial cells. These results show that free HIV-1 can cross the BBB by an event related to adsorptive endocytosis and mediated by the envelope proteins.
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Affiliation(s)
- W A Banks
- GRECC, Veterans Affairs Medical Center-St. Louis, and Division of Geriatrics, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, Missouri 63106, USA.
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Sullivan PG, Rabchevsky AG, Hicks RR, Gibson TR, Fletcher-Turner A, Scheff SW. Dose-response curve and optimal dosing regimen of cyclosporin A after traumatic brain injury in rats. Neuroscience 2001; 101:289-95. [PMID: 11074152 DOI: 10.1016/s0306-4522(00)00380-8] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Acute neuropathology following experimental traumatic brain injury results in the rapid necrosis of cortical tissue at the site of injury. This primary injury is exacerbated in the ensuing hours and days via the progression of secondary injury mechanism(s) leading to significant neurological dysfunction. Recent evidence from our laboratory demonstrates that the immunosuppressant cyclosporin A significantly ameliorates cortical damage following traumatic brain injury. The present study extends the previous findings utilizing a unilateral controlled cortical impact model of traumatic brain injury in order to establish a dose-response curve and optimal dosing regimen of cyclosporin A. Following injury to adult rats, cyclosporin A was administrated at various dosages and the therapy was initiated at different times post-injury. In addition to examining the effect of cyclosporin A on the acute disruption of the blood-brain barrier following controlled cortical impact, we also assessed the efficacy of cyclosporin A to reduce tissue damage utilizing the fluid percussion model of traumatic brain injury. The findings demonstrate that the neuroprotection afforded by cyclosporin A is dose-dependent and that a therapeutic window exists up to 24h post-injury. Furthermore, the optimal cyclosporin dosage and regimen markedly reduces disruption of the blood-brain barrier acutely following a cortical contusion injury, and similarly affords significant neuroprotection following fluid percussion injury. These findings clearly suggest that the mechanisms responsible for tissue necrosis following traumatic brain injury are amenable to pharmacological intervention.
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Affiliation(s)
- P G Sullivan
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA
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Najbauer J, Schuman EM, Mamelak AN. The aspirin metabolite sodium salicylate causes focal cerebral hemorrhage and cell death in rats with kainic acid-induced seizures. Neuroscience 2000; 99:107-17. [PMID: 10924956 DOI: 10.1016/s0306-4522(00)00158-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aspirin (acetylsalicylic acid), and its main metabolite sodium salicylate, have been shown to protect neurons from excitotoxic cell death in vitro. The objective of our study was to investigate the possible neuroprotective effects of sodium salicylate in vivo in rats with kainic acid-induced seizures, a model for temporal lobe epilepsy in human patients. Male Sprague-Dawley rats received intraperitoneal injections of kainic acid either alone, or with sodium salicylate given before and for 40h after kainic acid injections. The control group received either phosphate-buffered saline or sodium salicylate without co-administration of kainic acid. Animals developed status epilepticus, which was aborted 1.5-2h later with diazepam. On day 3 following kainic acid-induced seizures, animals received bromodeoxyuridine to measure cellular proliferation, and were killed under anesthesia 24h later. Brains were removed, sectioned, and analysed for gross histological changes, evidence of hemorrhage, DNA fragmentation, cellular proliferation, and microglial immunohistochemistry. We report that sodium salicylate did not protect neurons from seizure-induced cell death, and to the contrary, it caused focal hemorrhage and cell death in the hippocampal formation and the entorhinal/piriform cortex of rats with kainic acid-induced seizures. Hemorrhage was never observed in animals that received vehicle, kainic acid or sodium salicylate only, which indicated that sodium salicylate exerted its effect only in animals with seizures, and was confined to select regions of the brain that undergo seizure activity. Large numbers of cells displaying DNA fragmentation were detected in the hippocampal formation, entorhinal/piriform cortex and the dorsomedial thalamic nucleus of rats that received kainic acid or kainic acid in combination with sodium salicylate. Bromodeoxyuridine immunohistochemistry revealed large numbers of proliferating cells in and around the areas with most severe neural injury induced by kainic acid or kainic acid co-administered with sodium salicylate. These same brain regions displayed intense staining with a microglia-specific marker, an indication of microglial activation in response to brain damage. In all cases, the degree of cell death, cell proliferation and microglia staining was more severe in animals that received the combination of kainic acid and sodium salicylate when compared to animals that received kainic acid alone. We hypothesize that our findings are attributable to sodium salicylate-induced blockade of cellular mechanisms that protect cells from calcium-mediated injury. These initial observations may have important clinical implications for patients with epilepsy who take aspirin while affected by these conditions, and should promote further investigation of this relationship.
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Affiliation(s)
- J Najbauer
- Division of Biology 216-76 and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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Sakaeda T, Siahaan TJ, Audus KL, Stella VJ. Enhancement of transport of D-melphalan analogue by conjugation with L-glutamate across bovine brain microvessel endothelial cell monolayers. J Drug Target 2000; 8:195-204. [PMID: 10938529 DOI: 10.3109/10611860008996865] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this paper, the L-glutamate (L-Glu) transport system was targeted to improve the delivery of a model compound, p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD), through the blood-brain barrier (BBB) in vitro cell culture model. D-MOD is an analogue of an antitumor agent D-melphalan. To target the L-Glu transport system, D-MOD was conjugated to L-Glu to give D-MOD-L-Glu conjugate. D-MOD and D-MOD-L-Glu transport properties were evaluated using the bovine brain microvessel endothelial cell (BBMEC) monolayers. The results suggest that D-MOD-L-Glu conjugate permeates through the BBMEC monolayers more readily than the parent D-MOD. The improvement of transport may be due to the recognition of D-MOD-L-Glu by the L-Glu transport system. The transport mechanism was evaluated using several different experiments including: (a) concentration-dependent studies; (b) temperature-dependent studies; (c) substrate inhibition studies; and (d) metabolic inhibitor studies. The D-MOD-L-Glu transport was inhibited by the change of temperature from 37 degrees C to 4 degrees C. At higher concentrations, the transport of D-MOD-L-Glu reached plateau due to saturation. Furthermore, some amino acids (i.e., L-Glu, L-Asp, D-Asp, and L-Gln) inhibited the transport of D-MOD-L-Glu; presumably the conjugate was competing with these amino acids for the same transport system. Metabolic inhibitors (i.e., 2,4-dinitrophenol and sodium azide) suppressed the transport of the conjugate. However, the conjugate was not transported by monocarboxylic acid, dipeptide and neutral amino acid transporters. In conclusion, the L-Glu transport system can be utilized to facilitate a non-permeable drug across the BBB by conjugating the drug with L-Glu amino acid.
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Affiliation(s)
- T Sakaeda
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA
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Ohtani K, Tanaka H, Yasuda H, Maruoka Y, Kawabe A, Nakamura M. Blocking the glycine-binding site of NMDA receptors prevents the progression of ischemic pathology induced by bilateral carotid artery occlusion in spontaneously hypertensive rats. Brain Res 2000; 871:311-8. [PMID: 10899297 DOI: 10.1016/s0006-8993(00)02486-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study was designed to investigate the participation of N-methyl-D-aspartate (NMDA) receptors in the progression of the pathology induced by bilateral carotid artery occlusion (BCAo) in spontaneously hypertensive rats (SHRs). We examined the effects of the selective NMDA receptor glycine-binding site antagonist SM-18400 on the mortality rate, deterioration of neurological signs, and formation of brain edema in the SHR-BCAo model. SM-18400 (15 or 30 mg/kg) was administered via the tail vein immediately and 2 h after BCAo. Neurological signs were monitored continuously for 8 h after BCAo, and the mortality rates were followed for 5 days. All SM-18400-treated animals were still alive 5 h after BCAo, whereas 38% of the animals died in the vehicle-treated group. The mortality rates of the SM-18400-treated groups were still lower than those of the vehicle-treated group 5 days after BCAo. In addition, SM-18400 markedly prevented the deterioration of neurological signs. The water content of the telencephalon and diencephalon/mesencephalon in the vehicle-treated group, measured 3 h after BCAo, was significantly higher than in the sham-operated group. SM-18400 significantly inhibited the increase in water content in both regions in a dose-dependent manner. These findings suggest that NMDA receptors participate in the increase in the mortality rate, deterioration of neurological signs, and formation of brain edema following ischemic brain damage in the SHR-BCAo model, and that SM-18400 can prevent ischemic insults.
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Affiliation(s)
- K Ohtani
- Research Center, Sumitomo Pharmaceuticals Co., Ltd., 3-1-98 Kasugadenaka, Konohana-ku, 554-0022, Osaka, Japan.
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Behrens PF, Langemann H, Strohschein R, Draeger J, Hennig J. Extracellular glutamate and other metabolites in and around RG2 rat glioma: an intracerebral microdialysis study. J Neurooncol 2000; 47:11-22. [PMID: 10930095 DOI: 10.1023/a:1006426917654] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The current study determined the extracellular content of glutamate, 10 additional amino acids, lactate, glucose and some antioxidants in a rodent model of malignant glioma, its peritumoral space and the adjacent cortex. RG2 tumors were induced in the right frontal cortex of Fischer-344 rats (n = 10) by a standardized procedure to obtain a maximum sagittal tumor width of 3-4 mm diameter. After confirmation of tumor growth and localization by contrast enhanced MRI three microdialysis probes were implanted simultaneously in the cortex: at the tumor implantation site (tumor), 2 mm caudally, brain around tumor (BAT) and 4 mm caudally (cortex) to the site of implantation. Dialysate concentrations of glutamate were increased 3.9-fold in tumor and 2-fold in BAT compared with cortex. Glycine was elevated 11.4-fold in tumor and 2.6-fold in BAT. Lactate was increased 1.7-fold in tumor, 1.2-fold in BAT. Levels of glucose, ascorbic acid and uric acid were not significantly different in tumor, BAT and cortex. The increased dialysate levels of glutamate and glycine in the peritumoral space may contribute to impaired neuronal function and epileptiform activity associated with this tumor type in humans.
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Affiliation(s)
- P F Behrens
- Department of Neurology, Albert-Ludwigs Universität Freiburg, Germany.
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45
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Exacerbation of damage and altered NF-kappaB activation in mice lacking tumor necrosis factor receptors after traumatic brain injury. J Neurosci 1999. [PMID: 10414954 DOI: 10.1523/jneurosci.19-15-06248.1999] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tumor necrosis factor alpha (TNFalpha) is widely expressed in both neurons and glia and has been shown to be upregulated after traumatic brain injury (TBI). TNFalpha receptor activation results in activation of the transcription factor nuclear factor kappaB (NF-kappaB), which may serve an antiapoptotic role via the induction of target genes manganese superoxide dismutase (MnSOD) and/or calbindin. In the present study, we used a controlled cortical impact model of TBI with pertinent lines of transgenic mice to combine both morphological characterization and molecular analysis to elucidate the role of TNFalpha after TBI. Measurements of both the lesion volume and the blood-brain barrier breach indicated exacerbations in mice rendered genetically deficient in both the p55 and p75 TNFalpha receptors (TNFR-KO) compared with wild-type animals. Additionally, animals genetically altered to overexpress MnSOD showed a significant decrease in lesion volume compared with that of control littermates, whereas no alterations were observed in mice lacking the calcium-binding protein calbindin D28k. Analysis of NF-kappaB activation and relative levels of MnSOD revealed delayed responses in the injured cortex of TNFR-KO animals compared with wild-type animals, implying that endogenous TNFalpha may be neuroprotective after TBI.
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46
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Yoshikawa T, Sugawara T, Hirano K, Stella VJ. A novel chemical delivery system for brain targeting. Adv Drug Deliv Rev 1999; 36:255-275. [PMID: 10837719 DOI: 10.1016/s0169-409x(98)00091-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two different chemical approaches for brain drug delivery and targeting are proposed in the present review. One is a chemical drug delivery using a ring-closure reaction to the hydrophilic quaternary thiazolium compound in the brain. The other is a chemical drug targeting utilizing the nutrient receptor (transporter) system on the blood-brain barrier. The brain delivery system has been optimized and it was demonstrated that the brain delivery of three drugs, a drug for Parkinson's disease, an excitatory amino acid antagonist and a free radical scavenger, were improved by the conjugation with cis-2-formylaminoethenylthio derivatives in vivo. As for the brain targeting system, it was demonstrated that the conjugation with L-Glu improved the drug's brain distribution via the L-Glu excitatory and/or transport receptors in vitro and in vivo. These findings suggest that the concepts of two chemical approaches will contribute to the development of new central nervous system drugs.
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Affiliation(s)
- T Yoshikawa
- Shionogi Research Laboratories, Shionogi & Co. Ltd., Osaka 553-0002, Japan
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47
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Preston E, Webster J, Palmer GC. Lack of evidence for direct involvement of NMDA receptors or polyamines in blood-brain barrier injury after cerebral ischemia in rats. Brain Res 1998; 813:191-4. [PMID: 9824696 DOI: 10.1016/s0006-8993(98)00981-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It is hypothesized that after various types of brain injury, blood-brain barrier (BBB) opening and vasogenic edema result from excessive neuronal release of glutamate and stimulation of capillary N-methyl-d-aspartate (NMDA) receptors linked to polyamine (putrescine) synthesis in endothelial cells. We produced cerebral ischemia in rats and measured BBB opening 6 h later as the increase in regional transfer constants (Ki) for blood to brain diffusion of [3H]sucrose. Such BBB opening was not mitigated by drugs which block NMDA receptors (MK801 or AR-R 15896AR) or polyamine synthesis (difluoromethylornithine). These results question generality of the capillary NMDA receptor/polyamine hypothesis.
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Affiliation(s)
- E Preston
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada.
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48
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Smith SL, Hall ED. Tirilazad widens the therapeutic window for riluzole-induced attenuation of progressive cortical degeneration in an infant rat model of the shaken baby syndrome. J Neurotrauma 1998; 15:707-19. [PMID: 9753218 DOI: 10.1089/neu.1998.15.707] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our infant rat model of traumatic subarchnoid hemorrhage combines violent shaking and hypoxia to produce subdural hemorrhaging and progressive cortical degeneration similar to that seen in victims of the shaken baby syndrome. Anesthetized, 6-day-old male rats were subjected to one episode of shaking under hypoxic conditions. Brain histologies revealed moderate-to-severe cortical hemorrhaging at 48 h postinjury and progressive cortical degeneration, as indicated by a 15.3% and 20.2% reduction in cortical wet weight, at 7 and 14 days postinjury, respectively. The purpose of the present study was to assess the effects of two antioxidant lipid peroxidation inhibitors (tirilazad mesylate and PNU-101033E), and the glutamate release inhibitor (riluzole), upon the brain pathology seen in this model. A significant, 54.3-75.3%, reduction in cortical hemorrhaging was observed in rats that were treated with a total of three doses of tirilazad (10 mg/kg, i.p.): 10 min before or 5-30 min after injury, and again at 2 and 24 h postinjury (p < 0.01 vs. vehicle). However, treatment with tirilazad or the more potent, brain-penetrating pyrrolopyrimidine, PNU-101033E (10 min before plus 2, 24, 48, and 72 h after), did not attenuate the progressive cortical degeneration typically seen at 14 days postinjury. These results suggest that free radicals play an important role in the pathophysiology of secondary brain hemorrhaging due to shaking + hypoxia, but may not be critical in the mediation of the subsequent neurodegeneration. Rather, glutamate neurotoxicity may be a key factor here. This is suggested by our observation that the glutamate release inhibitor, riluzole, significantly reduced cortical degeneration when it was administered up to 1 h postinjury in the present model. Specifically, the cortical wet weights of rats treated with 8 mg/kg riluzole (i.p.) 10 min before or 1 h after shaking + hypoxia (and again at 24 h postinjury) were 95.3% and 97.4% of noninjured controls, respectively, at 14 days postinjury (p < 0.02 vs. vehicle). Riluzole treatment beyond 1 h (e.g., 2 or 4 h postinjury) did not reduce the neurodegeneration. Lastly, we attempted to demonstrate that the therapeutic window for riluzole-induced attenuation of cortical degeneration could be extended beyond 1 h through the use of combination therapy. In this experiment, rat pups were treated with 10 mg/kg tirilazad (i.p.) at 30 min postinjury followed by 8 mg/kg riluzole (i.p.) at 4 and 24 h postinjury. At 14 days postinjury, the cortical wet weights of these rats were 94.5% of noninjured controls, thus demonstrating significant neuroprotection (p < 0.05 vs. vehicle) and a widening of the therapeutic window from 1 to 4 h in length. These results suggest that early attenuation of free radical-induced lipid peroxidation may slow down the biochemical cascade of events related to glutamate-induced excitotoxicity and, in doing so, prolong the time during which a glutamate release inhibitor, such as riluzole, is effective.
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Affiliation(s)
- S L Smith
- CNS Disease Research, Pharmacia & Upjohn, Inc., Kalamazoo, Michigan 49001, USA
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49
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Morley P, Small DL, Murray CL, Mealing GA, Poulter MO, Durkin JP, Stanimirovic DB. Evidence that functional glutamate receptors are not expressed on rat or human cerebromicrovascular endothelial cells. J Cereb Blood Flow Metab 1998; 18:396-406. [PMID: 9538905 DOI: 10.1097/00004647-199804000-00008] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Excitatory amino acids can modify the tone of cerebral vessels and permeability of the blood-brain barrier (BBB) by acting directly on endothelial cells of cerebral vessels or indirectly by activating receptors expressed on other brain cells. In this study we examined whether rat or human cerebromicrovascular endothelial cells (CEC) express ionotropic and metabotropic glutamate receptors. Glutamate and the glutamate receptor agonists N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA), and kainate failed to increase [Ca2+]i in either rat or human microvascular and capillary CEC but elicited robust responses in primary rat cortical neurons, as measured by fura-2 fluorescence. The absence of NMDA and AMPA receptors in rat and human CEC was further confirmed by the lack of immunocytochemical staining of cells by antibodies specific for the AMPA receptor subunits GluR1, GluR2/3, and GluR4 and the NMDA receptor subunits NR1, NR2A, and NR2B. We failed to detect mRNA expression of the AMPA receptor subunits GluR1 to GluR4 or the NMDA receptor subunits NR1(1XX); NR1(0XX), and NR2A to NR2C in both freshly isolated rat and human microvessels and cultured CEC using reverse transcriptase polymerase chain reaction (RT-PCR). Cultured rat CEC expressed mRNA for KA1 or KA2 and GluR5 subunits. Primary rat cortical neurons were found to express GluR1 to GluR3 and NR1, NR2A, and NR2B by both immunocytochemistry and RT-PCR and KA1, KA2, GluR5, GluR6, and GluR7 by RT-PCR. Moreover, the metabotropic glutamate receptor agonist 1-amino-cyclopentyl-1S, 3R-dicorboxylate (1S,3R-trans-ACPD), while eliciting both inositol trisphosphate and [Ca2+]i increases and inhibiting forskolin-stimulated cyclic AMP in cortical neurons, was unable to induce either of these responses in rat or human CEC. These results strongly suggest that both rat and human CEC do not express functional glutamate receptors. Therefore, excitatory amino acid-induced changes in the cerebral microvascular tone and BBB permeability must be affected indirectly, most likely by mediators released from the adjacent glutamate-responsive cells.
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MESH Headings
- Animals
- Brain Ischemia/metabolism
- Calcium/physiology
- Capillaries/cytology
- Cattle
- Cells, Cultured
- Cerebrovascular Circulation/drug effects
- Cerebrovascular Circulation/physiology
- Colforsin/antagonists & inhibitors
- Cyclic AMP/physiology
- Cycloleucine/analogs & derivatives
- Cycloleucine/pharmacology
- Endothelin-1/pharmacology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Gene Expression
- Humans
- Inositol 1,4,5-Trisphosphate/physiology
- Kainic Acid/pharmacology
- Mice
- N-Methylaspartate/pharmacology
- Neurons/drug effects
- Polymerase Chain Reaction
- RNA, Messenger/analysis
- Rats
- Receptors, AMPA/chemistry
- Receptors, AMPA/drug effects
- Receptors, AMPA/physiology
- Receptors, Glutamate/analysis
- Receptors, Glutamate/biosynthesis
- Receptors, Glutamate/drug effects
- Receptors, Glutamate/physiology
- Receptors, Kainic Acid/analysis
- Receptors, Kainic Acid/drug effects
- Receptors, Kainic Acid/physiology
- Receptors, Metabotropic Glutamate/analysis
- Receptors, Metabotropic Glutamate/drug effects
- Receptors, Metabotropic Glutamate/physiology
- Receptors, N-Methyl-D-Aspartate/chemistry
- Receptors, N-Methyl-D-Aspartate/drug effects
- Receptors, N-Methyl-D-Aspartate/physiology
- Second Messenger Systems/drug effects
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
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Affiliation(s)
- P Morley
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada
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50
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Skultétyová I, Tokarev D, Jezová D. Stress-induced increase in blood-brain barrier permeability in control and monosodium glutamate-treated rats. Brain Res Bull 1998; 45:175-8. [PMID: 9443836 DOI: 10.1016/s0361-9230(97)00335-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glutamate administration in neonatal rats causes reversible changes in blood-brain barrier (BBB) permeability and known neurotoxic lesions. This study was aimed to evaluate whether glutamate administered to neonatal rats influences properties of the developing BBB with consequences on adult BBB function. The vulnerability of the BBB was examined after short-lasting stress exposure by measurement of plasma albumin extravasation using immunoelectrophoresis. In control rats, 30 min of immobilization stress resulted in increased endogenous albumin extravasation in the hypothalamus, hippocampus, brain stem and cerebellum, but not in the cortex and striatum. Basal levels of albumin in adult glutamate-treated rats (4 mg monosodium glutamate/g BW, IP, five times during neonatal period) were significantly lower in the hypothalamus compared to that in controls. Stress-induced increase in albumin levels was lower in the brain stem, higher in the hypothalamus, and similar in other brain regions studied in glutamate-treated rats in comparison with controls. It is concluded that short-lasting immobilization stress increased BBB permeability in some but not all brain regions studied. Glutamate treatment of neonatal rats resulted in low basal albumin levels in the hypothalamus but did not exert a pronounced influence on adult BBB function. BBB vulnerability in glutamate-treated rats during stress exposure was increased in the hypothalamus and decreased in the brain stem.
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Affiliation(s)
- I Skultétyová
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava
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