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Warming H, Deinhardt K, Garland P, More J, Bulters D, Galea I, Vargas-Caballero M. Functional effects of haemoglobin can be rescued by haptoglobin in an in vitro model of subarachnoid haemorrhage. J Neurochem 2023; 167:90-103. [PMID: 37702203 DOI: 10.1111/jnc.15936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 09/14/2023]
Abstract
During subarachnoid haemorrhage, a blood clot forms in the subarachnoid space releasing extracellular haemoglobin (Hb), which causes oxidative damage and cell death in surrounding tissues. High rates of disability and cognitive decline in SAH survivors are attributed to loss of neurons and functional connections during secondary brain injury. Haptoglobin sequesters Hb for clearance, but this scavenging system is overwhelmed after a haemorrhage. Whilst exogenous haptoglobin application can attenuate cytotoxicity of Hb in vitro and in vivo, the functional effects of sub-lethal Hb concentrations on surviving neurons and whether cellular function can be protected with haptoglobin treatment remain unclear. Here we use cultured neurons to investigate neuronal health and function across a range of Hb concentrations to establish the thresholds for cellular damage and investigate synaptic function. Hb impairs ATP concentrations and cytoskeletal structure. At clinically relevant but sub-lethal Hb concentrations, we find that synaptic AMPAR-driven currents are reduced, accompanied by a reduction in GluA1 subunit expression. Haptoglobin co-application can prevent these deficits by scavenging free Hb to reduce it to sub-threshold concentrations and does not need to be present at stoichiometric amounts to achieve efficacy. Haptoglobin itself does not impair measures of neuronal health and function at any concentration tested. Our data highlight a role for Hb in modifying synaptic function in surviving neurons, which may link to impaired cognition or plasticity after SAH and support the development of haptoglobin as a therapy for subarachnoid haemorrhage.
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Affiliation(s)
- Hannah Warming
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Katrin Deinhardt
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | | | - John More
- Bio Products Laboratory Limited, Elstree, UK
| | - Diederik Bulters
- Department of Neurosurgery, Wessex Neurological Centre, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Ian Galea
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, UK
| | - Mariana Vargas-Caballero
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
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Breakdown of phospholipids and the elevated nitric oxide are involved in M3 muscarinic regulation of acetylcholine secretion in the frog motor synapse. Biochem Biophys Res Commun 2020; 524:589-594. [DOI: 10.1016/j.bbrc.2020.01.112] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/20/2020] [Indexed: 12/18/2022]
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Fiáth R, Beregszászi P, Horváth D, Wittner L, Aarts AAA, Ruther P, Neves HP, Bokor H, Acsády L, Ulbert I. Large-scale recording of thalamocortical circuits: in vivo electrophysiology with the two-dimensional electronic depth control silicon probe. J Neurophysiol 2016; 116:2312-2330. [PMID: 27535370 DOI: 10.1152/jn.00318.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/13/2016] [Indexed: 12/12/2022] Open
Abstract
Recording simultaneous activity of a large number of neurons in distributed neuronal networks is crucial to understand higher order brain functions. We demonstrate the in vivo performance of a recently developed electrophysiological recording system comprising a two-dimensional, multi-shank, high-density silicon probe with integrated complementary metal-oxide semiconductor electronics. The system implements the concept of electronic depth control (EDC), which enables the electronic selection of a limited number of recording sites on each of the probe shafts. This innovative feature of the system permits simultaneous recording of local field potentials (LFP) and single- and multiple-unit activity (SUA and MUA, respectively) from multiple brain sites with high quality and without the actual physical movement of the probe. To evaluate the in vivo recording capabilities of the EDC probe, we recorded LFP, MUA, and SUA in acute experiments from cortical and thalamic brain areas of anesthetized rats and mice. The advantages of large-scale recording with the EDC probe are illustrated by investigating the spatiotemporal dynamics of pharmacologically induced thalamocortical slow-wave activity in rats and by the two-dimensional tonotopic mapping of the auditory thalamus. In mice, spatial distribution of thalamic responses to optogenetic stimulation of the neocortex was examined. Utilizing the benefits of the EDC system may result in a higher yield of useful data from a single experiment compared with traditional passive multielectrode arrays, and thus in the reduction of animals needed for a research study.
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Affiliation(s)
- Richárd Fiáth
- Group of Comparative Psychophysiology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter, Catholic University, Budapest, Hungary.,School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
| | - Patrícia Beregszászi
- Faculty of Information Technology and Bionics, Pázmány Péter, Catholic University, Budapest, Hungary
| | - Domonkos Horváth
- Group of Comparative Psychophysiology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter, Catholic University, Budapest, Hungary.,School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
| | - Lucia Wittner
- Group of Comparative Psychophysiology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Patrick Ruther
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany
| | - Hercules P Neves
- Unitec Semicondutores, Ribeirão das Neves, Brazil.,Solid State Electronics, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden; and
| | - Hajnalka Bokor
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Acsády
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - István Ulbert
- Group of Comparative Psychophysiology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; .,Faculty of Information Technology and Bionics, Pázmány Péter, Catholic University, Budapest, Hungary
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Yang B, Rajput PS, Kumar U, Sastry BR. Regulation of GABA Equilibrium Potential by mGluRs in Rat Hippocampal CA1 Neurons. PLoS One 2015; 10:e0138215. [PMID: 26389591 PMCID: PMC4577114 DOI: 10.1371/journal.pone.0138215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 08/27/2015] [Indexed: 12/03/2022] Open
Abstract
The equilibrium potential for GABA-A receptor mediated currents (EGABA) in neonatal central neurons is set at a relatively depolarized level, which is suggested to be caused by a low expression of K+/Cl- co-transporter (KCC2) but a relatively high expression of Na+-K+-Cl- cotransporter (NKCC1). Theta-burst stimulation (TBS) in stratum radiatum induces a negative shift in EGABA in juvenile hippocampal CA1 pyramidal neurons. In the current study, the effects of TBS on EGABA in neonatal and juvenile hippocampal CA1 neurons and the underlying mechanisms were examined. Metabotropic glutamate receptors (mGluRs) are suggested to modulate KCC2 and NKCC1 levels in cortical neurons. Therefore, the involvement of mGluRs in the regulation of KCC2 or NKCC1 activity, and thus EGABA, following TBS was also investigated. Whole-cell patch recordings were made from Wistar rat hippocampal CA1 pyramidal neurons, in a slice preparation. In neonates, TBS induces a positive shift in EGABA, which was prevented by NKCC1 antisense but not NKCC1 sense mRNA. (RS)-a-Methyl-4-carboxyphenylglycine (MCPG), a group I and II mGluR antagonist, blocked TBS-induced shifts in both juvenile and neonatal hippocampal neurons. While blockade of mGluR1 or mGluR5 alone could interfere with TBS-induced shifts in EGABA in neonates, only a combined blockade could do the same in juveniles. These results indicate that TBS induces a negative shift in EGABA in juvenile hippocampal neurons but a positive shift in neonatal hippocampal neurons via corresponding changes in KCC2 and NKCC1 expressions, respectively. mGluR activation seems to be necessary for both shifts to occur while the specific receptor subtype involved seems to vary.
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Affiliation(s)
- Bo Yang
- Neuroscience Research Laboratory, Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - Padmesh S. Rajput
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada
| | - Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada
| | - Bhagavatula R. Sastry
- Neuroscience Research Laboratory, Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
- * E-mail:
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Pak N, Siegle JH, Kinney JP, Denman DJ, Blanche TJ, Boyden ES. Closed-loop, ultraprecise, automated craniotomies. J Neurophysiol 2015; 113:3943-53. [PMID: 25855700 DOI: 10.1152/jn.01055.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 04/07/2015] [Indexed: 11/22/2022] Open
Abstract
A large array of neuroscientific techniques, including in vivo electrophysiology, two-photon imaging, optogenetics, lesions, and microdialysis, require access to the brain through the skull. Ideally, the necessary craniotomies could be performed in a repeatable and automated fashion, without damaging the underlying brain tissue. Here we report that when drilling through the skull a stereotypical increase in conductance can be observed when the drill bit passes through the skull base. We present an architecture for a robotic device that can perform this algorithm, along with two implementations--one based on homebuilt hardware and one based on commercially available hardware--that can automatically detect such changes and create large numbers of precise craniotomies, even in a single skull. We also show that this technique can be adapted to automatically drill cranial windows several millimeters in diameter. Such robots will not only be useful for helping neuroscientists perform both small and large craniotomies more reliably but can also be used to create precisely aligned arrays of craniotomies with stereotaxic registration to standard brain atlases that would be difficult to drill by hand.
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Affiliation(s)
- Nikita Pak
- Media Lab and McGovern Institute, Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | | | - Justin P Kinney
- Media Lab and McGovern Institute, Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | | | - Edward S Boyden
- Media Lab and McGovern Institute, Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts;
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Kamp MA, Dibué M, Etminan N, Steiger HJ, Schneider T, Hänggi D. Evidence for direct impairment of neuronal function by subarachnoid metabolites following SAH. Acta Neurochir (Wien) 2013. [PMID: 23180171 DOI: 10.1007/s00701-012-1559-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dysfunction of neuronal signal processing and transmission occurs after subarachnoid hemorrhage (SAH) and contributes to the high morbidity and mortality of this pathology. The underlying mechanisms include early brain injury due to elevation of the intracranial pressure, disruption of the blood-brain barrier, brain edema, reduction of cerebral blood flow, and neuronal cell death. Direct influence of subarachnoid blood metabolites on neuronal signaling should be considered. After SAH, some metabolites were shown to directly induce disruption of neuronal integrity and neuronal signaling, whereas the effects of other metabolites on neurotoxicity and neuronal signaling have not yet been investigated. Therefore, this mini-review will discuss recent evidence for a direct influence of subarachnoid blood and its metabolites on neuronal function.
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Affiliation(s)
- Marcel A Kamp
- Department of Neurosurgery, University Hospital, Heinrich-Heine-University, Düsseldorf, Moorenstraße 5, D-40225, Düsseldorf, Germany.
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Bao X, Wu G, Hu S, Huang F. Poly(ADP-ribose) polymerase activation and brain edema formation by hemoglobin after intracerebral hemorrhage in rats. CEREBRAL HEMORRHAGE 2009; 105:23-7. [DOI: 10.1007/978-3-211-09469-3_5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ortegon DP, Davis MR, Dixon PS, Smith DL, Josephs JD, Mueller DL, Jenkins DH, Kerby JD. The polymerized bovine hemoglobin-based oxygen-carrying solution (HBOC-201) is not toxic to neural cells in culture. THE JOURNAL OF TRAUMA 2002; 53:1068-72. [PMID: 12478030 DOI: 10.1097/00005373-200212000-00007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Recent data suggest that a neurotoxic effect of blood or its components may contribute to secondary neural cell dysfunction. This study investigated the effects of HBOC-201 (Hemopure) and purified human hemoglobin (hHgb) on rat fetal neural cell culture. METHODS Neural cell cultures were exposed to HBOC-201 and hHgb (0.02, 0.2, 2.0, and 6.5 g/dL) for 24 hours, and then analyzed for proliferation, metabolism, and neurolysis. RESULTS Cultures exposed to HBOC-201 maintained levels of proliferation and metabolism similar to controls while demonstrating no cellular lysis. However, cultures exposed to hHgb demonstrated decreased proliferation after exposure to 0.2, 2.0, and 6.5 g/dL hHgb (14,252.14, 3,221.89, and 343.12 vs. 19,509.53; p< 0.05) when compared with controls. In addition, cultures exposed to hHgb demonstrated decreased metabolic activity and increased cell lysis when compared with controls (p < 0.05). CONCLUSION Cultures exposed to HBOC-201 displayed sustained metabolic activity and proliferation, and demonstrated no neurolysis, suggesting that HBOC-201 does not display the toxic characteristics of hHgb.
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Affiliation(s)
- Delio P Ortegon
- Department of General Surgery, University of Texas Health Science Center at San Antonio, USA
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Abstract
BACKGROUND AND PURPOSE In humans, intracerebral hemorrhage (ICH) causes marked perihematomal edema formation and neurological deficits. A rat ICH model, involving infusion of autologous blood into the caudate, has been used extensively to study mechanisms of edema formation, but an examination of behavioral outcome would improve its preclinical utility and provide a more rigorous assessment of the pathological cascade of events over time. The purpose of this study was to use a battery of sensorimotor function tests to examine the neurological effects of ICH in the rat and to examine which components of the hematoma are involved in generating those effects. METHODS The behavioral tests used were forelimb placing, preference for forelimb use for weight shifts during vertical exploration of a cylindrical enclosure, and a corner turn test. Rats were tested from day 1 to day 28 after injection of autologous whole blood; injection of blood plus hirudin (thrombin inhibitor), packed red blood cells, thrombin, or saline; or needle placement only. RESULTS The battery of tests indicated that there were marked neurological deficits by day 1 after ICH, with progressive recovery of function over 4 weeks. The forelimb placing score paralleled changes in edema. Injection of thrombin caused and injection of hirudin reduced the ICH-induced neurological deficits. Injection of packed red blood cells, which causes delayed edema formation, induced delayed neurological deficits CONCLUSIONS These tests allow continuous monitoring of neurological deficits after rat ICH and assessment of therapeutic interventions. The time course of the neurological deficit closely matched the time course of cerebral edema for both ICH and injection of blood components. There was marked recovery of function after ICH, which may be amenable to therapeutic manipulation.
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Affiliation(s)
- Ya Hua
- Department of Neurosurgery, University of Michigan, Ann Arbor 48109-0532, USA.
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Huang FP, Xi G, Keep RF, Hua Y, Nemoianu A, Hoff JT. Brain edema after experimental intracerebral hemorrhage: role of hemoglobin degradation products. J Neurosurg 2002; 96:287-93. [PMID: 11838803 DOI: 10.3171/jns.2002.96.2.0287] [Citation(s) in RCA: 347] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The mechanisms involved in brain edema formation following intracerebral hemorrhage (ICH) have not been fully elucidated. The authors have found that red blood cell lysis plays an important role in edema development after ICH. In the present study, they sought to determine whether degradation products of hemoglobin cause brain edema. METHODS Hemoglobin, hemin, bilirubin, or FeCl2 were infused with stereotactic guidance into the right basal ganglia of Sprague-Dawley rats. The animals were killed 24 hours later to determine brain water and ion contents. Western blot analysis and immunohistochemistry were applied for heme oxygenase-1 (HO-1) measurement. The effects of an HO inhibitor, tin-protoporphyrin (SnPP), and the iron chelator deferoxamine, on hemoglobin-induced brain edema were also examined. Intracerebral infusion of hemoglobin, hemin, bilirubin, or FeCl2 caused an increase in brain water content at 24 hours. The HO-1 was upregulated after hemoglobin infusion and HO inhibition by SnPP-attenuated hemoglobin-induced edema. Brain edema induced by hemoglobin was also attenuated by the intraperitoneal injection of 500 mg/kg deferoxamine. CONCLUSIONS Hemoglobin causes brain edema, at least in part, through its degradation products. Limiting hemoglobin degradation coupled with the use of iron chelators may be a novel therapeutic approach to limit brain edema after ICH.
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Affiliation(s)
- Feng-Ping Huang
- Department of Neurosurgery, University of Michigan, Ann Arbor 48109-0532, USA
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Yip S, Sastry BR. Effects of hemoglobin and its breakdown products on synaptic transmission in rat hippocampal CA1 neurons. Brain Res 2000; 864:1-12. [PMID: 10793181 DOI: 10.1016/s0006-8993(00)02067-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
During head injuries and hemorrhagic stroke, blood is released into the extravascular space. The pooled erythrocytes get lysed and hemoglobin is released into the intracranial cavities. Therefore, neurons may be exposed to hemoglobin and/or its breakdown products, hemin and iron, for long periods of time. In this study, the electrophysiological actions of these agents on synaptic transmission in rat hippocampal CA1 pyramidal neurons were studied using extracellular field- and whole cell patch-recordings. Previously our laboratory reported that commercially available hemoglobin produced a dose dependent suppression of synaptic transmission in hippocampal CA1 neurons. In the present study, however, we found that this depression was caused by impurities present in the hemoglobin samples. Commercially available hemoglobin and methemoglobin did not have a significant effect on synaptic transmission. Although, reduced-hemoglobin prepared using a method described by Martin et al. [J. Pharm. Exp. Ther. 232 (1985) 708], produced a significant depression of synaptic transients, these effects were due to contamination with bisulfite that was present due to the reducing procedure. Therefore, the technique of Martin et al. was inadequate in removing the reducing agents or their breakdown products. A number of studies in literature used commercial samples of hemoglobin or reduced hemoglobin prepared using the method of Martin et al. Our observations indicate that it would be important to determine if contaminants, rather than hemoglobin, are responsible for the observed effects in these studies. Unlike hemoglobin, its breakdown products, ferrous chloride and hemin, produced an irreversible and significant depression of field excitatory postsynaptic potentials. The relevance of these effects in neurological complications that follow head injuries and hemorrhagic stroke awaits further investigation.
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Affiliation(s)
- S Yip
- Neuroscience Research Laboratory, Department of Pharmacology and Therapeutics, The University of British Columbia, Vancouver, Canada
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Nitric oxide acts as a postsynaptic signaling molecule in calcium/calmodulin-induced synaptic potentiation in hippocampal CA1 pyramidal neurons. J Neurosci 1999. [PMID: 10436036 DOI: 10.1523/jneurosci.19-16-06784.1999] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Postsynaptic injection of Ca(2+)/calmodulin (Ca(2+)/CaM) into hippocampal CA1 pyramidal neurons induces synaptic potentiation, which can occlude tetanus-induced potentiation (Wang and Kelly, 1995). Because Ca(2+)/CaM activates the major forms of nitric oxide synthase (NOS) to produce nitric oxide (NO), NO may play a role during Ca(2+)/CaM-induced potentiation. Here we show that extracellular application of the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) or postsynaptic co-injection of L-NAME with Ca(2+)/CaM blocked Ca(2+)/CaM-induced synaptic potentiation. Thus, NO is necessary for Ca(2+)/CaM-induced synaptic potentiation. In contrast, extracellular perfusion of membrane-impermeable NO scavengers N-methyl-D-glucamine dithiocarbamate/ferrous sulfate mixture (MGD-Fe) or 2-(4-carboxyphenyl)-4,4,5, 5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) did not attenuate Ca(2+)/CaM-induced synaptic potentiation, even though MGD-Fe or carboxy-PTIO blocked tetanus-induced synaptic potentiation. This result indicates that NO is not a retrograde messenger in Ca(2+)/CaM-induced synaptic potentiation. However, postsynaptic co-injection of carboxy-PTIO with Ca(2+)/CaM blocked Ca(2+)/CaM-induced potentiation. Postsynaptic injection of carboxy-PTIO alone blocked tetanus-induced synaptic potentiation without affecting basal synaptic transmission. Our results suggest that NO works as a postsynaptic (intracellular) messenger during Ca(2+)/CaM-induced synaptic potentiation.
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Xi G, Keep RF, Hoff JT. Erythrocytes and delayed brain edema formation following intracerebral hemorrhage in rats. J Neurosurg 1998; 89:991-6. [PMID: 9833826 DOI: 10.3171/jns.1998.89.6.0991] [Citation(s) in RCA: 270] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECT The mechanisms of brain edema formation following spontaneous intracerebral hemorrhage (ICH) are not well understood. In previous studies, no significant edema formation has been found 24 hours after infusion of packed red blood cells (RBCs) into the brain of a rat or pig; however, there is evidence that hemoglobin can be neurotoxic. In this study, the authors reexamined the role of RBCs and hemoglobin in edema formation after ICH. METHODS The experiments involved infusion of whole blood, packed RBCs, lysed RBCs, rat hemoglobin, or thrombin into the right basal ganglia of Sprague-Dawley rats. The animals were killed at different time points and brain water and ion contents were measured. The results showed that lysed autologous erythrocytes, but not packed erythrocytes, produced marked brain edema 24 hours after infusion and that this edema formation could be mimicked by hemoglobin infusion. Although infusion of packed RBCs did not produce dramatic brain edema during the first 2 days, it did induce a marked increase in brain water content 3 days postinfusion. Edema formation following thrombin infusion peaked at 24 to 48 hours. This is earlier than the peak in edema formation that follows ICH, suggesting that there is a delayed, nonthrombin-mediated, edemogenic component of ICH. CONCLUSIONS These results demonstrate that RBCs play a potentially important role in delayed edema development after ICH and that RBC lysis and hemoglobin toxicity may be useful targets for therapeutic intervention.
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Affiliation(s)
- G Xi
- Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor 48109-0532, USA.
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Abstract
The vulnerability of spinal cord neurons to hemoglobin was quantitatively assessed in primary cultures derived from fetal mice. Exposure to hemoglobin for 28 h in a serum-free medium resulted in concentration-dependent neuronal death, with an EC50 of 0.9 microM; glia were not injured. Neuronal death was decreased by the ferric iron chelator deferoxamine, the alpha-tocopherol analogue Trolox C, ascorbate, and exogenous catalase, but was potentiated by superoxide dismutase. Neuronal death was also increased by depletion of cellular glutathione with the gamma-glutamylcysteine synthetase inhibitor buthionine sulfoxamine; inhibition of endogenous catalase with 3-amino-1,2,4-triazole had no significant effect. These results suggest that hemoglobin is toxic to spinal neurons via an iron-dependent, oxidative mechanism involving a hydrogen peroxide intermediate, and support the hypothesis that hemoglobin release may contribute to neuronal loss after spinal cord trauma.
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Affiliation(s)
- R F Regan
- Division of Emergency Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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