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ATPergic signalling during seizures and epilepsy. Neuropharmacology 2015; 104:140-53. [PMID: 26549853 DOI: 10.1016/j.neuropharm.2015.11.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/01/2015] [Accepted: 11/02/2015] [Indexed: 10/22/2022]
Abstract
Much progress has been made over the last few decades in the identification of new anti-epileptic drugs (AEDs). However, 30% of epilepsy patients suffer poor seizure control. This underscores the need to identify alternative druggable neurotransmitter systems and drugs with novel mechanisms of action. An emerging concept is that seizure generation involves a complex interplay between neurons and glial cells at the tripartite synapse and neuroinflammation has been proposed as one of the main drivers of epileptogenesis. The ATP-gated purinergic receptor family is expressed throughout the brain and is functional on neurons and glial cells. ATP is released in high amounts into the extracellular space after increased neuronal activity and during chronic inflammation and cell death to act as a neuro- and gliotransmitter. Emerging work shows pharmacological targeting of ATP-gated purinergic P2 receptors can potently modulate seizure generation, inflammatory processes and seizure-induced brain damage. To date, work showing the functional contribution of P2 receptors has been mainly performed in animal models of acute seizures, in particular, by targeting the ionotropic P2X7 receptor subtype. Other ionotropic P2X and metabotropic P2Y receptor family members have also been implicated in pathological processes following seizures such as the P2X4 receptor and the P2Y12 receptor. However, during epilepsy, the characterization of P2 receptors was mostly restricted to the study of expressional changes of the different receptor subtypes. This review summarizes the work to date on ATP-mediated signalling during seizures and the functional impact of targeting the ATP-gated purinergic receptors on seizures and seizure-induced pathology. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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152
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Handa RK, Lingeman JE, Bledsoe SB, Evan AP, Connors BA, Johnson CD. Intraluminal measurement of papillary duct urine pH, in vivo: a pilot study in the swine kidney. Urolithiasis 2015; 44:211-7. [PMID: 26526044 DOI: 10.1007/s00240-015-0834-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022]
Abstract
We describe the in vivo use of an optic-chemo microsensor to measure intraluminal papillary duct urine pH in a large mammal. Fiber-optic pH microsensors have a tip diameter of 140-µm that allows insertion into papillary Bellini ducts to measure tubule urine proton concentration. Anesthetized adult pigs underwent percutaneous nephrolithotomy to access the lower pole of the urinary collecting system. A flexible nephroscope was advanced towards an upper pole papilla with the fiber-optic microsensor contained within the working channel. The microsensor was then carefully inserted into Bellini ducts to measure tubule urine pH in real time. We successfully recorded tubule urine pH values in five papillary ducts from three pigs (1 farm pig and 2 metabolic syndrome Ossabaw pigs). Our results demonstrate that optical microsensor technology can be used to measure intraluminal urine pH in real time in a living large mammal. This opens the possibility for application of this optical pH sensing technology in nephrolithiasis.
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Affiliation(s)
- Rajash K Handa
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA. .,Department of Urology (JEL), Indiana University Health at Methodist Hospital, Indianapolis, IN, USA.
| | - James E Lingeman
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sharon B Bledsoe
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew P Evan
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bret A Connors
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA
| | - Cynthia D Johnson
- Department of Anatomy and Cell Biology (RKH, SBB, APE, BAC, CDJ), Indiana University School of Medicine, Indianapolis, IN, USA
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153
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Liang JJ, Huang LF, Chen XM, Pan SQ, Lu ZN, Xiao ZM. Amiloride suppresses pilocarpine-induced seizures via ASICs other than NHE in rats. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:14507-14513. [PMID: 26823770 PMCID: PMC4713556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND AND PURPOSE Although recent studies have indicated that acid-sensing ion channels (ASICs) may play an important role in suppressing status epilepticus (SE) in rats, the precise mechanism is unclear. We attempted to investigate the antiepileptic effect of amiloride in SE rats and its mechanism. METHODS Rats with seizures induced by Li-pilocarpine were randomly divided into four groups, phosphate buffer saline (PBS) group, amiloride group, levetiracetam group and acidic liquid group, respectively. The electroencephalogram (EEG) of each group was recorded. Then rats treated with different drugs (2 h after amiloride or PBS injection or 1 h after PBS injection) and a normal control group was selected for reverse transcription-polymerase chain reaction (RT-PCR). The expression of ASIC1a, ASIC3 and sodium-hydrogen exchanger (NHE) in each group was detected. RESULTS Amiloride reduced the frequency of discharge in 60~90 min after injection significantly. In acidic liquid group, the epileptic discharge was increased in 0~30 min. Moreover, the expression of ASIC1a, ASIC3 and NHE was obviously increased in the SE groups. Compared with SE groups, the expression of ASIC1a and ASIC3 mRNA in amiloride group decreased significantly. While NHE mRNA expression in the SE groups showed no significant difference. CONCLUSION Amiloride inhibited pilocarpine-induced SE and the anti-epileptic mechanism was associated with deactivation of the ASIC1a and ASIC3 instead of NHE in rats.
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Affiliation(s)
- Jing-Jing Liang
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
| | - Li-Fang Huang
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
| | - Xu-Ming Chen
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
| | - Song-Qing Pan
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
| | - Zu-Neng Lu
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
| | - Zhe-Man Xiao
- Department of Neurology, Renmin Hospital of Wuhan University Wuhan 430060, Hubei Province, P. R. C
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154
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Huang L, Zhao S, Lu W, Guan S, Zhu Y, Wang JH. Acidosis-Induced Dysfunction of Cortical GABAergic Neurons through Astrocyte-Related Excitotoxicity. PLoS One 2015; 10:e0140324. [PMID: 26474076 PMCID: PMC4608795 DOI: 10.1371/journal.pone.0140324] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/24/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Acidosis impairs cognitions and behaviors presumably by acidification-induced changes in neuronal metabolism. Cortical GABAergic neurons are vulnerable to pathological factors and their injury leads to brain dysfunction. How acidosis induces GABAergic neuron injury remains elusive. As the glia cells and neurons interact each other, we intend to examine the role of the astrocytes in acidosis-induced GABAergic neuron injury. RESULTS Experiments were done at GABAergic cells and astrocytes in mouse cortical slices. To identify astrocytic involvement in acidosis-induced impairment, we induced the acidification in single GABAergic neuron by infusing proton intracellularly or in both neurons and astrocytes by using proton extracellularly. Compared the effects of intracellular acidification and extracellular acidification on GABAergic neurons, we found that their active intrinsic properties and synaptic outputs appeared more severely impaired in extracellular acidosis than intracellular acidosis. Meanwhile, extracellular acidosis deteriorated glutamate transporter currents on the astrocytes and upregulated excitatory synaptic transmission on the GABAergic neurons. Moreover, the antagonists of glutamate NMDA-/AMPA-receptors partially reverse extracellular acidosis-induced injury in the GABAergic neurons. CONCLUSION Our studies suggest that acidosis leads to the dysfunction of cortical GABAergic neurons by astrocyte-mediated excitotoxicity, in addition to their metabolic changes as indicated previously.
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Affiliation(s)
- Li Huang
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Shidi Zhao
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Wei Lu
- Collaborative Innovation Center for Neurodegenerative Disorders in Shandong, Qingdao University, Medical College, 38 Dengzhou, Shandong China 266021
| | - Sudong Guan
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Yan Zhu
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Jin-Hui Wang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing China 100101
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155
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Peng Z, Li WG, Huang C, Jiang YM, Wang X, Zhu MX, Cheng X, Xu TL. ASIC3 Mediates Itch Sensation in Response to Coincident Stimulation by Acid and Nonproton Ligand. Cell Rep 2015; 13:387-98. [PMID: 26440887 DOI: 10.1016/j.celrep.2015.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/20/2015] [Accepted: 08/31/2015] [Indexed: 11/25/2022] Open
Abstract
The regulation and mechanisms underlying itch sensation are complex. Here, we report a role for acid-sensing ion channel 3 (ASIC3) in mediating itch evoked by certain pruritogens during tissue acidosis. Co-administration of acid with Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SL-NH2) increased scratching behavior in wild-type, but not ASIC3-null, mice, implicating the channel in coincident detection of acidosis and pruritogens. Mechanistically, SL-NH2 slowed desensitization of proton-evoked currents by targeting the previously identified nonproton ligand-sensing domain located in the extracellular region of ASIC3 channels in primary sensory neurons. Ablation of the ASIC3 gene reduced dry-skin-induced scratching behavior and pathological changes under conditions with concomitant inflammation. Taken together, our data suggest that ASIC3 mediates itch sensation via coincident detection of acidosis and nonproton ligands that act at the nonproton ligand-sensing domain of the channel.
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Affiliation(s)
- Zhong Peng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Guang Li
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chen Huang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yi-Ming Jiang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiang Wang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Michael Xi Zhu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Xiaoyang Cheng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Tian-Le Xu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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156
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Saez NJ, Deplazes E, Cristofori-Armstrong B, Chassagnon IR, Lin X, Mobli M, Mark AE, Rash LD, King GF. Molecular dynamics and functional studies define a hot spot of crystal contacts essential for PcTx1 inhibition of acid-sensing ion channel 1a. Br J Pharmacol 2015; 172:4985-95. [PMID: 26248594 DOI: 10.1111/bph.13267] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/29/2015] [Accepted: 07/13/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The spider-venom peptide PcTx1 is the most potent and selective inhibitor of acid-sensing ion channel (ASIC) 1a. It has centrally acting analgesic activity and is neuroprotective in rodent models of ischaemic stroke. Understanding the molecular details of the PcTx1 : ASIC1a interaction should facilitate development of therapeutically useful ASIC1a modulators. Previously, we showed that several key pharmacophore residues of PcTx1 reside in a dynamic β-hairpin loop; conclusions confirmed by recent crystal structures of the complex formed between PcTx1 and chicken ASIC1 (cASIC1). Numerous peptide : channel contacts were observed in these crystal structures, but it remains unclear which of these are functionally important. EXPERIMENTAL APPROACH We combined molecular dynamics (MD) simulations of the PcTx1 : cASIC1 complex with mutagenesis of PcTx1 and rat ASIC1a. KEY RESULTS Crystal structures of the PcTx1 : cASIC1 complex indicated that 15 PcTx1 residues form a total of 57 pairwise intermolecular contacts (<5 Å) with 32 channel residues. MD simulations, however, suggested that about half of these interactions do not persist in solution. Mutation to alanine of only eight of 15 PcTx1 contact residues substantially altered ASIC1a inhibition by PcTx1. Our data reveal that many of the peptide-channel interactions observed in the PcTx1 : cASIC1 crystal structures are not important for PcTx1 inhibition of rat ASIC1a. CONCLUSIONS AND IMPLICATIONS We identified the atomic interactions that are critical for PcTx1 inhibition of ASIC1a. Our data highlight the value of combining structural information, MD and functional experiments to obtain detailed insight into the molecular basis of protein : protein interactions.
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Affiliation(s)
- Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Evelyne Deplazes
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Irène R Chassagnon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | | | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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157
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Osmakov DI, Andreev YA, Kozlov SA. Acid-sensing ion channels and their modulators. BIOCHEMISTRY (MOSCOW) 2015; 79:1528-45. [PMID: 25749163 DOI: 10.1134/s0006297914130069] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
According to a modern look acid-sensing ion channels (ASICs) are one of the most important receptors that perceive pH change in the body. ASICs represent proton-gated Na+-selective channels, which are expressed in neurons of the central and peripheral nervous system. These channels are attracting attention of researchers around the world, as they are involved in various physiological processes in the body. Drop of pH may occur in tissues in norm (e.g. the accumulation of lactic acid, the release of protons upon ATP hydrolysis) and pathology (inflammation, ischemic stroke, tissue damage and seizure). These processes are accompanied by unpleasant pain sensations, which may be short-lived or can lead to chronic inflammatory diseases. Modulators of ASIC channels activity are potential candidates for new effective analgesic and neuroprotection drugs. This review summarizes available information about structure, function, and physiological role of ASIC channels. In addition a description of all known ligands of these channels and their practical relevance is provided.
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Affiliation(s)
- D I Osmakov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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158
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Zeng WZ, Liu DS, Liu L, She L, Wu LJ, Xu TL. Activation of acid-sensing ion channels by localized proton transient reveals their role in proton signaling. Sci Rep 2015; 5:14125. [PMID: 26370138 PMCID: PMC4569896 DOI: 10.1038/srep14125] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 08/18/2015] [Indexed: 12/31/2022] Open
Abstract
Extracellular transients of pH alterations likely mediate signal transduction in the nervous system. Neuronal acid-sensing ion channels (ASICs) act as sensors for extracellular protons, but the mechanism underlying ASIC activation remains largely unknown. Here, we show that, following activation of a light-activated proton pump, Archaerhodopsin-3 (Arch), proton transients induced ASIC currents in both neurons and HEK293T cells co-expressing ASIC1a channels. Using chimera proteins that bridge Arch and ASIC1a by a glycine/serine linker, we found that successful coupling occurred within 15 nm distance. Furthermore, two-cell sniffer patch recording revealed that regulated release of protons through either Arch or voltage-gated proton channel Hv1 activated neighbouring cells expressing ASIC1a channels. Finally, computational modelling predicted the peak proton concentration at the intercellular interface to be at pH 6.7, which is acidic enough to activate ASICs in vivo. Our results highlight the pathophysiological role of proton signalling in the nervous system.
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Affiliation(s)
- Wei-Zheng Zeng
- Discipline of Neuroscience, Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Di-Shi Liu
- Discipline of Neuroscience, Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lu Liu
- Institute of Neuroscience, Chinese Academy of Sciences, Shanghai 200031, China
| | - Liang She
- Institute of Neuroscience, Chinese Academy of Sciences, Shanghai 200031, China
| | - Long-Jun Wu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Tian-Le Xu
- Discipline of Neuroscience, Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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159
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Afra P, Jouny CC, Bergey GK. Termination patterns of complex partial seizures: An intracranial EEG study. Seizure 2015; 32:9-15. [PMID: 26552555 DOI: 10.1016/j.seizure.2015.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 07/08/2015] [Accepted: 08/12/2015] [Indexed: 01/02/2023] Open
Abstract
PURPOSE While seizure onset patterns have been the subject of many reports, there have been few studies of seizure termination. In this study we report the incidence of synchronous and asynchronous termination patterns of partial seizures recorded with intracranial arrays. METHODS Data were collected from patients with intractable complex partial seizures undergoing presurgical evaluations with intracranial electrodes. Patients with seizures originating from mesial temporal and neocortical regions were grouped into three groups based on patterns of seizure termination: synchronous only (So), asynchronous only (Ao), or mixed (S/A, with both synchronous and asynchronous termination patterns). RESULTS 88% of the patients in the MT group had seizures with a synchronous pattern of termination exclusively (38%) or mixed (50%). 82% of the NC group had seizures with synchronous pattern of termination exclusively (52%) or mixed (30%). In the NC group, there was a significant difference of the range of seizure durations between So and Ao groups, with Ao exhibiting higher variability. Seizures with synchronous termination had low variability in both groups. CONCLUSIONS Synchronous seizure termination is a common pattern for complex partials seizures of both mesial temporal or neocortical onset. This may reflect stereotyped network behavior or dynamics at the seizure focus.
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Affiliation(s)
- Pegah Afra
- Department of Neurology, School of Medicine, University of Utah, Salt Lake City, UT, United States.
| | - Christopher C Jouny
- Department of Neurology, Johns Hopkins Epilepsy Center, Johns Hopkins University School of Medicine, United States
| | - Gregory K Bergey
- Department of Neurology, Johns Hopkins Epilepsy Center, Johns Hopkins University School of Medicine, United States
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160
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Eccentricity mapping of the human visual cortex to evaluate temporal dynamics of functional T1ρ mapping. J Cereb Blood Flow Metab 2015; 35:1213-9. [PMID: 25966957 PMCID: PMC4640285 DOI: 10.1038/jcbfm.2015.94] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 11/08/2022]
Abstract
Recent experiments suggest that T1 relaxation in the rotating frame (T(1ρ)) is sensitive to metabolism and can detect localized activity-dependent changes in the human visual cortex. Current functional magnetic resonance imaging (fMRI) methods have poor temporal resolution due to delays in the hemodynamic response resulting from neurovascular coupling. Because T(1ρ) is sensitive to factors that can be derived from tissue metabolism, such as pH and glucose concentration via proton exchange, we hypothesized that activity-evoked T(1ρ) changes in visual cortex may occur before the hemodynamic response measured by blood oxygenation level-dependent (BOLD) and arterial spin labeling (ASL) contrast. To test this hypothesis, functional imaging was performed using T(1ρ), BOLD, and ASL in human participants viewing an expanding ring stimulus. We calculated eccentricity phase maps across the occipital cortex for each functional signal and compared the temporal dynamics of T(1ρ) versus BOLD and ASL. The results suggest that T(1ρ) changes precede changes in the two blood flow-dependent measures. These observations indicate that T(1ρ) detects a signal distinct from traditional fMRI contrast methods. In addition, these findings support previous evidence that T(1ρ) is sensitive to factors other than blood flow, volume, or oxygenation. Furthermore, they suggest that tissue metabolism may be driving activity-evoked T(1ρ) changes.
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161
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Baron A, Lingueglia E. Pharmacology of acid-sensing ion channels – Physiological and therapeutical perspectives. Neuropharmacology 2015; 94:19-35. [DOI: 10.1016/j.neuropharm.2015.01.005] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/15/2014] [Accepted: 01/07/2015] [Indexed: 12/29/2022]
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162
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Tao AF, Xu ZH, Chen B, Wang Y, Wu XH, Zhang J, Tang YS, Xu CL, Zhao HW, Hu WW, Shi LY, Zhang SH, Chen Z. The Pro-inflammatory Cytokine Interleukin-1β is a Key Regulatory Factor for the Postictal Suppression in Mice. CNS Neurosci Ther 2015; 21:642-50. [PMID: 26096304 DOI: 10.1111/cns.12416] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 01/18/2023] Open
Abstract
AIMS The postictal suppression (PS) is a common and important period following an epileptic seizure but has not been well studied. This study was designed to determine whether interleukin-1β (IL-1β) is involved in the PS. METHODS The effects of IL-1β on the PS were tested in three independent seizure models induced by hippocampal kindling, maximal electroshock seizure (MES), and 4-aminopyridine, respectively. RESULTS IL-1R1 knockout or IL-1RA enhanced the seizure refractory phenomenon without influencing the baseline seizure threshold in intermittent MES model. IL-1β attenuated the seizure refractory phenomenon without affecting the severity of the preceding seizures in hippocampal kindling model, while IL-1RA enhanced it. Besides, IL-1β reduced the postictal EEG suppression period, while IL-1RA prolonged it. And IL-1β showed no further effect on the postictal EEG suppression and seizure refractory phenomenon in IL-1R1 knockout mice. In addition, 30 min after intrahippocampal injection of 4-aminopyridine, IL-1β increased the incidence of SE, while IL-1RA prolonged the intervals between recurrent seizures. CONCLUSIONS This study provides the first direct evidence that IL-1β is key regulatory factor for the PS, and its receptor IL-1R1 may be a potential target for adjuvant treatment of postictal problems.
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Affiliation(s)
- An-Feng Tao
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zheng-Hao Xu
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Bin Chen
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi Wang
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiao-Hua Wu
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jing Zhang
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yang-Shun Tang
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ceng-Lin Xu
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hua-Wei Zhao
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wei-Wei Hu
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Li-Yun Shi
- Department of Basic Medical Science, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Shi-Hong Zhang
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhong Chen
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China and Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Wolfart J, Laker D. Homeostasis or channelopathy? Acquired cell type-specific ion channel changes in temporal lobe epilepsy and their antiepileptic potential. Front Physiol 2015; 6:168. [PMID: 26124723 PMCID: PMC4467176 DOI: 10.3389/fphys.2015.00168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/19/2015] [Indexed: 01/16/2023] Open
Abstract
Neurons continuously adapt the expression and functionality of their ion channels. For example, exposed to chronic excitotoxicity, neurons homeostatically downscale their intrinsic excitability. In contrast, the “acquired channelopathy” hypothesis suggests that proepileptic channel characteristics develop during epilepsy. We review cell type-specific channel alterations under different epileptic conditions and discuss the potential of channels that undergo homeostatic adaptations, as targets for antiepileptic drugs (AEDs). Most of the relevant studies have been performed on temporal lobe epilepsy (TLE), a widespread AED-refractory, focal epilepsy. The TLE patients, who undergo epilepsy surgery, frequently display hippocampal sclerosis (HS), which is associated with degeneration of cornu ammonis subfield 1 pyramidal cells (CA1 PCs). Although the resected human tissue offers insights, controlled data largely stem from animal models simulating different aspects of TLE and other epilepsies. Most of the cell type-specific information is available for CA1 PCs and dentate gyrus granule cells (DG GCs). Between these two cell types, a dichotomy can be observed: while DG GCs acquire properties decreasing the intrinsic excitability (in TLE models and patients with HS), CA1 PCs develop channel characteristics increasing intrinsic excitability (in TLE models without HS only). However, thorough examination of data on these and other cell types reveals the coexistence of protective and permissive intrinsic plasticity within neurons. These mechanisms appear differentially regulated, depending on the cell type and seizure condition. Interestingly, the same channel molecules that are upregulated in DG GCs during HS-related TLE, appear as promising targets for future AEDs and gene therapies. Hence, GCs provide an example of homeostatic ion channel adaptation which can serve as a primer when designing novel anti-epileptic strategies.
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Affiliation(s)
- Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Debora Laker
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
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164
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The brain acid–base homeostasis and serotonin: A perspective on the use of carbon dioxide as human and rodent experimental model of panic. Prog Neurobiol 2015; 129:58-78. [DOI: 10.1016/j.pneurobio.2015.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 12/14/2022]
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165
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Liu S, Cheng XY, Wang F, Liu CF. Acid-sensing ion channels: potential therapeutic targets for neurologic diseases. Transl Neurodegener 2015; 4:10. [PMID: 26029363 PMCID: PMC4449961 DOI: 10.1186/s40035-015-0031-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 05/14/2015] [Indexed: 01/14/2023] Open
Abstract
Maintaining the physiological pH of interstitial fluid is crucial for normal cellular functions. In disease states, tissue acidosis is a common pathologic change causing abnormal activation of acid-sensing ion channels (ASICs), which according to cumulative evidence, significantly contributes to inflammation, mitochondrial dysfunction, and other pathologic mechanisms (i.e., pain, stroke, and psychiatric conditions). Thus, it has become increasingly clear that ASICs are critical in the progression of neurologic diseases. This review is focused on the importance of ASICs as potential therapeutic targets in combating neurologic diseases.
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Affiliation(s)
- Sha Liu
- />Department of Neurology, the Second Affiliated Hospital of Soochow University, Soochow University, 1055 Sanxiang Road, Suzhou, 215004 China
| | - Xiao-Yu Cheng
- />Department of Neurology, the Second Affiliated Hospital of Soochow University, Soochow University, 1055 Sanxiang Road, Suzhou, 215004 China
| | - Fen Wang
- />Department of Neurology, the Second Affiliated Hospital of Soochow University, Soochow University, 1055 Sanxiang Road, Suzhou, 215004 China
- />Institute of Neuroscience, Soochow University, Suzhou, 215123 China
| | - Chun-Feng Liu
- />Department of Neurology, the Second Affiliated Hospital of Soochow University, Soochow University, 1055 Sanxiang Road, Suzhou, 215004 China
- />Institute of Neuroscience, Soochow University, Suzhou, 215123 China
- />Beijing Key Laboratory for Parkinson’s Disease, Beijing, 100053 China
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166
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Lin SH, Chien YC, Chiang WW, Liu YZ, Lien CC, Chen CC. Genetic mapping of ASIC4 and contrasting phenotype to ASIC1a in modulating innate fear and anxiety. Eur J Neurosci 2015; 41:1553-68. [PMID: 25828470 DOI: 10.1111/ejn.12905] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 01/23/2023]
Abstract
Although ASIC4 is a member of the acid-sensing ion channel (ASIC) family, we have limited knowledge of its expression and physiological function in vivo. To trace the expression of this ion channel, we generated the ASIC4-knockout/CreERT(2)-knockin (Asic4(Cre) (ERT) (2)) mouse line. After tamoxifen induction in the Asic4(Cre) (ERT)(2)::CAG-STOP(floxed)-Td-tomato double transgenic mice, we mapped the expression of ASIC4 at the cellular level in the central nervous system (CNS). ASIC4 was expressed in many brain regions, including the olfactory bulb, cerebral cortex, striatum, hippocampus, amygdala, thalamus, hypothalamus, brain stem, cerebellum, spinal cord and pituitary gland. Colocalisation studies further revealed that ASIC4 was expressed mainly in three types of cells in the CNS: (i) calretinin (CR)-positive and/or vasoactive intestine peptide (VIP)-positive interneurons; (ii) neural/glial antigen 2 (NG2)-positive glia, also known as oligodendrocyte precursor cells; and (iii) cerebellar granule cells. To probe the possible role of ASIC4, we hypothesised that ASIC4 could modulate the membrane expression of ASIC1a and thus ASIC1a signaling in vivo. We conducted behavioral phenotyping of Asic4(Cre) (ERT)(2) mice by screening many of the known behavioral phenotypes found in Asic1a knockouts and found ASIC4 not involved in shock-evoked fear learning and memory, seizure termination or psychostimulant-induced locomotion/rewarding effects. In contrast, ASIC4 might play an important role in modulating the innate fear response to predator odor and anxious state because ASIC4-mutant mice showed increased freezing response to 2,4,5-trimethylthiazoline and elevated anxiety-like behavior in both the open-field and elevated-plus maze. ASIC4 may modulate fear and anxiety by counteracting ASIC1a activity in the brain.
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Affiliation(s)
- Shing-Hong Lin
- Graduate institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, 115, Taiwan
| | - Ya-Chih Chien
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 115, Taiwan
| | - Wei-Wei Chiang
- Taiwan Mouse Clinic-National Comprehensive Mouse Phenotyping and Drug Testing Center, Academia Sinica, Taipei, Taiwan
| | - Yan-Zhen Liu
- Taiwan Mouse Clinic-National Comprehensive Mouse Phenotyping and Drug Testing Center, Academia Sinica, Taipei, Taiwan
| | - Cheng-Chang Lien
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Cheng Chen
- Graduate institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, 115, Taiwan.,Taiwan Mouse Clinic-National Comprehensive Mouse Phenotyping and Drug Testing Center, Academia Sinica, Taipei, Taiwan
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167
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TLR9 signalling in microglia attenuates seizure-induced aberrant neurogenesis in the adult hippocampus. Nat Commun 2015; 6:6514. [PMID: 25751136 PMCID: PMC4366529 DOI: 10.1038/ncomms7514] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 02/04/2015] [Indexed: 12/18/2022] Open
Abstract
Pathological conditions such as epilepsy cause misregulation of adult neural stem/progenitor populations in the adult hippocampus in mice, and the resulting abnormal neurogenesis leads to impairment in learning and memory. However, how animals cope with abnormal neurogenesis remains unknown. Here we show that microglia in the mouse hippocampus attenuate convulsive seizure-mediated aberrant neurogenesis through the activation of Toll-like receptor 9 (TLR9), an innate immune sensor known to recognize microbial DNA and trigger inflammatory responses. We found that microglia sense self-DNA from degenerating neurons following seizure, and secrete tumour necrosis factor-α, resulting in attenuation of aberrant neurogenesis. Furthermore, TLR9 deficiency exacerbated seizure-induced cognitive decline and recurrent seizure severity. Our findings thus suggest the existence of bidirectional communication between the innate immune and nervous systems for the maintenance of adult brain integrity. Epileptic seizures generate aberrant neurogenesis in the adult mouse hippocampal region but how animals cope with abnormal neurogenesis remains unknown. Here the authors show that microglia are activated through TLR9 signaling and that this leads to sustained expression of TNF-α which attenuates induced aberrant neurogenesis.
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168
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Wu H, Wang C, Liu B, Li H, Zhang Y, Dong S, Gao G, Zhang H. Altered Expression Pattern of Acid-Sensing Ion Channel Isoforms in Piriform Cortex After Seizures. Mol Neurobiol 2015; 53:1782-1793. [PMID: 25744567 DOI: 10.1007/s12035-015-9130-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/22/2015] [Indexed: 12/24/2022]
Abstract
The piriform cortex (PC) is highly susceptible to chemical and electrical seizure induction. Epileptiform activity is associated with an acid shift in extracellular pH, suggesting that acid-sensing ion channels (ASICs) expressed by PC neurons may contribute to this enhanced epileptogenic potential. In epileptic rats and surgical samples from patients with medial temporal lobe epilepsy (TLE), PC layer II ASIC1a-immunopositive neurons appeared swollen with dendritic elongation, and there was loss of ASIC1a-positive neurons in layer III, consistent with enhanced vulnerability to TLE-induced plasticity and cell death. In rats, pilocarpine-induced seizures led to transient downregulation of ASIC1a and concomitant upregulation of ASIC2a in the first few days post-seizure. These changes in expression may be due to seizure-induced oxidative stress as a similar reciprocal change in ASIC1a, and ASIC2a expression was observed in PC12 cells following H2O2 application. The proportion of ASIC1a/ASIC2a heteromers was reduced in the acute phase following status epilepticus (SE) but increased during the latent phase when rats developed spontaneous seizures. Knockdown of ASIC2a by RNAi reduced dendritic length and spine density in primary neurons, suggesting that seizure-induced upregulation of ASIC2a contributes to dendritic lengthening in PC layer II in rats. Administration of the ASIC inhibitor amiloride before pilocarpine reduced the proportion of rats reaching Racine level IV seizures, protected layer II and III neurons, and prolonged survival in the acute phase following SE. Our findings suggest that ASICs may enhance susceptibility to epileptogenesis in the PC. Inhibition of ASICs, particularly ASIC2a, may suppress seizures originating in the PC.
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Affiliation(s)
- Hao Wu
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Chao Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Bei Liu
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Huanfa Li
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Yu Zhang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Shan Dong
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China
| | - Guodong Gao
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China.
| | - Hua Zhang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xin-si Road, Xi'an, Shaanxi, 710038, People's Republic of China.
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169
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de Ceglia R, Chaabane L, Biffi E, Bergamaschi A, Ferrigno G, Amadio S, Del Carro U, Mazzocchi N, Comi G, Bianchi V, Taverna S, Forti L, D'Adamo P, Martino G, Menegon A, Muzio L. Down-sizing of neuronal network activity and density of presynaptic terminals by pathological acidosis are efficiently prevented by Diminazene Aceturate. Brain Behav Immun 2015; 45:263-76. [PMID: 25499583 DOI: 10.1016/j.bbi.2014.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 12/02/2014] [Accepted: 12/02/2014] [Indexed: 11/26/2022] Open
Abstract
Local acidosis is associated with neuro-inflammation and can have significant effects in several neurological disorders, including multiple sclerosis, brain ischemia, spinal cord injury and epilepsy. Despite local acidosis has been implicated in numerous pathological functions, very little is known about the modulatory effects of pathological acidosis on the activity of neuronal networks and on synaptic structural properties. Using non-invasive MRI spectroscopy we revealed protracted extracellular acidosis in the CNS of Experimental Autoimmune Encephalomyelitis (EAE) affected mice. By multi-unit recording in cortical neurons, we established that acidosis affects network activity, down-sizing firing and bursting behaviors as well as amplitudes. Furthermore, a protracted acidosis reduced the number of presynaptic terminals, while it did not affect the postsynaptic compartment. Application of the diarylamidine Diminazene Aceturate (DA) during acidosis significantly reverted both the loss of neuronal firing and bursting and the reduction of presynaptic terminals. Finally, in vivo DA delivery ameliorated the clinical disease course of EAE mice, reducing demyelination and axonal damage. DA is known to block acid-sensing ion channels (ASICs), which are proton-gated, voltage-insensitive, Na(+) permeable channels principally expressed by peripheral and central nervous system neurons. Our data suggest that ASICs activation during acidosis modulates network electrical activity and exacerbates neuro-degeneration in EAE mice. Therefore pharmacological modulation of ASICs in neuroinflammatory diseases could represent a new promising strategy for future therapies aimed at neuro-protection.
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Affiliation(s)
- Roberta de Ceglia
- Neuroimmunolgy Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Linda Chaabane
- Neuroimmunolgy Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Italy; Department of Neurology, Institute of Experimental Neurology (INSPE), Vita Salute San Raffaele University, Milan, Italy
| | - Emilia Biffi
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy; Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Andrea Bergamaschi
- Neuroimmunolgy Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Giancarlo Ferrigno
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Stefano Amadio
- Neurophysiology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Ubaldo Del Carro
- Neurophysiology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Italy
| | - Nausicaa Mazzocchi
- Advanced Light and Electron Microscopy Bio-Imaging Centre, Experimental Imaging Centre, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Giancarlo Comi
- Department of Neurology, Institute of Experimental Neurology (INSPE), Vita Salute San Raffaele University, Milan, Italy
| | - Veronica Bianchi
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy
| | - Stefano Taverna
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Lia Forti
- Center for Neuroscience and Dept. of Theoretical and Applied Sciences, Biomedical Division, University of Insubria, 21052 Busto Arsizio, Italy
| | - Patrizia D'Adamo
- Dulbecco Telethon Institute at San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy
| | - Gianvito Martino
- Neuroimmunolgy Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Italy.
| | - Andrea Menegon
- Advanced Light and Electron Microscopy Bio-Imaging Centre, Experimental Imaging Centre, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Luca Muzio
- Neuroimmunolgy Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Italy.
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170
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Jernigan NL. Smooth muscle acid-sensing ion channel 1: pathophysiological implication in hypoxic pulmonary hypertension. Exp Physiol 2015; 100:111-20. [DOI: 10.1113/expphysiol.2014.081612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/04/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Nikki L. Jernigan
- Vascular Physiology Group; Department of Cell Biology and Physiology; University of New Mexico Health Sciences Center; Albuquerque, NM 87131-0001 USA
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171
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Vick JS, Askwith CC. ASICs and neuropeptides. Neuropharmacology 2015; 94:36-41. [PMID: 25592215 DOI: 10.1016/j.neuropharm.2014.12.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/04/2014] [Accepted: 12/08/2014] [Indexed: 11/30/2022]
Abstract
The acid sensing ion channels (ASICs) are proton-gated cation channels expressed throughout the nervous system. ASICs are activated during acidic pH fluctuations, and recent work suggests that they are involved in excitatory synaptic transmission. ASICs can also induce neuronal degeneration and death during pathological extracellular acidosis caused by ischemia, autoimmune inflammation, and traumatic injury. Many endogenous neuromodulators target ASICs to affect their biophysical characteristics and contributions to neuronal activity. One of the most unconventional types of modulation occurs with the interaction of ASICs and neuropeptides. Collectively, FMRFamide-related peptides and dynorphins potentiate ASIC activity by decreasing the proton-sensitivity of steady state desensitization independent of G protein-coupled receptor activation. By decreasing the proton-sensitivity of steady state desensitization, the FMRFamide-related peptides and dynorphins permit ASICs to remain active at more acidic basal pH. Unlike the dynorphins, some FMRFamide-related peptides also potentiate ASIC activity by slowing inactivation and increasing the sustained current. Through mechanistic studies, the modulation of ASICs by FMRFamide-related peptides and dynorphins appears to be through distinct interactions with the extracellular domain of ASICs. Dynorphins are expressed throughout the nervous system and can increase neuronal death during prolonged extracellular acidosis, suggesting that the interaction between dynorphins and ASICs may have important consequences for the prevention of neurological injury. The overlap in expression of FMRFamide-related peptides with ASICs in the dorsal horn of the spinal cord suggests that their interaction may have important consequences for the treatment of pain during injury and inflammation. This article is part of the Special Issue entitled 'Acid-Sensing Ion Channels in the Nervous System'.
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Affiliation(s)
- Jonathan S Vick
- The Department of Neuroscience, The Ohio State University Wexner Medical Center, United States
| | - Candice C Askwith
- The Department of Neuroscience, The Ohio State University Wexner Medical Center, United States.
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172
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Lin SH, Sun WH, Chen CC. Genetic exploration of the role of acid-sensing ion channels. Neuropharmacology 2015; 94:99-118. [PMID: 25582292 DOI: 10.1016/j.neuropharm.2014.12.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 12/27/2022]
Abstract
Advanced gene targeting technology and related tools in mice have been incorporated into studies of acid-sensing ion channels (ASICs). A single ASIC subtype can be knocked out specifically and screened thoroughly for expression in the nervous system at the cellular level. Mapping studies have further shed light on the initiation and identification of related behavioral phenotypes. Here we review studies involving genetically engineered mouse models used to investigate the physiological function of individual ASIC subtypes: ASIC1 (and ASIC1a), ASIC2, ASIC3 and ASIC4. We discuss the detailed expression studies and significant phenotypes revealed with gene knockout for most known Asic subtypes. Each strategy designed to manipulate mouse genetics has advantages and disadvantages. We discuss the limitations of these Asic-knockout models and propose future directions to solve the genetic issues. This article is part of the Special Issue entitled 'Acid-Sensing Ion Channels in the Nervous System'.
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Affiliation(s)
- Shing-Hong Lin
- Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| | - Wei-Hsin Sun
- Department of Life Sciences, National Central University, Jhongli 32054, Taiwan.
| | - Chih-Cheng Chen
- Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan; Taiwan Mouse Clinic, National Comprehensive Mouse Phenotyping and Drug Testing Center, Academia Sinica, Taipei 115, Taiwan.
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173
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Shu Y, Xiao B, Wu Q, Liu T, Du Y, Tang H, Chen S, Feng L, Long L, Li Y. The Ephrin-A5/EphA4 Interaction Modulates Neurogenesis and Angiogenesis by the p-Akt and p-ERK Pathways in a Mouse Model of TLE. Mol Neurobiol 2014; 53:561-576. [PMID: 25502292 DOI: 10.1007/s12035-014-9020-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/18/2014] [Indexed: 02/07/2023]
Abstract
Studies have shown that neurogenesis and angiogenesis do exist in temporal lobe epilepsy (TLE). The ephrin ligands and Eph receptors are the largest members of receptor tyrosine kinases, and their interaction via cell-cell contact participates in cell proliferation, differentiation, migration, and tissue remodeling. However, there is little information about the function of the ephrin-A5/EphA4 complex in TLE. In the current study, we found that ephrin-A5 was expressed in astrocytes, while EphA4 existed in endothelial cells in the hippocampus in a mouse model of TLE. Furthermore, the messenger RNA (mRNA) and protein levels of both ephrin-A5 and EphA4 and the binding capacity of ephrin-A5/EphA4 showed gradual increase in spatiotemporal course. When ephrin-A5-Fc was injected into the hippocampus at 3 days post-status epilepticus (SE) for 7 days, the spontaneous recurrent seizure (SRS) frequency and intensity of the mice attenuated in the following 2 weeks. Furthermore, doublecortin-positive neuronal progenitor cells were reduced in the subgranular zone, and the density of microvessels decreased in the hilus. The molecular mechanism was attributed to ephrin-A5-Fc-induced inhibition of phosphorylated ERK (p-ERK) and phosphorylated Akt (p-Akt), and also EphA4 and VEGF reduction. In summary, interaction between ephrin-A5 and EphA4 could mediate the ERK and Akt signaling pathways in pilocarpine-induced epilepsy, and intervention of the ephrin/Eph interaction may play an essential role in the suppression of newborn neuron generation, microvessel remodeling, and SRS in a mouse model of TLE. The ephrin-A5/EphA4 communication may provide a potential therapy for the treatment of TLE.
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Affiliation(s)
- Yi Shu
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China.
| | - Qian Wu
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Tiantian Liu
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Yang Du
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Haiyun Tang
- Department of Radiology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Si Chen
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Li Feng
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China
| | - Yi Li
- Department of Neurology, Xiangya Hospital, Central South University, Hunan, 410008, China.
- Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, 01604, USA.
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174
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Cao Q, Wang W, Gu J, Jiang G, Wang K, Xu Z, Li J, Chen G, Wang X. Elevated Expression of Acid-Sensing Ion Channel 3 Inhibits Epilepsy via Activation of Interneurons. Mol Neurobiol 2014; 53:485-498. [PMID: 25476599 DOI: 10.1007/s12035-014-9014-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/18/2014] [Indexed: 12/21/2022]
Abstract
Recent studies have indicated that acid-sensing ion channels may play a significant role in the termination of epilepsy. In particular, acid-sensing ion channel 3 (ASIC3) is expressed in the central nervous system and is most sensitive to extracellular pH. However, whether ASIC3 plays a role in epilepsy is unknown. In this study, qRT-PCR, Western blot, immunohistochemistry, double immunofluorescence labeling, and slice recordings were used. We first detected elevated ASIC3 expression patterns in the brains of temporal lobe epilepsy patients and epileptic rats. ASIC3 was expressed in neurons and glia in both humans and in an experimental model of epilepsy, and ASIC3 was colocalized with inhibitory GABAergic interneurons. By blocking ASIC3 with its antagonist APETx2, we observed that injected APETx2 shortened the latency to seizure and increased the incidence of generalized tonic clonic seizure compared to the control group in models of both pilocarpine- and pentylenetetrazole (PTZ)-induced seizures. Additionally, blocking ASIC3 significantly decreased the frequency of action potential (AP) firing in interneurons. Moreover, APETx2 significantly reduced the amplitudes and frequencies of miniature inhibitory postsynaptic currents (mIPSCs) while showed no differences with the APETx2 + bicuculline group and the bicuculline group. These findings suggest that elevated levels of ASIC3 may serve as an anti-epileptic mechanism via postsynaptic mechanisms in interneurons. It could represent a novel therapeutic strategy for epilepsy treatment.
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Affiliation(s)
- Qingqing Cao
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China.,Department of Neurology, The People's Hospital of Bishan District, 82 Xinsheng Road, Chongqing, 402760, China
| | - Wei Wang
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China
| | - Juan Gu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China
| | - Guohui Jiang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong, 637000, China
| | - Kewei Wang
- Department of Pharmacology, Peking University, 5 Summer Palace road, Beijing, 100871, China
| | - Zucai Xu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China
| | - Jie Li
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China
| | - Guojun Chen
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China.
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, 1Youyi Rd, Chongqing, 400016, China. .,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China.
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175
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Kellenberger S, Schild L. International Union of Basic and Clinical Pharmacology. XCI. Structure, Function, and Pharmacology of Acid-Sensing Ion Channels and the Epithelial Na+ Channel. Pharmacol Rev 2014; 67:1-35. [DOI: 10.1124/pr.114.009225] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Abstract
OPINION STATEMENT The shift in our understanding of migraine as a vascular disorder to a brain disorder has opened new avenues for the development of novel therapeutics with neural targets. The advent of 5-HT1B/1D receptor agonists, the triptans, in the 1990s was a crucial step in the modern evolution of treatment. The use of triptans, like their predecessors, is limited by their vasoconstrictor effects, and new development has been slowed by poor academic research funding to identify new targets. The development of agents without vascular effects, such as calcitonin gene-related peptide receptor antagonists and selective serotonin 5-HT1F receptor agonists, will bring more effective treatments to a population currently without migraine-specific options. In addition, advances in understanding migraine pathophysiology have identified new potential pharmacologic targets such as acid-sensing ion channels, glutamate and orexin receptors, nitric oxide synthase (NOS), and transient receptor potential (TRP) channels. Although previous attempts to block subtypes of glutamate receptors, NOS, and TRP channels have had mixed outcomes, new molecules for the same targets are currently under investigation. Finally, an entirely new approach to migraine treatment with noninvasive neuromodulation via transcutaneous neurostimulation or transcranial magnetic stimulation is just beginning. Hopefully in the coming years we will see a new era of migraine therapy, with multiple classes of better-tolerated, more effective agents targeting diverse yet specific migraine mechanisms.
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Affiliation(s)
- Amy R Tso
- Headache Group, Department of Neurology, University of California San Francisco, 2330 Post Street, 6th floor, San Francisco, CA, 94115, USA,
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177
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Wang J, Xu Y, Lian Z, Zhang J, Zhu T, Li M, Wei Y, Dong B. Does closure of acid-sensing ion channels reduce ischemia/reperfusion injury in the rat brain? Neural Regen Res 2014; 8:1169-79. [PMID: 25206411 PMCID: PMC4107604 DOI: 10.3969/j.issn.1673-5374.2013.13.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 03/07/2013] [Indexed: 11/18/2022] Open
Abstract
Acidosis is a common characteristic of brain damage. Because studies have shown that permeable Ca2+-acid-sensing ion channels can mediate the toxic effects of calcium ions, they have become new targets against pain and various intracranial diseases. However, the mechanism associated with expression of these channels remains unclear. This study sought to observe the expression characteristics of permeable Ca2+-acid-sensing ion channels during different reperfusion inflows in rats after cerebral ischemia. The rat models were randomly divided into three groups: adaptive ischemia/reperfusion group, one-time ischemia/reperfusion group, and severe cerebral ischemic injury group. Western blot assays and immunofluorescence staining results exhibited that when compared with the one-time ischemia/reperfusion group, acid-sensing ion channel 3 and Bcl-x/l expression decreased in the adaptive ischemia/reperfusion group. Calmodulin expression was lowest in the adaptive ischemia/reperfusion group. Following adaptive reperfusion, common carotid artery flow was close to normal, and the pH value improved. Results verified that adaptive reperfusion following cerebral ischemia can suppress acid-sensing ion channel 3 expression, significantly reduce Ca2+ influx, inhibit calcium overload, and diminish Ca2+ toxicity. The effects of adaptive ischemia/reperfusion on suppressing cell apoptosis and relieving brain damage were better than that of one-time ischemia/reperfusion.
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Affiliation(s)
- Jie Wang
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Yinghui Xu
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Zhigang Lian
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Jian Zhang
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Tingzhun Zhu
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Mengkao Li
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Yi Wei
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Bin Dong
- Department of Neurosurgery, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
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178
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Yang H, Wu J, Guo R, Peng Y, Zheng W, Liu D, Song Z. Glycolysis in energy metabolism during seizures. Neural Regen Res 2014; 8:1316-26. [PMID: 25206426 PMCID: PMC4107649 DOI: 10.3969/j.issn.1673-5374.2013.14.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 03/27/2013] [Indexed: 01/23/2023] Open
Abstract
Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-minobutyric acid, and changes in the intra- and extracellular environment.
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Affiliation(s)
- Heng Yang
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Jiongxing Wu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ren Guo
- Department of Pharmacy, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Yufen Peng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Wen Zheng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ding Liu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Zhi Song
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
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179
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Boido D, Gnatkovsky V, Uva L, Francione S, de Curtis M. Simultaneous enhancement of excitation and postburst inhibition at the end of focal seizures. Ann Neurol 2014; 76:826-36. [PMID: 24916758 DOI: 10.1002/ana.24193] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/04/2014] [Accepted: 06/04/2014] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Comprehension of the events that lead to seizure termination contributes to the development of strategies to confine propagation of ictal discharges. It is commonly assumed that the inhibitory control fails during seizures and recovers after the end of the ictal event. We examine the possibility that a progressive increase of inhibition that counters an increase in the strength of excitation contributes to terminating a focal seizure. METHODS We analyzed seizures acutely induced by pharmacological manipulations (bicuculline and 4-aminopyridine) in the entorhinal cortex and in the hippocampus of the in vitro isolated guinea pig brain. RESULTS As seizures ended, extracellular and intracellular recordings showed periodic bursting that progressively decreased in frequency. During the late bursting phase, the duration, number, and rate of occurrence of spikes within single bursts remained constant, whereas cumulative spike amplitude (index of excitation during a burst) and interburst interval (index of inhibition between bursts) progressively increased. The increment of average/cumulative burst excitation and interburst interval toward seizure end was confirmed in human focal seizures recorded with intracerebral electrodes in patients with drug-resistant partial epilepsies. A postburst refractory period of circa 2 seconds that increases with time toward the end of the seizure was confirmed in the experimental model by probing interburst epochs in the CA1 region with local dentate gyrus stimulation just suprathreshold for burst generation. INTERPRETATION Our findings support the concept that focal seizures are terminated by the simultaneous and opposing enhancement of excitation (burst activity) in addition to postburst inhibition. We hypothesize that a seizure stops when postburst inhibition becomes large enough to prevent reactivation of excitation.
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Affiliation(s)
- Davide Boido
- Unit of Epileptology and Experimental Neurophysiology, Carlo Besta Neurological Institute Foundation, Milan, Italy
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180
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Xu A, Durosier LD, Ross MG, Hammond R, Richardson BS, Frasch MG. Adaptive brain shut-down counteracts neuroinflammation in the near-term ovine fetus. Front Neurol 2014; 5:110. [PMID: 25071698 PMCID: PMC4074896 DOI: 10.3389/fneur.2014.00110] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/13/2014] [Indexed: 11/18/2022] Open
Abstract
Objective: Repetitive umbilical cord occlusions (UCOs) in ovine fetus leading to severe acidemia result in adaptive shut-down of electrocortical activity [electrocorticogram (ECoG)] as well as systemic and brain inflammation. We hypothesized that the fetuses with earlier ECoG shut-down as a neuroprotective mechanism in response to repetitive UCOs will show less brain inflammation and, moreover, that chronic hypoxia will impact this relationship. Methods: Near-term fetal sheep were chronically instrumented with ECoG leads, vascular catheters, and a cord occluder and then underwent repetitive UCOs for up to 4 h or until fetal arterial pH was <7.00. Eight animals, hypoxic prior to the UCOs (SaO2 <55%), were allowed to recover 24 h post insult, while 14 animals, 5 of whom also were chronically hypoxic, were allowed to recover 48 h post insult, after which brains were perfusion-fixed. Time of ECoG shut-down and corresponding pH were noted, as well as time to then reach pH <7.00 (ΔT). Microglia (MG) were counted as a measure of inflammation in gray matter layers 4–6 (GM4–6) where most ECoG activity is generated. Results are reported as mean ± SEM for p < 0.05. Results: Repetitive UCOs resulted in worsening acidosis over 3–4 h with arterial pH decreasing to 6.97 ± 0.02 all UCO groups’ animals, recovering to baseline by 24 h. ECoG shut-down occurred 52 ± 7 min before reaching pH <7.00 at pH 7.23 ± 0.02 across the animal groups. MG counts were inversely correlated to ΔT in 24 h recovery animals (R = −0.84), as expected. This was not the case in normoxic 48 h recovery animals, and, surprisingly, in hypoxic 48 h recovery animals, this relationship was reversed (R = 0.90). Conclusion: Adaptive brain shut-down during labor-like worsening acidemia counteracts neuroinflammation in a hypoxia- and time-dependent manner.
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Affiliation(s)
- Alex Xu
- Department of Obstetrics and Gynecology, Western University , London, ON , Canada
| | - Lucien Daniel Durosier
- Department of Obstetrics and Gynaecology and Department of Neurosciences, CHU Sainte-Justine Centre de Recherche, Université de Montréal , Montréal, QC , Canada
| | - Michael G Ross
- Department of Obstetrics and Gynecology, LA BioMed at Harbor-UCLA Medical Center , Torrance, CA , USA
| | - Robert Hammond
- Department of Pathology, Western University , London, ON , Canada
| | - Bryan S Richardson
- Department of Obstetrics and Gynecology, Western University , London, ON , Canada
| | - Martin G Frasch
- Department of Obstetrics and Gynaecology and Department of Neurosciences, CHU Sainte-Justine Centre de Recherche, Université de Montréal , Montréal, QC , Canada
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181
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Quansah H, N'Gouemo P. Amiloride and SN-6 suppress audiogenic seizure susceptibility in genetically epilepsy-prone rats. CNS Neurosci Ther 2014; 20:860-6. [PMID: 24948133 DOI: 10.1111/cns.12296] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 01/27/2023] Open
Abstract
AIMS We have recently reported that amiloride, a potent and nonselective blocker of acid-sensing ion channels, prevents the development of pilocarpine-induced seizures and status epilepticus. Amiloride is also known to suppress the activity of Na(+) /Ca(2+) and Na(+) /H(+) exchangers that have been implicated in the pathophysiology of seizures. Here, we evaluated the effects of amiloride, SN-6 (a potent blocker of Na(+) /Ca(2+) exchangers) and zoniporide (a potent blocker of Na(+) /H(+) exchangers) on acoustically evoked seizures (audiogenic seizures, AGS) in genetically epilepsy-prone rats (GEPR-3s), a model of inherited generalized epilepsy. METHODS Male, six-week-old GEPR-3s were used. The GEPR-3s were tested for AGS susceptibility before and after treatment with various doses of amiloride, SN-6, and zoniporide (1, 3, 10, and 30 mg/kg; per os). RESULTS We found that pretreatment with amiloride and SN-6 markedly reduced the incidence and severity of AGS in the GEPR-3s. In contrast, administration of zoniporide only minimally reduced the incidence and severity of AGS in the GEPR-3s. A combination of noneffective doses of SN-6 and zoniporide also suppressed AGS susceptibility in the GEPR-3s. CONCLUSIONS These findings suggest acid-sensing ion channels and the Na(+) /Ca(2+) exchanger may play an important role in the pathophysiology of inherited AGS susceptibility in the GEPR-3s.
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Affiliation(s)
- Hillary Quansah
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
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182
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Zhao D, Ning N, Lei Z, Sun H, Wei C, Chen D, Li J. Identification of a novel protein complex containing ASIC1a and GABAA receptors and their interregulation. PLoS One 2014; 9:e99735. [PMID: 24923912 PMCID: PMC4055689 DOI: 10.1371/journal.pone.0099735] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/15/2014] [Indexed: 11/18/2022] Open
Abstract
Acid-sensing ion channels (ASICs) belong to the family of the epithelial sodium channel/degenerin (ENaC/DEG) and are activated by extracellular protons. They are widely distributed within both the central and peripheral nervous systems. ASICs were modified by the activation of γ-aminobutyric acid receptors (GABAA), a ligand-gated chloride channels, in hippocampal neurons. In contrast, the activity of GABAA receptors were also modulated by extracellular pH. However so far, the mechanisms underlying this intermodulation remain obscure. We hypothesized that these two receptors-GABAA receptors and ASICs channels might form a novel protein complex and functionally interact with each other. In the study reported here, we found that ASICs were modified by the activation of GABAA receptors either in HEK293 cells following transient co-transfection of GABAA and ASIC1a or in primary cultured dorsal root ganglia (DRG) neurons. Conversely, activation of ASIC1a also modifies the GABAA receptor-channel kinetics. Immunoassays showed that both GABAA and ASIC1a proteins were co-immunoprecipitated mutually either in HEK293 cells co-transfected with GABAA and ASIC1a or in primary cultured DRG neurons. Our results indicate that putative GABAA and ASIC1a channels functionally interact with each other, possibly via an inter-molecular association by forming a novel protein complex.
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Affiliation(s)
- Dongbo Zhao
- Department of Thoracic Surgery, Shandong Cancer Hospital and Institute, Jinan, China
| | - Nannan Ning
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
| | - Zhen Lei
- Department of Anesthesiology, Qilu Hospital, Shandong University, Jinan, China
| | - Hua Sun
- Department of Thoracic Surgery, Shandong Cancer Hospital and Institute, Jinan, China
| | - Chuanfei Wei
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
| | - Dawei Chen
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
| | - Jingxin Li
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
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183
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Abstract
The discovery that even small changes in extracellular acidity can alter the excitability of neuronal networks via activation of acid-sensing ion channels (ASICs) could have therapeutic application in a host of neurological and psychiatric illnesses. Recent evidence suggests that activation of ASIC1a, a subtype of ASICs that is widely distributed in the brain, is necessary for the expression of fear and anxiety. Antagonists of ASIC1a, therefore, have been proposed as a potential treatment for anxiety. The basolateral amygdala (BLA) is central to fear generation, and anxiety disorders are characterized by BLA hyperexcitability. To better understand the role of ASIC1a in anxiety, we attempted to provide a direct assessment of whether ASIC1a activation increases BLA excitability. In rat BLA slices, activation of ASIC1a by low pH or ammonium elicited inward currents in both interneurons and principal neurons, and increased spontaneous IPSCs recorded from principal cells significantly more than spontaneous EPSCs. Epileptiform activity induced by high potassium and low magnesium was suppressed by ammonium. Antagonism of ASIC1a decreased spontaneous IPSCs more than EPSCs, and increased the excitability of the BLA network, as reflected by the pronounced increase of evoked field potentials, suggesting that ASIC1a channels are active in the basal state. In vivo activation or blockade of ASIC1a in the BLA suppressed or increased, respectively, anxiety-like behavior. Thus, in the rat BLA, ASIC1a has an inhibitory and anxiolytic function. The discovery of positive ASIC1a modulators may hold promise for the treatment of anxiety disorders.
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184
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Harding AMS, Kusama N, Hattori T, Gautam M, Benson CJ. ASIC2 subunits facilitate expression at the cell surface and confer regulation by PSD-95. PLoS One 2014; 9:e93797. [PMID: 24699665 PMCID: PMC3974781 DOI: 10.1371/journal.pone.0093797] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/06/2014] [Indexed: 12/28/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are Na+ channels activated by changes in pH within the peripheral and central nervous systems. Several different isoforms of ASICs combine to form trimeric channels, and their properties are determined by their subunit composition. ASIC2 subunits are widely expressed throughout the brain, where they heteromultimerize with their partnering subunit, ASIC1a. However, ASIC2 contributes little to the pH sensitivity of the channels, and so its function is not well understood. We found that ASIC2 increased cell surface levels of the channel when it is coexpressed with ASIC1a, and genetic deletion of ASIC2 reduced acid-evoked current amplitude in mouse hippocampal neurons. Additionally, ASIC2a interacted with the neuronal synaptic scaffolding protein PSD-95, and PSD-95 reduced cell surface expression and current amplitude in ASICs that contain ASIC2a. Overexpression of PSD-95 also reduced acid-evoked current amplitude in hippocampal neurons. This result was dependent upon ASIC2 since the effect of PSD-95 was abolished in ASIC2−/− neurons. These results lend support to an emerging role of ASIC2 in the targeting of ASICs to surface membranes, and allows for interaction with PSD-95 to regulate these processes.
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Affiliation(s)
- Anne Marie S. Harding
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Veterans Medical Center, Iowa City, Iowa, United States of America
| | - Nobuyoshi Kusama
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Tomonori Hattori
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Mamta Gautam
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Veterans Medical Center, Iowa City, Iowa, United States of America
| | - Christopher J. Benson
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Veterans Medical Center, Iowa City, Iowa, United States of America
- * E-mail:
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185
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Down-Regulated Expression of Acid-Sensing Ion Channel 1a in Cortical Lesions of Patients with Focal Cortical Dysplasia. J Mol Neurosci 2014; 53:176-82. [DOI: 10.1007/s12031-014-0270-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
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186
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Yang XF, Shi XY, Ju J, Zhang WN, Liu YJ, Li XY, Zou LP. 5% CO2 inhalation suppresses hyperventilation-induced absence seizures in children. Epilepsy Res 2014; 108:345-8. [DOI: 10.1016/j.eplepsyres.2013.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/28/2013] [Accepted: 11/12/2013] [Indexed: 11/17/2022]
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187
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Proton-sensitive cation channels and ion exchangers in ischemic brain injury: new therapeutic targets for stroke? Prog Neurobiol 2014; 115:189-209. [PMID: 24467911 DOI: 10.1016/j.pneurobio.2013.12.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/28/2013] [Accepted: 12/24/2013] [Indexed: 12/13/2022]
Abstract
Ischemic brain injury results from complicated cellular mechanisms. The present therapy for acute ischemic stroke is limited to thrombolysis with the recombinant tissue plasminogen activator (rtPA) and mechanical recanalization. Therefore, a better understanding of ischemic brain injury is needed for the development of more effective therapies. Disruption of ionic homeostasis plays an important role in cell death following cerebral ischemia. Glutamate receptor-mediated ionic imbalance and neurotoxicity have been well established in cerebral ischemia after stroke. However, non-NMDA receptor-dependent mechanisms, involving acid-sensing ion channel 1a (ASIC1a), transient receptor potential melastatin 7 (TRPM7), and Na(+)/H(+) exchanger isoform 1 (NHE1), have recently emerged as important players in the dysregulation of ionic homeostasis in the CNS under ischemic conditions. These H(+)-sensitive channels and/or exchangers are expressed in the majority of cell types of the neurovascular unit. Sustained activation of these proteins causes excessive influx of cations, such as Ca(2+), Na(+), and Zn(2+), and leads to ischemic reperfusion brain injury. In this review, we summarize recent pre-clinical experimental research findings on how these channels/exchangers are regulated in both in vitro and in vivo models of cerebral ischemia. The blockade or transgenic knockdown of these proteins was shown to be neuroprotective in these ischemia models. Taken together, these non-NMDA receptor-dependent mechanisms may serve as novel therapeutic targets for stroke intervention.
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188
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Kweon HJ, Suh BC. Acid-sensing ion channels (ASICs): therapeutic targets for neurological diseases and their regulation. BMB Rep 2014; 46:295-304. [PMID: 23790972 PMCID: PMC4133903 DOI: 10.5483/bmbrep.2013.46.6.121] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extracellular acidification occurs not only in pathological conditions such as inflammation and brain ischemia, but also in normal physiological conditions such as synaptic transmission. Acid-sensing ion channels (ASICs) can detect a broad range of physiological pH changes during pathological and synaptic cellular activities. ASICs are voltage-independent, proton-gated cation channels widely expressed throughout the central and peripheral nervous system. Activation of ASICs is involved in pain perception, synaptic plasticity, learning and memory, fear, ischemic neuronal injury, seizure termination, neuronal degeneration, and mechanosensation. Therefore, ASICs emerge as potential therapeutic targets for manipulating pain and neurological diseases. The activity of these channels can be regulated by many factors such as lactate, Zn2+, and Phe-Met-Arg-Phe amide (FMRFamide)-like neuropeptides by interacting with the channel’s large extracellular loop. ASICs are also modulated by G protein-coupled receptors such as CB1 cannabinoid receptors and 5-HT2. This review focuses on the physiological roles of ASICs and the molecular mechanisms by which these channels are regulated. [BMB Reports 2013; 46(6): 295-304]
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Affiliation(s)
- Hae-Jin Kweon
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea
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189
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Noël J, Salinas M, Baron A, Diochot S, Deval E, Lingueglia E. Current perspectives on acid-sensing ion channels: new advances and therapeutic implications. Expert Rev Clin Pharmacol 2014; 3:331-46. [DOI: 10.1586/ecp.10.13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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190
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191
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Guirgis M, Serletis D, Zhang J, Florez C, Dian JA, Carlen PL, Bardakjian BL. Classification of Multiple Seizure-Like States in Three Different Rodent Models of Epileptogenesis. IEEE Trans Neural Syst Rehabil Eng 2014; 22:21-32. [DOI: 10.1109/tnsre.2013.2267543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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192
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Urbano FJ, Lino NG, González-Inchauspe CMF, González LE, Colettis N, Vattino LG, Wunsch AM, Wemmie JA, Uchitel OD. Acid-sensing ion channels 1a (ASIC1a) inhibit neuromuscular transmission in female mice. Am J Physiol Cell Physiol 2013; 306:C396-406. [PMID: 24336653 PMCID: PMC3919981 DOI: 10.1152/ajpcell.00301.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Acid-sensing ion channels (ASIC) open in response to extracellular acidosis. ASIC1a, a particular subtype of these channels, has been described to have a postsynaptic distribution in the brain, being involved not only in ischemia and epilepsy, but also in fear and psychiatric pathologies. High-frequency stimulation of skeletal motor nerve terminals (MNTs) can induce presynaptic pH changes in combination with an acidification of the synaptic cleft, known to contribute to muscle fatigue. Here, we studied the role of ASIC1a channels on neuromuscular transmission. We combined a behavioral wire hanging test with electrophysiology, pharmacological, and immunofluorescence techniques to compare wild-type and ASIC1a lacking mice (ASIC1a −/− knockout). Our results showed that 1) ASIC1a −/− female mice were weaker than wild type, presenting shorter times during the wire hanging test; 2) spontaneous neurotransmitter release was reduced by ASIC1a activation, suggesting a presynaptic location of these channels at individual MNTs; 3) ASIC1a-mediated effects were emulated by extracellular local application of acid saline solutions (pH = 6.0; HEPES/MES-based solution); and 4) immunofluorescence techniques revealed the presence of ASIC1a antigens on MNTs. These results suggest that ASIC1a channels might be involved in controlling neuromuscular transmission, muscle contraction and fatigue in female mice.
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Affiliation(s)
- Francisco J Urbano
- Laboratorio de Fisiología y Biología Molecular (LFBM), Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, UBA-CONICET), Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires, Argentina; and
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Kaushik MK, Aritake K, Kamauchi S, Hayaishi O, Huang ZL, Lazarus M, Urade Y. Prostaglandin D(2) is crucial for seizure suppression and postictal sleep. Exp Neurol 2013; 253:82-90. [PMID: 24333565 DOI: 10.1016/j.expneurol.2013.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/22/2013] [Accepted: 12/01/2013] [Indexed: 10/25/2022]
Abstract
Epilepsy is a neurological disorder with the occurrence of seizures, which are often accompanied by sleep. Prostaglandin (PG) D2 is produced by hematopoietic or lipocalin-type PGD synthase (H- or L-PGDS) and involved in the regulation of physiological sleep. Here, we show that H-PGDS, L/H-PGDS or DP1 receptor (DP1R) KO mice exhibited more intense pentylenetetrazole (PTZ)-induced seizures in terms of latency of seizure onset, duration of generalized tonic-clonic seizures, and number of seizure spikes. Seizures significantly increased the PGD2 content of the brain in wild-type mice. This PTZ-induced increase in PGD2 was attenuated in the brains of L- or H-PGDS KO and abolished in L/H-PGDS KO mice. Postictal non-rapid eye movement sleep was observed in the wild-type and H-PGDS or DP2R KO, but not in the L-, L/H-PGDS or DP1R KO, mice. These findings demonstrate that PGD2 produced by H-PGDS and acting on DP1R is essential for seizure suppression and that the L-PGDS/PGD2/DP1R system regulates sleep that follows seizures.
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Affiliation(s)
- Mahesh K Kaushik
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Kosuke Aritake
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Shinya Kamauchi
- Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Osamu Hayaishi
- Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan
| | - Zhi-Li Huang
- Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan; Department of Pharmacology, Fudan University Shanghai Medical College, 138 Yixueyuan Road, Shanghai 200032, China
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan.
| | - Yoshihiro Urade
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan.
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194
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Catterall WA, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: ion channels. Br J Pharmacol 2013; 170:1607-51. [PMID: 24528239 PMCID: PMC3892289 DOI: 10.1111/bph.12447] [Citation(s) in RCA: 224] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Ion channels are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
- *
Author for correspondence;
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - William A Catterall
- University of Washington, School of Medicine, Department of PharmacologyBox 357280, Seattle, WA 98195-7280, USA
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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195
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Henshall DC, Diaz-Hernandez M, Miras-Portugal MT, Engel T. P2X receptors as targets for the treatment of status epilepticus. Front Cell Neurosci 2013; 7:237. [PMID: 24324404 PMCID: PMC3840793 DOI: 10.3389/fncel.2013.00237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/08/2013] [Indexed: 11/26/2022] Open
Abstract
Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA) transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4, and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection.
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Affiliation(s)
- David C Henshall
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland Dublin, Ireland ; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland Dublin, Ireland
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196
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Li X, Wu FR, Xu RS, Hu W, Jiang DL, Ji C, Chen FH, Yuan FL. Acid-sensing ion channel 1a-mediated calcium influx regulates apoptosis of endplate chondrocytes in intervertebral discs. Expert Opin Ther Targets 2013; 18:1-14. [DOI: 10.1517/14728222.2014.859248] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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197
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Kozlenkov A, Lapatsina L, Lewin GR, Smith ESJ. Subunit-specific inhibition of acid sensing ion channels by stomatin-like protein 1. J Physiol 2013; 592:557-69. [PMID: 24247984 PMCID: PMC3934701 DOI: 10.1113/jphysiol.2013.258657] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There are five mammalian stomatin-domain genes, all of which encode peripheral membrane proteins that can modulate ion channel function. Here we examined the ability of stomatin-like protein 1 (STOML1) to modulate the proton-sensitive members of the acid-sensing ion channel (ASIC) family. STOML1 profoundly inhibits ASIC1a, but has no effect on the splice variant ASIC1b. The inactivation time constant of ASIC3 is also accelerated by STOML1. We examined STOML1 null mutant mice with a β-galactosidase-neomycin cassette gene-trap reporter driven from the STOML1 gene locus, which indicated that STOML1 is expressed in at least 50% of dorsal root ganglion (DRG) neurones. Patch clamp recordings from mouse DRG neurones identified a trend for larger proton-gated currents in neurones lacking STOML1, which was due to a contribution of effects upon both transient and sustained currents, at different pH, a finding consistent with an endogenous inhibitory function for STOML1.
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Affiliation(s)
- Alexey Kozlenkov
- Department of Neuroscience, Growth Factor & Regeneration Group, Max-Delbrueck Center for Molecular Medicine, Robert-Roessle Strasse 10, D-13092 Berlin, Germany. or
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198
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Chu XP, Grasing KA, Wang JQ. Acid-sensing ion channels contribute to neurotoxicity. Transl Stroke Res 2013; 5:69-78. [PMID: 24323724 DOI: 10.1007/s12975-013-0305-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/06/2013] [Accepted: 11/04/2013] [Indexed: 12/13/2022]
Abstract
Acidosis that occurs under pathological conditions not only affects intracellular signaling molecules, but also directly activates a unique family of ligand-gated ion channels: acid-sensing ion channels (ASICs). ASICs are widely expressed throughout the central and peripheral nervous systems and play roles in pain sensation, learning and memory, and fear conditioning. Overactivation of ASICs contributes to neurodegenerative diseases such as ischemic brain/spinal cord injury, multiple sclerosis, Parkinson's disease, and Huntington's disease. Thus, targeting ASICs might be a potential therapeutic strategy for these conditions. This mini-review focuses on the electrophysiology and pharmacology of ASICs and roles of ASICs in neuronal toxicity.
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Affiliation(s)
- Xiang-Ping Chu
- Departments of Basic Medical Science and Anesthesiology, School of Medicine, University of Missouri-Kansas City, 2411 Holmes Street, Room M3-417, Kansas City, MO, 64108-2792, USA,
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199
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Christensen HL, Nguyen AT, Pedersen FD, Damkier HH. Na(+) dependent acid-base transporters in the choroid plexus; insights from slc4 and slc9 gene deletion studies. Front Physiol 2013; 4:304. [PMID: 24155723 PMCID: PMC3804831 DOI: 10.3389/fphys.2013.00304] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/02/2013] [Indexed: 02/02/2023] Open
Abstract
The choroid plexus epithelium (CPE) is located in the ventricular system of the brain, where it secretes the majority of the cerebrospinal fluid (CSF) that fills the ventricular system and surrounds the central nervous system. The CPE is a highly vascularized single layer of cuboidal cells with an unsurpassed transepithelial water and solute transport rate. Several members of the slc4a family of bicarbonate transporters are expressed in the CPE. In the basolateral membrane the electroneutral Na+ dependent Cl−/HCO3− exchanger, NCBE (slc4a10) is expressed. In the luminal membrane, the electrogenic Na+:HCO3− cotransporter, NBCe2 (slc4a5) is expressed. The electroneutral Na+:HCO3− cotransporter, NBCn1 (slc4a7), has been located in both membranes. In addition to the bicarbonate transporters, the Na+/H+ exchanger, NHE1 (slc9a1), is located in the luminal membrane of the CPE. Genetically modified mice targeting slc4a2, slc4a5, slc4a7, slc4a10, and slc9a1 have been generated. Deletion of slc4a5, 7 or 10, or slc9a1 has numerous impacts on CP function and structure in these mice. Removal of the transporters affects brain ventricle size (slc4a5 and slc4a10) and intracellular pH regulation (slc4a7 and slc4a10). In some instances, removal of the proteins from the CPE (slc4a5, 7, and 10) causes changes in abundance and localization of non-target transporters known to be involved in pH regulation and CSF secretion. The focus of this review is to combine the insights gathered from these knockout mice to highlight the impact of slc4 gene deletion on the CSF production and intracellular pH regulation resulting from the deletion of slc4a5, 7 and 10, and slc9a1. Furthermore, the review contains a comparison of the described human mutations of these genes to the findings in the knockout studies. Finally, the future perspective of utilizing these proteins as potential targets for the treatment of CSF disorders will be discussed.
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200
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Goadsby PJ. Therapeutic prospects for migraine: Can paradise be regained? Ann Neurol 2013; 74:423-34. [DOI: 10.1002/ana.23996] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 08/04/2013] [Accepted: 08/04/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Peter J. Goadsby
- Headache Group, Department of Neurology; University of California, San Francisco; San Francisco CA
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