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Tan HT, Smith PF, Zheng Y. Time-dependent effects of acoustic trauma and tinnitus on extracellular levels of amino acids in the inferior colliculus of rats. Hear Res 2024; 443:108948. [PMID: 38219615 DOI: 10.1016/j.heares.2024.108948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/16/2024]
Abstract
Chronic tinnitus is a debilitating condition with very few management options. Acoustic trauma that causes tinnitus has been shown to induce neuronal hyperactivity in multiple brain areas in the auditory pathway, including the inferior colliculus. This neuronal hyperactivity could be attributed to an imbalance between excitatory and inhibitory neurotransmission. However, it is not clear how the levels of neurotransmitters, especially neurotransmitters in the extracellular space, change over time following acoustic trauma and the development of tinnitus. In the present study, a range of amino acids were measured in the inferior colliculus of rats during acoustic trauma as well as at 1 week and 5 months post-trauma using in vivo microdialysis and high-performance liquid chromatography. Amino acid levels in response to sound stimulation were also measured at 1 week and 5 months post-trauma. It was found that unilateral exposure to a 16 kHz pure tone at 115 dB SPL for 1 h caused immediate hearing loss in all the animals and chronic tinnitus in 58 % of the animals. Comparing to the sham condition, extracellular levels of GABA were significantly increased at both the acute and 1 week time points after acoustic trauma. However, there was no significant difference in any of the amino acid levels measured between sham, tinnitus positive and tinnitus negative animals at 5 months post-trauma. There was also no clear pattern in the relationship between neurochemical changes and sound frequency/acoustic trauma/tinnitus status, which might be due to the relatively poorer temporal resolution of the microdialysis compared to electrophysiological responses.
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Affiliation(s)
- Huey Tieng Tan
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand
| | - Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand.
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2
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Watanabe M, Ito T, Fukuda A. Effects of Taurine Depletion on Body Weight and Mouse Behavior during Development. Metabolites 2022; 12:631. [PMID: 35888755 PMCID: PMC9318136 DOI: 10.3390/metabo12070631] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 07/04/2022] [Accepted: 07/07/2022] [Indexed: 02/05/2023] Open
Abstract
Taurine (2-aminoethanesulfonic acid) plays an important role in various physiological functions and is abundant in the brain and skeletal muscle. Extracellular taurine is an endogenous agonist of gamma-aminobutyric acid type A and glycine receptors. Taurine actively accumulates in cells via the taurine transporter (TauT). Adult taurine-knockout (TauT-/-) mice exhibit lower body weights and exercise intolerance. To further examine the physiological role of taurine, we examined the effect of its depletion on mouse behavior, startle responses, muscular endurance, and body weight during development from postnatal day 0 (P0) until P60. In the elevated plus maze test, TauT-/- mice showed decreased anxiety-like behavior. In addition, TauT-/- mice did not show a startle response to startle stimuli, suggesting they have difficulty hearing. Wire-hang test revealed that muscular endurance was reduced in TauT-/- mice. Although a reduction of body weight was observed in TauT-/- mice during the developmental period, changes in body weight during 60% food restriction were similar to wild-type mice. Collectively, these results suggest that taurine has important roles in anxiety-like behavior, hearing, muscular endurance, and maintenance of body weight.
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Affiliation(s)
- Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan;
| | - Takashi Ito
- Department of Bioscience and Technology, Graduate School of Bioscience and Technology, Fukui Prefectural University, Fukui 910-1195, Japan;
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan;
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3
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Oja SS, Saransaari P. Taurine and the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1370:325-331. [DOI: 10.1007/978-3-030-93337-1_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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4
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Shu FQ, Lu YG, Tang HP, Ye ZY, Huang YN, Wang M, Tang ZQ, Chen L. Resveratrol noncompetitively inhibits glycine receptor-mediated currents in neurons of rat central auditory neurons. Brain Res Bull 2021; 169:18-24. [PMID: 33400956 DOI: 10.1016/j.brainresbull.2020.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/21/2020] [Accepted: 12/30/2020] [Indexed: 01/17/2023]
Abstract
Resveratrol, a naturally occurring stilbene found in red wine, is known to modulate the activity of several types of ion channels and membrane receptors, including Ca2+, K+, and Na+ ion channels. However, little is known about the effects of resveratrol on some important receptors, such as glycine receptors and GABAA receptors, in the central nervous system (CNS). In the present study, the effects of resveratrol on glycine receptor or GABAA receptor-mediated currents in cultured rat inferior colliculus (IC) and auditory cortex (AC) neurons were studied using whole-cell voltage-clamp recordings. Resveratrol itself did not evoke any currents in IC neurons but it reversibly decreased the amplitude of glycine-induced current (IGly) in a concentration-dependent manner. Resveratrol did not change the reversal potential of IGly but it shifted the concentration-response relationship to the right without changing the Hill coefficient and with decreasing the maximum response of IGly. Interestingly, resveratrol inhibited the amplitude of IGly but not that of GABA-induced current (IGABA) in AC neurons. More importantly, resveratrol inhibited GlyR-mediated but not GABAAR-mediated inhibitory postsynaptic currents in IC neurons using brain slice recordings. Together, these results demonstrate that resveratrol noncompetitively inhibits IGly in auditory neurons by decreasing the affinity of glycine to its receptor. These findings suggest that the native glycine receptors but not GABAA receptors in central neurons are targets of resveratrol during clinical administrations.
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Affiliation(s)
- Fang-Qi Shu
- School of Life Sciences, Anhui University, Hefei, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, 230601, China
| | - Yun-Gang Lu
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China; Auditory Research Laboratory, University of Science and Technology of China, Hefei, 230027, China
| | - Hui-Ping Tang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China; Auditory Research Laboratory, University of Science and Technology of China, Hefei, 230027, China
| | - Zeng-You Ye
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China
| | - Yi-Na Huang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China; Auditory Research Laboratory, University of Science and Technology of China, Hefei, 230027, China
| | - Ming Wang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China; Auditory Research Laboratory, University of Science and Technology of China, Hefei, 230027, China
| | - Zheng-Quan Tang
- School of Life Sciences, Anhui University, Hefei, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, 230601, China.
| | - Lin Chen
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China; Auditory Research Laboratory, University of Science and Technology of China, Hefei, 230027, China.
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5
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Tang ZQ, Lu YG, Huang YN, Chen L. Cross-talk pattern between GABA A- and glycine-receptors in CNS neurons is shaped by their relative expression levels. Brain Res 2020; 1748:147071. [PMID: 32827550 DOI: 10.1016/j.brainres.2020.147071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/03/2020] [Accepted: 08/17/2020] [Indexed: 11/17/2022]
Abstract
GABAA receptors (GABAARs) and glycine receptors (GlyRs) are two principal inhibitory chloride ion channels in the central nervous system. The two receptors do not function independently but cross-talk to each other, i.e., the activation of one receptor would inhibit the other. This cross-talk is present in different patterns across various regions in the central nervous system; however, the factor that determines these patterns is not understood. Here, we show that the pattern of cross-talk between the two receptors is shaped by their relative expression level in a neuron: a higher expression level correlates with louder talk. In line with a tendency of decrease in expression level of GlyRs and increase in expression level of GABAARs from the spinal cord, the brainstem to the neocortex, GlyRs talked much louder (i.e. produced greater inhibition) than GABAARs (one-way pattern) in spinal cord neurons, about equally loud as GABAARs (symmetric pattern) in inferior colliculus neurons and less loud (i.e. less inhibition) than GABAARs (asymmetric pattern) in auditory cortex neurons. Overexpression of GlyRs in inferior colliculus neurons produced an asymmetric pattern that should otherwise have been observed in spinal cord neurons. These expression level-dependent patterns of cross-talk between the two receptors may suggest how the central nervous system uses an alternative mechanism to maintain a delicate level of inhibition through adjusting the proportion of the two receptors in a neuron along its pathway.
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Affiliation(s)
- Zheng-Quan Tang
- School of Life Sciences, Anhui University, Hefei 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, China.
| | - Yun-Gang Lu
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yi-Na Huang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Lin Chen
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.
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6
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Zheng Y, McTavish J, Smith PF. Pharmacological Evaluation of Drugs in Animal Models of Tinnitus. Curr Top Behav Neurosci 2020; 51:51-82. [PMID: 33590458 DOI: 10.1007/7854_2020_212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Despite the pressing need for effective drug treatments for tinnitus, currently, there is no single drug that is approved by the FDA for this purpose. Instead, a wide range of unproven over-the-counter tinnitus remedies are available on the market with little or no benefit for tinnitus but with potential harm and adverse effects. Animal models of tinnitus have played a critical role in exploring the pathophysiology of tinnitus, identifying therapeutic targets and evaluating novel and existing drugs for tinnitus treatment. This review summarises and compares the studies on pharmacological evaluation of tinnitus treatment in different animal models based on the pharmacological properties of the drug and provides insights into future directions for tinnitus drug discovery.
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Affiliation(s)
- Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand. .,Brain Research New Zealand, Auckland, New Zealand. .,Brain Health Research Centre, University of Otago, Dunedin, New Zealand. .,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand.
| | - Jessica McTavish
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
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7
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Sun Y, Jia Y, Guo Y, Chen F, Yan Z. Taurine Transporter dEAAT2 is Required for Auditory Transduction in Drosophila. Neurosci Bull 2018; 34:939-950. [PMID: 30043098 PMCID: PMC6246829 DOI: 10.1007/s12264-018-0255-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/20/2018] [Indexed: 12/22/2022] Open
Abstract
Drosophila dEAAT2, a member of the excitatory amino-acid transporter (EAAT) family, has been described as mediating the high-affinity transport of taurine, which is a free amino-acid abundant in both insects and mammals. However, the role of taurine and its transporter in hearing is not clear. Here, we report that dEAAT2 is required for the larval startle response to sound stimuli. dEAAT2 was found to be enriched in the distal region of chordotonal neurons where sound transduction occurs. The Ca2+ imaging and electrophysiological results showed that disrupted dEAAT2 expression significantly reduced the response of chordotonal neurons to sound. More importantly, expressing dEAAT2 in the chordotonal neurons rescued these mutant phenotypes. Taken together, these findings indicate a critical role for Drosophila dEAAT2 in sound transduction by chordotonal neurons.
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Affiliation(s)
- Ying Sun
- State Key Laboratory of Medical Neurobiology, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Yanyan Jia
- State Key Laboratory of Medical Neurobiology, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Yifeng Guo
- State Key Laboratory of Medical Neurobiology, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Department of Human Anatomy, School of Basic Medicine Sciences, Southwest Medical University, Luzhou, 646000, China.
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8
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Li SJ, Luo YN, Li Y, Chen JW, Mo YH, Yuan ZX, Ou SY, Ou CY, Jiang YM, Deng XF. Sodium para-aminosalicylate protected cultured basal ganglia astrocytes from manganese-induced DNA damages and alteration of amino acid neurotransmitter levels. J Toxicol Sci 2017; 41:573-81. [PMID: 27665767 DOI: 10.2131/jts.41.573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Sodium para-aminosalicylate (PAS-Na) was first applied successfully in clinical treatment of two manganism patients with good prognosis. However, the mechanism of how PAS-Na protects against Mn-induced neurotoxicity is still elusive. The current study was conducted to explore the effects of PAS-Na on Mn-induced basal ganglia astrocyte injury, and the involvement of amino acid neurotransmitter in vitro. Basal ganglia astrocytes were exposed to 500 μM manganese chloride (MnCl2) for 24 hr, following by 50, 150, or 450 μM PAS-Na treatment for another 24 hr. MnCl2 significantly decreased viability of astrocytes and induced DNA damages via increasing the percentage of tail DNA and Olive tail moment of DNA. Moreover, Mn interrupted amino acid neurotransmitters by decreasing Gln levels and increasing Glu, Gly levels. In contrast, PAS-Na treatment reversed the aforementioned Mn-induced toxic effects on basal ganglia astrocytes. Taken together, our results demonstrated that excessive Mn exposure may induce toxic effects on basal ganglia astrocytes, while PAS-Na could protect basal ganglia astrocytes from Mn-induced neurotoxicity.
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Affiliation(s)
- Shao-Jun Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, China
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9
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Feng Y, Zhu H, Zhang X, Wang X, Xu F, Tang H, Ye C, Liu M. NMR Based Cerebrum Metabonomic Analysis Reveals Simultaneous Interconnected Changes during Chick Embryo Incubation. PLoS One 2015; 10:e0139948. [PMID: 26485040 PMCID: PMC4618859 DOI: 10.1371/journal.pone.0139948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 09/18/2015] [Indexed: 11/18/2022] Open
Abstract
To find out if content changes of the major functional cerebrum metabolites are interconnected and formed a network during the brain development, we obtained high-resolution magic-angle-spinning (HR-MAS) 1H NMR spectra of cerebrum tissues of chick embryo aged from incubation day 10 to 20, and postnatal day 1, and analyzed the data with principal component analysis (PCA). Within the examined time window, 26 biological important molecules were identified and 12 of them changed their relative concentration significantly in a time-dependent manner. These metabolites are generally belonged to three categories, neurotransmitters, nutrition sources, and neuronal or glial markers. The relative concentration changes of the metabolites were interconnected among/between the categories, and, more interestingly, associated with the number and size of Nissl-positive neurons. These results provided valuable biochemical and neurochemical information to understand the development of the embryonic brain.
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Affiliation(s)
- Yue Feng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201, United States of America
| | - Hang Zhu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Xu Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Xuxia Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Fuqiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Huiru Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Chaohui Ye
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
- * E-mail:
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10
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Luo B, Hu L, Liu C, Guo Y, Wang H. Activation of 5-HT2A/C receptor reduces glycine receptor-mediated currents in cultured auditory cortical neurons. Amino Acids 2015; 48:349-56. [PMID: 26371055 DOI: 10.1007/s00726-015-2086-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/25/2015] [Indexed: 01/28/2023]
Abstract
Glycine receptors (GlyRs) permeable to chloride only mediate tonic inhibition in the cerebral cortex where glycinergic projection is completely absent. The functional modulation of GlyRs was largely studied in subcortical brain regions with glycinergic transmissions, but the function of cortical GlyRs was rarely addressed. Serotonin could broadly modulate many ion channels through activating 5-HT2 receptor, but whether cortical GlyRs are subjected to serotonergic modulation remains unexplored. The present study adopted patch clamp recordings to examine functional regulation of strychnine-sensitive GlyRs currents in cultured cortical neurons by DOI (2,5-Dimethoxy-4-iodoamphetamine), a 5-HT2A/C receptor agonist. DOI caused a concentration-dependent reduction of GlyR currents with unchanged reversal potential. This reduction was blocked by the selective receptor antagonists (ritanserin and risperidone) and G protein inhibitor (GDP-β-s) demonstrated that the reducing effect of DOI on GlyR current required the activation of 5-HT2A/C receptors. Strychnine-sensitive tonic currents revealed the inhibitory tone mediated by nonsynaptic GlyRs, and DOI similarly reduced the tonic inhibition. The impaired microtube-dependent trafficking or clustering of GlyRs was thought to be involved in that nocodazole as a microtube depolymerizing drug largely blocked the inhibition mediated by 5-HT2A/C receptors. Our results suggested that activation of 5-HT2A/C receptors might suppress cortical tonic inhibition mediated by GlyRs, and the findings would provide important insight into serotonergic modulation of tonic inhibition mediated by GlyRs, and possibly facilitate to develop the therapeutic treatment of neurological diseases such as tinnitus through regulating cortical GlyRs.
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Affiliation(s)
- Bin Luo
- Department of Otolaryngology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, 230001, China
| | - Lingli Hu
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, Guangdong, China
| | - Chunhua Liu
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, Guangdong, China
| | - Yiping Guo
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, Guangdong, China
| | - Haitao Wang
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, Guangdong, China.
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11
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Song NY, Li CY, Yin XL, Liang M, Shi HB, Han GY, Yin SK. Taurine protects against bilirubin-induced hyperexcitation in rat anteroventral cochlear nucleus neurons. Exp Neurol 2014; 254:216-23. [PMID: 24382452 DOI: 10.1016/j.expneurol.2013.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 11/24/2013] [Accepted: 12/20/2013] [Indexed: 02/05/2023]
Abstract
No effective medication for hyperbilirubinemia yet exists. Taurine is believed to exert a neuroprotective action. The aim of the present study was to determine whether taurine protected neurons of the rat anteroventral cochlear nucleus (AVCN) against bilirubin-induced neuronal hyperexcitation. AVCN neurons were isolated from 13 to 15-day-old Sprague-Dawley rats. The effects of bilirubin on the spontaneous excitatory postsynaptic currents (sEPSCs) and action potential currents were compared with those exerted by bilirubin and taurine together. Bilirubin dramatically increased the frequencies of sEPSCs and action potential currents, but not sEPSC amplitude. Taurine suppressed the enhanced frequency of action potentials induced by bilirubin, in a dose-dependent manner. In addition, taurine decreased the amplitude of voltage-dependent calcium channel currents that were enhanced upon addition of bilirubin. We explored the mechanism of the protective effects exerted by taurine using GABAA and glycine receptor antagonists, bicuculline and strychnine, respectively. Addition of bicuculline and strychnine eliminated the protective effects of taurine. Neither bilirubin nor taurine affected the sensitivity of the glutamate receptor. Our findings thus indicate that taurine protected AVCN neurons against bilirubin-induced neuronal hyperexcitation by activating the GABAA and glycine receptors and inhibiting calcium flow through voltage-gated channels. Thus, taurine may be effective in treatment of neonatal hyperbilirubinemia.
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Affiliation(s)
- Ning-ying Song
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China; Department of Otorhinolaryngology, West China Hospital, Sichuan University, Chengdu, China
| | - Chun-yan Li
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China.
| | - Xin-lu Yin
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
| | - Min Liang
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
| | - Hai-bo Shi
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
| | - Guo-ying Han
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
| | - Shan-kai Yin
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China.
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12
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Activation of glycine and extrasynaptic GABA(A) receptors by taurine on the substantia gelatinosa neurons of the trigeminal subnucleus caudalis. Neural Plast 2013; 2013:740581. [PMID: 24379976 PMCID: PMC3863572 DOI: 10.1155/2013/740581] [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] [Received: 09/17/2013] [Revised: 11/05/2013] [Accepted: 11/12/2013] [Indexed: 11/23/2022] Open
Abstract
The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) has been known for the processing and transmission of orofacial nociceptive information. Taurine, one of the most plentiful free amino-acids in humans, has proved to be involved in pain modulation. In this study, using whole-cell patch clamp technique, we investigated the direct membrane effects of taurine and the action mechanism behind taurine-mediated responses on the SG neurons of the Vc. Taurine showed non-desensitizing and repeatable membrane depolarizations and inward currents which remained in the presence of amino-acid receptors blocking cocktail (AARBC) with tetrodotoxin, indicating that taurine acts directly on the postsynaptic SG neurons. Further, application of taurine at different doses (10 μM to 3 mM) showed a concentration dependent depolarizations and inward currents with the EC50 of 84.3 μM and 723 μM, respectively. Taurine-mediated responses were partially blocked by picrotoxin (50 μM) and almost completely blocked by strychnine (2 μM), suggesting that taurine-mediated responses are via glycine receptor (GlyR) activation. In addition, taurine (1 mM) activated extrasynaptic GABAA receptor (GABAAR)-mediated currents. Taken together, our results indicate that taurine can be a target molecule for orofacial pain modulation through the activation of GlyRs and/or extrasynaptic GABAARs on the SG neurons.
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Blüml S, Wisnowski JL, Nelson MD, Paquette L, Gilles FH, Kinney HC, Panigrahy A. Metabolic maturation of the human brain from birth through adolescence: insights from in vivo magnetic resonance spectroscopy. Cereb Cortex 2012; 23:2944-55. [PMID: 22952278 DOI: 10.1093/cercor/bhs283] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Between birth and late adolescence, the human brain undergoes exponential maturational changes. Using in vivo magnetic resonance spectroscopy, we determined the developmental profile for 6 metabolites in 5 distinct brain regions based on spectra from 309 children from 0 to 18 years of age. The concentrations of N-acetyl-aspartate (an indicator for adult-type neurons and axons), creatine (energy metabolite), and glutamate (excitatory neurotransmitter) increased rapidly between birth and 3 months, a period of rapid axonal growth and synapse formation. Myo-inositol, implicated in cell signaling and a precursor of membrane phospholipid, as well as an osmolyte and astrocyte marker, declined rapidly during this period. Choline, a membrane metabolite and indicator for de novo myelin and cell membrane synthesis, peaked from birth until approximately 3 months, and then declined gradually, reaching a plateau at early childhood. Similarly, taurine, involved in neuronal excitability, synaptic potentiation, and osmoregulation, was high until approximately 3 months and thereafter declined. These data indicate that the first 3 months of postnatal life are a critical period of rapid metabolic changes in the development of the human brain. This study of the developmental profiles of the major brain metabolites provides essential baseline information for future analyses of the pediatric health and disease.
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Interaction between taurine and GABA(A)/glycine receptors in neurons of the rat anteroventral cochlear nucleus. Brain Res 2012; 1472:1-10. [PMID: 22796293 DOI: 10.1016/j.brainres.2012.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 06/30/2012] [Accepted: 07/03/2012] [Indexed: 10/28/2022]
Abstract
Taurine, one of the most abundant endogenous amino acids in the mammalian central nervous system (CNS), is involved in neural development and many physiological functions. In this study, the interaction between taurine and GABA(A)/glycine receptors was investigated in young rat (P13-P15) anteroventral cochlear nucleus (AVCN) neurons using the whole-cell patch-clamp method. We found that taurine at low (0.1mM) and high (1mM) concentrations activated both GABA(A) and glycine receptors, but not AMPA and NMDA receptors. The reversal potentials of taurine-, GABA- or glycine-evoked currents were close to the expected chloride equilibrium potential, indicating that receptors activated by these agonists were mediating chloride conductance. Moreover, our results showed that the currents activated by co-application of GABA and glycine were cross-inhibitive. Sequential application of GABA and glycine or vice versa also reduced the glycine or GABA evoked currents. There was no cross-inhibition when taurine and GABA or taurine and glycine were applied simultaneously, but the response was larger than that evoked by GABA or glycine alone. These results suggest that taurine can serve as a neuromodulator to strengthen GABAergic and glycinergic neurotransmission in the rat AVCN.
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Manzoor NF, Gao Y, Licari F, Kaltenbach JA. Comparison and contrast of noise-induced hyperactivity in the dorsal cochlear nucleus and inferior colliculus. Hear Res 2012; 295:114-23. [PMID: 22521905 DOI: 10.1016/j.heares.2012.04.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/26/2012] [Accepted: 04/03/2012] [Indexed: 01/13/2023]
Abstract
Induction of hyperactivity in the central auditory system is one of the major physiological hallmarks of animal models of noise-induced tinnitus. Although hyperactivity occurs at various levels of the auditory system, it is not clear to what extent hyperactivity originating in one nucleus contributes to hyperactivity at higher levels of the auditory system. In this study we compared the time courses and tonotopic distribution patterns of hyperactivity in the dorsal cochlear nucleus (DCN) and inferior colliculus (IC). A model of acquisition of hyperactivity in the IC by passive relay from the DCN would predict that the two nuclei show similar time courses and tonotopic profiles of hyperactivity. A model of acquisition of hyperactivity in the IC by compensatory plasticity mechanisms would predict that the IC and DCN would show differences in these features, since each adjusts to changes of spontaneous activity of opposite polarity. To test the role of these two mechanisms, animals were exposed to an intense hyperactivity-inducing tone (10 kHz, 115 dB SPL, 4 h) then studied electrophysiologically at three different post-exposure recovery times (from 1 to 6 weeks after exposure). For each time frame, multiunit spontaneous activity was mapped as a function of location along the tonotopic gradient in the DCN and IC. Comparison of activity profiles from the two nuclei showed a similar progression toward increased activity over time and culminated in the development of a central peak of hyperactivity at a similar tonotopic location. These similarities suggest that the shape of the activity profile is determined primarily by passive relay from the cochlear nucleus. However, the absolute levels of activity were generally much lower in the IC than in the DCN, suggesting that the magnitude of hyperactivity is greatly attenuated by inhibition.
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Affiliation(s)
- N F Manzoor
- Department of Neurosciences, The Cleveland Clinic, NE-63, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Richardson BD, Brozoski TJ, Ling LL, Caspary DM. Targeting inhibitory neurotransmission in tinnitus. Brain Res 2012; 1485:77-87. [PMID: 22405692 DOI: 10.1016/j.brainres.2012.02.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 02/06/2012] [Accepted: 02/06/2012] [Indexed: 02/07/2023]
Abstract
Tinnitus perception depends on the presence of its neural correlates within the auditory neuraxis and associated structures. Targeting specific circuits and receptors within the central nervous system in an effort to relieve the perception of tinnitus and its impact on one's emotional and mental state has become a focus of tinnitus research. One approach is to upregulate endogenous inhibitory neurotransmitter levels (e.g., glycine and GABA) and selectively target inhibitory receptors in key circuits to normalize tinnitus pathophysiology. Thus, the basic functional and molecular properties of two major ligand-gated inhibitory receptor systems, the GABA(A) receptor (GABA(A)R) and glycine receptor (GlyR) are described. Also reviewed is the rationale for targeting inhibition, which stems from reported tinnitus-related homeostatic plasticity of inhibitory neurotransmitter systems and associated enhanced neuronal excitability throughout most central auditory structures. However, the putative role of the medial geniculate body (MGB) in tinnitus has not been previously addressed, specifically in terms of its inhibitory afferents from inferior colliculus and thalamic reticular nucleus and its GABA(A)R functional heterogeneity. This heterogeneous population of GABA(A)Rs, which may be altered in tinnitus pathology, and its key anatomical position in the auditory CNS make the MGB a compelling structure for tinnitus research. Finally, some selective compounds, which enhance tonic inhibition, have successfully ameliorated tinnitus in animal studies, suggesting that the MGB and, to a lesser degree, the auditory cortex may be their primary locus of action. These pharmacological interventions are examined in terms of their mechanism of action and why these agents may be effective in tinnitus treatment. This article is part of a Special Issue entitled: Tinnitus Neuroscience.
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Affiliation(s)
- Ben D Richardson
- Department of Pharmacology, Southern Illinois University School of Medicine, 801 N Rutledge St, Rm. 3234, PO Box 19629, Springfield, IL 62794, USA.
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Le-Corronc H, Rigo JM, Branchereau P, Legendre P. GABA(A) receptor and glycine receptor activation by paracrine/autocrine release of endogenous agonists: more than a simple communication pathway. Mol Neurobiol 2011; 44:28-52. [PMID: 21547557 DOI: 10.1007/s12035-011-8185-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 04/14/2011] [Indexed: 02/04/2023]
Abstract
It is a common and widely accepted assumption that glycine and GABA are the main inhibitory transmitters in the central nervous system (CNS). But, in the past 20 years, several studies have clearly demonstrated that these amino acids can also be excitatory in the immature central nervous system. In addition, it is now established that both GABA receptors (GABARs) and glycine receptors (GlyRs) can be located extrasynaptically and can be activated by paracrine release of endogenous agonists, such as GABA, glycine, and taurine. Recently, non-synaptic release of GABA, glycine, and taurine gained further attention with increasing evidence suggesting a developmental role of these neurotransmitters in neuronal network formation before and during synaptogenesis. This review summarizes recent knowledge about the non-synaptic activation of GABA(A)Rs and GlyRs, both in developing and adult CNS. We first present studies that reveal the functional specialization of both non-synaptic GABA(A)Rs and GlyRs and we discuss the neuronal versus non-neuronal origin of the paracrine release of GABA(A)R and GlyR agonists. We then discuss the proposed non-synaptic release mechanisms and/or pathways for GABA, glycine, and taurine. Finally, we summarize recent data about the various roles of non-synaptic GABAergic and glycinergic systems during the development of neuronal networks and in the adult.
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Affiliation(s)
- Herve Le-Corronc
- Institut National de la Santé et de la Recherche Médicale, U952, Centre National de la Recherche Scientifique, UMR 7224, Université Pierre et Marie Curie, 9 quai Saint Bernard, Paris, Ile de France, France
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Brozoski TJ, Caspary DM, Bauer CA, Richardson BD. The effect of supplemental dietary taurine on tinnitus and auditory discrimination in an animal model. Hear Res 2010; 270:71-80. [PMID: 20868734 DOI: 10.1016/j.heares.2010.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 09/08/2010] [Accepted: 09/14/2010] [Indexed: 10/19/2022]
Abstract
Loss of central inhibition has been hypothesized to underpin tinnitus and impact auditory acuity. Taurine, a partial agonist at inhibitory glycine and γ-amino butyric acid receptors, was added to the daily diet of rats to examine its effects on chronic tinnitus and normal auditory discrimination. Eight rats were unilaterally exposed once to a loud sound to induce tinnitus. The rats were trained and tested in an operant task shown to be sensitive to tinnitus. An equivalent unexposed control group was run in parallel. Months after exposure, 6 of the exposed rats showed significant evidence of chronic tinnitus. Two concentrations of taurine in drinking water were given over several weeks (attaining average daily doses of 67 mg/kg and 294 mg/kg). Water consumption was unaffected. Three main effects were obtained: (1) The high taurine dose significantly attenuated tinnitus, which returned to near pre-treatment levels following washout. (2) Auditory discrimination was significantly improved in unexposed control rats at both doses. (3) As indicated by lever pressing, taurine at both doses had a significant group-equivalent stimulant effect. These results are consistent with the hypothesis that taurine attenuates tinnitus and improves auditory discrimination by increasing inhibitory tone and decreasing noise in the auditory pathway.
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Affiliation(s)
- Thomas J Brozoski
- Division of Otolaryngology, Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, IL 62794, USA.
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Fordahl SC, Anderson JG, Cooney PT, Weaver TL, Colyer CL, Erikson KM. Manganese exposure inhibits the clearance of extracellular GABA and influences taurine homeostasis in the striatum of developing rats. Neurotoxicology 2010; 31:639-46. [PMID: 20832424 DOI: 10.1016/j.neuro.2010.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/02/2010] [Accepted: 09/02/2010] [Indexed: 11/28/2022]
Abstract
Manganese (Mn) accumulation in the brain has been shown to alter the neurochemistry of the basal ganglia. Mn-induced alterations in dopamine biology are fairly well understood, but recently more evidence has emerged characterizing the role of γ-aminobutyric acid (GABA) in this dysfunction. The purpose of this study was to determine if the previously observed Mn-induced increase in extracellular GABA (GABA(EC)) was due to altered GABA transporter (GAT) function, and whether Mn perturbs other amino acid neurotransmitters, namely taurine and glycine (known modulators of GABA). Extracellular GABA, taurine, and glycine concentrations were collected from the striatum of control (CN) or Mn-exposed Sprague-Dawley rats using in vivo microdialysis, and the GAT inhibitor nipecotic acid (NA) was used to probe GAT function. Tissue and extracellular Mn levels were significantly increased, and the Fe:Mn ratio was decreased 36-fold in the extracellular space due to Mn-exposure. NA led to a 2-fold increase in GABA(EC) of CNs, a response that was attenuated by Mn. Taurine responded inversely to GABA, and a novel 10-fold increase in taurine was observed after the removal of NA in CNs. Mn blunted this response and nearly abolished extracellular taurine throughout collection. Striatal taurine transporter (Slc6a6) mRNA levels were significantly increased with Mn-exposure, and Mn significantly increased (3)H-Taurine uptake after 3-min exposure in primary rat astrocytes. These data suggest that Mn increases GABA(EC) by inhibiting the function of GAT, and that perturbed taurine homeostasis potentially impacts neural function by jeopardizing the osmoregulatory and neuromodulatory functions of taurine in the brain.
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Affiliation(s)
- Steve C Fordahl
- Department of Nutrition, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
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Tang ZQ, Lu YG, Chen L. Developmental stability of taurine's activation on glycine receptors in cultured neurons of rat auditory cortex. Neurosci Lett 2008; 430:54-9. [DOI: 10.1016/j.neulet.2007.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Revised: 09/22/2007] [Accepted: 10/14/2007] [Indexed: 11/25/2022]
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Zhang CG, Kim SJ. Taurine Induces Anti-Anxiety by Activating Strychnine-Sensitive Glycine Receptor in vivo. ANNALS OF NUTRITION AND METABOLISM 2007; 51:379-86. [PMID: 17728537 DOI: 10.1159/000107687] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Accepted: 03/09/2007] [Indexed: 11/19/2022]
Abstract
Taurine has a variety of actions in the body such as cardiotonic, host-defensive, radioprotective and glucose-regulatory effects. However, its action in the central nervous system remains to be characterized. In the present study, we tested to see whether taurine exerts anti-anxiety effects and to explore its mechanism of anti-anxiety activity in vivo. The staircase test and elevated plus maze test were performed to test the anti-anxiety action of taurine. Convulsions induced by strychnine, picrotoxin, yohimbine and isoniazid were tested to explore the mechanism of anti-anxiety activity of taurine. The Rotarod test was performed to test muscle relaxant activity and the passive avoidance test was carried out to test memory activity in response to taurine. Taurine (200 mg/kg, p.o.) significantly reduced rearing numbers in the staircase test while it increased the time spent in the open arms as well as the number of entries to the open arms in the elevated plus maze test, suggesting that it has a significant anti-anxiety activity. Taurine's action could be due to its binding to and activating of strychnine-sensitive glycine receptor in vivo as it inhibited convulsion caused by strychnine; however, it has little effect on picrotoxin-induced convulsion, suggesting its anti-anxiety activity may not be linked to GABA receptor. It did not alter memory function and muscle activity. Taken together, these results suggest that taurine could be beneficial for the control of anxiety in the clinical situations.
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Affiliation(s)
- Cheng Gao Zhang
- Department of Pharmacology and Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul, Korea
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