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Wu M, Liu S, Hu L, Qu H, Pan C, Lei P, Shen Y, Yang M. Global transcriptomic analysis of zebrafish in response to embryonic exposure to three antidepressants, amitriptyline, fluoxetine and mianserin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 192:274-283. [PMID: 28992598 DOI: 10.1016/j.aquatox.2017.09.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/26/2017] [Accepted: 09/27/2017] [Indexed: 06/07/2023]
Abstract
Antidepressants are among the most commonly detected pharmaceuticals in aqueous systems, and, as emerging organic pollutants, may exert negative effects on non-target aquatic organisms. Previously, it has been revealed that antidepressant exposure significantly inhibits the growth and development of fish during their early developmental stages. Thus, in the present study, we aimed to identify and compare the underlying mechanisms of action of different antidepressants at the transcriptional level using zebrafish (Danio rerio) embryos. Through high-throughput RNA sequencing (RNA-Seq) data analysis, 32, 34, and 130 differentially expressed genes (DEGs) were obtained from zebrafish larvae after 120h of embryonic exposure to sublethal concentrations of amitriptyline, fluoxetine, and mianserin, respectively. The expression profiles of the identified DEGs showed similar trends in response to the three antidepressant treatments, suggesting consistent toxic effects of low concentrations of these three drugs on the regulation of gene expression in fish. Several metabolic and signaling pathways, including glycolysis/gluconeogenesis and the insulin pathway, were affected in the exposed fish larvae. The expression profiles of selected DEGs were then verified by the qRT-PCR method, which indicated significant positive correlations with the RNA-Seq results. Next, we determined the concentration-dependent expression patterns of 6 selected DEGs in fish larvae exposed to three antidepressants at a series of environmentally relevant concentrations. The results revealed a significant concentration-dependent reduction in the levels of dual-specificity phosphatase 5 (dusp5) mRNA, as well as a non-concentration-dependent gene expression inhibition of prostaglandin D2 synthase b (ptgdsb); the circadian rhythm-related genes, i.e. those encoding nuclear receptor subfamily 1, group D, member 1 (nr1d1) and period 2 (per2); and genes encoding early growth response factors (egr1 and egr4), in the antidepressant-treated fish larvae. In summary, to our knowledge, our findings demonstrate, for the first time, that the three different categories of antidepressants have common effects on the gene expression involved in multiple biological processes and signaling pathways during the early development of fish and thus provide information for characterizing the adverse outcome pathways and on the ecological risk assessment of these pharmaceutical pollutants in the aquatic environment.
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Affiliation(s)
- Minghong Wu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 China.
| | - Shuai Liu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 China; College of the Environment & Ecology, Xiamen University, Xiamen, Fujian 361005, China.
| | - Lei Hu
- School of Life Sciences, Shanghai University, Shanghai 200444, China.
| | - Haidong Qu
- College of the Environment & Ecology, Xiamen University, Xiamen, Fujian 361005, China.
| | - Chenyuan Pan
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 China.
| | - Penghui Lei
- School of Life Sciences, Shanghai University, Shanghai 200444, China.
| | - Yingjia Shen
- College of the Environment & Ecology, Xiamen University, Xiamen, Fujian 361005, China.
| | - Ming Yang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 China.
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Tran NQV, Nguyen AN, Takabe K, Yamagata Z, Miyake K. Pre-treatment with amitriptyline causes epigenetic up-regulation of neuroprotection-associated genes and has anti-apoptotic effects in mouse neuronal cells. Neurotoxicol Teratol 2017; 62:1-12. [PMID: 28511916 DOI: 10.1016/j.ntt.2017.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 05/09/2017] [Accepted: 05/11/2017] [Indexed: 12/12/2022]
Abstract
Antidepressants, such as imipramine and fluoxetine, are known to alter gene expression patterns by inducing changes in the epigenetic status of neuronal cells. There is also some evidence for the anti-apoptotic effect of various groups of antidepressants; however, this effect is complicated and cell-type dependent. Antidepressants of the tricyclic group, in particular amitriptyline, have been suggested to be beneficial in the treatment of neurodegenerative disorders. We examined whether amitriptyline exerts an anti-apoptotic effect via epigenetic mechanisms. Using DNA microarray, we analyzed global gene expression in mouse primary cultured neocortical neurons after treatment with amitriptyline and imipramine. The neuroprotection-associated genes, activating transcription factor 3 (Atf3) and heme oxygenase 1 (Hmox1), were up-regulated at both mRNA and protein levels by treatment with amitriptyline. Quantitative chromatin immunoprecipitation assay revealed that amitriptyline increased enrichments of trimethylation of histone H3 lysine 4 in the promoter regions of Atf3 and Hmox1 and acetylation of histone H3 lysine 9 in the promoter regions of Atf3, which indicate an active epigenetic status. Amitriptyline pre-treatment attenuated 1-methyl-4-phenylpyridinium ion (MPP+)- or amyloid β peptide 1-42 (Aβ1-42)-induced neuronal cell death and inhibited the activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2). We found that Atf3 and Hmox1 were also up-regulated after Aβ1-42 treatment, and were further increased when pre-treated with amitriptyline. Interestingly, the highest up-regulation of Atf3 and Hmox1, at least at mRNA level, was observed after co-treatment with Aβ1-42 and amitriptyline, together with the loss of the neuroprotective effect. These findings suggest preconditioning and neuroprotective effects of amitriptyline; however, further investigations are needed for clarifying the contribution of epigenetic up-regulation of Atf3 and Hmox1 genes.
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Affiliation(s)
- Nguyen Quoc Vuong Tran
- Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - An Nghia Nguyen
- Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Kyoko Takabe
- Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Zentaro Yamagata
- Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Kunio Miyake
- Department of Health Sciences, Graduate School of Interdisciplinary Research, University of Yamanashi, 1110, Shimokato, Chuo, Yamanashi 409-3898, Japan.
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Sanna MD, Ghelardini C, Galeotti N. Spinal astrocytic c-Jun N-terminal kinase (JNK) activation as counteracting mechanism to the amitriptyline analgesic efficacy in painful peripheral neuropathies. Eur J Pharmacol 2017; 798:85-93. [DOI: 10.1016/j.ejphar.2017.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/19/2017] [Accepted: 01/19/2017] [Indexed: 12/19/2022]
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O'Neill E, Kwok B, Day JS, Connor TJ, Harkin A. Amitriptyline protects against TNF-α-induced atrophy and reduction in synaptic markers via a Trk-dependent mechanism. Pharmacol Res Perspect 2016; 4:e00195. [PMID: 27069625 PMCID: PMC4804321 DOI: 10.1002/prp2.195] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 10/09/2015] [Indexed: 12/20/2022] Open
Abstract
Neuritic degeneration and synaptic loss are features of both neuroinflammation and neurodegenerative disease. The tricyclic antidepressant amitriptyline has neurotrophic and anti-inflammatory properties and acts as a novel agonist of the neurotrophin Trk receptors. Primary cortical neurons were treated with amitriptyline, nortriptyline and NGF and tested for neuronal complexity by Sholl analysis, protein expression by Western immunoblotting, and synapse number by colocalization of pre and postsynaptic makers. Amitriptyline (500 nmol/L) and its active metabolite nortriptyline (50 nmol/L) are found to induce neurite outgrowth in rat primary cortical neurons. Amitriptyline-induced neurite outgrowth is blocked by inhibition of Trk signaling using Trk antagonist K252a (200 nmol/L) but not by the neurotrophin inhibitor Y1036 (40 μmol/L), indicating that amitriptyline binds directly to the Trk receptor to initiate neurite outgrowth. MEK inhibitor PD98059 (10 μmol/L) also blocks amitriptyline-induced neurite outgrowth, implicating activation of the MAPK signaling pathway downstream of Trk receptor activation. Furthermore, pretreatment of primary cortical neurons with amitriptyline and nortriptyline prevents the effects of the proinflammatory cytokine TNF-α (10 ng/mL) on neurite outgrowth and colocalization of synaptic proteins. These findings suggest that amitriptyline and nortriptyline can exert neurotrophic effects in primary cortical neurons via activation of a Trk/MAPK signaling pathway. These compounds therefore have significant potential to be used in the treatment of neurodegenerative conditions where atrophy and loss of synaptic connections contribute to progression of disease.
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Affiliation(s)
- Eimear O'Neill
- Neuropsychopharmacology Research Group School of Pharmacy & Pharmaceutical Sciences and Trinity College Institute of Neuroscience Dublin Ireland; Neuroimmunology Research Group Department of Physiology School of Medicine and Trinity College Institute of Neuroscience Dublin Ireland
| | - Billy Kwok
- Neuroimmunology Research Group Department of Physiology School of Medicine and Trinity College Institute of Neuroscience Dublin Ireland
| | - Jennifer S Day
- Neuroimmunology Research Group Department of Physiology School of Medicine and Trinity College Institute of Neuroscience Dublin Ireland
| | - Thomas J Connor
- Neuroimmunology Research Group Department of Physiology School of Medicine and Trinity College Institute of Neuroscience Dublin Ireland
| | - Andrew Harkin
- Neuropsychopharmacology Research Group School of Pharmacy & Pharmaceutical Sciences and Trinity College Institute of Neuroscience Dublin Ireland
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Kajitani N, Hisaoka-Nakashima K, Okada-Tsuchioka M, Hosoi M, Yokoe T, Morioka N, Nakata Y, Takebayashi M. Fibroblast growth factor 2 mRNA expression evoked by amitriptyline involves extracellular signal-regulated kinase-dependent early growth response 1 production in rat primary cultured astrocytes. J Neurochem 2015; 135:27-37. [DOI: 10.1111/jnc.13247] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 01/17/2023]
Affiliation(s)
- Naoto Kajitani
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences; Hiroshima University; Minami-ku Hiroshima Japan
- Division of Psychiatry and Neuroscience; Institute for Clinical Research; National Hospital Organization (NHO) Kure Medical Center and Chugoku Cancer Center; Kure Japan
| | - Kazue Hisaoka-Nakashima
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences; Hiroshima University; Minami-ku Hiroshima Japan
| | - Mami Okada-Tsuchioka
- Division of Psychiatry and Neuroscience; Institute for Clinical Research; National Hospital Organization (NHO) Kure Medical Center and Chugoku Cancer Center; Kure Japan
| | - Mayu Hosoi
- Division of Psychiatry and Neuroscience; Institute for Clinical Research; National Hospital Organization (NHO) Kure Medical Center and Chugoku Cancer Center; Kure Japan
| | - Toshiki Yokoe
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences; Hiroshima University; Minami-ku Hiroshima Japan
| | - Norimitsu Morioka
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences; Hiroshima University; Minami-ku Hiroshima Japan
| | - Yoshihiro Nakata
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences; Hiroshima University; Minami-ku Hiroshima Japan
| | - Minoru Takebayashi
- Division of Psychiatry and Neuroscience; Institute for Clinical Research; National Hospital Organization (NHO) Kure Medical Center and Chugoku Cancer Center; Kure Japan
- Department of Psychiatry; National Hospital Organization (NHO) Kure Medical Center and Chugoku Cancer Center; Kure Japan
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Morioka N, Suekama K, Zhang FF, Kajitani N, Hisaoka-Nakashima K, Takebayashi M, Nakata Y. Amitriptyline up-regulates connexin43-gap junction in rat cultured cortical astrocytes via activation of the p38 and c-Fos/AP-1 signalling pathway. Br J Pharmacol 2014; 171:2854-67. [PMID: 24641259 DOI: 10.1111/bph.12614] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 01/09/2014] [Accepted: 01/25/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Intercellular communication via gap junctions, comprised of connexin (Cx) proteins, allow for communication between astrocytes, which in turn is crucial for maintaining CNS homeostasis. The expression of Cx43 is decreased in post-mortem brains from patients with major depression. A potentially novel mechanism of tricyclic antidepressants is to increase the expression and functioning of gap junctions in astrocytes. EXPERIMENTAL APPROACH The effect of amitriptyline on the expression of Cx43 and gap junction intercellular communication (GJIC) in rat primary cultured cortical astrocytes was investigated. We also investigated the role of p38 MAPK intracellular signalling pathway in the amitriptyline-induced expression of Cx43 and GJIC. KEY RESULTS Treatment with amitriptyline for 48 h significantly up-regulated Cx43 mRNA, protein and GJIC. The up-regulation of Cx43 was not monoamine-related since noradrenaline, 5-HT and dopamine did not induce Cx43 expression and pretreatment with α- and β-adrenoceptor antagonists had no effect. Intracellular signalling involved p38 MAPK, as amitriptyline significantly increased p38 MAPK phosphorylation and Cx43 expression and GJIC were significantly blocked by the p38 inhibitor SB 202190. Furthermore, amitriptyline-induced Cx43 expression and GJIC were markedly reduced by transcription factor AP-1 inhibitors (curcumin and tanshinone IIA). The translocation of c-Fos from the cytosol and the nucleus of cortical astrocytes was increased by amitriptyline, and this response was dependent on p38 activity. CONCLUSION AND IMPLICATION These findings indicate a novel mechanism of action of amitriptyline through cortical astrocytes, and further suggest that targeting this mechanism could lead to the development of a new class of antidepressants.
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Affiliation(s)
- N Morioka
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Minami-ku, Hiroshima, Japan
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Huang YN, Tsai RY, Lin SL, Chien CC, Cherng CH, Wu CT, Yeh CC, Wong CS. Amitriptyline attenuates astrocyte activation and morphine tolerance in rats: Role of the PSD-95/NR1/nNOS/PKCγ signaling pathway. Behav Brain Res 2012; 229:401-11. [DOI: 10.1016/j.bbr.2012.01.044] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/19/2012] [Accepted: 01/23/2012] [Indexed: 12/13/2022]
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Mut M, Lule S, Demir O, Kurnaz IA, Vural I. Both mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 and phosphatidylinositide-3-OH kinase (PI3K)/Akt pathways regulate activation of E-twenty-six (ETS)-like transcription factor 1 (Elk-1) in U138 glioblastoma cells. Int J Biochem Cell Biol 2011; 44:302-10. [PMID: 22085529 DOI: 10.1016/j.biocel.2011.10.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 10/27/2011] [Accepted: 10/28/2011] [Indexed: 02/02/2023]
Abstract
Epidermal growth factor (EGF) and its receptor (EGFR) have been shown to play a significant role in the pathogenesis of glioblastoma. In our study, the EGFR was stimulated with EGF in human U138 glioblastoma cells. We show that the activated mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 pathway phosphorylated the E twenty-six (ETS)-like transcription factor 1 (Elk-1) mainly at serine 383 residue. Mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, UO126 and ERK inhibitor II, FR180204 blocked the Elk-1 phosphorylation and activation. The phosphatidylinositide-3-OH kinase (PI3K)/Akt pathway was also involved in the Elk-1 activation. Activation of the Elk-1 led to an increased survival and a proliferative response with the EGF stimulation in the U138 glioblastoma cells. Knocking-down the Elk-1 using an RNA interference technique caused a decrease in survival of the unstimulated U138 glioblastoma cells and also decreased the proliferative response to the EGF stimulation. The Elk-1 transcription factor was important for the survival and proliferation of U138 glioblastoma cells upon the stimulation of EGFR with EGF. The MAPK/ERK1/2 and PI3K/Akt pathways regulated this response via activation of the Elk-1 transcription factor. The Elk-1 may be one of the convergence points for pathways located downstream of EGFR in glioblastoma cells. Utilization of the Elk-1 as a therapeutic target may lead to a novel strategy in treatment of glioblastoma.
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Affiliation(s)
- Melike Mut
- Hacettepe University Department of Neurosurgery, Institute of Neurological Sciences and Psychiatry, 06100 Ankara, Turkey.
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Kim Y, Kim SH, Kim YS, Lee YH, Ha K, Shin SY. Imipramine activates glial cell line-derived neurotrophic factor via early growth response gene 1 in astrocytes. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:1026-32. [PMID: 21354245 DOI: 10.1016/j.pnpbp.2011.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/17/2011] [Accepted: 02/17/2011] [Indexed: 01/08/2023]
Abstract
Recent evidence has suggested that deficits in glial plasticity contribute to the pathophysiology of depressive disorders. The present study explored early growth response 1 (EGR-1) transcriptional regulation of imipramine-induced glial cell line-derived neurotrophic factor (GDNF) expression in astrocytes. After we observed the induction of GDNF mRNA expression in rat astrocytes in response to imipramine, deletion mutant studies showed that the proximal region between -493 and -114 of the GDNF promoter, which contains three binding sites for EGR-1, was essential for maximal imipramine-induced activation of GDNF promoter. The dose-dependent upregulation of EGR-1 by imipramine, the activation of GDNF by the over-expression of EGR-1 without imipramine and the reduction in the imipramine-induced GDNF mRNA expression after silencing of endogenous EGR-1 demonstrated that EGR-1 is upregulated by imipramine to activate the GDNF promoter. Furthermore, imipramine-induced GDNF mRNA expression was strongly attenuated in primary astrocytes from Egr-1(-/-) mice, and the immunoreactivity to an anti-GDNF antibody in glial fibrillary acidic protein-positive cells was lower in imipramine-treated astrocytes from Egr-1(-/-) mice than in those from Egr-1(+/-) mice. To determine whether mitogen-activated protein kinases (MAPKs) were associated with imipramine-induced EGR-1 expression, we examined the induction of MAPK phosphorylation in response to imipramine. Pretreatment of rat primary astrocytes with the MAPK kinase inhibitor U0126 or the JNK inhibitor SP600125 strongly inhibited imipramine-stimulated EGR-1 expression. In conclusion, we found that imipramine induction of EGR-1 upregulated GDNF in astrocytes in a dose-dependent manner. This upregulation may occur through the MEK/ERK and JNK MAPK pathways, which suggests a new therapeutic mechanism of action for depressive disorders.
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Affiliation(s)
- Yeni Kim
- Department of Adolescent Psychiatry, National Center for Child and Adolescent Psychiatry, Seoul National Hospital, Seoul 143-711, Republic of Korea
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Park HG, Kim SH, Kim HS, Ahn YM, Kang UG, Kim YS. Repeated electroconvulsive seizure treatment in rats reduces inducibility of early growth response genes and hyperactivity in response to cocaine administration. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:1014-21. [PMID: 21334415 DOI: 10.1016/j.pnpbp.2011.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/28/2011] [Accepted: 02/11/2011] [Indexed: 12/27/2022]
Abstract
Regulated expression of immediate early genes (IEGs) in the brain reflects neuronal activity in response to various stimuli and recruits specific gene programs involved in long-term neuronal modification and behavioral alterations. Repeated electroconvulsive seizure (ECS) treatment reduces the expression level of several IEGs, such as c-fos, which play important roles in psychostimulant-induced behavioral changes. In this study, we investigated the effects of repeated ECS treatment on the basal expression level of IEGs and its effects on cocaine-induced activation of IEGs and locomotor activity in rats. Repeated ECS treatment for 10days (E10×) reduced Egr1, Egr2, Egr3, and c-fos mRNA and protein levels in the rat frontal cortex at 24h after the last ECS treatment, and these changes were evident in the neuronal cells of the prefrontal cortex. In particular, downregulation of Egr1 and c-fos was evident until 5days after the last ECS treatment. Moreover, E10× pretreatment attenuated the cocaine-induced increase in Egr1, Egr2, and c-fos expression in the rat frontal cortex, whereas phosphorylation of ERK1/2, one of the representative upstream activators of these genes, increased significantly following cocaine treatment. Additionally, E10× pretreatment attenuated the increase in locomotor activity in response to a cocaine injection. In conclusion, repeated ECS treatment reduced the expression and inducibility of Egrs and c-fos, which could attenuate the response of the brain to psychostimulants.
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Affiliation(s)
- Hong Geun Park
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
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Abstract
BACKGROUND As a result of amitriptyline's vast array of actions, it could potentially be used as an intraspinal adjuvant in neuraxial anesthesia and/or in the treatment of refractory neuropathic pain. None of the previous studies examining the safety profile of intraspinal single doses of amitriptyline found signs of toxicity at concentrations below 15.4 mM/L (0.5%) and the current hypothesis regarding the pathophysiology of amitriptyline toxicity suggests it might be safe at low concentrations while still having relevant clinical effects. Hence, we conducted this study to assess the clinical and histological toxicity of intraspinal amitriptyline at the lowest dosages previously known to be effective. METHODS Twenty-one dogs were randomized to receive a 1-mL single intraspinal dose of one of the three solutions: saline (0.9%), amitriptyline (0.15%), or amitriptyline (0.3%). The dogs were evaluated clinically 1 h after awakening from anesthesia and 21 days later. At 21 days, all animals were killed, and histological sections of the spinal cord and surrounding meninges were retrieved for analysis. RESULTS All dogs recovered motor function, anal sphincter tone and sensibility. With the exception of one dog in the 0.15% amitriptyline group, all animals in both amitriptyline groups had marked adhesive arachnoiditis, which was absent in the control group. No evidence of direct neural damage was found on histological sections stained by glial fibrillary acidic protein technique in any of the study animals. CONCLUSION The intraspinal administration of amitriptyline to dogs even in low concentrations is strongly associated with the development of intense meningeal adhesive arachnoiditis and is not safe even at low concentrations for which there was no previous evidence of toxicity.
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Shin SY, Song H, Kim CG, Choi YK, Lee KS, Lee SJ, Lee HJ, Lim Y, Lee YH. Egr-1 is necessary for fibroblast growth factor-2-induced transcriptional activation of the glial cell line-derived neurotrophic factor in murine astrocytes. J Biol Chem 2009; 284:30583-93. [PMID: 19721135 DOI: 10.1074/jbc.m109.010678] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glial cell line-derived neurotrophic factor (Gdnf) promotes neurite outgrowth and survival of neuronal cells, but its transcriptional regulation is poorly understood. Here, we sought to investigate the mechanism underlying fibroblast growth factor-2 (FGF2) induction of Gdnf expression in astrocytes. We found that FGF2 stimulation of rat astrocytes induced expression of Egr-1 at a high level. Sequence analysis of the rat Gdnf gene identified three overlapping Egr-1-binding sites between positions -185 and -163 of the rat Gdnf promoter. Transfection studies using a series of deleted Gdnf promoters revealed that these Egr-1-binding sites are required for maximal activation of the Gdnf promoter by FGF2. Chromatin immunoprecipitation analysis indicated that Egr-1 binds to the Gdnf promoter. Furthermore, the induction of Gdnf expression by FGF2 is strongly attenuated both in C6 glioma cells stably expressing Egr-1-specific small interfering RNA and in primary cultured astrocytes from the Egr-1 knock-out mouse. Additionally, we found that stimulation of the ERK and JNK pathways by FGF2 is functionally linked to Gdnf expression through the induction of Egr-1. These data demonstrate that FGF2-induced Gdnf expression is mediated by the induction of Egr-1 through activation of the ERK and JNK/Elk-1 signaling pathways.
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Affiliation(s)
- Soon Young Shin
- Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology, Konkuk University Hospital, Seoul 143-729, Korea
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