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Demori I, Losacco S, Giordano G, Mucci V, Blanchini F, Burlando B. Fibromyalgia pathogenesis explained by a neuroendocrine multistable model. PLoS One 2024; 19:e0303573. [PMID: 38990866 DOI: 10.1371/journal.pone.0303573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/26/2024] [Indexed: 07/13/2024] Open
Abstract
Fibromyalgia (FM) is a central disorder characterized by chronic pain, fatigue, insomnia, depression, and other minor symptoms. Knowledge about pathogenesis is lacking, diagnosis difficult, clinical approach puzzling, and patient management disappointing. We conducted a theoretical study based on literature data and computational analysis, aimed at developing a comprehensive model of FM pathogenesis and addressing suitable therapeutic targets. We started from the evidence that FM must involve a dysregulation of central pain processing, is female prevalent, suggesting a role for the hypothalamus-pituitary-gonadal (HPG) axis, and is stress-related, suggesting a role for the HP-adrenocortical (HPA) axis. Central pathogenesis was supposed to involve a pain processing loop system including the thalamic ventroposterolateral nucleus (VPL), the primary somatosensory cortex (SSC), and the thalamic reticular nucleus (TRN). For decreasing GABAergic and/or increasing glutamatergic transmission, the loop system crosses a bifurcation point, switching from monostable to bistable, and converging on a high-firing-rate steady state supposed to be the pathogenic condition. Thereafter, we showed that GABAergic transmission is positively correlated with gonadal-hormone-derived neurosteroids, notably allopregnanolone, whereas glutamatergic transmission is positively correlated with stress-induced glucocorticoids, notably cortisol. Finally, we built a dynamic model describing a multistable, double-inhibitory loop between HPG and HPA axes. This system has a high-HPA/low-HPG steady state, allegedly reached in females under combined premenstrual/postpartum brain allopregnanolone withdrawal and stress condition, driving the thalamocortical loop to the high-firing-rate steady state, and explaining the connection between endocrine and neural mechanisms in FM pathogenesis. Our model accounts for FM female prevalence and stress correlation, suggesting the use of neurosteroid drugs as a possible solution to currently unsolved problems in the clinical treatment of the disease.
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Affiliation(s)
- Ilaria Demori
- Department of Pharmacy, DIFAR, University of Genova, Genova, Italy
| | - Serena Losacco
- Department of Pharmacy, DIFAR, University of Genova, Genova, Italy
| | - Giulia Giordano
- Department of Industrial Engineering, University of Trento, Trento, (TN), Italy
- Delft Center for Systems and Control, Delft University of Technology, Delft, The Netherlands
| | - Viviana Mucci
- School of Science, Western Sydney University, Penrith, Australia
| | - Franco Blanchini
- Department of Mathematics, Computer Science and Physics, University of Udine, Udine, Italy
| | - Bruno Burlando
- Department of Pharmacy, DIFAR, University of Genova, Genova, Italy
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Sun C, Zhu H, Clark S, Gouaux E. Cryo-EM structures reveal native GABA A receptor assemblies and pharmacology. Nature 2023; 622:195-201. [PMID: 37730991 PMCID: PMC10550821 DOI: 10.1038/s41586-023-06556-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 08/21/2023] [Indexed: 09/22/2023]
Abstract
Type A γ-aminobutyric acid receptors (GABAARs) are the principal inhibitory receptors in the brain and the target of a wide range of clinical agents, including anaesthetics, sedatives, hypnotics and antidepressants1-3. However, our understanding of GABAAR pharmacology has been hindered by the vast number of pentameric assemblies that can be derived from 19 different subunits4 and the lack of structural knowledge of clinically relevant receptors. Here, we isolate native murine GABAAR assemblies containing the widely expressed α1 subunit and elucidate their structures in complex with drugs used to treat insomnia (zolpidem (ZOL) and flurazepam) and postpartum depression (the neurosteroid allopregnanolone (APG)). Using cryo-electron microscopy (cryo-EM) analysis and single-molecule photobleaching experiments, we uncover three major structural populations in the brain: the canonical α1β2γ2 receptor containing two α1 subunits, and two assemblies containing one α1 and either an α2 or α3 subunit, in which the single α1-containing receptors feature a more compact arrangement between the transmembrane and extracellular domains. Interestingly, APG is bound at the transmembrane α/β subunit interface, even when not added to the sample, revealing an important role for endogenous neurosteroids in modulating native GABAARs. Together with structurally engaged lipids, neurosteroids produce global conformational changes throughout the receptor that modify the ion channel pore and the binding sites for GABA and insomnia medications. Our data reveal the major α1-containing GABAAR assemblies, bound with endogenous neurosteroid, thus defining a structural landscape from which subtype-specific drugs can be developed.
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Affiliation(s)
- Chang Sun
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Hongtao Zhu
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Sarah Clark
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA.
- Howard Hughes Medical Institute, Oregon Health and Science University, Portland, OR, USA.
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Sun C, Zhu H, Clark S, Gouaux E. Regulated assembly and neurosteroid modulation constrain GABA A receptor pharmacology in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528867. [PMID: 36824901 PMCID: PMC9949137 DOI: 10.1101/2023.02.16.528867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Type A GABA receptors (GABA A Rs) are the principal inhibitory receptors in the brain and the target of a wide range of clinical agents, including anesthetics, sedatives, hypnotics, and antidepressants. However, our understanding of GABA A R pharmacology has been hindered by the vast number of pentameric assemblies that can be derived from a total 19 different subunits and the lack of structural knowledge of clinically relevant receptors. Here, we isolate native murine GABA A R assemblies containing the widely expressed α 1 subunit, and elucidate their structures in complex with drugs used to treat insomnia (zolpidem and flurazepam) and postpartum depression (the neurosteroid allopregnanolone). Using cryo-EM analysis and single-molecule photobleaching experiments, we uncover only three structural populations in the brain: the canonical α 1 β2γ 2 receptor containing two α 1 subunits and two unanticipated assemblies containing one α 1 and either an α 2 , α 3 or α 5 subunit. Both of the noncanonical assemblies feature a more compact arrangement between the transmembrane and extracellular domains. Interestingly, allopregnanolone is bound at the transmembrane α/β subunit interface, even when not added to the sample, revealing an important role for endogenous neurosteroids in modulating native GABA A Rs. Together with structurally engaged lipids, neurosteroids produce global conformational changes throughout the receptor that modify both the pore diameter and binding environments for GABA and insomnia medications. Together, our data reveal that GABA A R assembly is a strictly regulated process that yields a small number of structurally distinct complexes, defining a structural landscape from which subtype-specific drugs can be developed.
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Zamora-Sánchez CJ, Camacho-Arroyo I. Allopregnanolone: Metabolism, Mechanisms of Action, and Its Role in Cancer. Int J Mol Sci 2022; 24:ijms24010560. [PMID: 36614002 PMCID: PMC9820109 DOI: 10.3390/ijms24010560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/17/2022] [Accepted: 12/17/2022] [Indexed: 12/30/2022] Open
Abstract
Allopregnanolone (3α-THP) has been one of the most studied progesterone metabolites for decades. 3α-THP and its synthetic analogs have been evaluated as therapeutic agents for pathologies such as anxiety and depression. Enzymes involved in the metabolism of 3α-THP are expressed in classical and nonclassical steroidogenic tissues. Additionally, due to its chemical structure, 3α-THP presents high affinity and agonist activity for nuclear and membrane receptors of neuroactive steroids and neurotransmitters, such as the Pregnane X Receptor (PXR), membrane progesterone receptors (mPR) and the ionotropic GABAA receptor, among others. 3α-THP has immunomodulator and antiapoptotic properties. It also induces cell proliferation and migration, all of which are critical processes involved in cancer progression. Recently the study of 3α-THP has indicated that low physiological concentrations of this metabolite induce the progression of several types of cancer, such as breast, ovarian, and glioblastoma, while high concentrations inhibit it. In this review, we explore current knowledge on the metabolism and mechanisms of action of 3α-THP in normal and tumor cells.
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Wang T, Ye X, Bian W, Chen Z, Du J, Li M, Zhou P, Cui H, Ding YQ, Qi S, Liao M, Sun C. Allopregnanolone Modulates GABAAR-Dependent CaMKIIδ3 and BDNF to Protect SH-SY5Y Cells Against 6-OHDA-Induced Damage. Front Cell Neurosci 2020; 13:569. [PMID: 31998078 PMCID: PMC6970471 DOI: 10.3389/fncel.2019.00569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022] Open
Abstract
Allopregnanolone (APα), as a functional neurosteroid, exhibits the neuroprotective effect on neurodegenerative diseases such as Parkinson’s disease (PD) through γ-aminobutyric acid A receptor (GABAAR), but it has not been completely understood about its molecular mechanisms. In order to investigate the neuroprotective effect of APα, as well as to clarify its possible molecular mechanisms, SH-SY5Y neuronal cell lines were incubated with 6-hydroxydopamine (6-OHDA), which has been widely used as an in vitro model for PD, along with APα alone or in combination with GABAAR antagonist (bicuculline, Bic), intracellular Ca2+ chelator (EGTA) and voltage-gated L-type Ca2+ channel blocker (Nifedipine). The viability, proliferation, and differentiation of SH-SY5Y cells, the expression levels of calmodulin (CaM), Ca2+/calmodulin-dependent protein kinase II δ3 (CaMKIIδ3), cyclin-dependent kinase-1 (CDK1) and brain-derived neurotrophic factor (BDNF), as well as the interaction between CaMKIIδ3 and CDK1 or BDNF, were detected by morphological and molecular biological methodology. Our results found that the cell viability and the number of tyrosine hydroxylase (TH), bromodeoxyuridine (BrdU) and TH/BrdU-positive cells in 6-OHDA-treated SH-SY5Y cells were significantly decreased with the concomitant reduction in the expression levels of aforementioned proteins, which were ameliorated following APα administration. In addition, Bic could further increase the number of TH or BrdU-positive cells as well as the expression levels of aforementioned proteins except for TH/BrdU-double positive cells, while EGTA and Nifedipine could attenuate the expression levels of CaM, CaMKIIδ3 and BDNF. Moreover, there existed a direct interaction between CaMKIIδ3 and CDK1 or BDNF. As a result, APα-induced an increase in the number of TH-positive SH-SY5Y cells might be mediated through GABAAR via Ca2+/CaM/CaMKIIδ3/BDNF (CDK1) signaling pathway, which would ultimately facilitate to elucidate PD pathogenesis and hold a promise as an alternative therapeutic target for PD.
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Affiliation(s)
- Tongtong Wang
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xin Ye
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Wei Bian
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Zhichi Chen
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Juanjuan Du
- Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Department of Histology and Embryology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Mengyi Li
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Peng Zhou
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Huairui Cui
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yu-Qiang Ding
- Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Shuangshuang Qi
- Department of Pharmacy, Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Min Liao
- Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Department of Histology and Embryology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Chenyou Sun
- Department of Anatomy, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Neuroscience, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
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Morrison KE, Cole AB, Thompson SM, Bale TL. Brexanolone for the treatment of patients with postpartum depression. Drugs Today (Barc) 2019; 55:537-544. [PMID: 31584571 PMCID: PMC8033597 DOI: 10.1358/dot.2019.55.9.3040864] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
On March 19, 2019, the United States Food and Drug Administration (FDA) approved Zulresso (brexanolone) for intravenous use for the treatment of postpartum depression (PPD) in adult women. The decision was based on three recent clinical trials following an FDA priority review and breakthrough therapy designation. Brexanolone is now available through a restricted process called the Zulresso Risk Evaluation and Mitigation Strategy Program that requires the drug to be administered by a healthcare provider in a certified healthcare facility. Brexanolone represents an important new treatment option to address treatment-resistant depressive symptoms. In this article, we discuss the current critical need for PPD treatments, the mechanisms of brexanolone action, and the efficacy and drug safety studies that led to FDA approval. Additionally, we discuss some limitations of the current formulation, specific populations of women that might benefit from this treatment, and how new drugs on the horizon may increase the ability to treat PPD in a variety of patient populations.
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Affiliation(s)
- K E Morrison
- Departments of Pharmacology and Psychiatry and Center for Epigenetic Research in Child Health and Brain Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - A B Cole
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - S M Thompson
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - T L Bale
- Departments of Pharmacology and Psychiatry and Center for Epigenetic Research in Child Health and Brain Development, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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Tanaka M, Ogaeri T, Samsonov M, Sokabe M. The 5α-Reductase Inhibitor Finasteride Exerts Neuroprotection Against Ischemic Brain Injury in Aged Male Rats. Transl Stroke Res 2018; 10:67-77. [PMID: 29574659 DOI: 10.1007/s12975-018-0624-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 01/24/2018] [Accepted: 03/14/2018] [Indexed: 11/29/2022]
Abstract
Progesterone (P4) exerts potent neuroprotection both in young and aged animal models of stroke. The neuroprotection is likely to be mediated by allopregnanolone (ALLO) metabolized from P4 by 5α-reductase, since the neuroprotection is attenuated by the 5α-reductase inhibitor finasteride, which was done only with young animals though. Thus, we do not know the contribution of ALLO to the P4-induced neuroprotection in aged animals. We examined effects of finasteride on the P4-induced neuroprotection in aged (16-18-month-old) male rats subjected to transient focal cerebral ischemia. Transient focal cerebral ischemia was induced by left middle cerebral artery occlusion (MCAO) and occlusion of the bilateral common carotid arteries. MCAO rats were given an 8 mg/kg P4 6 h after MCAO followed by the same treatment once a day for successive 3 days. Finasteride, a 5α-reductase inhibitor, at 20 mg/kg was intraperitoneally injected 30 min prior to the P4-injections. P4 markedly reduced neuronal damage 72 h after MCAO, and the P4-induced neuroprotection was apparently suppressed by finasteride in the aged animals. However, post-ischemic administration of finasteride alone (20 mg/kg) significantly prevented neuronal damage and the impairment of Rotarod performance after MCAO in aged male rats, but not in young ones. The androgen receptor antagonist flutamide markedly suppressed the neuroprotection of finasteride in the cerebral cortex, but not in the striatum, suggesting the androgen receptor-dependent mechanism of the finasteride-induced neuroprotection in the cerebral cortex. Our findings suggested, for the first time, the potential of finasteride as a therapeutic agent in post-ischemic treatment of strokes in aged population.
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Affiliation(s)
- Motoki Tanaka
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Takunori Ogaeri
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan
| | | | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
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Johansson M, Strömberg J, Ragagnin G, Doverskog M, Bäckström T. GABAA receptor modulating steroid antagonists (GAMSA) are functional in vivo. J Steroid Biochem Mol Biol 2016; 160:98-105. [PMID: 26523675 DOI: 10.1016/j.jsbmb.2015.10.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/16/2015] [Accepted: 10/25/2015] [Indexed: 12/18/2022]
Abstract
GABAA receptor modulating steroid antagonists (GAMSA) selectively inhibit neurosteroid-mediated enhancement of GABA-evoked currents at the GABAA receptor. 3α-hydroxy-neurosteroids, notably allopregnanolone and tetrahydrodeoxycorticosterone (THDOC), potentiate GABAA receptor-mediated currents. On the contrary, various 3β-hydroxy-steroids antagonize this positive neurosteroid-mediated modulation. Importantly, GAMSAs are specific antagonists of the positive neurosteroid-modulation of the receptor and do not inhibit GABA-evoked currents. Allopregnanolone and THDOC have both negative and positive actions. Allopregnanolone can impair encoding/consolidation and retrieval of memories. Chronic administration of a physiological allopregnanolone concentration reduces cognition in mice models of Alzheimer's disease. In humans an allopregnanolone challenge impairs episodic memory and in hepatic encephalopathy cognitive deficits are accompanied by increased brain ammonia and allopregnanolone. Hippocampal slices react in vitro to ammonia by allopregnanolone synthesis in CA1 neurons, which blocks long-term potentiation (LTP). Thus, allopregnanolone may impair learning and memory by interfering with hippocampal LTP. Contrary, pharmacological treatment with allopregnanolone can promote neurogenesis and positively influence learning and memory of trace eye-blink conditioning in mice. In rat the GAMSA UC1011 inhibits an allopregnanolone-induced learning impairment and the GAMSA GR3027 restores learning and motor coordination in rats with hepatic encephalopathy. In addition, the GAMSA isoallopregnanolone antagonizes allopregnanolone-induced anesthesia in rats, and in humans it antagonizes allopregnanolone-induced sedation and reductions in saccadic eye velocity. 17PA is also an effective GAMSA in vivo, as it antagonizes allopregnanolone-induced anesthesia and spinal analgesia in rats. In vitro the allopregnanolone/THDOC-increased GABA-mediated GABAA receptor activity is antagonized by isoallopregnanolone, UC1011, GR3027 and 17PA, while the effect of GABA itself is not affected.
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Affiliation(s)
- Maja Johansson
- Umeå Neurosteroid research center, Obstetrics and Gynecology, Clinical Sciences at Umeå University, Building 6M, 4th floor at NUS, SE-901 85 Umeå, Sweden; Umecrine Cognition AB, Sweden.
| | - Jessica Strömberg
- Umeå Neurosteroid research center, Obstetrics and Gynecology, Clinical Sciences at Umeå University, Building 6M, 4th floor at NUS, SE-901 85 Umeå, Sweden
| | - Gianna Ragagnin
- Umeå Neurosteroid research center, Obstetrics and Gynecology, Clinical Sciences at Umeå University, Building 6M, 4th floor at NUS, SE-901 85 Umeå, Sweden
| | | | - Torbjörn Bäckström
- Umeå Neurosteroid research center, Obstetrics and Gynecology, Clinical Sciences at Umeå University, Building 6M, 4th floor at NUS, SE-901 85 Umeå, Sweden
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López-Griego L, Nava-Castro KE, López-Salazar V, Hernández-Cervantes R, Tiempos Guzmán N, Muñiz-Hernández S, Hernández-Bello R, Besedovsky HO, Pavón L, Becerril Villanueva LE, Morales-Montor J. Gender-associated differential expression of cytokines in specific areas of the brain during helminth infection. J Interferon Cytokine Res 2014; 35:116-25. [PMID: 25495255 DOI: 10.1089/jir.2013.0141] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Intraperitoneal infection with Taenia crassiceps cysticerci in mice alters several behaviors, including sexual, aggressive, and cognitive function. Cytokines and their receptors are produced in the central nervous system (CNS) by specific neural cell lineages under physiological and pathological conditions, regulating such processes as neurotransmission. This study is aimed to determine the expression patterns of cytokines in various areas of the brain in normal and T. crassiceps-infected mice in both genders and correlate them with the pathology of the CNS and parasite counts. IL-4, IFN-γ, and TNF-α levels in the hippocampus and olfactory bulb increased significantly in infected male mice, but IL-6 was downregulated in these regions in female mice. IL-1β expression in the hippocampus was unaffected by infection in either gender. Our novel findings demonstrate a clear gender-associated pattern of cytokine expression in specific areas of the brain in mammals that parasitic infection can alter. Thus, we hypothesize that intraperitoneal infection is sensed by the CNS of the host, wherein cytokines are important messengers in the host-parasite neuroimmunoendocrine network.
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Affiliation(s)
- Lorena López-Griego
- 1 Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, México
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Dolgun H, Turkoglu E, Kertmen H, Gurer B, Yilmaz ER, Comoglu SS, Sekerci Z. Gabapentin versus pregabalin in relieving early post-surgical neuropathic pain in patients after lumbar disc herniation surgery: a prospective clinical trial. Neurol Res 2014; 36:1080-5. [PMID: 24938318 DOI: 10.1179/1743132814y.0000000404] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES The roles of gabapentin and pregabalin are well established in the management of chronic neuropathic pain. Here, we investigated the effectiveness of pregabalin and gabapentin for treating acute neuropathic pain following lumbar discectomy. METHODS This prospective, non-randomized, and observational study included 54 patients who experienced acute neuropathic pain after lumbar discectomy. The assessments included the Leeds assessment of neuropathic symptoms and signs scale (LANSS), the Oswestry disability index (ODI), and the visual analog scale (VAS) pre-operatively and at 3 days, 6 months, and 1 year after surgery. The LANSS scores ≧12 suggest the presence of neuropathic pain. Those patients who reported neuropathic pain were randomly treated with gabapentin or pregabalin. RESULTS In the gabapentin group, the LANSS scores increased to 14 at 3 days after surgery. The patients improved neurologically and on the LANSS, which decreased to 10 points 6 months after surgery and to 4 points at 1 year (P < 0.001). In the pregabalin group, the LANSS scores increased from 12 to 16 points on post-operative day 3 and then decreased to 12 and 5 at the 6-month and 1-year follow-ups, respectively (both P < 0.001). The ODI and VAS scores significantly improved in both groups (P < 0.001). DISCUSSION Many patients may suffer from neuropathic pain in the early post-surgical period after lumbar discectomy. Gabapentin and pregabalin are anticonvulsant agents that may decrease perioperative central sensitization and early post-surgical neuropathic pain. Gabapentin and pregabalin effectively relieved neuropathic pain and prevented the conversion of acute pain to chronic pain at the 1-year follow-up after lumbar discectomy.
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Effect of acute ethanol and acute allopregnanolone on spatial memory in adolescent and adult rats. Alcohol 2011; 45:473-83. [PMID: 21600728 DOI: 10.1016/j.alcohol.2011.03.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 02/17/2011] [Accepted: 03/02/2011] [Indexed: 11/20/2022]
Abstract
The effects of ethanol differ in adolescent and adult rats on a number of measures. The evidence of the effects of ethanol on spatial memory in adolescents and adults is equivocal. Whether adolescents are more or less sensitive to ethanol-induced impairment of spatial memory acquisition remains unclear; with regard to the effects of acute ethanol on spatial memory retrieval there is almost no research looking into any age difference. Thus, we examined the effects of acute ethanol on spatial memory in the Morris Watermaze in adolescents and adults. Allopregnanolone (ALLO) is a modulator of the GABA(A) receptor and has similar behavioral effects as ethanol. We sought to also determine the effects of allopreganolone on spatial memory in adolescent and adults. Male adolescent (post natal [PN]28-30) and adult (PN70-72) rats were trained in the Morris Watermaze for 6 days and acute doses of ethanol (saline, 1.5 and 2.0 g/kg) or ALLO (vehicle, 9 and 18 mg/kg) were administered on Day 7. A probe trial followed on Day 8. As expected, there were dose effects; higher doses of both ethanol and ALLO impaired spatial memory. However, in both the ethanol and ALLO conditions adolescents and adults had similar spatial memory impairments. The current results suggest that ethanol and ALLO both impair hippocampal-dependent spatial memory regardless of age in that once learning has occurred, ethanol or ALLO does not differentially impair the retrieval of spatial memory in adolescents and adults. Given the mixed results on the effect of ethanol on cognition in adolescent rats, additional research is needed to ascertain the factors critical for the reported differential results.
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Giuliani FA, Yunes R, Mohn CE, Laconi M, Rettori V, Cabrera R. Allopregnanolone induces LHRH and glutamate release through NMDA receptor modulation. Endocrine 2011; 40:21-6. [PMID: 21455639 DOI: 10.1007/s12020-011-9451-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 02/25/2011] [Indexed: 11/27/2022]
Abstract
LHRH release from hypothalamus is influenced by the neurotransmitter glutamate that acts, among others, on NMDA receptors present in LHRH neurons. On the other hand, the neurosteroid allopregnanolone can modulate the activity of specific neurotransmitter receptors and affect neurotransmitter release. We examined the role of allopregnanolone on in vitro LHRH and glutamate release from mediobasal hypothalamus and anterior preoptic area of ovariectomized rats with estrogen and progesterone replacement. Moreover, we evaluated whether the neurosteroid might act through modulation of NMDA receptors. Allopregnanolone induced an increase in LHRH release. This effect was reversed when the NMDA receptors were blocked by the NMDA antagonist 2-amino-7-phosphonoheptanoic acid (AP-7) indicating that this neurosteroid would interact with NMDA receptors. Moreover allopregnanolone induced an augment in K(+) evoked [(3)H]-glutamate release from mediobasal hypothalamus-anterior preoptic area explants and this effect was also reversed when NMDA receptors were blocked with AP-7. These results suggest an important physiologic function of allopregnanolone on the regulation of neuroendocrine function in female adult rats. Not only appears to be involved in enhancing LHRH release through modulation of NMDA receptors but also in the release of glutamate which is critical in the control of LHRH release.
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Affiliation(s)
- Fernando A Giuliani
- Instituto de Investigaciones Biomédicas, Universidad de Mendoza, IMBECU-CONICET, Paseo Dr. Emilio Descotte 720, 5500, Mendoza, Argentina
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Sabeti J. Ethanol exposure in early adolescence inhibits intrinsic neuronal plasticity via sigma-1 receptor activation in hippocampal CA1 neurons. Alcohol Clin Exp Res 2011; 35:885-904. [PMID: 21314692 PMCID: PMC3083503 DOI: 10.1111/j.1530-0277.2010.01419.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND We demonstrated previously that rats exposed to chronic intermittent ethanol (CIE) vapors in early adolescence show increased magnitudes of long-term potentiation (LTP) of excitatory transmission when recorded at dendritic synapses in hippocampus. Large amplitude LTP following CIE exposure is mediated by sigma-1 receptors; however, not yet addressed is the role of sigma-1 receptors in modulating the intrinsic properties of neurons to alter their action potential firing during LTP. METHODS Activity-induced plasticity of spike firing was investigated using rat hippocampal slice recordings to measure changes in both field excitatory postsynaptic potentials (fEPSPs) and population spikes (pop. spikes) concomitantly at dendritic inputs and soma of CA1 pyramidal neurons, respectively. RESULTS We observed unique modifications in plasticity of action potential firing in hippocampal slices from CIE exposed adolescent rats, where the induction of large amplitude LTP by 100 Hz stimulations was accompanied by reduced CA1 neuronal excitability--reflected as decreased pop. spike efficacy and impaired activity-induced fEPSP-to-spike (E-S) potentiation. In contrast, LTP induction in ethanol-naïve control slices resulted in increased spike efficacy and robust E-S potentiation. E-S potentiation impairments emerged at 24 hours after CIE treatment cessation, but not before the alcohol withdrawal period, and were restored with bath-application of the sigma-1 receptor selective antagonist BD1047, but not the NMDA receptor antagonist d-AP5. Further evidence revealed a significantly shortened somatic fEPSP time course in adolescent CIE-withdrawn hippocampal slices during LTP; however, paired-pulse data show no apparent correspondence between E-S dissociation and altered recurrent feedback inhibition. CONCLUSIONS Results here suggest that acute withdrawal from adolescent CIE exposure triggers sigma-1 receptors that act to depress the efficacy of excitatory inputs in triggering action potentials during LTP. Such withdrawal-induced depression of E-S plasticity in hippocampus probably entails sigma-1 receptor modulation of 1 or several voltage-gated ion channels controlling the neuronal input-output dynamics.
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Affiliation(s)
- Jilla Sabeti
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, La Jolla, California, USA.
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A mutant residue in the third transmembrane region of the GABA(A) alpha1 subunit causes increased agonistic neurosteroid responses. Neurochem Int 2011; 58:794-803. [PMID: 21397651 DOI: 10.1016/j.neuint.2011.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 03/02/2011] [Accepted: 03/05/2011] [Indexed: 11/24/2022]
Abstract
Pregnane derived steroids have agonistic and antagonistic actions at GABA(A) receptors. Putative binding sites for agonistic neurosteroids are located within the transmembrane (TM) regions. A mutation within the rat α(1) TM3 region, S299C, caused the expressed receptors to have unusual and extreme sensitivity to agonistic neurosteroids. For mutant α1S299C receptors, with wild type β and γ subunits, expressed in Xenopus oocytes, steroids activated the GABA(A) receptors in the absence of GABA. Maximal steroid induced currents were about half of maximal GABA currents. The steroid activation was biphasic with EC(50)'s much lower than wild type, in subnanomolar and nanomolar concentrations, while the wild type had only one activation peak with near micromolar EC(50). These currents could be blocked by both picrotoxin and an antagonist neurosteroid. The steroids did not seem to potentiate significantly submaximal GABA currents. The α1S299C mutation did not affect responses to the extracellularly acting partial agonist piperidine-4-sulfate. Substituted cysteine experiments indicate that this mutant can be modified by pCMBS(-) when the sulfhydryl reagent is added with the higher steroid concentration for activation but not the lower steroid concentration. The pCMBS(-) will also immediately block the high concentration steroid current. Taken together the data suggest that α1S299 is important in at least the in transduction of the steroid binding to the rest of the receptor.
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15
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Hengen KB, Behan M, Carey HV, Jones MV, Johnson SM. Hibernation induces pentobarbital insensitivity in medulla but not cortex. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1028-36. [PMID: 19675281 DOI: 10.1152/ajpregu.00239.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 13-lined ground squirrel (Ictidomys tridecemlineatus), a hibernating species, is a natural model of physiological adoption to an extreme environment. During torpor, body temperature drops to 0-4 degrees C, and the cortex is electrically silent, yet the brain stem continues to regulate cardiorespiratory function. The mechanisms underlying selective inhibition in the brain during torpor are not known. To test whether altered GABAergic function is involved in regional and seasonal differences in neuronal activity, cortical and medullary slices from summer-active (SA) and interbout aroused (IBA) squirrels were placed in a standard in vitro recording chamber. Silicon multichannel electrodes were placed in cortex, ventral respiratory column (VRC), and nucleus tractus solitarius (NTS) to record spontaneous neuronal activity. In slices from IBA squirrels, bath-applied pentobarbital sodium (300 microM) nearly abolished cortical neuronal activity, but VRC and NTS neuronal activity was unaltered. In contrast, pentobarbital sodium (300 microM) nearly abolished all spontaneous cortical, VRC, and NTS neuronal activity in slices from SA squirrels. Muscimol (20 microM; GABA(A) receptor agonist) abolished all neuronal activity in cortical and medullary slices from both IBA and SA squirrels, thereby demonstrating the presence of functional GABA(A) receptors. Pretreatment of cortical slices from IBA squirrels with bicuculline (100 microM; GABA(A) receptor antagonist) blocked pentobarbital-dependent inhibition of spontaneous neuronal activity. We hypothesize that GABA(A) receptors undergo a seasonal modification in subunit composition, such that cardiorespiratory neurons are uniquely unaffected by surges of an endogenous positive allosteric modulator.
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Affiliation(s)
- Keith B Hengen
- School of Veterinary Medicine, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA
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16
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TYAGI NEETU, GILLESPIE WILLIAM, VACEK JONATHANC, SEN UTPAL, TYAGI SURESHC, LOMINADZE DAVID. Activation of GABA-A receptor ameliorates homocysteine-induced MMP-9 activation by ERK pathway. J Cell Physiol 2009; 220:257-66. [PMID: 19308943 PMCID: PMC2811271 DOI: 10.1002/jcp.21757] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hyperhomocysteinemia (HHcy) is a risk factor for neuroinflammatory and neurodegenerative diseases. Homocysteine (Hcy) induces redox stress, in part, by activating matrix metalloproteinase-9 (MMP-9), which degrades the matrix and leads to blood-brain barrier dysfunction. Hcy competitively binds to gamma-aminbutyric acid (GABA) receptors, which are excitatory neurotransmitter receptors. However, the role of GABA-A receptor in Hcy-induced cerebrovascular remodeling is not clear. We hypothesized that Hcy causes cerebrovascular remodeling by increasing redox stress and MMP-9 activity via the extracellular signal-regulated kinase (ERK) signaling pathway and by inhibition of GABA-A receptors, thus behaving as an inhibitory neurotransmitter. Hcy-induced reactive oxygen species production was detected using the fluorescent probe, 2'-7'-dichlorodihydrofluorescein diacetate. Hcy increased nicotinamide adenine dinucleotide phosphate-oxidase-4 concomitantly suppressing thioredoxin. Hcy caused activation of MMP-9, measured by gelatin zymography. The GABA-A receptor agonist, muscimol ameliorated the Hcy-mediated MMP-9 activation. In parallel, Hcy caused phosphorylation of ERK and selectively decreased levels of tissue inhibitors of metalloproteinase-4 (TIMP-4). Treatment of the endothelial cell with muscimol restored the levels of TIMP-4 to the levels in control group. Hcy induced expression of iNOS and decreased eNOS expression, which lead to a decreased NO bioavailability. Furthermore muscimol attenuated Hcy-induced MMP-9 via ERK signaling pathway. These results suggest that Hcy competes with GABA-A receptors, inducing the oxidative stress transduction pathway and leading to ERK activation.
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Affiliation(s)
- NEETU TYAGI
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - WILLIAM GILLESPIE
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - JONATHAN C. VACEK
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - UTPAL SEN
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - SURESH C. TYAGI
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - DAVID LOMINADZE
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, Kentucky
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17
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Wang JM, Brinton RD. Allopregnanolone-induced rise in intracellular calcium in embryonic hippocampal neurons parallels their proliferative potential. BMC Neurosci 2008; 9 Suppl 2:S11. [PMID: 19090984 PMCID: PMC2604895 DOI: 10.1186/1471-2202-9-s2-s11] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Factors that regulate intracellular calcium concentration are known to play a critical role in brain function and neural development, including neural plasticity and neurogenesis. We previously demonstrated that the neurosteroid allopregnanolone (APα; 5α-pregnan-3α-ol-20-one) promotes neural progenitor proliferation in vitro in cultures of rodent hippocampal and human cortical neural progenitors, and in vivo in triple transgenic Alzheimer's disease mice dentate gyrus. We also found that APα-induced proliferation of neural progenitors is abolished by a calcium channel blocker, nifedipine, indicating a calcium dependent mechanism for the proliferation. Methods In the present study, we investigated the effect of APα on the regulation of intracellular calcium concentration in E18 rat hippocampal neurons using ratiometric Fura2-AM imaging. Results Results indicate that APα rapidly increased intracellular calcium concentration in a dose-dependent and developmentally regulated manner, with an EC50 of 110 ± 15 nM and a maximal response occurring at three days in vitro. The stereoisomers 3β-hydroxy-5α-hydroxy-pregnan-20-one, and 3β-hydroxy-5β-hydroxy-pregnan-20-one, as well as progesterone, were without significant effect. APα-induced intracellular calcium concentration increase was not observed in calcium depleted medium and was blocked in the presence of the broad spectrum calcium channel blocker La3+, or the L-type calcium channel blocker nifedipine. Furthermore, the GABAA receptor blockers bicuculline and picrotoxin abolished APα-induced intracellular calcium concentration rise. Conclusion Collectively, these data indicate that APα promotes a rapid, dose-dependent, stereo-specific, and developmentally regulated increase of intracellular calcium concentration in rat embryonic hippocampal neurons via a mechanism that requires both the GABAA receptor and L-type calcium channel. These data suggest that APα-induced intracellular calcium concentration increase serves as the initiation mechanism whereby APα promotes neurogenesis.
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Affiliation(s)
- Jun Ming Wang
- Department of Pharmacology and Pharmaceutical Sciences and Program in Neuroscience, University of Southern California, Los Angeles, CA 90089, USA.
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18
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Frye CA, Walf AA. In the ventral tegmental area, progestogens' membrane-mediated actions for lordosis of rats involve the second-messenger phospholipase C. Brain Res 2008; 1230:218-23. [PMID: 18671954 DOI: 10.1016/j.brainres.2008.07.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 07/03/2008] [Accepted: 07/08/2008] [Indexed: 11/16/2022]
Abstract
Steroid hormones have pervasive functional effects. Although steroids are generally known to have actions via binding to their cognate steroid receptors, it is becoming clearer that steroids can have non-traditional actions that do not require activation of cognate steroid receptors. We have found that progestogen-facilitated lordosis of rodents is enhanced by activation of dopamine type 1 (D1) or GABA(A) receptors and their downstream effectors, such as second messengers, in the ventral tegmental area (VTA). The role of phospholipase C in these effects is not clear. If progestins' actions through D1 and GABA(A) receptors in the VTA are mediated through PLC, then inhibiting PLC formation in the VTA, via infusions of U73122 (400nM/side), should reduce progestin (5alpha-pregnan-3alpha-ol-20-one; 3alpha,5alpha-THP; 100 or 200ng/side)-facilitated lordosis and its enhancement by D1 (SKF38393; 100ng/side) or GABA(A) (muscimol; 100ng/side) receptor agonists in ovariectomized, estradiol-primed rats. We found that 3alpha,5alpha-THP-, SKF38393-, and muscimol-facilitated lordosis was attenuated by infusions of the PLC inhibitor, U73122, but not vehicle, to the VTA. Thus, progestogens' non-traditional actions in the VTA to enhance lordosis through D1 and/or GABA(A) include activity of PLC.
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Affiliation(s)
- Cheryl A Frye
- Department of Psychology, Research, The University at Albany - SUNY, Albany, NY 12222, USA.
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19
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Miao P, Madec K, Gong Y, Shen H, Eisenstat D, Melanson M, Gu X, Leong C, Klowak M, Namaka M. Axotomy-induced up-regulation of tumor necrosis factor-alpha in the dorsal root ganglia. Neurol Res 2008; 30:623-31. [PMID: 18489817 DOI: 10.1179/174313208x289606] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Neuropathic pain is a chronic pain syndrome associated with drug, injury or disease-induced damage or destruction of sensory afferent fibers of the dorsal root ganglia (DRG). Although the exact underlying pathologic mechanisms are not known, pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) are recognized as potential modulators of peripheral and central nervous system inflammatory responses. They play a crucial role in injury and the pathologic development of chronic pain syndromes such as neuropathic pain. METHODS Twenty-four rats were divided into a naive control (n=6), sham (surgery exposing sciatic nerve, n=6), and peripheral nerve lesion group (unilateral axotomy of sciatic nerve, n=12). RESULTS The results of this study demonstrate a transient up-regulation of TNF-alpha expression within ipsi- and contralateral DRG following complete unilateral sciatic nerve axotomy as confirmed by immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR. Elevated expression of TNF-alpha was noted to occur within the first 7 days post-axotomy, which subsequently normalized to baseline levels by day 14. This transient up-regulation was also associated with a switch in cellular source from predominant satellite cell expression at baseline to that involving satellite cells and abundant numbers of sensory neurons. DISCUSSION These results support the role of TNF-alpha in the upstream cascade of cellular events involved in the underlying pathogenesis of neuropathic pain. Strategies targeting the early attenuation of TNF-alpha within the DRG during the first week post-injury may have significant clinical impact in preventing the downstream cascade of events involved in the underlying cellular pathology of neuropathic pain.
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Affiliation(s)
- Pinhui Miao
- Faculty of Pharmacy, University of Manitoba, Winnipeg, Man., Canada
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20
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Frye CA, Walf AA. In the ventral tegmental area, the membrane-mediated actions of progestins for lordosis of hormone-primed hamsters involve phospholipase C and protein kinase C. J Neuroendocrinol 2007; 19:717-24. [PMID: 17680887 DOI: 10.1111/j.1365-2826.2007.01580.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Progestin-facilitated lordosis of rodents is enhanced by activation of dopamine type 1 (D(1)) or GABA(A) receptors, their downstream G-proteins, and/or second messengers in the ventral tegmental area (VTA). We examined whether the ability of progestins to enhance lordosis via actions at D(1) and/or GABA(A) receptors is contingent upon activation of the second messenger phospholipase C (PLC) and its associated kinase, protein kinase C (PKC), in the VTA. If the actions of progestins through D(1) and GABA(A) receptors in the VTA are mediated through PLC and PKC, then inhibiting PLC formation (Experiment 1) or blocking PKC (Experiment 2) should reduce progestin-facilitated lordosis and its enhancement by D(1) (SKF38393) or GABA(A) (muscimol) receptor agonists. In Experiment 1, ovariectomised hamsters, primed with oestradiol (10 microg; h 0) + progesterone (100 microg; h 45), were pretested for lordosis and motor behaviour (h 48) and then infused with the PLC inhibitor, U73122 (400 nM/side), or vehicle. Thirty minutes later, hamsters were retested and then received infusions of SKF38393 (100 ng/side), muscimol (100 ng/side), or vehicle to the VTA. Hamsters were post-tested for lordosis and motor behaviour 30 min later. In Experiment 2, a similar protocol was utilised except that instead of the PLC inhibitor hamsters were infused with the PKC inhibitor, bisindolylmaleimide (75 nM/side). Systemic progesterone, SKF38393-, and muscimol-facilitated lordosis was attenuated by infusion of the PLC inhibitor, U73122, or the PKC inhibitor, bisindolylmaleimide, compared to vehicle to the VTA. Thus, the actions of progestins in the VTA to enhance lordosis through D(1) and/or GABA(A) may include downstream activity of PLC and PKC.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/metabolism
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Cell Membrane/metabolism
- Cricetinae
- Dopamine Agonists/metabolism
- Dopamine Agonists/pharmacology
- Estrenes/metabolism
- Estrenes/pharmacology
- Female
- GABA Agonists/metabolism
- GABA Agonists/pharmacology
- Indoles/metabolism
- Indoles/pharmacology
- Lordosis
- Maleimides/metabolism
- Maleimides/pharmacology
- Motor Activity/drug effects
- Motor Activity/physiology
- Muscimol/metabolism
- Muscimol/pharmacology
- Ovariectomy
- Progestins/metabolism
- Progestins/pharmacology
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Pyrrolidinones/metabolism
- Pyrrolidinones/pharmacology
- Receptors, Dopamine D1/metabolism
- Receptors, GABA-A/metabolism
- Type C Phospholipases/antagonists & inhibitors
- Type C Phospholipases/metabolism
- Ventral Tegmental Area/metabolism
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Affiliation(s)
- C A Frye
- Departments of Psychology and Biological Sciences, and the Centers for Neurosience and Life Sciences Research, The University at Albany-SUNY, 1400 Washington Avenue, Albany, NY 12222, USA.
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Li P, Shu HJ, Wang C, Mennerick S, Zorumski CF, Covey DF, Steinbach JH, Akk G. Neurosteroid migration to intracellular compartments reduces steroid concentration in the membrane and diminishes GABA-A receptor potentiation. J Physiol 2007; 584:789-800. [PMID: 17761771 PMCID: PMC2276993 DOI: 10.1113/jphysiol.2007.142794] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neurosteroids are potent modulators of GABA-A receptors. We have examined the time course of development of potentiation of alpha1beta2gamma2L GABA-A receptors during coapplication of GABA and an endogenous neurosteroid (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha5alphaP). The simultaneous application of 3alpha5alphaP with 5 microm GABA resulted in a biphasic rising phase of current with time constants of 50-60 ms for the rapid phase and 0.3-3 s for the slow phase. The properties of the rapid phase were similar at all steroid concentrations but the time constant of the slower phase became successively shorter as the steroid concentration was increased. Potentiation developed very rapidly (tau = 130 ms) when cells were preincubated with 300 nm 3alpha5alphaP before application of GABA + 3alpha5alphaP, and in outside-out patch recordings, suggesting that steroid diffusion to intracellular compartments competes with receptor potentiation by depleting the cell membrane of steroid. Very low steroid concentrations (3-5 nm) potentiated GABA responses but the effects took minutes to develop. Intracellular accumulation of a fluorescent steroid analogue followed a similar time course, suggesting that slow potentiation results from slow accumulation within plasma membrane rather than indirect effects, such as activation of second messenger systems. In cell-attached single-channel recordings, where 3alpha5alphaP is normally applied through the pipette solution, addition of steroid to the bath solution dramatically shifted the steroid potentiation concentration-effect curve to lower steroid concentrations. We propose that bath-supplied steroid compensates for the diffusion of pipette-supplied steroid out of the patch to the rest of the cell membrane and/or intracellular compartments. The findings suggest that previous studies overestimate the minimum concentration of steroid capable of potentiating GABA actions at GABA-A receptors. The results have implications for the physiological role of endogenous neurosteroids.
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Affiliation(s)
- Ping Li
- Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
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22
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De Nicola E, Meriç S, Gallo M, Iaccarino M, Della Rocca C, Lofrano G, Russo T, Pagano G. Vegetable and synthetic tannins induce hormesis/toxicity in sea urchin early development and in algal growth. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2007; 146:46-54. [PMID: 16895741 DOI: 10.1016/j.envpol.2006.06.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 06/22/2006] [Accepted: 06/24/2006] [Indexed: 05/11/2023]
Abstract
Mimosa tannin and phenol-based synthetic tannin (syntan) were tested for toxicity to sea urchin (Paracentrotus lividus and Sphaerechinus granularis) early development and to marine algal growth (Dunaliella tertiolecta). Sea urchin embryogenesis was affected by vegetable tannin and syntan water extracts (VTWE and STWE) at levels >or=1mg/L. Developmental defects were significantly decreased at VTWE and STWE levels of 0.1 and 0.3mg/L when control cultures displayed suboptimal quality, i.e. <70% "viable" (normal or retarded) larvae. Fertilization success of sea urchin sperm was increased up to 0.3 mg/L STWE or VTWE, then was inhibited by increasing tannin levels (1-30 mg/L). Offspring abnormalities, following sperm exposure to VTWE or STWE, showed the same shift from hormesis to toxicity. Cell growth bioassays in D. tertiolecta exposed to VTWE or STWE (0.1-30 mg/L) showed non-linear concentration-related toxicity. Novel criteria are suggested in defining control quality that should reveal hormetic effects.
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Affiliation(s)
- Elena De Nicola
- Italian National Cancer Institute, G. Pascale Foundation, via M. Semmola, I-80131 Naples, Italy
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23
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Ahboucha S, Coyne L, Hirakawa R, Butterworth RF, Halliwell RF. An interaction between benzodiazepines and neuroactive steroids at GABA A receptors in cultured hippocampal neurons. Neurochem Int 2006; 48:703-7. [PMID: 16487630 DOI: 10.1016/j.neuint.2005.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 12/13/2005] [Accepted: 12/15/2005] [Indexed: 11/21/2022]
Abstract
Neurosteroids are modulators of several receptors and ion channels and are implicated in the pathophysiology of several neuropsychiatric diseases including hepatic encephalopathy (HE). The neurosteroid, allopregnanolone, a positive allosteric modulator of GABA(A) receptors, accumulates in the brains of HE patients where it can potentiate GABA(A) receptor-mediated responses. Attenuation of the effects of neurosteroids on GABA-ergic neurotransmission is therefore of interest for the management of HE. In the present study, we determined the effect of the benzodiazepine partial inverse agonist, Ro15-4513, and the benzodiazepine antagonist, flumazenil on modulation of the GABA(A) mediated chloride currents by allopregnanolone and on spontaneous synaptic activity in cultured hippocampal neurons using the patch-clamp technique. Allopregnanolone (0.03-0.3 microM), dose-dependently potentiated GABA-induced currents, an action significantly reduced by Ro15-4513 (10 microM). In contrast, flumazenil (10 microM) had no effect on the ability of allopregnanolone to potentiate GABA(A) currents but it blocked the effects of Ro15-4513. The frequency of spontaneous synaptic activity was significantly reduced in the presence of allopregnanolone (0.1 microM) from 1.5+/-0.7 to 0.1+/-0.04Hz. This action was partially reversed by Ro15-4513 (10 microM) but was not significantly influenced by flumazenil (10 microM). These findings suggest that the beneficial affects of Ro15-4513 in experimental HE result from attenuation of the effects of neurosteroids at GABA(A) receptors. Our results may provide a rational basis for the use of benzodiazepine inverse agonists in the management and treatment of hepatic encephalopathy in patients with liver failure.
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Affiliation(s)
- Samir Ahboucha
- Neuroscience Research Unit, CHUM-Hôpital Saint-Luc, 1058 St. Denis, Montreal, Quebec, Canada H2X 3J4
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24
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Labombarda F, Pianos A, Liere P, Eychenne B, Gonzalez S, Cambourg A, De Nicola AF, Schumacher M, Guennoun R. Injury elicited increase in spinal cord neurosteroid content analyzed by gas chromatography mass spectrometry. Endocrinology 2006; 147:1847-59. [PMID: 16396987 DOI: 10.1210/en.2005-0955] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effects of spinal cord injury (SCI), combined with castration and adrenalectomy, and of progesterone (PROG) treatment on neurosteroid levels and steroidogenic enzyme expression were investigated in the adult male rat spinal cord (SC). Steroid levels were quantified by gas chromatography/mass spectrometry in SC and plasma, and mRNAs of enzymes by quantitative real-time RT-PCR. The levels of pregnenolone (PREG), PROG, 5alpha-dihydroprogesterone, 3alpha,5alpha-tetrahydroprogesterone increased in SC 75 h after transection without significant increase in the plasma. After combined adrenalectomy and gonadectomy, significant levels of PREG and PROG remained in the SC, suggesting their local biosynthesis. In the SC of adrenalectomized and gonadectomized rats, there was an increase of PREG 24 h after SCI, followed at 75 h by a concomitant increase in its direct metabolite, PROG. These observations are consistent with a sequential increase of PREG biosynthesis and its conversion to PROG within the SC in response to injury. However, no significant change in P450-side chain cleavage and 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase mRNA levels was observed after SCI. Systemic PROG treatment after SCI, resulted in a very large increase in PROG, 5alpha-dihydroprogesterone, and 3alpha,5alpha-tetrahydroprogesterone in both plasma and SC. Furthermore, high levels of 3beta,5alpha-tetrahydroprogesterone were detected in SC, whereas their plasma levels remained barely detectable. Because the ratio of reduced metabolites to PROG was 65-times higher in SC than in the plasma, it appears likely that reduced metabolites mainly originated from local biosynthesis. Our results strongly suggest an important role for locally biosynthesized neurosteroids in the response of the SC to injury.
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Affiliation(s)
- F Labombarda
- Institut National de la Santé et de la Recherche Médicale Unité 488, Bicêtre, France
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25
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Wang JM, Johnston PB, Ball BG, Brinton RD. The neurosteroid allopregnanolone promotes proliferation of rodent and human neural progenitor cells and regulates cell-cycle gene and protein expression. J Neurosci 2006; 25:4706-18. [PMID: 15888646 PMCID: PMC6724768 DOI: 10.1523/jneurosci.4520-04.2005] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Our previous research demonstrated that the neuroactive progesterone metabolite allopregnanolone (3alpha-hydroxy-5alpha-pregnan-20-one) rapidly induced hippocampal neuron neurite regression (Brinton, 1994). We hypothesized that allopregnanolone-induced neurite regression was a prelude to mitogenesis initiated by a rise in intracellular calcium. Supporting this hypothesis, the current data demonstrate that allopregnanolone, in a dose-dependent manner, induces a significant increase in proliferation of neuroprogenitor cells (NPCs) derived from the rat hippocampus and human neural stem cells (hNSCs) derived from the cerebral cortex. Proliferation was determined by incorporation of bromodeoxyuridine and [3H]thymidine, fluorescence-activated cell sorter analysis of murine leukemia virus-green fluorescent protein-labeled mitotic NPCs, and total cell number counting. Allopregnanolone-induced proliferation was isomer and steroid specific, in that the stereoisomer 3beta-hydroxy-5beta-pregnan-20-one and related steroids did not increase [3H]thymidine uptake. Immunofluorescent analyses for the NPC markers nestin and Tuj1 indicated that newly formed cells were of neuronal lineage. Furthermore, microarray analysis of cell-cycle genes and real-time reverse transcription-PCR and Western blot validation revealed that allopregnanolone increased the expression of genes that promote mitosis and inhibited the expression of genes that repress cell proliferation. Allopregnanolone-induced proliferation was antagonized by the voltage-gated L-type calcium channel (VGLCC) blocker nifedipine, consistent with the finding that allopregnanolone induces a rapid increase in intracellular calcium in hippocampal neurons via a GABA type A receptor-activated VGLCC (Son et al., 2002). These data demonstrate that allopregnanolone significantly increased rat NPC and hNSC proliferation with concomitant regulation in mitotic cell-cycle genes via a VGLCC mechanism. The therapeutic potential of allopregnanolone as a neurogenic molecule is discussed.
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Affiliation(s)
- Jun Ming Wang
- Department of Molecular Pharmacology and Toxicology and Program in Neuroscience, Pharmaceutical Science Center, University of Southern California, Los Angeles, California 90033, USA
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Petralia SM, Walf AA, Frye CA. In the ventral tegmental area, progestins' membrane-mediated actions for lordosis of hamsters and rats involve protein kinase A. Neuroendocrinology 2006; 84:405-14. [PMID: 17384517 DOI: 10.1159/000100510] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 11/24/2006] [Indexed: 01/17/2023]
Abstract
Progestin-facilitated lordosis of hamsters and rats is enhanced by activation of dopamine type 1 (D1) or GABAA/benzodiazepine receptor complexes (GBRs) in the ventral tegmental area (VTA) and these effects involve G-proteins and second messengers, such as adenosine 3',5'-monophosphate (cAMP). We examined whether D1- and/or GBR-mediated increases in progestin-facilitated lordosis of female hamsters and rats involve the cAMP-dependent protein kinase, protein kinase A (PKA), in the VTA. In experiment 1, ovariectomized hamsters, primed with estradiol (E2; 10 microg at h 0) + progesterone (P; 100 microg at h 45), were first pre-tested for lordosis and motor behavior (h 48) and then infused with the PKA inhibitor, Rp-cAMP (100 ng/side), or vehicle. Thirty minutes later, hamsters were retested and then received infusions of the D1 agonist, SKF38393 (100 ng/side), the GBR agonist, muscimol (100 ng/side), or vehicle to the VTA. Hamsters were post-tested for lordosis and motor behavior 30 min later. In Experiment 2, ovariectomized rats, primed with E2 (10 microg at h 0), were first pre-tested for lordosis and then infused with Rp-cAMP (100 ng/side) or vehicle to the VTA at h 44. Immediately after testing, rats received infusions of SKF38393 (100 ng/side), muscimol (100 ng/side), or vehicle and were retested for lordosis. Rats were then infused with the neurosteroid, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP; 100 or 200 ng/side), or beta-cyclodextrin vehicle and were post-tested for lordosis and motor behavior 10 and 60 min later. The enhancing effects of progestins or progestins plus D1 or GBR activation on lordosis of E2-primed hamsters and rats were blocked by the PKA inhibitor, Rp-cAMP. Thus, in the VTA, progestins' membrane actions involving D1 or GBRs are mediated, in part, by PKA.
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Affiliation(s)
- Sandra M Petralia
- Department of Psychology , The University at Albany, SUNY, Albany, NY 12222, USA
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Rhodes ME, Frye CA. Actions at GABA(A) receptors in the hippocampus may mediate some antiseizure effects of progestins. Epilepsy Behav 2005; 6:320-7. [PMID: 15820338 DOI: 10.1016/j.yebeh.2005.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Revised: 02/03/2005] [Accepted: 02/05/2005] [Indexed: 11/20/2022]
Abstract
Progestins can have antiseizure effects; however, the mechanisms and sites of action of these effects are not well-understood. Whether progesterone's actions at GABA(A) receptors in the hippocampus are important for its antiseizure effects was investigated. In Experiment 1, ovariectomized rats were administered sesame oil vehicle or a regimen of progesterone (500 microg sc, which produces physiological concentrations in plasma and the hippocampus), followed 2.5 hours later by administration of saline vehicle or a regimen of bicuculline (1 mg/kg, sc), a GABA(A) receptor antagonist, which does not produce any intrinsic effects on seizures. Progesterone, compared with vehicle, significantly increased the latency to, and decreased the number of, pentylenetetrazole-induced tonic seizures and increased GABA-stimulated chloride flux. Co-administration of bicuculline attenuated progesterone's antiseizure effects and decreased GABA-stimulated chloride flux in the hippocampus. Bicuculline did not alter ictal behavior compared with vehicle. In Experiment 2, ovariectomized rats were subcutaneously administered sesame oil or progesterone (500 microg), followed 2.5 hours later by bilateral infusions of bicuculline (100 ng) or vehicle (saline) into the hippocampus. Infusion of bicuculline into the hippocampus of progesterone-primed rats significantly increased ictal activity, compared with that induced by progesterone administration alone, but alone did not alter seizures compared with that produced by saline infusions into the hippocampus. These data suggest that actions of progesterone at GABA(A) receptors in the hippocampus are important for progesterone's antiseizure effects.
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Affiliation(s)
- Madeline E Rhodes
- Department of Psychology, University at Albany-SUNY, Albany, NY 12222, USA
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Shu HJ, Eisenman LN, Jinadasa D, Covey DF, Zorumski CF, Mennerick S. Slow actions of neuroactive steroids at GABAA receptors. J Neurosci 2005; 24:6667-75. [PMID: 15282269 PMCID: PMC6729712 DOI: 10.1523/jneurosci.1399-04.2004] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuroactive steroids are potent and efficacious modulators of GABA(A) receptor activity and are potent sedatives and anesthetics. These positive modulators of GABA(A) receptors both potentiate the actions of GABA at the receptor and, at higher concentrations, directly gate the channel. The contribution of direct gating to the cellular and behavioral effects of neuroactive steroids is considered of little significance because it has been generally found that concentrations well above those needed for anesthesia are required to gate channels. By studying solitary glutamatergic neurons devoid of synaptic GABA input, we show that direct gating occurs and significantly alters membrane excitability at concentrations < or =100 nm. We propose that the relevance of direct gating has been overlooked partly because of the extremely slow kinetics of receptor activation and deactivation. We show that slow deactivation of directly gated currents does not result from an inherently tight ligand-receptor interaction because the slow deactivation is markedly accelerated by gamma-cyclodextrin application. We hypothesize that steroids access the relevant GABA(A) receptor site from a non-aqueous reservoir, likely the plasma membrane, and that it is slow reservoir accumulation and departure that accounts for the slow kinetics of receptor gating by neuroactive steroids.
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Affiliation(s)
- Hong-Jin Shu
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Onda A, Murata Y, Rydevik B, Larsson K, Kikuchi S, Olmarker K. Infliximab attenuates immunoreactivity of brain-derived neurotrophic factor in a rat model of herniated nucleus pulposus. Spine (Phila Pa 1976) 2004; 29:1857-61. [PMID: 15534405 DOI: 10.1097/01.brs.0000137054.08788.b2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The effect of infliximab, a chimeric monoclonal antibody to TNF-alpha, on induction of brain-derived neurotrophic factor (BDNF) was examined using an experimental herniated nucleus pulposus (NP) model. OBJECTIVES To investigate whether treatment of infliximab could attenuate an induction of BDNF, which functions as a modulator of pain, following NP application to the nerve root. SUMMARY OF BACKGROUND DATA Evidence from basic scientific studies proposes that TNF-alpha is involved in the development of NP-induced nerve injuries. However, the therapeutic mechanisms of infliximab against pain have not been elucidated experimentally. METHODS Twenty rats were used in this study. In the test groups, the animals underwent application of NP to the L4 nerve roots and received a single systemic (intraperitoneal) injection of infliximab at the time of surgery (Infli-0 group, n = 5) or at 1 day after operation (Infli-1 group, n = 5). As a control treatment, sterile water was administered intraperitoneally to 5 rats with NP application (NP group) and to 5 sham-operated rats (sham group). On day 3 after surgery, the L4 dorsal root ganglion (DRG) and L4 spinal segment were harvested and assessed regarding BDNF immunoreactivity. RESULTS.: Application of NP induced a marked increase of BDNF immunoreactivity in number in the DRG neurons and within the superficial layer in the dorsal horn compared with the sham group (P < 0.01). Infliximab treatment in the Infli-0 and Infli-1 groups reduced the BDNF induction in both DRG and spinal cord (P < 0.05). CONCLUSION These findings indicate that infliximab attenuates the elevated BDNF levels induced by NP. The present study therefore further indicates the importance of TNF-alpha in sciatica due to disc herniation and the possible therapeutic use of a TNF-alpha inhibitor for this condition.
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Affiliation(s)
- Akira Onda
- Department of Orthopaedics, Sahlgrenska University Hospital, Göteborg University, Göteborg, Sweden
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Tobinick E, Davoodifar S. Efficacy of etanercept delivered by perispinal administration for chronic back and/or neck disc-related pain: a study of clinical observations in 143 patients. Curr Med Res Opin 2004; 20:1075-85. [PMID: 15265252 DOI: 10.1185/030079903125004286] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Documentation of the clinical results obtained utilizing perispinal etanercept off-label for treatment-refractory back and neck pain in a clinical practice setting. RESEARCH DESIGN AND METHODS The medical charts of all patients who were treated with etanercept for back or neck pain at a single private medical clinic in 2003 were reviewed retrospectively. Patients were treated if they had disc-related pain which was chronic, treatment-refractory, present every day for at least 8 h, and of moderate or severe intensity. Patients with active infection, demyelinating disease, uncontrolled diabetes, lymphoma or immunosuppression were excluded from treatment with etanercept. Etanercept 25 mg was administered by subcutaneous injection directly overlying the spine. Visual Analogue Scales (VAS, 0-10 cm) for intensity of pain, sensory disturbance, and weakness prior to and 20 min, 1 day, 1 week, 2 weeks, and 1 month after treatment were completed. Inclusion criteria for analysis required baseline and treatment VAS data. MAIN OUTCOME MEASURES Before and after treatment VAS comparisons for intensity of pain, sensory disturbance, and weakness. RESULTS 143 charts out of 204 met the inclusion VAS criteria. The 143 patients had a mean age of 55.8 +/- 14, duration of pain of 9.8 +/- 11 years, and an initial Oswestry Disability Index of 42.8 +/- 18, with 83% having back pain, 61% sciatica, and 33% neck pain. 30% had previous spinal surgery, and 69% had previously received epidural steroid injections (mean 3.0 +/- 3). The patients received a mean of 2.3 +/- 0.7 doses of perispinal etanercept separated by a mean interval of 13.6 +/- 16.3 days. The mean VAS intensity of pain, sensory disturbance, and weakness were significantly reduced after perispinal etanercept at 20 min, 1 day, 1 week, 2 weeks, and 1 month with a p < 0.0001 at each time interval for the first dose in this patient population. CONCLUSIONS Perispinal etanercept is a new treatment modality which can lead to significant clinical improvement in selected patients with chronic, treatment-refractory disc-related pain. Generalizability of the present study results is limited by the open-label, uncontrolled methodology employed. Based on this and other accumulating recent studies, etanercept may be useful for both acute and chronic disc-related pain. Further study of this new treatment modality utilizing double-blind placebo controlled methodology is indicated. NOTE: This treatment method is protected by multiple patents awarded to Edward Tobinick MD, including U. S. patents 6 015 557; 6 177 077; 6 419 944; 6 537 549 and Australian patent 758 523.
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Affiliation(s)
- Edward Tobinick
- Institute Research Associates, A Medical Group, Inc, Los Angeles, CA, USA.
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Petralia SM, Frye CA. In the ventral tegmental area, G-proteins and cAMP mediate the neurosteroid 3alpha,5alpha-THP's actions at dopamine type 1 receptors for lordosis of rats. Neuroendocrinology 2004; 80:233-43. [PMID: 15604595 DOI: 10.1159/000082752] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 09/30/2004] [Indexed: 11/19/2022]
Abstract
Progestins have multiple mechanisms of action in the central nervous system that are important for modulating lordosis of female rats. In the ventral tegmental area (VTA), progestins, such as the progesterone metabolite and neurosteroid 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), regulate lordosis via actions independent of intracellular progestin receptors. We hypothesized that if, in the VTA, dopamine type 1 receptors (D1), G-proteins, and adenosine 3',5'-monophosphate (cAMP) are downstream effectors of 3alpha,5alpha-THP's actions for lordosis, then pharmacological manipulations of these signaling molecules will produce changes in 3alpha,5alpha-THP-facilitated lordosis of estradiol (E2)-primed rats. VTA infusions of 3alpha,5alpha-THP (50 ng) or 3alpha,5alpha-THP and the D1 agonist SKF38393 (100 ng) increased lordosis of ovariectomized, E2 (10 microg)-primed rats, compared to vehicle. Both 3alpha,5alpha-THP- and 3alpha,5alpha-THP plus SKF38393-facilitated lordosis was reduced by VTA infusions of the G-protein inhibitor guanosine 5'-O-(2-thiodiphosphate) (GDP-beta-S; 50 microM), but not vehicle. Also, in the VTA, blocking D1 with SCH23390 (100 ng) decreased, or increasing cAMP with 8-bromo-cAMP (200 ng) enhanced, 3alpha,5alpha-THP-facilitated lordosis of E2-primed rats. Notably, SCH23390's inhibitory effects on 3alpha,5alpha-THP-facilitated lordosis were reversed by 8-bromo-cAMP. Thus, in the VTA, 3alpha,5alpha-THP's actions for lordosis may involve activation of D1 and initiation of the G-protein-mediated second messenger cAMP.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- 8-Bromo Cyclic Adenosine Monophosphate/pharmacology
- Analysis of Variance
- Animals
- Behavior, Animal
- Benzazepines/pharmacology
- Cyclic AMP/analogs & derivatives
- Cyclic AMP/metabolism
- Desoxycorticosterone/analogs & derivatives
- Desoxycorticosterone/pharmacology
- Drug Interactions
- Female
- GTP-Binding Proteins/agonists
- GTP-Binding Proteins/antagonists & inhibitors
- GTP-Binding Proteins/metabolism
- Guanosine Diphosphate/analogs & derivatives
- Guanosine Diphosphate/pharmacology
- Male
- Models, Biological
- Posture
- Rats
- Rats, Long-Evans
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/physiology
- Sexual Behavior, Animal/drug effects
- Thionucleotides/pharmacology
- Ventral Tegmental Area/drug effects
- Ventral Tegmental Area/metabolism
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Affiliation(s)
- Sandra M Petralia
- Department of Psychology, University at Albany-SUNY, Albany, NY 12222, USA
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Sullivan SD, Moenter SM. Neurosteroids alter gamma-aminobutyric acid postsynaptic currents in gonadotropin-releasing hormone neurons: a possible mechanism for direct steroidal control. Endocrinology 2003; 144:4366-75. [PMID: 12960018 DOI: 10.1210/en.2003-0634] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pulsatile GnRH release is required for fertility and is regulated by steroid feedback. Whether or not steroids or their metabolites act directly on GnRH neurons is not well established. In some neurons, steroid metabolites known as neurosteroids modulate the function of the GABAA receptor. Specifically, the progesterone derivative allopregnanolone is an allosteric agonist at this receptor, whereas the androgen dehydroepiandrosterone sulfate (DHEAS) is an allosteric antagonist. We hypothesized these metabolites act similarly on GnRH neurons to modify the response to GABA. Whole-cell voltage-clamp recordings of GABAergic miniature postsynaptic currents (mPSCs) were made from green fluorescent protein-identified GnRH neurons in brain slices from diestrous mice. Glutamatergic currents were blocked with antagonists and action potentials blocked with tetrodotoxin, minimizing presynaptic effects of treatments. Allopregnanolone (5 microm) increased mPSC rate of rise, amplitude and decay time by 15.9 +/- 6.1%, 16.5 +/- 6.3%, and 58.3 +/- 18.6%, respectively (n = 7 cells). DHEAS (5 microm) reduced mPSC rate of rise (32.1 +/- 5.7%) and amplitude (27.6 +/- 4.3%) but did not alter decay time (n = 8). Effects of both neurosteroids were dose dependent between 0.1 and 10 microm. In addition to independent actions, DHEAS also reversed effects of allopregnanolone on rate of rise and amplitude so that these parameters were returned to pretreatment baseline values (n = 6). These data indicate allopregnanolone increases and DHEAS decreases responsiveness of GnRH neurons to activation of GABAA receptors by differentially modulating current flow through GABAA receptor chloride channels. This provides one mechanism for direct steroid feedback to GnRH neurons.
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Affiliation(s)
- Shannon D Sullivan
- Department of Internal Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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Frye CA, Petralia SM. Mitochondrial benzodiazepine receptors in the ventral tegmental area modulate sexual behaviour of cycling or hormone-primed hamsters. J Neuroendocrinol 2003; 15:677-86. [PMID: 12787052 DOI: 10.1046/j.1365-2826.2003.01047.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hamsters are highly dependent upon the central actions of progesterone (P4) for facilitation of sexual behaviour. In the ventral tegmental area (VTA), P4 has actions through its neurosteroid metabolite 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP). The effects of enhancing or inhibiting neurosteroidogenesis (and thereby 3alpha,5alpha-THP concentrations), through manipulations of mitochondrial benzodiazepine receptors, in the VTA on socio-sexual behaviour of female hamsters were examined. Intact, naturally receptive hamsters and ovariectomized (OVX), hormone-primed hamsters were unilaterally infused via chronic guide cannula to the VTA with the mitochondrial benzodiazepine receptor antagonist 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboximide (PK-11195) or the mitochondrial benzodiazepine receptor agonist, N,N-dihexyl-2-(4-fluorophenyl)indole-30-acetamide (FGIN 1-27) and tested for sexual responsiveness and lordosis. PK-11195 (5.6, 11.2 or 22.4 nm) to the VTA attenuated sexual responsiveness of naturally receptive or oestradiol benzoate (EB) + P4-primed hamsters compared to vehicle. In addition, FGIN 1-27 (11.4 nm) infusions to the VTA increased sexual responsiveness and lordosis of cycling or OVX, EB + P4-primed hamsters, compared to vehicle infusions. In OVX, EB + P4-primed hamsters, decrements in sexual responsiveness produced by VTA infusions of PK-11195 (5.6 nm) were attenuated by VTA infusions of 3alpha,5alpha-THP. VTA infusions of PK-11195 (5.6 nm) or FGIN 1-27 (11.4 nm), respectively, decreased and increased midbrain levels of 3alpha,5alpha-THP compared to each other. Together, these findings indicate that manipulating actions of mitochondrial benzodiazepine receptors in the VTA can augment and inhibit neurosteroidogenesis and sexual responsiveness of hormone-primed and naturally receptive hamsters.
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Affiliation(s)
- C A Frye
- Departments of Psychology, The University at Albany-SUNY, Albany, NY 12222, USA.
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