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Apland JP, Aroniadou-Anderjaska V, Figueiredo TH, Prager EM, Olsen CH, Braga MFM. Susceptibility to Soman Toxicity and Efficacy of LY293558 Against Soman-Induced Seizures and Neuropathology in 10-Month-Old Male Rats. Neurotox Res 2017; 32:694-706. [PMID: 28776308 DOI: 10.1007/s12640-017-9789-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/13/2017] [Accepted: 07/21/2017] [Indexed: 12/23/2022]
Abstract
Acute nerve agent exposure causes prolonged status epilepticus (SE), leading to death or long-term brain damage. We have previously demonstrated that LY293558, an AMPA/GluK1 kainate receptor antagonist, terminates SE induced by the nerve agent soman and protects from long-term brain damage, in immature rats and young-adult rats, even if administered with a relatively long latency from the time of exposure. However, susceptibility to the lethal consequences of SE increases with age, and mortality by SE induced by soman is substantially greater in older animals. Therefore, in the present study, we compared the susceptibility to soman toxicity of 10-month-old male rats with that of young-adult male rats (42 to 50 days old) and examined the protective efficacy of LY293558 in the older group. A lower percentage of the 10-month-old rats developed SE after injection of 1.2 × LD50 soman, compared to the young adults, the latency to seizure onset was longer in the older rats, and seizure intensity did not differ between the two age groups. However, mortality rate in the older rats who developed SE was higher than in the young adults. Acetylcholinesterase activity in the amygdala, hippocampus, and piriform cortex did not differ between the two age groups. Administration of LY293558 at 20 or 60 min post-exposure suppressed SE, increased 24-h survival rate, decreased the long-term risk of death, reduced neuronal degeneration in the amygdala, hippocampus, piriform, and entorhinal cortices, and facilitated recovery from body weight loss. Thus, LY293558 is an effective countermeasure against soman toxicity also in older animals.
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Affiliation(s)
- James P Apland
- Neuroscience Program, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, MD, 21010, USA
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Eric M Prager
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.,John Wiley and Sons, Inc., 111 River Street, Hoboken, NJ, 07030, USA
| | - Cara H Olsen
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA. .,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA.
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Zhang JQ, Xu WY, Xu CQ. Neonatal Propofol and Etomidate Exposure Enhance Inhibitory Synaptic Transmission in Hippocampal Cornus Ammonis 1 Pyramidal Neurons. Chin Med J (Engl) 2017; 129:2714-2724. [PMID: 27824005 PMCID: PMC5126164 DOI: 10.4103/0366-6999.193459] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Background: Propofol and etomidate are the most important intravenous general anesthetics in the current clinical use and that mediate gamma-aminobutyric acid's (GABAergic) synaptic transmission. However, their long-term effects on GABAergic synaptic transmission induced by neonatal propofol or etomidate exposure remain unclear. We investigated the long-term GABAergic neurotransmission alterations, following neonatal propofol and etomidate administration. Methods: Sprague-Dawley rat pups at postnatal days 4–6 were underwent 6-h-long propofol-induced or 5-h-long etomidate-induced anesthesia. We performed whole-cell patch-clamp recording from pyramidal cells in the cornus ammonis 1 area of acute hippocampal slices of postnatal 80–90 days. Spontaneous and miniature inhibitory GABAergic currents (spontaneous inhibitory postsynaptic currents [sIPSCs] and miniature inhibitory postsynaptic currents [mIPSCs]) and their kinetic characters were measured. The glutamatergic tonic effect on inhibitory transmission and the effect of bumetanide on neonatal propofol exposure were also examined. Results: Neonatal propofol exposure significantly increased the frequency of mIPSCs (from 1.87 ± 0.35 Hz to 3.43 ± 0.51 Hz, P < 0.05) and did not affect the amplitude of mIPSCs and sIPSCs. Both propofol and etomidate slowed the decay time of mIPSCs kinetics (168.39 ± 27.91 ms and 267.02 ± 100.08 ms vs. 68.18 ± 12.43 ms; P < 0.05). Bumetanide significantly blocked the frequency increase and reversed the kinetic alteration of mIPSCs induced by neonatal propofol exposure (3.01 ± 0.45 Hz and 94.30 ± 32.56 ms). Conclusions: Neonatal propofol and etomidate exposure has long-term effects on inhibitory GABAergic transmission. Propofol might act at pre- and post-synaptic GABA receptor A (GABAA) receptors within GABAergic synapses and impairs the glutamatergic tonic input to GABAergic synapses; etomidate might act at the postsynaptic site.
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Affiliation(s)
- Jia-Qiang Zhang
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL 32611, USA; Department of Anesthesiology, The People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China,
| | - Wan-Ying Xu
- Department of Neurobiology, Wake Forest University, Winston-Salem, NC 27106, USA
| | - Chang-Qing Xu
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL 32611, USA
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Mojabi FS, Fahimi A, Moghadam S, Moghadam S, Windy McNerneny M, Ponnusamy R, Kleschevnikov A, Mobley WC, Salehi A. GABAergic hyperinnervation of dentate granule cells in the Ts65Dn mouse model of down syndrome: Exploring the role of App. Hippocampus 2016; 26:1641-1654. [PMID: 27701794 DOI: 10.1002/hipo.22664] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2016] [Indexed: 12/20/2022]
Abstract
It has been suggested that increased GABAergic innervation in the hippocampus plays a significant role in cognitive dysfunction in Down syndrome (DS). Bolstering this notion, are studies linking hyper-innervation of the dentate gyrus (DG) by GABAergic terminals to failure in LTP induction in the Ts65Dn mouse model of DS. Here, we used extensive morphometrical methods to assess the status of GABAergic interneurons in the DG of young and old Ts65Dn mice and their 2N controls. We detected an age-dependent increase in GABAergic innervation of dentate granule cells (DGCs) in Ts65Dn mice. The primary source of GABAergic terminals to DGCs somata is basket cells (BCs). For this reason, we assessed the status of these cells and found a significant increase in the number of BCs in Ts65Dn mice compared with controls. Then we aimed to identify the gene/s whose overexpression could be linked to increased number of BCs in Ts65Dn and found that deleting the third copy of App gene in Ts65Dn mice led to normalization of the number of BCs in these mice. Our data suggest that App overexpression plays a major role in the pathophysiology of GABAergic hyperinnervation of the DG in Ts65Dn mice. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Fatemeh S Mojabi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | - Atoossa Fahimi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | | | | | - M Windy McNerneny
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | | | | | - William C Mobley
- Department of Neurosciences, University of California, San Diego, California
| | - Ahmad Salehi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
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Xu C, Hermes DJ, Mackie K, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Cannabinoids Occlude the HIV-1 Tat-Induced Decrease in GABAergic Neurotransmission in Prefrontal Cortex Slices. J Neuroimmune Pharmacol 2016; 11:316-31. [PMID: 26993829 DOI: 10.1007/s11481-016-9664-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/10/2016] [Indexed: 01/03/2023]
Abstract
In the era of combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is now considered a chronic disease that specifically targets the brain and causes HIV-1-associated neurocognitive disorders (HAND). Endocannabinoids exhibit neuroprotective and anti-inflammatory properties in several central nervous system (CNS) disease models, but their effects in HAND are poorly understood. To address this issue, whole-cell recordings were performed on young (14-24 day old) C57BL/6J mice. We investigated the actions of the synthetic cannabinoid WIN55,212-2 (1 μM) and the endocannabinoid N-arachidonoyl ethanolamine (anandamide; AEA, 1 μM) in the presence of HIV-1 Tat on GABAergic neurotransmission in mouse prefrontal cortex (PFC) slices. We found a Tat concentration-dependent (5-50 nM) decrease in the frequency and amplitude of miniature inhibitory postsynaptic currents (mIPSCs). The cannabinoid 1 receptor (CB1R) antagonist rimonabant (1 μM) and zero extracellular calcium prevented the significant Tat-induced decrease in mIPSCs. Further, bath-applied WIN55,212-2 or AEA by itself, significantly decreased the frequency, but not amplitude of mIPSCs and/or spontaneous IPSCs (sIPSCs), and occluded a further downregulation of IPSCs by Tat. Pretreatment with rimonabant but not the CB2R antagonist AM630 (1 μM) prevented the WIN55,212-2- and AEA-induced decrease in IPSCs frequency without any further Tat effect. Results indicated a Tat-induced decrease in GABAergic neurotransmission, which was occluded by cannabinoids via a CB1R-related mechanism. Understanding the relationship between Tat toxicity and endocannabinoid signaling has the potential to identify novel therapeutic interventions to benefit individuals suffering from HAND and other cognitive impairments.
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Affiliation(s)
- Changqing Xu
- Department of Psychology & Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Douglas J Hermes
- Department of Psychology & Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Ken Mackie
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Aron H Lichtman
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | | | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA.
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5
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Xu C, Liu QY, Alkon DL. PKC activators enhance GABAergic neurotransmission and paired-pulse facilitation in hippocampal CA1 pyramidal neurons. Neuroscience 2014; 268:75-86. [PMID: 24637095 DOI: 10.1016/j.neuroscience.2014.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/18/2022]
Abstract
Bryostatin-1, a potent agonist of protein kinase C (PKC), has recently been found to enhance spatial learning and long-term memory in rats, mice, rabbits and the nudibranch Hermissenda, and to exert profound neuroprotective effects on Alzheimer's disease (AD) in transgenic mice. However, details of the mechanistic effects of bryostatin on learning and memory remain unclear. To address this issue, whole-cell recording, a dual-recording approach and extracellular recording techniques were performed on young (2-4months) Brown-Norway rats. We found that bath-applied bryostatin-1 significantly increased the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs). The firing rate of GABAergic interneurons significantly was also increased as recorded with a loosely-attached extracellular recording configuration. Simultaneous recordings from communicating cell pairs of interneuron and pyramidal neuron revealed unique activity-dependent properties of GABAergic synapses. Furthermore, the bryostatin-induced increase of the frequency and amplitude of IPSCs was blocked by methionine enkephalin which selectively suppressed the excitability of interneurons. Pretreatment with RO-32-0432, a relatively specific PKCα antagonist, blocked the effect of bryostatin on sIPSCs. Finally, bryostatin increased paired-pulse ratio of GABAergic synapses that lasted for at least 20min while pretreatment with RO-32-0432 significantly reduced the ratio. In addition, 8-[2-(2-pentyl-cyclopropylmethl)-cyclopropyl]-octanoic acid (DCP-LA), a selective PKCε activator, also increased the frequency and amplitude of sIPSCs. Taken together, these results suggest that bryostatin enhances GABAergic neurotransmission in pyramidal neurons by activating the PKCα & ε-dependent pathway and by a presynaptic mechanism with excitation of GABAergic interneurons. These effects of bryostatin on GABAergic transmissions and modifiability may contribute to the improvement of learning and memory previously observed to be induced by bryostatin.
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Affiliation(s)
- C Xu
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV 26506, United States of America.
| | - Q-Y Liu
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV 26506, United States of America
| | - D L Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV 26506, United States of America
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Hongpaisan J, Xu C, Sen A, Nelson TJ, Alkon DL. PKC activation during training restores mushroom spine synapses and memory in the aged rat. Neurobiol Dis 2013; 55:44-62. [DOI: 10.1016/j.nbd.2013.03.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 03/14/2013] [Accepted: 03/19/2013] [Indexed: 01/24/2023] Open
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Huxter JR, Miranda JA, Dias R. The hippocampal physiology of approaching middle-age: early indicators of change. Hippocampus 2012; 22:1923-40. [PMID: 22674542 DOI: 10.1002/hipo.22027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2012] [Indexed: 12/24/2022]
Abstract
Age-related cognitive decline presents serious lifestyle challenges, and anatomical changes to the hippocampus are often implicated in clinical conditions later in life. However, relatively little is known about how hippocampal physiology is altered in the transition to middle-age, when early detection may offer the best opportunity for successful treatment. High-yield extracellular recording is a powerful tool for understanding brain function in freely moving animals at single-cell resolution and with millisecond precision. We used this technique to characterize changes to hippocampal physiology associated with maturation in 35-week-old rats. Combining a series of behavioral tasks with recordings of large numbers of neurons, local field potentials (LFP), and network patterns of activation, we were able to generate a comprehensive picture based on more than 25 different assays for each subject. Notable changes associated with aging included increased firing rates in interneurons, reduced LFP power but increased frequency in the 4-12 Hz theta band, and impairment in hippocampal pattern-separation for different environments. General properties of pyramidal cell firing and spatial map integrity were preserved. There was no impairment in theta phase-precession, experience-dependent place field expansion, or sleep reactivation of waking network patterns. There were however changes in foraging strategy and behavioral responses to the introduction of a novel environment. Taken together the results reveal a diverse pattern of changes which are of increasing relevance in an aging population. They also highlight areas where high-yield electrophysiological assays can be used to provide the sensitivity and throughput required for pre-clinical drug-discovery programs.
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Affiliation(s)
- John R Huxter
- Neusentis, Pfizer Ltd., The Portway Building, Granta Park, Great Abington, United Kingdom.
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8
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Lauri S, Taira T. Kainate receptors in developing presynaptic terminals. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/wmts.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Effect of ageing on CA3 interneuron sAHP and gamma oscillations is activity-dependent. Neurobiol Aging 2011; 32:956-65. [DOI: 10.1016/j.neurobiolaging.2009.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 05/05/2009] [Accepted: 05/07/2009] [Indexed: 01/21/2023]
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10
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Liu P, Jing Y, Zhang H. Age-related changes in arginine and its metabolites in memory-associated brain structures. Neuroscience 2009; 164:611-28. [DOI: 10.1016/j.neuroscience.2009.08.029] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 07/13/2009] [Accepted: 08/12/2009] [Indexed: 10/20/2022]
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Bond AM, Vangompel MJW, Sametsky EA, Clark MF, Savage JC, Disterhoft JF, Kohtz JD. Balanced gene regulation by an embryonic brain ncRNA is critical for adult hippocampal GABA circuitry. Nat Neurosci 2009; 12:1020-7. [PMID: 19620975 PMCID: PMC3203213 DOI: 10.1038/nn.2371] [Citation(s) in RCA: 300] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 06/19/2009] [Indexed: 12/19/2022]
Abstract
Genomic studies demonstrate that while the majority of the mammalian genome is transcribed, only about 2% of these transcripts are protein coding. We have been investigating how the long, polyadenylated Evf2 non-coding RNA regulates transcription of homeodomain transcription factors DLX5 and DLX6 in the developing mouse forebrain. Here we show that in developing ventral forebrain, Evf2 recruits DLX and MECP2 transcription factors to key DNA regulatory elements in the Dlx 5/6 intergenic region and controls Dlx5, Dlx6, and GAD67 expression through trans and cis-acting mechanisms. Evf2 mouse mutants have reduced numbers of GABAergic interneurons in early post-natal hippocampus and dentate gyrus. Although the numbers of GABAergic interneurons and GAD67 RNA levels return to normal in Evf2 mutant adult hippocampus, reduced synaptic inhibition occurs. These results suggest that non-coding RNA-dependent balanced gene regulation in embryonic brain is critical for proper formation of GABA-dependent neuronal circuitry in adult brain.
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Affiliation(s)
- Allison M Bond
- Developmental Biology and Department of Pediatrics, Children's Memorial Hospital and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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