1
|
Singh N, Golime R, Kumar A, Roy T. Attenuation of Nerve Agent Induced Neurodegenerative and Neuroinflammatory Changes in Rats with New Combination Treatment of Galantamine, Atropine and Midazolam. Mol Neurobiol 2024:10.1007/s12035-024-04294-2. [PMID: 38867111 DOI: 10.1007/s12035-024-04294-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 06/07/2024] [Indexed: 06/14/2024]
Abstract
Acute nerve agent exposure can kill a person within minutes or produce multiple neurotoxic effects and subsequent brain damage with potential long-term adverse outcomes. Recent abuse of nerve-agents on Syrian civilians, during Japan terrorist attacks, and personal assassinations in the UK, and Malaysia indicate their potential threat to world population. Existing nerve agent antidotes offer only incomplete protection especially, if the treatment is delayed. To develop the effective drugs, it is advantageous to elucidate the underlying mechanisms of nerve agent-induced multiple neurological impairments. This study aimed to investigate the molecular basis of neuroinflammation during nerve agent toxicity with focus on inflammasome-associated proteins and neurodegeneration. In rats, NOD-like receptor family pyrin domain containing 3 (NLRP3), and glial fibrillary acidic protein (GFAP) immunoreactivity levels were considerably increased in the hippocampus, piriform cortex, and amygdala areas after single subcutaneous soman exposure (90 µg/kg-1). Western analysis indicated a notable increase in the neuroinflammatory indicator proteins, high mobility group box 1 (HMGB1) and inducible nitric oxide synthase (iNOS) levels. The presence of fluorojade-C-stained degenerating neurons in distinct rat brain areas is indicating the neurodegeneration during nerve agent toxicity. Pre-treatment with galantamine (3 mg/kg, - 30 min) followed by post-treatment of atropine (10 mg/kg, i.m.) and midazolam (5 mg/kg, i.m.), has completely protected animals from death induced by supra-lethal dose of soman (2XLD50) and reduced the neuroinflammatory and neurodegenerative changes. Results highlight that this new prophylactic and therapeutic drug combination might be an effective treatment option for soldiers deployed in conflict areas and first responders dealing with accidental/deliberate release of nerve agents.
Collapse
Affiliation(s)
- Naveen Singh
- Biomedical Verification Division, Defence Research and Development Establishment (DRDE), Jhansi Road, Gwalior, M.P, India
| | - RamaRao Golime
- Biomedical Verification Division, Defence Research and Development Establishment (DRDE), Jhansi Road, Gwalior, M.P, India.
- Department of Epidemiology and Public Health, Central University of Tamil Nadu, Thiruvarur, India.
| | - Abdhesh Kumar
- Animal Facility Division, DRDE, Jhansi Road, Gwalior, M.P, India
| | - Tuhin Roy
- Process Technology Development Division, DRDE, Jhansi Road, Gwalior, M.P, India
| |
Collapse
|
2
|
Lazar S, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Glick P, Cohen M, Gutman H, Chapman S, Gore A. Efficacy of a combined anti-seizure treatment against cholinergic established status epilepticus following a sarin nerve agent insult in rats. Toxicol Appl Pharmacol 2024; 484:116870. [PMID: 38395364 DOI: 10.1016/j.taap.2024.116870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/11/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
The development of refractory status epilepticus (SE) following sarin intoxication presents a therapeutic challenge. Here, we evaluated the efficacy of delayed combined double or triple treatment in reducing abnormal epileptiform seizure activity (ESA) and the ensuing long-term neuronal insult. SE was induced in rats by exposure to 1.2 LD50 sarin followed by treatment with atropine and TMB4 (TA) 1 min later. Double treatment with ketamine and midazolam or triple treatment with ketamine, midazolam and levetiracetam was administered 30 min post-exposure, and the results were compared to those of single treatment with midazolam alone or triple treatment with ketamine, midazolam, and valproate, which was previously shown to ameliorate this neurological insult. Toxicity and electrocorticogram activity were monitored during the first week, and behavioral evaluations were performed 2 weeks post-exposure, followed by biochemical and immunohistopathological analyses. Both double and triple treatment reduced mortality and enhanced weight recovery compared to TA-only treatment. Triple treatment and, to a lesser extent, double treatment significantly ameliorated the ESA duration. Compared to the TA-only or the TA+ midazolam treatment, both double and triple treatment reduced the sarin-induced increase in the neuroinflammatory marker PGE2 and the brain damage marker TSPO and decreased gliosis, astrocytosis and neuronal damage. Finally, both double and triple treatment prevented a change in behavior, as measured in the open field test. No significant difference was observed between the efficacies of the two triple treatments, and both triple combinations completely prevented brain injury (no differences from the naïve rats). Delayed double and, to a greater extent, triple treatment may serve as an efficacious delayed therapy, preventing brain insult propagation following sarin-induced refractory SE.
Collapse
Affiliation(s)
- Shlomi Lazar
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Inbal Egoz
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Baranes
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Rellie Gez
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Pnina Glick
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Maayan Cohen
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Hila Gutman
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shira Chapman
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Ariel Gore
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| |
Collapse
|
3
|
Lumley LA, Nguyen DA, de Araujo Furtado M, Niquet J, Linz EO, Schultz CR, Stone MF, Wasterlain CG. Efficacy of Lacosamide and Rufinamide as Adjuncts to Midazolam-Ketamine Treatment Against Cholinergic-Induced Status Epilepticus in Rats. J Pharmacol Exp Ther 2024; 388:347-357. [PMID: 37977809 PMCID: PMC10801783 DOI: 10.1124/jpet.123.001789] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023] Open
Abstract
Benzodiazepine pharmacoresistance develops when treatment of status epilepticus (SE) is delayed. This response may result from gamma-aminobutyric acid A receptors (GABAAR) internalization that follows prolonged SE; this receptor trafficking results in fewer GABAAR in the synapse to restore inhibition. Increase in synaptic N-methyl-D-aspartate receptors (NMDAR) also occurs in rodent models of SE. Lacosamide, a third-generation antiseizure medication (ASM), acts on the slow inactivation of voltage-gated sodium channels. Another ASM, rufinamide, similarly acts on sodium channels by extending the duration of time spent in the inactivation stage. Combination therapy of the benzodiazepine midazolam, NMDAR antagonist ketamine, and ASMs lacosamide (or rufinamide) was investigated for efficacy against soman (GD)-induced SE and neuropathology. Adult male rats implanted with telemetry transmitters for monitoring electroencephalographic (EEG) activity were exposed to a seizure-inducing dose of GD and treated with an admix of atropine sulfate and HI-6 1 minute later and with midazolam monotherapy or combination therapy 40 minutes after EEG seizure onset. Rats were monitored continuously for seizure activity for two weeks, after which brains were processed for assessment of neurodegeneration, neuronal loss, and neuroinflammatory responses. Simultaneous administration of midazolam, ketamine, and lacosamide (or rufinamide) was more protective against GD-induced SE compared with midazolam monotherapy. In general, lacosamide triple therapy had more positive outcomes on measures of epileptogenesis, EEG power integral, and the number of brain regions protected from neuropathology compared with rats treated with rufinamide triple therapy. Overall, both drugs were well tolerated in these combination models. SIGNIFICANCE STATEMENT: We currently report on improved efficacy of antiseizure medications lacosamide and rufinamide, each administered in combination with ketamine (NMDAR antagonist) and midazolam (benzodiazepine), in combatting soman (GD)-induced seizure, epileptogenesis, and brain pathology over that provided by midazolam monotherapy, or dual therapy of midazolam and lacosamide (or rufinamide) in rats. Administration of lacosamide as adjunct to midazolam and ketamine was particularly effective against GD-induced toxicity. However, protection was incomplete, suggesting the need for further study.
Collapse
Affiliation(s)
- Lucille A Lumley
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Donna A Nguyen
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Marcio de Araujo Furtado
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Jerome Niquet
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Emily O Linz
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Caroline R Schultz
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Michael F Stone
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Claude G Wasterlain
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| |
Collapse
|
4
|
Shah EJ, Grunwald WC, Garrett TL, Brown TL, Cool DR. Sarin-Induced Neuroinflammation in Mouse Brain Is Attenuated by the Caspase Inhibitor Q-VD-OPh. J Pharmacol Exp Ther 2024; 388:367-375. [PMID: 37918856 PMCID: PMC10801781 DOI: 10.1124/jpet.123.001820] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 11/04/2023] Open
Abstract
Organophosphates cause hyperstimulation of the central nervous system, leading to extended seizures, convulsions, and brain damage. Sarin is a highly toxic organophosphate nerve agent that has been employed in several terrorist attacks. The prolonged toxicity of sarin may be enhanced by the neuroinflammatory response initiated by the inflammasome, caspase involvement, and generation/release of proinflammatory cytokines. Since neurodegeneration and neuroinflammation are prevalent in sarin-exposed animals, we were interested in evaluating the capacity of quinolyl-valyl-O-methylaspartyl-[-2,6-difluorophenoxy]-methyl ketone (Q-VD-OPh), a pan caspase inhibitor to attenuate neuroinflammation following sarin exposure. To test this hypothesis, sarin-exposed C57BL/6 mice were treated with Q-VD-OPh or negative control quinolyl-valyl-O-methylglutamyl-[-2,6-difluorophenoxy]-methyl ketone, sacrificed at 2- and 14-day time points, followed by removal of the amygdala and hippocampus. A Bio-Rad 23-Plex cytokine analysis was completed on each tissue. The results suggest that exposure to sarin induced a dramatic increase in interleukin-1β and 6 other cytokines and a decrease in 2 of the 23 cytokines at 2 days in the amygdala compared with controls. Q-VD-OPh attenuated these changes at the 2-day time point. At 14 days, six of these cytokines were still significantly different from controls. Hippocampus was less affected at both time points. Diazepam, a neuroprotective drug against nerve agents, caused an increase in several cytokines but did not have a synergistic effect with Q-VD-OPh. Treatment of sarin exposure with apoptosis inhibitors appears to be a worthwhile approach for further testing as a comprehensive counteragent against organophosphate exposure. SIGNIFICANCE STATEMENT: A pan inhibitor of caspases (Q-VD-OPh) was proposed as a potential antidote for sarin-induced neuroinflammation by reducing the level of inflammation via inflammasome caspase inhibition. Q-VD-OPh added at 30 minutes post-sarin exposure attenuated the inflammatory response of a number of cytokines and chemokines in the amygdala and hippocampus, two brain regions sensitive to organophosphate exposure. Apoptotic marker reduction at 2 and 14 days further supports further testing of inhibitors of apoptosis as a means to lessen extended organophosphate toxicity in the brain.
Collapse
Affiliation(s)
- Ekta J Shah
- Departments of Pharmacology and Toxicology (E.J.S., W.C.G, T.L.G., D.R.C) and Neuroscience, Cell Biology and Physiology (T.L.G., T.L.B.), Wright State University, Dayton, Ohio
| | - William C Grunwald
- Departments of Pharmacology and Toxicology (E.J.S., W.C.G, T.L.G., D.R.C) and Neuroscience, Cell Biology and Physiology (T.L.G., T.L.B.), Wright State University, Dayton, Ohio
| | - Teresa L Garrett
- Departments of Pharmacology and Toxicology (E.J.S., W.C.G, T.L.G., D.R.C) and Neuroscience, Cell Biology and Physiology (T.L.G., T.L.B.), Wright State University, Dayton, Ohio
| | - Thomas L Brown
- Departments of Pharmacology and Toxicology (E.J.S., W.C.G, T.L.G., D.R.C) and Neuroscience, Cell Biology and Physiology (T.L.G., T.L.B.), Wright State University, Dayton, Ohio
| | - David R Cool
- Departments of Pharmacology and Toxicology (E.J.S., W.C.G, T.L.G., D.R.C) and Neuroscience, Cell Biology and Physiology (T.L.G., T.L.B.), Wright State University, Dayton, Ohio
| |
Collapse
|
5
|
Aracava Y, Albuquerque EX, Pereira EFR. (R,S)-trihexyphenidyl, acting via a muscarinic receptor-independent mechanism, inhibits hippocampal glutamatergic and GABAergic synaptic transmissions: Potential relevance for treatment of organophosphorus intoxication. Neuropharmacology 2023; 239:109684. [PMID: 37549771 PMCID: PMC10590273 DOI: 10.1016/j.neuropharm.2023.109684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Preclinical studies have reported that, compared to the muscarinic receptor (mAChR) antagonist atropine, (R,S)-trihexyphenidyl (THP) more effectively counters the cholinergic crisis, seizures, and neuropathology triggered by organophosphorus (OP)-induced acetylcholinesterase (AChE) inhibition. The greater effectiveness of THP was attributed to its ability to block mAChRs and N-methyl-d-aspartate-type glutamatergic receptors (NMDARs) in the brain. However, THP also inhibits α7 nicotinic receptors (nAChRs). The present study examined whether THP-induced inhibition of mAChRs, α7 nAChRs, and NMDARs is required to suppress glutamatergic synaptic transmission, whose overstimulation sustains OP-induced seizures. In primary hippocampal cultures, THP (1-30 μM) suppressed the frequency of excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs, respectively) recorded from neurons in nominally Mg2+-free solution. A single sigmoidal function adequately fit the overlapping concentration-response relationships for THP-induced suppression of IPSC and EPSC frequencies yielding an IC50 of 6.3 ± 1.3 μM. Atropine (1 μM), the NMDAR antagonist d,l-2-amino-5-phosphonopentanoic acid (D,L-AP5, 50 μM), and the α7 nAChR antagonist methyllycaconitine (MLA, 10 nM) did not prevent THP-induced inhibition of synaptic transmission. THP (10 μM) did not affect the probability of transmitter release because it had no effect on the frequency of miniature IPSCs and EPSCs recorded in the presence of tetrodotoxin. Additionally, THP had no effect on the amplitudes and decay-time constants of miniature IPSCs and EPSCs; therefore, it did not affect the activity of postsynaptic GABAA and glutamate receptors. This study provides the first demonstration that THP can suppress action potential-dependent synaptic transmission via a mechanism independent of NMDAR, mAChR, and α7 nAChR inhibition.
Collapse
Affiliation(s)
- Yasco Aracava
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edna F R Pereira
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
6
|
Niquet J, Nguyen D, de Araujo Furtado M, Lumley L. Treatment of cholinergic-induced status epilepticus with polytherapy targeting GABA and glutamate receptors. Epilepsia Open 2023; 8 Suppl 1:S117-S140. [PMID: 36807554 PMCID: PMC10173853 DOI: 10.1002/epi4.12713] [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: 10/27/2022] [Accepted: 02/15/2023] [Indexed: 02/23/2023] Open
Abstract
Despite new antiseizure medications, the development of cholinergic-induced refractory status epilepticus (RSE) continues to be a therapeutic challenge as pharmacoresistance to benzodiazepines and other antiseizure medications quickly develops. Studies conducted by Epilepsia. 2005;46:142 demonstrated that the initiation and maintenance of cholinergic-induced RSE are associated with trafficking and inactivation of gamma-aminobutyric acid A receptors (GABAA R) thought to contribute to the development of benzodiazepine pharmacoresistance. In addition, Dr. Wasterlain's laboratory reported that increased N-methyl-d-aspartate receptors (NMDAR) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) contribute to enhanced glutamatergic excitation (Neurobiol Dis. 2013;54:225; Epilepsia. 2013;54:78). Thus, Dr. Wasterlain postulated that targeting both maladaptive responses of reduced inhibition and increased excitation that is associated with cholinergic-induced RSE should improve therapeutic outcome. We currently review studies in several animal models of cholinergic-induced RSE that demonstrate that benzodiazepine monotherapy has reduced efficacy when treatment is delayed and that polytherapy with drugs that include a benzodiazepine (eg midazolam and diazepam) to counter loss of inhibition, concurrent with an NMDA antagonist (eg ketamine) to reduce excitation provide improved efficacy. Improved efficacy with polytherapy against cholinergic-induced seizure is demonstrated by reduction in (1) seizure severity, (2) epileptogenesis, and (3) neurodegeneration compared with monotherapy. Animal models reviewed include pilocarpine-induced seizure in rats, organophosphorus nerve agent (OPNA)-induced seizure in rats, and OPNA-induced seizure in two mouse models: (1) carboxylesterase knockout (Es1-/- ) mice which, similarly to humans, lack plasma carboxylesterase and (2) human acetylcholinesterase knock-in carboxylesterase knockout (KIKO) mice. We also review studies showing that supplementing midazolam and ketamine with a third antiseizure medication (valproate or phenobarbital) that targets a nonbenzodiazepine site rapidly terminates RSE and provides further protection against cholinergic-induced SE. Finally, we review studies on the benefits of simultaneous compared with sequential drug treatments and the clinical implications that lead us to predict improved efficacy of early combination drug therapies. The data generated from seminal rodent studies of efficacious treatment of cholinergic-induced RSE conducted under Dr. Wasterlain's guidance suggest that future clinical trials should treat the inadequate inhibition and temper the excess excitation that characterize RSE and that early combination therapies may provide improved outcome over benzodiazepine monotherapy.
Collapse
Affiliation(s)
- Jerome Niquet
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
- Epilepsy Research LaboratoryVeterans Affairs Greater Los Angeles Healthcare SystemLos AngelesCaliforniaUSA
| | - Donna Nguyen
- Neuroscience DepartmentU.S. Army Medical Research Institute of Chemical Defense (USAMRICD)Aberdeen Proving GroundMarylandUSA
| | | | - Lucille Lumley
- Neuroscience DepartmentU.S. Army Medical Research Institute of Chemical Defense (USAMRICD)Aberdeen Proving GroundMarylandUSA
| |
Collapse
|
7
|
Shih TM. A novel genetically modified mouse seizure model for evaluating anticonvulsive and neuroprotective efficacy of an A 1 adenosine receptor agonist following soman intoxication. Toxicol Appl Pharmacol 2023; 464:116437. [PMID: 36849019 PMCID: PMC10228141 DOI: 10.1016/j.taap.2023.116437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/27/2023] [Accepted: 02/19/2023] [Indexed: 02/27/2023]
Abstract
Recently a novel humanized mouse strain has been successfully generated, in which serum carboxylesterase (CES) knock out (KO) mice (Es1-/-) were further genetically modified by knocking in (KI), or adding, the gene that encodes the human form of acetylcholinesterase (AChE). The resulting human AChE KI and serum CES KO (or KIKO) mouse strain should not only exhibit organophosphorus nerve agent (NA) intoxication in a manner more similar to humans, but also display AChE-specific treatment responses more closely mimicking those of humans to facilitate data translation to pre-clinic trials. In this study, we utilized the KIKO mouse to develop a seizure model for NA medical countermeasure investigation, and then applied it to evaluate the anticonvulsant and neuroprotectant (A/N) efficacy of a specific A1 adenosine receptor (A1AR) agonist, N-bicyclo-(2.2.1)hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA), which has been shown in a rat seizure model to be a potent A/N compound. Male mice surgically implanted with cortical electroencephalographic (EEG) electrodes a week earlier were pretreated with HI-6 and challenged with various doses (26 to 47 μg/kg, SC) of soman (GD) to determine a minimum effective dose (MED) that induced sustained status epilepticus (SSE) activity in 100% of animals while causing minimum lethality at 24 h. The GD dose selected was then used to investigate the MED doses of ENBA when given either immediately following SSE initiation (similar to wartime military first aid application) or at 15 min after ongoing SSE seizure activity (applicable to civilian chemical attack emergency triage). The selected GD dose of 33 μg/kg (1.4 x LD50) generated SSE in 100% of KIKO mice and produced only 30% mortality. ENBA at a dose as little as 10 mg/kg, IP, caused isoelectric EEG activity within minutes after administration in naïve un-exposed KIKO mice. The MED doses of ENBA to terminate GD-induced SSE activity were determined to be 10 and 15 mg/kg when treatment was given at the time of SSE onset and when seizure activity was ongoing for 15 min, respectively. These doses were much lower than in the non-genetically modified rat model, which required an ENBA dose of 60 mg/kg to terminate SSE in 100% GD-exposed rats. At MED doses, all mice survived for 24 h, and no neuropathology was observed when the SSE was stopped. The findings confirmed that ENBA is a potent A/N for both immediate and delayed (i.e., dual purposed) therapy to victims of NA exposure and serves as a promising neuroprotective antidotal and adjunctive medical countermeasure candidate for pre-clinical research and development for human application.
Collapse
Affiliation(s)
- Tsung-Ming Shih
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen, Proving Ground, MD 21010-5400, USA..
| |
Collapse
|
8
|
Neurotoxicity evoked by organophosphates and available countermeasures. Arch Toxicol 2023; 97:39-72. [PMID: 36335468 DOI: 10.1007/s00204-022-03397-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022]
Abstract
Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.
Collapse
|
9
|
Weitman M, Eisenkraft A, TaShma Z, Makarovsky I, Last D, Daniels D, Guez D, Shneor R, Mardor Y, Nudelman A, Krivoy A. Synthesis and preliminary biological evaluation of gabactyzine, a benactyzine-GABA mutual prodrug, as an organophosphate antidote. Sci Rep 2022; 12:18078. [PMID: 36302937 PMCID: PMC9613653 DOI: 10.1038/s41598-022-23141-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/25/2022] [Indexed: 01/09/2023] Open
Abstract
Organophosphates (OPs) are inhibitors of acetylcholinesterase and have deleterious effects on the central nervous system. Clinical manifestations of OP poisoning include convulsions, which represent an underlying toxic neuro-pathological process, leading to permanent neuronal damage. This neurotoxicity is mediated through the cholinergic, GABAergic and glutamatergic (NMDA) systems. Pharmacological interventions in OP poisoning are designed to mitigate these specific neuro-pathological pathways, using anticholinergic drugs and GABAergic agents. Benactyzine is a combined anticholinergic, anti-NMDA compound. Based on previous development of novel GABA derivatives (such as prodrugs based on perphenazine for the treatment of schizophrenia and nortriptyline against neuropathic pain), we describe the synthesis and preliminary testing of a mutual prodrug ester of benactyzine and GABA. It is assumed that once the ester crosses the blood-brain-barrier it will undergo hydrolysis, releasing benactyzine and GABA, which are expected to act synergistically. The combined release of both compounds in the brain offers several advantages over the current OP poisoning treatment protocol: improved efficacy and safety profile (where the inhibitory properties of GABA are expected to counteract the anticholinergic cognitive adverse effects of benactyzine) and enhanced chemical stability compared to benactyzine alone. We present here preliminary results of animal studies, showing promising results with early gabactyzine administration.
Collapse
Affiliation(s)
- Michal Weitman
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - Arik Eisenkraft
- grid.9619.70000 0004 1937 0538The Institute for Research in Military Medicine, The Hebrew University Faculty of Medicine and The IDF Medical Corps, Jerusalem, Israel ,The IDF Medical Corps Headquarters, Ramat Gan, Israel
| | - Zeev TaShma
- The IDF Medical Corps Headquarters, Ramat Gan, Israel
| | - Igor Makarovsky
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - David Last
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Dianne Daniels
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - David Guez
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Ran Shneor
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Yael Mardor
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel ,grid.12136.370000 0004 1937 0546Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Abraham Nudelman
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - Amir Krivoy
- The IDF Medical Corps Headquarters, Ramat Gan, Israel ,grid.415340.70000 0004 0403 0450Geha Mental Health Center, Petach-Tikva, Israel
| |
Collapse
|
10
|
Figueiredo TH, Aroniadou-Anderjaska V, Pidoplichko VI, Apland JP, Braga MFM. Antiseizure and Neuroprotective Efficacy of Midazolam in Comparison with Tezampanel (LY293558) against Soman-Induced Status Epilepticus. TOXICS 2022; 10:409. [PMID: 35893842 PMCID: PMC9330837 DOI: 10.3390/toxics10080409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 12/12/2022]
Abstract
Acute exposure to nerve agents induces status epilepticus (SE), which can cause death or long-term brain damage. Diazepam is approved by the FDA for the treatment of nerve agent-induced SE, and midazolam (MDZ) is currently under consideration to replace diazepam. However, animal studies have raised questions about the neuroprotective efficacy of benzodiazepines. Here, we compared the antiseizure and neuroprotective efficacy of MDZ (5 mg/kg) with that of tezampanel (LY293558; 10 mg/kg), an AMPA/GluK1 receptor antagonist, administered 1 h after injection of the nerve agent, soman (1.2 × LD50), in adult male rats. Both of the anticonvulsants promptly stopped SE, with MDZ having a more rapid effect. However, SE reoccurred to a greater extent in the MDZ-treated group, resulting in a significantly longer total duration of SE within 24 h post-exposure compared with the LY293558-treated group. The neuroprotective efficacy of the two drugs was studied in the basolateral amygdala, 30 days post-exposure. Significant neuronal and inter-neuronal loss, reduced ratio of interneurons to the total number of neurons, and reduction in spontaneous inhibitory postsynaptic currents accompanied by increased anxiety were found in the MDZ-treated group. The rats treated with LY293558 did not differ from the control rats (not exposed to soman) in any of these measurements. Thus, LY293558 has significantly greater efficacy than midazolam in protecting against prolonged seizures and brain damage caused by acute nerve agent exposure.
Collapse
Affiliation(s)
- Taiza H. Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Volodymyr I. Pidoplichko
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
| | - James P. Apland
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, MD 21010, USA;
| | - Maria F. M. Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; (T.H.F.); (V.A.-A.); (V.I.P.)
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| |
Collapse
|
11
|
Lumley LA, Marrero-Rosado B, Rossetti F, Schultz CR, Stone MF, Niquet J, Wasterlain CG. Combination of antiseizure medications phenobarbital, ketamine, and midazolam reduces soman-induced epileptogenesis and brain pathology in rats. Epilepsia Open 2021; 6:757-769. [PMID: 34657398 PMCID: PMC8633481 DOI: 10.1002/epi4.12552] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 12/16/2022] Open
Abstract
Objective Cholinergic‐induced status epilepticus (SE) is associated with a loss of synaptic gamma‐aminobutyric acid A receptors (GABAAR) and an increase in N‐methyl‐D‐aspartate receptors (NMDAR) and amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors (AMPAR) that may contribute to pharmacoresistance when treatment with benzodiazepine antiseizure medication is delayed. The barbiturate phenobarbital enhances inhibitory neurotransmission by binding to a specific site in the GABAAR to increase the open state of the channel, decrease neuronal excitability, and reduce glutamate‐induced currents through AMPA/kainate receptors. We hypothesized that phenobarbital as an adjunct to midazolam would augment the amelioration of soman‐induced SE and associated neuropathological changes and that further protection would be provided by the addition of an NMDAR antagonist. Methods We investigated the efficacy of combining antiseizure medications to include a benzodiazepine and a barbiturate allosteric GABAAR modulator (midazolam and phenobarbital, respectively) to correct loss of inhibition, and ketamine to reduce excitation caused by increased synaptic localization of NMDAR and AMPAR, which are NMDA‐dependent. Rats implanted with transmitters to record electroencephalographic (EEG) activity were exposed to soman and treated with atropine sulfate and HI‐6 one min after exposure and with antiseizure medication(s) 40 minutes after seizure onset. Results The triple therapy combination of phenobarbital, midazolam, and ketamine administered at 40 minutes after seizure onset effectively prevented soman‐induced epileptogenesis and reduced neurodegeneration. In addition, dual therapy with phenobarbital and midazolam or ketamine was more effective than monotherapy (midazolam or phenobarbital) in reducing cholinergic‐induced toxicity. Significance Benzodiazepine efficacy is drastically reduced with time after seizure onset and inversely related to seizure duration. To overcome pharmacoresistance in severe benzodiazepine‐refractory cholinergic‐induced SE, simultaneous drug combination to include drugs that target both the loss of inhibition (eg, midazolam, phenobarbital) and the increased excitatory response (eg, ketamine) is more effective than benzodiazepine or barbiturate monotherapy.
Collapse
Affiliation(s)
- Lucille A Lumley
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, Maryland, USA
| | - Brenda Marrero-Rosado
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, Maryland, USA
| | - Franco Rossetti
- Military Psychiatry and Neuroscience Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Caroline R Schultz
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, Maryland, USA
| | - Michael F Stone
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, Maryland, USA
| | - Jerome Niquet
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Claude G Wasterlain
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA
| |
Collapse
|
12
|
McDonough JH, McMonagle JD, Capacio BR. Anticonvulsant effectiveness of scopolamine against soman-induced seizures in African green monkeys. Drug Chem Toxicol 2021; 45:2185-2192. [PMID: 34251950 DOI: 10.1080/01480545.2021.1916171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Prolonged seizures are a hallmark feature of intoxication with anticholinesterase nerve agents such as soman. While benzodiazepine drugs are typically used to control these seizures, studies in both rats and guinea pigs have shown that potent, centrally acting anticholinergic drugs such as scopolamine can also terminate such seizures. The present study was performed to determine if scopolamine could produce similar anticonvulsant effects in a nonhuman primate model of soman intoxication. Adult male African green monkeys, implanted with telemetry devices to record cortical electroencephalographic activity, were pretreated with pyridostigmine (0.02 mg/kg, intramuscularly [im]) and 40 min later challenged with 15 µg/kg (im) of the nerve agent soman. One min after soman exposure the animals were treated with atropine (0.4 mg/kg, im) and the oxime 2-PAM (25.7 mg/kg, im). One min after the start of seizure activity the animals were administered scopolamine (0.01-0.1 mg/kg, im), using an up-down dosing design over successive animals. Scopolamine was highly effective in stopping soman-induced seizures with an ED50 = 0.0312 mg/kg (0.021-0.047 mg/kg = 95% confidence limits). Seizure control was rapid, with all epileptiform activity stopping on average 21.7 min after scopolamine treatment. A separate pK study showed that scopolamine absorption peaked approximately 10 min after im administration and a dose of 0.032 mg/kg produced maximum plasma levels of 17.62 ng/ml. The results show that scopolamine exerts potent and rapid anticonvulsant action against soman-induced seizures and that it may serve as a valuable adjunct to current antidote treatments for nerve agent intoxication.
Collapse
Affiliation(s)
- John H McDonough
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Joseph D McMonagle
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Benedict R Capacio
- Medical Toxicology Research Division, Pharmaceutical Sciences Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| |
Collapse
|
13
|
Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Efrati R, David T, Dekel Jaoui H, Yampolsky M, Grauer E, Chapman S, Lazar S. Neuroprotection by delayed triple therapy following sarin nerve agent insult in the rat. Toxicol Appl Pharmacol 2021; 419:115519. [PMID: 33823148 DOI: 10.1016/j.taap.2021.115519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/25/2021] [Accepted: 04/01/2021] [Indexed: 02/08/2023]
Abstract
The development of refractory status epilepticus (SE) induced by sarin intoxication presents a therapeutic challenge. In our current research we evaluate the efficacy of a delayed combined triple treatment in ending the abnormal epileptiform seizure activity (ESA) and the ensuing of long-term neuronal insult. SE was induced in male Sprague-Dawley rats by exposure to 1.2LD50 sarin insufficiently treated by atropine and TMB4 (TA) 1 min later. Triple treatment of ketamine, midazolam and valproic acid was administered 30 min or 1 h post exposure and was compared to a delayed single treatment with midazolam alone. Toxicity and electrocorticogram activity were monitored during the first week and behavioral evaluation performed 3 weeks post exposure followed by brain biochemical and immunohistopathological analyses. The addition of both single and triple treatments reduced mortality and enhanced weight recovery compared to the TA-only treated group. The triple treatment also significantly minimized the duration of the ESA, reduced the sarin-induced increase in the neuroinflammatory marker PGE2, the brain damage marker TSPO, decreased the gliosis, astrocytosis and neuronal damage compared to the TA+ midazolam or only TA treated groups. Finally, the triple treatment eliminated the sarin exposed increased open field activity, as well as impairing recognition memory as seen in the other experimental groups. The delayed triple treatment may serve as an efficient therapy, which prevents brain insult propagation following sarin-induced refractory SE, even if treatment is postponed for up to 1 h.
Collapse
Affiliation(s)
- Ariel Gore
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Inbal Egoz
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shlomi Baranes
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Rellie Gez
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Rahav Efrati
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Tse'ela David
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Hani Dekel Jaoui
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Michael Yampolsky
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Ettie Grauer
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shira Chapman
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shlomi Lazar
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel.
| |
Collapse
|
14
|
Lumley L, Niquet J, Marrero-Rosado B, Schultz M, Rossetti F, de Araujo Furtado M, Wasterlain C. Treatment of acetylcholinesterase inhibitor-induced seizures with polytherapy targeting GABA and glutamate receptors. Neuropharmacology 2021; 185:108444. [PMID: 33359073 PMCID: PMC7944923 DOI: 10.1016/j.neuropharm.2020.108444] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 10/30/2020] [Accepted: 12/17/2020] [Indexed: 12/12/2022]
Abstract
The initiation and maintenance of cholinergic-induced status epilepticus (SE) are associated with decreased synaptic gamma-aminobutyric acid A receptors (GABAAR) and increased N-methyl-d-aspartate receptors (NMDAR) and amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR). We hypothesized that trafficking of synaptic GABAAR and glutamate receptors is maladaptive and contributes to the pharmacoresistance to antiseizure drugs; targeting these components should ameliorate the pathophysiological consequences of refractory SE (RSE). We review studies of rodent models of cholinergic-induced SE, in which we used a benzodiazepine allosteric GABAAR modulator to correct loss of inhibition, concurrent with the NMDA antagonist ketamine to reduce excitation caused by increased synaptic localization of NMDAR and AMPAR, which are NMDAR-dependent. Models included lithium/pilocarpine-induced SE in rats and soman-induced SE in rats and in Es1-/- mice, which similar to humans lack plasma carboxylesterase, and may better model soman toxicity. These model human soman toxicity and are refractory to benzodiazepines administered at 40 min after seizure onset, when enough synaptic GABAAR may not be available to restore inhibition. Ketamine-midazolam combination reduces seizure severity, epileptogenesis, performance deficits and neuropathology following cholinergic-induced SE. Supplementing that treatment with valproate, which targets a non-benzodiazepine site, effectively terminates RSE, providing further benefit against cholinergic-induced SE. The therapeutic index of drug combinations is also reviewed and we show the improved efficacy of simultaneous administration of midazolam, ketamine and valproate compared to sequential drug administration. These data suggest that future clinical trials should treat both the lack of sufficient inhibition and the excess excitation that characterize RSE, and include early combination drug therapies. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.
Collapse
Affiliation(s)
- Lucille Lumley
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, MD, USA.
| | - Jerome Niquet
- Department of Neurology, David Geffen School of Medicine at UCLA, Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Brenda Marrero-Rosado
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, MD, USA
| | - Mark Schultz
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), Aberdeen Proving Ground, MD, USA
| | - Franco Rossetti
- Military Psychiatry and Neuroscience Department, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | | | - Claude Wasterlain
- Department of Neurology, David Geffen School of Medicine at UCLA, Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| |
Collapse
|
15
|
Singh N, Golime R, Acharya J, Palit M. Quantitative Proteomic Changes after Organophosphorous Nerve Agent Exposure in the Rat Hippocampus. ACS Chem Neurosci 2020; 11:2638-2648. [PMID: 32702963 DOI: 10.1021/acschemneuro.0c00311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The widespread use of organophosphorous (OP) compounds and recent misuse of nerve agents on civilians requires an urgent need to decode their complex biological response to develop effective drugs. Proteomic profiling of biological target tissues helps in identification of molecular toxicity mechanisms. Quantitative proteomics profiling of the rat hippocampus was studied in this study. Liquid chromatography mass spectrometry (LC-MS) analysis of tandem mass tag (TMT)-labeled lysates identified 6356 proteins. A total of 69, 61, and 77 proteins were upregulated, and 66, 35, and 70 proteins were downregulated at 30 min, 1 day, and 7 days after soman exposure. This is the first report on the soman-induced proteomic changes to the best of our knowledge. Bioinformatics analysis revealed soman-induced broad-range proteomic changes in key pathways related to glutamate, acetylcholine, GABA, 5-hydroxytryptamine, and adrenergic receptors, G-protein signaling, chemokine and cytokine-mediated inflammation, cytoskeleton, neurodegeneration (Parkinson's and Alzheimer's), Wnt signaling, synaptic vesicle trafficking, MAP kinases, proteosome degradation, metabolism, and cell death. Selected protein changes were verified by immunoblotting, and neuropathological findings indicated significant brain damage. Results demonstrate that persistent proteomic changes in the brain can cause multiple neurological effects through cholinergic and non-cholinergic pathways, and these mechanistic insights are useful in the development of novel drugs.
Collapse
Affiliation(s)
- Naveen Singh
- Biochemistry-Vertox Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, M.P. 474002, India
| | - RamaRao Golime
- Biochemistry-Vertox Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, M.P. 474002, India
| | | | - Meehir Palit
- Biochemistry-Vertox Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, M.P. 474002, India
| |
Collapse
|
16
|
De Araujo Furtado M, Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Braga MFM. Electroencephalographic analysis in soman-exposed 21-day-old rats and the effects of midazolam or LY293558 with caramiphen. Ann N Y Acad Sci 2020; 1479:122-133. [PMID: 32237259 DOI: 10.1111/nyas.14331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 12/19/2022]
Abstract
Acute nerve agent exposure induces status epilepticus (SE), which can cause brain damage or death. Research aiming at developing effective therapies for controlling nerve agent-induced SE is commonly performed in adult rats. The characteristics of nerve agent-induced SE in young rats are less clear; relevant knowledge is necessary for developing effective pediatric therapies. Here, we have used electroencephalographic (EEG) recordings and analysis to study seizures in postnatal day 21 rats exposed to 1.2 × LD50 of soman, and compared the antiseizure efficacy of midazolam (MDZ)-currently considered by the Food and Drug Administration to replace diazepam for treating SE in victims of nerve agent exposure-with that of LY293558, an AMPA/GluK1 receptor antagonist, administered in combination with caramiphen, an antimuscarinic with N-methyl-d-aspartate receptor antagonistic properties. Prolonged SE developed in 80% of the rats and was reflected in behavioral seizures/convulsions. Both MDZ and LY293558 + caramiphen stopped the SE induced by soman, but there was a significant recurrence of seizures within 24 h postexposure only in the MDZ-treated group, as revealed in the raw EEG data and their representation in the frequency domain using a fast Fourier transform and in spectral analysis over 24 hours. In contrast to the high efficacy of LY293558 + caramiphen, MDZ is not an effective treatment for SE induced by soman in young animals.
Collapse
Affiliation(s)
- Marcio De Araujo Furtado
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - James P Apland
- Neurotoxicology Branch, the United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| |
Collapse
|
17
|
Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Grauer E, Chapman S, Lazar S. Efficacy of retigabine in ameliorating the brain insult following sarin exposure in the rat. Toxicol Appl Pharmacol 2020; 395:114963. [PMID: 32209366 DOI: 10.1016/j.taap.2020.114963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.
Collapse
Affiliation(s)
- Ariel Gore
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Inbal Egoz
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Baranes
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Rellie Gez
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Ettie Grauer
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shira Chapman
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Lazar
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| |
Collapse
|
18
|
Neurobiology of organophosphate-induced seizures. Epilepsy Behav 2019; 101:106426. [PMID: 31399343 DOI: 10.1016/j.yebeh.2019.07.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 11/24/2022]
Abstract
This review summarizes the efforts of our laboratories to develop a mechanism-based therapy for the treatment of organophosphate (OP) nerve agent-induced seizures. Organophosphate poisoning can occur during warfare and terrorist attacks and in the civilian sphere because of intentional or unintentional poisoning. Persons exposed to OPs experience seizures. We developed animal models of OP poisoning and then evaluated the effects of OP on excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated glutamatergic neurotransmission in the hippocampus using patch-clamp electrophysiology. Organophosphate agents enhance glutamatergic transmission by enhancing neurotransmitter release. M1 muscarinic receptors mediate this effect, at least in part. Muscarinic receptors exert this action by inhibiting specific KCNQ2/3 potassium channels, which mediate the M-current. Flupirtine, a drug that open channels, is effective against OP-induced seizures. This article is part of the Special Issue"Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".
Collapse
|
19
|
Niquet J, Lumley L, Baldwin R, Rossetti F, Suchomelova L, Naylor D, Estrada IBF, Schultz M, Furtado MDA, Wasterlain CG. Rational polytherapy in the treatment of cholinergic seizures. Neurobiol Dis 2019; 133:104537. [PMID: 31454548 DOI: 10.1016/j.nbd.2019.104537] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/25/2019] [Accepted: 07/18/2019] [Indexed: 10/26/2022] Open
Abstract
The initiation and maintenance phases of cholinergic status epilepticus (SE) are associated with maladaptive trafficking of synaptic GABAA and glutamate receptors. The resulting pharmacoresistance reflects a decrease in synaptic GABAA receptors and increase in NMDA and AMPA receptors, which tilt the balance between inhibition and excitation in favor of the latter. If these changes are important to the pathophysiology of SE, both should be treated, and blocking their consequences should have therapeutic potential. We used a model of benzodiazepine-refractory SE (RSE) (Tetz et al., 2006) and a model of soman-induced SE to test this hypothesis. Treatment of RSE with combinations of the GABAAR agonists midazolam or diazepam and the NMDAR antagonists MK-801 or ketamine terminated RSE unresponsive to high-dose monotherapy with benzodiazepines, ketamine or other antiepileptic drugs (AEDs). It also reduced RSE-associated neuronal injury, spatial memory deficits and the occurrence of spontaneous recurrent seizures (SRS), tested several weeks after SE. Treatment of sc soman-induced SE similarly showed much greater reduction of EEG power by a combination of midazolam with ketamine, compared to midazolam monotherapy. When treating late (40 min after seizure onset), there may not be enough synaptic GABAAR left to be able to restore inhibition with maximal GABAAR stimulation, and further benefit is derived from the addition of an AED which increases inhibition or reduces excitation by a non-GABAergic mechanism. The midazolam-ketamine-valproate combination is effective in terminating RSE. 3-D isobolograms demonstrate positive cooperativity between midazolam, ketamine and valproate, without any interaction between the toxicity of these drugs, so that the therapeutic index is increased by combination therapy between GABAAR agonist, NMDAR antagonist and selective AEDs. We compared this drug combination based on the receptor trafficking hypothesis to treatments based on clinical practice. The midazolam-ketamine-valproate combination is far more effective in stopping RSE than the midazolam-fosphenytoin-valproate combination inspired from clinical guidelines. Furthermore, sequential administration of midazolam, ketamine and valproate is far less effective than simultaneous treatment with the same drugs at the same dose. These data suggest that we should re-evaluate our traditional treatment of RSE, and that treatment should be based on pathophysiology. The search for a better drug has to deal with the fact that most monotherapy leaves half the problem untreated. The search for a better benzodiazepine should acknowledge the main cause of pharmacoresistance, which is loss of synaptic GABAAR. Future clinical trials should consider treating both the failure of inhibition and the runaway excitation which characterize RSE, and should include an early polytherapy arm.
Collapse
Affiliation(s)
- Jerome Niquet
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Lucille Lumley
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), 8350 Ricketts Point Rd., Aberdeen Proving Ground, MD 21010, USA
| | - Roger Baldwin
- Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Franco Rossetti
- Military Psychiatry and Neuroscience Department, Walter Reed Army institute of Research, Silver Spring, MD, USA
| | - Lucie Suchomelova
- Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - David Naylor
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ireri Betsabe Franco Estrada
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Mark Schultz
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), 8350 Ricketts Point Rd., Aberdeen Proving Ground, MD 21010, USA
| | - Marcio de Araujo Furtado
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense (USAMRICD), 8350 Ricketts Point Rd., Aberdeen Proving Ground, MD 21010, USA; Military Psychiatry and Neuroscience Department, Walter Reed Army institute of Research, Silver Spring, MD, USA
| | - Claude G Wasterlain
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA; Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA., USA.
| |
Collapse
|
20
|
Epigenetic and autophagic changes after nerve agent exposure in the rat piriform cortex and hippocampus. Toxicology 2019; 423:54-61. [DOI: 10.1016/j.tox.2019.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/17/2019] [Accepted: 05/13/2019] [Indexed: 11/18/2022]
|
21
|
Pearson-Smith JN, Patel M. Antioxidant drug therapy as a neuroprotective countermeasure of nerve agent toxicity. Neurobiol Dis 2019; 133:104457. [PMID: 31028872 PMCID: PMC7721294 DOI: 10.1016/j.nbd.2019.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
The use of chemical warfare agents is an ongoing, significant threat to both civilians and military personnel worldwide. Nerve agents are by far the most formidable toxicants in terms of their lethality and toxicity. Nerve agents initiate neurotoxicity by the irreversible inhibition of acetylcholinesterase and resultant accumulation of acetylcholine in excitable tissues. The cholinergic toxidrome presents as miosis, lacrimation, diarrhea, fasciculations, seizures, respiratory arrest and coma. Current medical countermeasures can attenuate acute mortality and confer limited protection against secondary neuronal injury when given rapidly after exposure. However, there is an urgent need for the development of novel, add-on neuroprotective therapies to prevent mortality and long-term toxicity of nerve agents. Increasing evidence suggests that pathways other than direct acetylcholinesterase inhibition contribute to neurotoxicity and secondary neuronal injury. Among these, oxidative stress is emerging as a key therapeutic target for nerve agent toxicity. In this review, we discuss the rationale for targeting oxidative stress in nerve agent toxicity and highlight research investigating antioxidant therapy as a neuroprotective medical countermeasure to attenuate oxidative stress, neuroinflammation and neurodegeneration.
Collapse
Affiliation(s)
- Jennifer N Pearson-Smith
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America.
| |
Collapse
|
22
|
Shih TM, Koenig JA, Acon Chen C. Comparative effects of scopolamine and phencynonate on organophosphorus nerve agent-induced seizure activity, neuropathology and lethality. Toxicol Mech Methods 2019; 29:322-333. [PMID: 30558458 DOI: 10.1080/15376516.2018.1558322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The efficacy of anticonvulsant therapies to stop seizure activities following organophosphorus nerve agents (NAs) has been documented as being time-dependent. We utilized the guinea pig NA-seizure model to compare the effectiveness of phencynonate (PCH) and scopolamine (SCP) when given at the early (at time of seizure onset) or late (40 min after seizure onset) phase of seizure progression. PCH possesses both anticholinergic and anti-NMDA activities, while SCP is a purely anti-muscarinic compound. Animals with cortical electrodes were pretreated with pyridostigmine bromide 30 min prior to exposure to a 2.0 x LD50 subcutaneous dose of a NA (GA, GB, GD, GF, VR, or VX), followed one min later with atropine sulfate and 2-PAM. At either early or late phase, animals were treated with either PCH or SCP and the 24-h anticonvulsant ED50 doses were determined. When administered at seizure onset, PCH, and SCP were both effective at terminating seizure activity against all NAs, with ED50 values for SCP generally being lower. At the 40 min time, ED50 values were obtained following GA, GD, GF, and VR challenges for SCP, but ED50 value was obtained only following GD for PCH, indicating a superior efficacy of SCP. When seizure activity was controlled, a significant improvement in weight loss, neuropathology, and survival was observed, regardless of treatment or NA. Overall, these results demonstrate the differing efficacies of these two similarly structured anticholinergic compounds with delayed administration and warrant further investigation into the timing and mechanisms of the seizure maintenance phase in different animal models.
Collapse
Affiliation(s)
- Tsung-Ming Shih
- a Medical Toxicology Research Division , US Army Medical Research Institute of Chemical Defense , Edgewood , MD , USA
| | - Jeffrey A Koenig
- a Medical Toxicology Research Division , US Army Medical Research Institute of Chemical Defense , Edgewood , MD , USA
| | - Cindy Acon Chen
- a Medical Toxicology Research Division , US Army Medical Research Institute of Chemical Defense , Edgewood , MD , USA
| |
Collapse
|
23
|
Jackson C, Ardinger C, Winter KM, McDonough JH, McCarren HS. Validating a model of benzodiazepine refractory nerve agent-induced status epilepticus by evaluating the anticonvulsant and neuroprotective effects of scopolamine, memantine, and phenobarbital. J Pharmacol Toxicol Methods 2019; 97:1-12. [PMID: 30790623 PMCID: PMC6529248 DOI: 10.1016/j.vascn.2019.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/05/2019] [Accepted: 02/14/2019] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Organophosphorus nerve agents (OPNAs) irreversibly block acetylcholinesterase activity, resulting in accumulation of excess acetylcholine at neural synapses, which can lead to a state of prolonged seizures known as status epilepticus (SE). Benzodiazepines, the current standard of care for SE, become less effective as latency to treatment increases. In a mass civilian OPNA exposure, concurrent trauma and limited resources would likely cause a delay in first response time. To address this issue, we have developed a rat model to test novel anticonvulsant/ neuroprotectant adjuncts at delayed time points. METHODS For model development, adult male rats with cortical electroencephalographic (EEG) electrodes were exposed to soman and administered saline along with atropine, 2-PAM, and midazolam 5, 20, or 40 min after SE onset. We validated our model using three drugs: scopolamine, memantine, and phenobarbital. Using the same procedure outlined above, rats were given atropine, 2-PAM, midazolam and test treatment 20 min after SE onset. RESULTS Using gamma power, delta power, and spike rate to quantify EEG activity, we found that scopolamine was effective, memantine was minimally effective, and phenobarbital had a delayed effect on terminating SE. Fluoro-Jade B staining was used to assess neuroprotection in five brain regions. Each treatment provided significant protection compared to saline + midazolam in at least two brain regions. DISCUSSION Because our data agree with previously published studies on the efficacy of these compounds, we conclude that this model is a valid way to test novel anticonvulsants/ neuroprotectants for controlling benzodiazepine-resistant OPNA-induced SE and subsequent neuropathology.
Collapse
Affiliation(s)
| | | | | | | | - Hilary S. McCarren
- Corresponding author at: U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD 21010, USA
| |
Collapse
|
24
|
Dunn EN, Ferrara-Bowens TM, Chachich ME, Honnold CL, Rothwell CC, Hoard-Fruchey HM, Lesyna CA, Johnson EA, Cerasoli DM, McDonough JH, Cadieux CL. Evaluating mice lacking serum carboxylesterase as a behavioral model for nerve agent intoxication. Toxicol Mech Methods 2018; 28:563-572. [PMID: 29768075 DOI: 10.1080/15376516.2018.1476637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mice and other rodents are typically utilized for chemical warfare nerve agent research. Rodents have large amounts of carboxylesterase in their blood, while humans do not. Carboxylesterase nonspecifically binds to and detoxifies nerve agent. The presence of this natural bioscavenger makes mice and other rodents poor models for studies identifying therapeutics to treat humans exposed to nerve agents. To obviate this problem, a serum carboxylesterase knockout (Es1 KO) mouse was created. In this study, Es1 KO and wild type (WT) mice were assessed for differences in gene expression, nerve agent (soman; GD) median lethal dose (MLD) values, and behavior prior to and following nerve agent exposure. No expression differences were detected between Es1 KO and WT mice in more than 34 000 mouse genes tested. There was a significant difference between Es1 KO and WT mice in MLD values, as the MLD for GD-exposed WT mice was significantly higher than the MLD for GD-exposed Es1 KO mice. Behavioral assessments of Es1 KO and WT mice included an open field test, a zero maze, a Barnes maze, and a sucrose preference test (SPT). While sex differences were observed in various measures of these tests, overall, Es1 KO mice behaved similarly to WT mice. The two genotypes also showed virtually identical neuropathological changes following GD exposure. Es1 KO mice appear to have an enhanced susceptibility to GD toxicity while retaining all other behavioral and physiological responses to this nerve agent, making the Es1 KO mouse a more human-like model for nerve agent research.
Collapse
Affiliation(s)
- Emily N Dunn
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Teresa M Ferrara-Bowens
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Mark E Chachich
- b Department of Psychology , Towson University , Towson , MD , USA
| | - Cary L Honnold
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Cristin C Rothwell
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Heidi M Hoard-Fruchey
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Catherine A Lesyna
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Erik A Johnson
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - Douglas M Cerasoli
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - John H McDonough
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| | - C Linn Cadieux
- a United States Army Medical Research Institute of Chemical Defense , Aberdeen Proving Ground , MD , USA
| |
Collapse
|
25
|
Scholl EA, Miller-Smith SM, Bealer SL, Lehmkuhle MJ, Ekstrand JJ, Dudek FE, McDonough JH. Age-dependent behaviors, seizure severity and neuronal damage in response to nerve agents or the organophosphate DFP in immature and adult rats. Neurotoxicology 2018; 66:10-21. [PMID: 29510177 PMCID: PMC5996394 DOI: 10.1016/j.neuro.2018.02.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/07/2018] [Accepted: 02/27/2018] [Indexed: 01/15/2023]
Abstract
Exposure to nerve agents (NAs) and other organophosphates (OPs) can initiate seizures that rapidly progress to status epilepticus (SE). While the electrographic and neuropathological sequelae of SE evoked by NAs and OPs have been characterized in adult rodents, they have not been adequately investigated in immature animals. In this study postnatal day (PND) 14, 21 and 28 rat pups, along with PND70 animals as adult controls, were exposed to NAs (sarin, VX) or another OP (diisopropylfluorophosphate, DFP). We then evaluated behavioral and electrographic (EEG) correlates of seizure activity, and performed neuropathology using Fluoro-Jade B. Although all immature rats exhibited behaviors that are often characterized as seizures, the incidence, duration, and severity of the electrographic seizure activity were age-dependent. No (sarin and VX) or brief (DFP) EEG seizure activity was evoked in PND14 rats, while SE progressively increased in severity as a function of age in PND21, 28 and 70 animals. Fluoro-Jade B staining was observed in multiple brain regions of animals that exhibited prolonged seizure activity. Neuronal injury in PND14 animals treated with DFP was lower than in older animals and absent in rats exposed to sarin or VX. In conclusion, we found that NAs and an OP provoked robust SE and neuronal injury similar to adults in PND21 and PND28, but not in PND14, rat pups. Convulsive behaviors were often present independent of EEG seizures and were unaccompanied by neuronal damage. These differential responses should be considered when investigating medical countermeasures for NA and OP exposure in pediatric populations.
Collapse
Affiliation(s)
- Erika A Scholl
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - Stephanie M Miller-Smith
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA
| | - Steven L Bealer
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84108 USA
| | - Mark J Lehmkuhle
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Epitel, Inc., Salt Lake City, UT, 84111 USA
| | - Jeffrey J Ekstrand
- Department of Pediatrics, University of Utah, Salt Lake City, UT, 84108 USA
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - John H McDonough
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA.
| |
Collapse
|
26
|
Assessment of brain oxygenation imbalance following soman exposure in rats. Neurotoxicology 2018; 65:28-37. [PMID: 29378300 DOI: 10.1016/j.neuro.2018.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 10/18/2022]
Abstract
Nerve agents (NAs) are potent organophosphorus (OP) compounds with applications in chemical warfare. OP compounds act by inhibiting acetylcholinesterase (AChE). Soman (O-pinacolyl methylphosphonofluoridate) is one of the most potent NAs. It is well known that small doses of NAs can be lethal, and that even non-lethal exposure leads to long-term mental debilitation/neurological damage. However, the neuropathology following exposure to sub-lethal nerve agents is not well understood. In this study, we examined changes in tissue oxygenation (pO2) in the cortex and hippocampus after a sub-lethal dose of soman [80-90 μg/kg; subcutaneous]. pO2 changes can provide information regarding oxygen delivery and utilization and may be indicative of a disruption in cerebral blood flow and/or metabolism. Changes in oxygenation were measured with chronically implanted oxygen sensors in awake and freely moving rats. Measurements were taken before, during, and after soman-induced convulsive seizures. Soman exposure resulted in an immediate increase in pO2 in the cortex, followed by an even greater increase that precedes the onset of soman-induced convulsive seizures. The rise in hippocampus pO2 was delayed relative to the cortex, although the general pattern of brain oxygenation between these two regions was similar. After convulsive seizures began, pO2 levels declined but usually remained hyperoxygenated. Following the decline in pO2, low frequency cycles of large amplitude changes were observed in both the cortex and hippocampus. This pattern is consistent with recurring seizures. Measuring real-time changes in brain pO2 provides new information on the physiological status of the brain following soman exposure. These results highlight that the measurement of brain oxygenation could provide a sensitive marker of nerve agent exposure and serve as a biomarker for treatment studies.
Collapse
|
27
|
Bittencourt S, Ferrazoli E, Valente MF, Romariz S, Janisset NR, Macedo CE, Antonio BDB, Barros V, Mundim M, Porcionatto M, Aarão MC, Miranda MF, Rodrigues AM, de Almeida ACG, Longo BM, Mello LE. Modification of the natural progression of epileptogenesis by means of biperiden in the pilocarpine model of epilepsy. Epilepsy Res 2017; 138:88-97. [DOI: 10.1016/j.eplepsyres.2017.10.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 10/11/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
|
28
|
Ferrara-Bowens TM, Chandler JK, Guignet MA, Irwin JF, Laitipaya K, Palmer DD, Shumway LJ, Tucker LB, McCabe JT, Wegner MD, Johnson EA. Neuropathological and behavioral sequelae in IL-1R1 and IL-1Ra gene knockout mice after soman (GD) exposure. Neurotoxicology 2017; 63:43-56. [DOI: 10.1016/j.neuro.2017.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 08/28/2017] [Accepted: 08/28/2017] [Indexed: 01/03/2023]
|
29
|
Golime R, Palit M, Acharya J, Dubey DK. Neuroprotective Effects of Galantamine on Nerve Agent-Induced Neuroglial and Biochemical Changes. Neurotox Res 2017; 33:738-748. [DOI: 10.1007/s12640-017-9815-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
|
30
|
Relat J, Pérez B, Camps P, Muñoz-Torrero D, Badia A, Victòria Clos M. Huprine X Attenuates The Neurotoxicity Induced by Kainic Acid, Especially Brain Inflammation. Basic Clin Pharmacol Toxicol 2017; 122:94-103. [PMID: 28724203 DOI: 10.1111/bcpt.12852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/07/2017] [Indexed: 11/28/2022]
Abstract
Huprine X (HX) is a synthetic anticholinesterasic compound that exerts a potent inhibitory action on acetylcholinesterase (AChE) activity, an agonist effect on cholinergic receptors, neuroprotective activity in different neurotoxicity models in vivo and in vitro and cognition enhancing effects in non-transgenic (C57BL/6) and transgenic (3xTg-AD, APPswe) mice. In this study, we assessed the ability of HX (0.8 mg/kg, 21 days) to prevent the damage induced by kainic acid (KA; 28 mg/kg) regarding apoptosis, glia reactivity and neurogenesis in mouse brain. KA administration significantly modified the levels of pAkt1, Bcl2, pGSK3β, p25/p35, increased the glial cell markers and reduced the neurogenesis process. We also observed that pre-treatment with HX significantly reduced the p25/p35 ratio and increased synaptophysin levels, which suggests a protective effect against apoptosis and an improvement of neuroplasticity. The increase in GFAP (88%) and Iba-1 (72%) induced by KA was totally prevented by HX pre-treatment, underlying a relevant anti-inflammatory action of the anticholinesterasic drug. Our findings highlight the potential of HX, in particular, and of AChEIs, in general, to treat a number of diseases that course with both cognitive deficits and chronic inflammatory processes.
Collapse
Affiliation(s)
- Júlia Relat
- Institute of Neurosciences, Autonomous University of Barcelona, Barcelona, Spain.,Department of Pharmacology, Therapeutics and Toxicology, Autonomous University of Barcelona, Barcelona, Spain
| | - Belén Pérez
- Institute of Neurosciences, Autonomous University of Barcelona, Barcelona, Spain.,Department of Pharmacology, Therapeutics and Toxicology, Autonomous University of Barcelona, Barcelona, Spain
| | - Pelayo Camps
- Laboratory of Pharmaceutical Chemistry (Unit Associated to the CSIC), Faculty of Agriculture and Science of Food and Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| | - Diego Muñoz-Torrero
- Laboratory of Pharmaceutical Chemistry (Unit Associated to the CSIC), Faculty of Agriculture and Science of Food and Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| | - Albert Badia
- Institute of Neurosciences, Autonomous University of Barcelona, Barcelona, Spain.,Department of Pharmacology, Therapeutics and Toxicology, Autonomous University of Barcelona, Barcelona, Spain
| | - M Victòria Clos
- Institute of Neurosciences, Autonomous University of Barcelona, Barcelona, Spain.,Department of Pharmacology, Therapeutics and Toxicology, Autonomous University of Barcelona, Barcelona, Spain
| |
Collapse
|
31
|
Abstract
Benzodiazepines represent the first-line treatment for the acute management of epileptic seizures and status epilepticus. The emergency use of benzodiazepines must be timely, and because most seizures occur outside of the hospital environment, there is a significant need for delivery methods that are easy for nonclinical caregivers to use and administer quickly and safely. In addition, the ideal route of administration should be reliable in terms of absorption. Rectal diazepam is the only licensed formulation in the USA, whereas rectal diazepam and buccal midazolam are currently licensed in the EU. However, the sometimes unpredictable absorption with rectal and buccal administration means they are not ideal routes. Several alternative routes are currently being explored. This is a narrative review of data about delivery methods for benzodiazepines alternative to the intravenous and oral routes for the acute treatment of seizures. Unconventional delivery options such as direct delivery to the central nervous system or inhalers are reported. Data show that intranasal diazepam or midazolam and the intramuscular auto-injector for midazolam are as effective as rectal or intravenous diazepam. Head-to-head comparisons with buccal midazolam are urgently needed. In addition, the majority of trials focused on children and adolescents, and further trials in adults are warranted.
Collapse
Affiliation(s)
- Marco Mula
- Atkinson Morley Regional Neuroscience Centre, St George's University Hospitals NHS Foundation Trust, London, SW17 0QT, UK.
- Institute of Medical and Biomedical Sciences, St George's University of London, London, UK.
| |
Collapse
|
32
|
Winkler JL, Skovira JW, Kan RK. Anticonvulsant efficacy of antihistamine cyproheptadine in rats exposed to the chemical warfare nerve agent soman. Neurotoxicology 2017; 58:153-160. [DOI: 10.1016/j.neuro.2016.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 11/15/2022]
|
33
|
Abou-Donia MB, Siracuse B, Gupta N, Sobel Sokol A. Sarin (GB, O-isopropyl methylphosphonofluoridate) neurotoxicity: critical review. Crit Rev Toxicol 2016; 46:845-875. [PMID: 27705071 PMCID: PMC5764759 DOI: 10.1080/10408444.2016.1220916] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Sarin (GB, O-isopropyl methylphosphonofluoridate) is a potent organophosphorus (OP) nerve agent that inhibits acetylcholinesterase (AChE) irreversibly. The subsequent build-up of acetylcholine (ACh) in the central nervous system (CNS) provokes seizures and, at sufficient doses, centrally-mediated respiratory arrest. Accumulation of ACh at peripheral autonomic synapses leads to peripheral signs of intoxication and overstimulation of the muscarinic and nicotinic receptors, which is described as "cholinergic crisis" (i.e. diarrhea, sweating, salivation, miosis, bronchoconstriction). Exposure to high doses of sarin can result in tremors, seizures, and hypothermia. More seriously, build-up of ACh at neuromuscular junctions also can cause paralysis and ultimately peripherally-mediated respiratory arrest which can lead to death via respiratory failure. In addition to its primary action on the cholinergic system, sarin possesses other indirect effects. These involve the activation of several neurotransmitters including gamma-amino-butyric acid (GABA) and the alteration of other signaling systems such as ion channels, cell adhesion molecules, and inflammatory regulators. Sarin exposure is associated with symptoms of organophosphate-induced delayed neurotoxicity (OPIDN) and organophosphate-induced chronic neurotoxicity (OPICN). Moreover, sarin has been involved in toxic and immunotoxic effects as well as organophosphate-induced endocrine disruption (OPIED). The standard treatment for sarin-like nerve agent exposure is post-exposure injection of atropine, a muscarinic receptor antagonist, accompanied by an oxime, an AChE reactivator, and diazepam.
Collapse
Affiliation(s)
- Mohamed B Abou-Donia
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Briana Siracuse
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Natasha Gupta
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Ashly Sobel Sokol
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| |
Collapse
|
34
|
Piermartiri T, Pan H, Figueiredo TH, Marini AM. α-Linolenic Acid, A Nutraceutical with Pleiotropic Properties That Targets Endogenous Neuroprotective Pathways to Protect against Organophosphate Nerve Agent-Induced Neuropathology. Molecules 2015; 20:20355-80. [PMID: 26569216 PMCID: PMC6332275 DOI: 10.3390/molecules201119698] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 10/29/2015] [Accepted: 11/03/2015] [Indexed: 01/23/2023] Open
Abstract
α-Linolenic acid (ALA) is a nutraceutical found in vegetable products such as flax and walnuts. The pleiotropic properties of ALA target endogenous neuroprotective and neurorestorative pathways in brain and involve the transcription factor nuclear factor kappa B (NF-κB), brain-derived neurotrophic factor (BDNF), a major neuroprotective protein in brain, and downstream signaling pathways likely mediated via activation of TrkB, the cognate receptor of BDNF. In this review, we discuss possible mechanisms of ALA efficacy against the highly toxic OP nerve agent soman. Organophosphate (OP) nerve agents are highly toxic chemical warfare agents and a threat to military and civilian populations. Once considered only for battlefield use, these agents are now used by terrorists to inflict mass casualties. OP nerve agents inhibit the critical enzyme acetylcholinesterase (AChE) that rapidly leads to a cholinergic crisis involving multiple organs. Status epilepticus results from the excessive accumulation of synaptic acetylcholine which in turn leads to the overactivation of muscarinic receptors; prolonged seizures cause the neuropathology and long-term consequences in survivors. Current countermeasures mitigate symptoms and signs as well as reduce brain damage, but must be given within minutes after exposure to OP nerve agents supporting interest in newer and more effective therapies. The pleiotropic properties of ALA result in a coordinated molecular and cellular program to restore neuronal networks and improve cognitive function in soman-exposed animals. Collectively, ALA should be brought to the clinic to treat the long-term consequences of nerve agents in survivors. ALA may be an effective therapy for other acute and chronic neurodegenerative disorders.
Collapse
Affiliation(s)
- Tetsade Piermartiri
- Molecular and Cellular Biology Graduate School Program, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Hongna Pan
- Department of Neurology and Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Ann M Marini
- Department of Neurology and Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| |
Collapse
|
35
|
Dramatic Increase in Cerebral Blood Flow following Soman Intoxication If Signs of Symptoms Can Be Seen. ACTA ACUST UNITED AC 2015. [DOI: 10.1155/2015/935069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Organophosphate poisoning is associated with adverse effects on the central nervous system such as seizure/convulsive activity and long term changes in neuronal networks. This study report an investigation designed to assess the consequences of Soman, a highly toxic organophosphorus compound, exposure on regional blood flow in the rat brain and peripheral organs. We performed repeated blood flow measurements in the same animal, using the microspheres technique, to characterize changes in regional blood flow at different times after Soman intoxication. In addition, the cardiopulmonary effects of Soman were followed during the intoxication. Administration of Soman (1 LD50; 90 µg/kg, s.c.) to anaesthetized rats produced a decrease in blood acetylcholinesterase activity in all animals tested. Although, only six out of ten rats showed signs of poisoning like a decrease in respiratory rate, the results show that only animals with significant signs of poisoning demonstrated an increase in cerebral blood flow. We conclude that it is of great importance to treat all data individually. An overall mean can easily be misinterpreted and conceal important effects. We also conclude that the increase in cerebral blood flow has an important role in the effect on respiration and that this effect is independent of the blood acetylcholinesterase activity.
Collapse
|
36
|
Myhrer T, Mariussen E, Enger S, Aas P. Supralethal poisoning by any of the classical nerve agents is effectively counteracted by procyclidine regimens in rats. Neurotoxicology 2015; 50:142-8. [PMID: 26318504 DOI: 10.1016/j.neuro.2015.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 11/15/2022]
Abstract
A treatment regimen consisting of HI-6, levetiracetam, and procyclidine (termed the triple regimen) has previously been shown to work as a universal therapy against soman poisoning in rats, since it has capacities to function as both prophylactic and therapeutic measure. The purpose of the present study was to examine whether the triple regimen may have antidotal efficacy against intoxication by other classical nerve agents than soman. The treatment was given 1 and 5 min after exposure to a supralethal dose of nerve agents, and the results showed that the triple regimen successfully prevented or terminated seizures and preserved the lives of rats exposed to 5×LD50 of soman, sarin, cyclosarin, or VX, but solely 3×LD50 of tabun was managed by this regimen. To meet the particular antidotal requirements of tabun, the triple regimen was reinforced with obidoxime and was made to a quadruple regimen that effectively treated rats intoxicated by 5×LD50 of tabun. The rats recovered very well and the majority gained pre-exposure body weight within 7 days. Neuropathology was seen in all groups regardless of whether the rats seized or not. The most extensive damage was produced by sarin and cyclosarin. Differentiation between the nerve agents' potency to cause lesions was probably seen because the efficacious treatments ensured survival of supralethal poisoning. A combination of 2 oximes and 2 anticonvulsants may be a prerequisite to counteract effectively high levels of poisoning by any classical nerve agent.
Collapse
Affiliation(s)
- Trond Myhrer
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, PO Box 25, No-2027 Kjeller, Norway
| | - Espen Mariussen
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, PO Box 25, No-2027 Kjeller, Norway
| | - Siri Enger
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, PO Box 25, No-2027 Kjeller, Norway
| | - Pål Aas
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, PO Box 25, No-2027 Kjeller, Norway.
| |
Collapse
|
37
|
Prager EM, Figueiredo TH, Long RP, Aroniadou-Anderjaska V, Apland JP, Braga MFM. LY293558 prevents soman-induced pathophysiological alterations in the basolateral amygdala and the development of anxiety. Neuropharmacology 2015; 89:11-8. [PMID: 25204221 PMCID: PMC4250288 DOI: 10.1016/j.neuropharm.2014.08.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/18/2014] [Accepted: 08/20/2014] [Indexed: 11/24/2022]
Abstract
Exposure to nerve agents can cause brain damage due to prolonged seizure activity, producing long-term behavioral deficits. We have previously shown that LY293558, a GluK1/AMPA receptor antagonist, is a very effective anticonvulsant and neuroprotectant against nerve agent exposure. In the present study, we examined whether the protection against nerve agent-induced seizures and neuropathology conferred by LY293558 translates into protection against pathophysiological alterations in the basolateral amygdala (BLA) and the development of anxiety, which is the most prevalent behavioral deficit resulting from exposure. LY293558 (15 mg/kg) was administered to rats, along with atropine and HI-6, at 20 min after exposure to soman (1.2 × LD50). At 24 h, 7 days, and 30 days after exposure, soman-exposed rats who did not receive LY293558 had reduced but prolonged evoked field potentials in the BLA, as well as increased paired-pulse ratio, suggesting neuronal damage and impaired synaptic inhibition; rats who received LY293558 did not differ from controls in these parameters. Long-term potentiation of synaptic transmission was impaired at 7 days after exposure in the soman-exposed rats who did not receive anticonvulsant treatment, but not in the LY293558-treated rats. Anxiety-like behavior assessed by the open field and acoustic startle response tests was increased in the soman-exposed rats at 30 and 90 days after exposure, while rats treated with LY293558 did not differ from controls. Along with our previous findings, the present data demonstrate the remarkable efficacy of LY293558 in counteracting nerve agent-induced seizures, neuropathology, pathophysiological alterations in the BLA, and anxiety-related behavioral deficits.
Collapse
Affiliation(s)
- 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; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, 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.
| | - Robert P Long
- 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; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, 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, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - James P Apland
- Neurotoxicology Branch, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, 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, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| |
Collapse
|
38
|
Verrotti A, Milioni M, Zaccara G. Safety and efficacy of diazepam autoinjector for the management of epilepsy. Expert Rev Neurother 2015; 15:127-33. [DOI: 10.1586/14737175.2015.1003043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
39
|
Shekh-Ahmad T, Mawasi H, McDonough JH, Finnell RH, Wlodarczyk BJ, Yavin E, Bialer M. Enantioselective pharmacodynamic and pharmacokinetic analysis of two chiral CNS-active carbamate derivatives of valproic acid. Epilepsia 2014; 55:1944-52. [DOI: 10.1111/epi.12857] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2014] [Indexed: 12/29/2022]
Affiliation(s)
- Tawfeeq Shekh-Ahmad
- Faculty of Medicine; Institute for Drug Research; School of Pharmacy; The Hebrew University of Jerusalem; Jerusalem Israel
| | - Hafiz Mawasi
- Faculty of Medicine; Institute for Drug Research; School of Pharmacy; The Hebrew University of Jerusalem; Jerusalem Israel
| | - John H. McDonough
- Pharmacology Branch; Research Division; US Army Medical Research Institute of Chemical Defense; Aberdeen Proving Ground; Maryland U.S.A
| | - Richard H. Finnell
- Department of Nutritional Sciences; Dell Pediatric Research Institute; The University of Texas at Austin; Austin Texas U.S.A
| | - Bogdan J. Wlodarczyk
- Department of Nutritional Sciences; Dell Pediatric Research Institute; The University of Texas at Austin; Austin Texas U.S.A
| | - Eylon Yavin
- Faculty of Medicine; Institute for Drug Research; School of Pharmacy; The Hebrew University of Jerusalem; Jerusalem Israel
| | - Meir Bialer
- Faculty of Medicine; Institute for Drug Research; School of Pharmacy; The Hebrew University of Jerusalem; Jerusalem Israel
- David R. Bloom Center for Pharmacy; The Hebrew University of Jerusalem; Jerusalem Israel
| |
Collapse
|
40
|
Kow RL, Cheng EM, Jiang K, Le JH, Stella N, Nathanson NM. Muscarinic M1 receptor and cannabinoid CB1 receptor do not modulate paraoxon-induced seizures. Pharmacol Res Perspect 2014; 3:e00100. [PMID: 25692018 PMCID: PMC4317231 DOI: 10.1002/prp2.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/19/2014] [Accepted: 09/16/2014] [Indexed: 11/24/2022] Open
Abstract
One of the major signs of severe organophosphate poisoning is seizures. Previous studies have shown that both muscarinic agonist- and organophosphate-induced seizures require activation of muscarinic acetylcholine receptors in the central nervous system. Seizures induced by the muscarinic agonist pilocarpine require the M1 receptor and are modulated by cannabinoid CB1 receptors. In this study, we determined whether M1 and CB1 receptors also regulated seizures induced by the organophosphate paraoxon. We found no differences in seizures induced by paraoxon in wild-type (WT) and M1 knockout (KO) mice, indicating that in contrast to pilocarpine seizures, M1 receptors are not required for paraoxon seizures. Furthermore, we found that pilocarpine administration resulted in seizure-independent activation of ERK in the hippocampus in a M1 receptor-dependent manner, while paraoxon did not induce seizure-independent activation of ERK in the mouse hippocampus. This shows that pilocarpine and paraoxon activated M1 receptors in the hippocampus to different extents. There were no differences in seizures induced by paraoxon in WT and CB1 KO mice, and neither CB1 agonist nor antagonist administration had significant effects on paraoxon seizures, indicating that, in contrast to pilocarpine seizures, paraoxon seizures are not modulated by CB1 receptors. These results demonstrate that there are fundamental molecular differences in the regulation of seizures induced by pilocarpine and paraoxon.
Collapse
Affiliation(s)
- Rebecca L Kow
- Department of Pharmacology, University of Washington Seattle, Washington
| | - Eugene M Cheng
- Department of Pharmacology, University of Washington Seattle, Washington
| | - Kelly Jiang
- Department of Pharmacology, University of Washington Seattle, Washington
| | - Joshua H Le
- Department of Pharmacology, University of Washington Seattle, Washington
| | - Nephi Stella
- Department of Pharmacology, University of Washington Seattle, Washington
| | - Neil M Nathanson
- Department of Pharmacology, University of Washington Seattle, Washington
| |
Collapse
|
41
|
Kaur S, Singh S, Chahal KS, Prakash A. Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity. Can J Physiol Pharmacol 2014; 92:893-911. [DOI: 10.1139/cjpp-2014-0113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.
Collapse
Affiliation(s)
- Shamsherjit Kaur
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
- Punjab Technical University, Kapurthala 144601, Punjab, India
| | - Satinderpal Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Karan Singh Chahal
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Atish Prakash
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| |
Collapse
|
42
|
Caramiphen edisylate: an optimal antidote against organophosphate poisoning. Toxicology 2014; 325:115-24. [PMID: 25201353 DOI: 10.1016/j.tox.2014.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/21/2014] [Accepted: 09/04/2014] [Indexed: 11/30/2022]
Abstract
Potent cholinesterase inhibitors such as sarin, induce an array of harmful effects including hypersecretion, convulsions and ultimately death. Surviving subjects demonstrate damage in specific brain regions that lead to cognitive and neurological dysfunctions. An early accumulation of acetylcholine in the synaptic clefts was suggested as the trigger of a sequence of neurochemical events such as an excessive outpour of glutamate and activation of its receptors. Indeed, alterations in NMDA and AMPA central receptors' densities were detected in brains of poisoned animals. Attempts to improve the current cholinergic-based treatment by adding potent anticonvulsants or antiglutamatergic drugs produced unsatisfactory results. In light of recent events in Syria and the probability of various scenarios of military or terrorist attacks involving organophosphate (OP) nerve agent, research should focus on finding markedly improved countermeasures. Caramiphen, an antimuscarinic drug with antiglutamatergic and GABAergic facilitating properties, was evaluated in a wide range of animals and experimental protocols against OP poisoning. Its remarkable efficacy against OP exposure was established both in prophylactic and post-exposure therapies in both small and large animals. The present review will highlight the outstanding neuroprotective effect of caramiphen as the optimal candidate for the treatment of OP-exposed subjects.
Collapse
|
43
|
Choice of approaches in developing novel medical countermeasures for nerve agent poisoning. Neurotoxicology 2014; 44:27-38. [DOI: 10.1016/j.neuro.2014.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/24/2014] [Accepted: 04/30/2014] [Indexed: 11/24/2022]
|
44
|
Galantamine prevents long-lasting suppression of excitatory synaptic transmission in CA1 pyramidal neurons of soman-challenged guinea pigs. Neurotoxicology 2014; 44:270-8. [PMID: 25064080 DOI: 10.1016/j.neuro.2014.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/08/2014] [Accepted: 07/15/2014] [Indexed: 12/27/2022]
Abstract
Galantamine, a drug currently approved for the treatment of Alzheimer's disease, has recently emerged as an effective pretreatment against the acute toxicity and delayed cognitive deficits induced by organophosphorus (OP) nerve agents, including soman. Since cognitive deficits can result from impaired glutamatergic transmission in the hippocampus, the present study was designed to test the hypothesis that hippocampal glutamatergic transmission declines following an acute exposure to soman and that this effect can be prevented by galantamine. To test this hypothesis, spontaneous excitatory postsynaptic currents (EPSCs) were recorded from CA1 pyramidal neurons in hippocampal slices obtained at 1h, 24h, or 6-9 days after guinea pigs were injected with: (i) 1×LD50 soman (26.3μg/kg, s.c.); (ii) galantamine (8mg/kg, i.m.) followed 30min later by 1×LD50 soman, (iii) galantamine (8mg/kg, i.m.), or (iv) saline (0.5ml/kg, i.m.). In soman-injected guinea pigs that were not pretreated with galantamine, the frequency of EPSCs was significantly lower than that recorded from saline-injected animals. There was no correlation between the severity of soman-induced acute toxicity and the magnitude of soman-induced reduction of EPSC frequency. Pretreatment with galantamine prevented the reduction of EPSC frequency observed at 6-9 days after the soman challenge. Prevention of soman-induced long-lasting reduction of hippocampal glutamatergic synaptic transmission may be an important determinant of the ability of galantamine to counter cognitive deficits that develop long after an acute exposure to the nerve agent.
Collapse
|
45
|
Chen J, Pan H, Chen C, Wu W, Iskandar K, He J, Piermartiri T, Jacobowitz DM, Yu QS, McDonough JH, Greig NH, Marini AM. (-)-Phenserine attenuates soman-induced neuropathology. PLoS One 2014; 9:e99818. [PMID: 24955574 PMCID: PMC4067273 DOI: 10.1371/journal.pone.0099818] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/15/2014] [Indexed: 11/18/2022] Open
Abstract
Organophosphorus (OP) nerve agents are deadly chemical weapons that pose an alarming threat to military and civilian populations. The irreversible inhibition of the critical cholinergic degradative enzyme acetylcholinesterase (AChE) by OP nerve agents leads to cholinergic crisis. Resulting excessive synaptic acetylcholine levels leads to status epilepticus that, in turn, results in brain damage. Current countermeasures are only modestly effective in protecting against OP-induced brain damage, supporting interest for evaluation of new ones. (-)-Phenserine is a reversible AChE inhibitor possessing neuroprotective and amyloid precursor protein lowering actions that reached Phase III clinical trials for Alzheimer's Disease where it exhibited a wide safety margin. This compound preferentially enters the CNS and has potential to impede soman binding to the active site of AChE to, thereby, serve in a protective capacity. Herein, we demonstrate that (-)-phenserine protects neurons against soman-induced neuronal cell death in rats when administered either as a pretreatment or post-treatment paradigm, improves motoric movement in soman-exposed animals and reduces mortality when given as a pretreatment. Gene expression analysis, undertaken to elucidate mechanism, showed that (-)-phenserine pretreatment increased select neuroprotective genes and reversed a Homer1 expression elevation induced by soman exposure. These studies suggest that (-)-phenserine warrants further evaluation as an OP nerve agent protective strategy.
Collapse
Affiliation(s)
- Jun Chen
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Hongna Pan
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Cynthia Chen
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Wei Wu
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Kevin Iskandar
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Jeffrey He
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - Tetsade Piermartiri
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| | - David M. Jacobowitz
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Qian-Sheng Yu
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - John H. McDonough
- Pharmacology Branch, Research Division, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland, United States of America
| | - Nigel H. Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Ann M. Marini
- Neurology Department, Uniformed Services University of Health Sciences, Bethesda, Maryland, United States of America
| |
Collapse
|
46
|
Prager EM, Aroniadou-Anderjaska V, Almeida-Suhett CP, Figueiredo TH, Apland JP, Rossetti F, Olsen CH, Braga MFM. The recovery of acetylcholinesterase activity and the progression of neuropathological and pathophysiological alterations in the rat basolateral amygdala after soman-induced status epilepticus: relation to anxiety-like behavior. Neuropharmacology 2014; 81:64-74. [PMID: 24486384 PMCID: PMC4005290 DOI: 10.1016/j.neuropharm.2014.01.035] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/12/2013] [Accepted: 01/21/2014] [Indexed: 02/05/2023]
Abstract
Organophosphorus nerve agents are powerful neurotoxins that irreversibly inhibit acetylcholinesterase (AChE) activity. One of the consequences of AChE inhibition is the generation of seizures and status epilepticus (SE), which cause brain damage, resulting in long-term neurological and behavioral deficits. Increased anxiety is the most common behavioral abnormality after nerve agent exposure. This is not surprising considering that the amygdala, and the basolateral nucleus of the amygdala (BLA) in particular, plays a central role in anxiety, and this structure suffers severe damage by nerve agent-induced seizures. In the present study, we exposed male rats to the nerve agent soman, at a dose that induce SE, and determined the time course of recovery of AChE activity, along with the progression of neuropathological and pathophysiological alterations in the BLA, during a 30-day period after exposure. Measurements were taken at 24 h, 7 days, 14 days, and 30 days after exposure, and at 14 and 30 days, anxiety-like behavior was also evaluated. We found that more than 90% of AChE is inhibited at the onset of SE, and AChE inhibition remains at this level 24 h later, in the BLA, as well as in the hippocampus, piriform cortex, and prelimbic cortex, which we analyzed for comparison. AChE activity recovered by day 7 in the BLA and day 14 in the other three regions. Significant neuronal loss and neurodegeneration were present in the BLA at 24 h and throughout the 30-day period. There was no significant loss of GABAergic interneurons in the BLA at 24 h post-exposure. However, by day 7, the number of GABAergic interneurons in the BLA was reduced, and at 14 and 30 days after soman, the ratio of GABAergic interneurons to the total number of neurons was lower compared to controls. Anxiety-like behavior in the open-field and the acoustic startle response tests was increased at 14 and 30 days post-exposure. Accompanying pathophysiological alterations in the BLA - studied in in vitro brain slices - included a reduction in the amplitude of field potentials evoked by stimulation of the external capsule, along with prolongation of their time course and an increase in the paired-pulse ratio. Long-term potentiation was impaired at 24 h, 7 days, and 14 days post-exposure. The loss of GABAergic interneurons in the BLA and the decreased interneuron to total number of neurons ratio may be the primary cause of the development of anxiety after nerve agent exposure.
Collapse
Affiliation(s)
- 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; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, 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, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Camila P Almeida-Suhett
- 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; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, 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
| | - James P Apland
- Neurotoxicology Branch, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Franco Rossetti
- 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
| | - Cara H Olsen
- Biostatistics Consulting Center, 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, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| |
Collapse
|
47
|
Myhrer T, Enger S, Aas P. Behavioral side effects of prophylactic therapies against soman-induced seizures and lethality in rats. Toxicol Rep 2014; 1:102-113. [PMID: 28962231 PMCID: PMC5598500 DOI: 10.1016/j.toxrep.2014.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/07/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022] Open
Abstract
Four medical therapies previously shown to exert varying degrees of protection against a convulsant dose of soman were assessed for potential behavioral side effects in a novelty test. In Experiment 1, HI-6 (1-[([4-(aminocarbonyl)pyridino] methoxy)methyl]-2-[(hydroxyimino)methyl]pyridinium) (125 mg/kg), scopolamine (1 mg/kg), physostigmine (0.1 mg/kg), levetiracetam (50 mg/kg), and procyclidine (20 mg/kg) were tested separately. In Experiment 2, the combination of HI-6, scopolamine, and physostigmine (termed the physostigmine regimen) or HI-6, levetiracetam, and procyclidine (termed the procyclidine regimen) were tested. In Experiment 3, the metabotropic glutamate modulators DCG-IV ((2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine) (4 mg/kg) and MPEP (2-Methyl-6-(phenylethynyl)pyridine hydrochloride) (30 mg/kg) were tested separately or each drug in combination with HI-6 and procyclidine (termed the DCG-IV regimen and the MPEP regimen, respectively). The results showed that the physostigmine and procyclidine regimens both produced severe cognitive impairment (lack of preference for novelty) and reduced locomotor and rearing activities. The DCG-IV and MPEP regimens caused milder deficits on the same behavioral measures. Some relations were seen between prophylactic capacity and degree of behavioral side effects. Only HI-6 or levetiracetam had no adverse effects on behavior. DCG-IV or MPEP produced some impairment, whereas the detrimental effects of scopolamine or procyclidine were pronounced. The relatively high dose of procyclidine (anticholinergic and antiglutamatergic) needed for prophylactic efficacy may have played a major role for the side effects of the regimens in which the drug was used. It was concluded that behavioral side effects are inevitable for potent prophylactic therapies against soman intoxication.
Collapse
Affiliation(s)
- Trond Myhrer
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, Kjeller, Norway
| | - Siri Enger
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, Kjeller, Norway
| | - Pål Aas
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, Kjeller, Norway
| |
Collapse
|
48
|
Deshpande LS, Carter DS, Phillips KF, Blair RE, DeLorenzo RJ. Development of status epilepticus, sustained calcium elevations and neuronal injury in a rat survival model of lethal paraoxon intoxication. Neurotoxicology 2014; 44:17-26. [PMID: 24785379 DOI: 10.1016/j.neuro.2014.04.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 01/23/2023]
Abstract
Paraoxon (POX) is an active metabolite of organophosphate (OP) pesticide parathion that has been weaponized and used against civilian populations. Exposure to POX produces high mortality. OP poisoning is often associated with chronic neurological disorders. In this study, we optimize a rat survival model of lethal POX exposures in order to mimic both acute and long-term effects of POX intoxication. Male Sprague-Dawley rats injected with POX (4mg/kg, ice-cold PBS, s.c.) produced a rapid cholinergic crisis that evolved into status epilepticus (SE) and death within 6-8min. The EEG profile for POX induced SE was characterized and showed clinical and electrographic seizures with 7-10Hz spike activity. Treatment of 100% lethal POX intoxication with an optimized three drug regimen (atropine, 2mg/kg, i.p., 2-PAM, 25mg/kg, i.m. and diazepam, 5mg/kg, i.p.) promptly stopped SE and reduced acute mortality to 12% and chronic mortality to 18%. This model is ideally suited to test effective countermeasures against lethal POX exposure. Animals that survived the POX SE manifested prolonged elevations in hippocampal [Ca(2+)]i (Ca(2+) plateau) and significant multifocal neuronal injury. POX SE induced Ca(2+) plateau had its origin in Ca(2+) release from intracellular Ca(2+) stores since inhibition of ryanodine/IP3 receptor lowered elevated Ca(2+) levels post SE. POX SE induced neuronal injury and alterations in Ca(2+) dynamics may underlie some of the long term morbidity associated with OP toxicity.
Collapse
Affiliation(s)
| | - Dawn S Carter
- Departments of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Kristin F Phillips
- Departments of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Robert E Blair
- Departments of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Robert J DeLorenzo
- Departments of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Departments of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Departments of Molecular Biophysics and Biochemistry, Virginia Commonwealth University, Richmond, VA 23298, USA.
| |
Collapse
|
49
|
Efficacy of antidotes (midazolam, atropine and HI-6) on nerve agent induced molecular and neuropathological changes. BMC Neurosci 2014; 15:47. [PMID: 24708580 PMCID: PMC3984638 DOI: 10.1186/1471-2202-15-47] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/24/2014] [Indexed: 11/10/2022] Open
Abstract
Background Recent alleged attacks with nerve agent sarin on civilians in Syria indicate their potential threat to both civilian and military population. Acute nerve agent exposure can cause rapid death or leads to multiple and long term neurological effects. The biochemical changes that occur following nerve agent exposure needs to be elucidated to understand the mechanisms behind their long term neurological effects and to design better therapeutic drugs to block their multiple neurotoxic effects. In the present study, we intend to study the efficacy of antidotes comprising of HI-6 (1-[[[4-(aminocarbonyl)-pyridinio]-methoxy]-methyl]-2-[(hydroxyimino) methyl] pyridinium dichloride), atropine and midazolam on soman induced neurodegeneration and the expression of c-Fos, Calpain, and Bax levels in discrete rat brain areas. Results Therapeutic regime consisting of HI-6 (50 mg/kg, i.m), atropine (10 mg/kg, i.m) and midazolam (5 mg/kg, i.m) protected animals against soman (2 × LD50, s.c) lethality completely at 2 h and 80% at 24 h. HI-6 treatment reactivated soman inhibited plasma and RBC cholinesterase up to 40%. Fluoro-Jade B (FJ-B) staining of neurodegenerative neurons showed that soman induced significant necrotic neuronal cell death, which was reduced by this antidotal treatment. Soman increased the expression of neuronal proteins including c-Fos, Bax and Calpain levels in the hippocampus, cerebral cortex and cerebellum regions of the brain. This therapeutic regime also reduced the soman induced Bax, Calpain expression levels to near control levels in the different brain regions studied, except a mild induction of c-Fos expression in the hippocampus. Conclusion Rats that received antidotal treatment after soman exposure were protected from mortality and showed reduction in the soman induced expression of c-Fos, Bax and Calpain and necrosis. Results highlight the need for timely administration of better antidotes than standard therapy in order to prevent the molecular and biochemical changes and subsequent long term neurological effects induced by nerve agents.
Collapse
|
50
|
Banerjee S, Chattopadhyay P, Ghosh A, Pathak MP, Gogoi J, Veer V. Protection by a transdermal patch containing eserine and pralidoxime chloride for prophylaxis against (±)-Anatoxin A poisoning in rats. Eur J Pharm Sci 2014; 56:28-36. [PMID: 24530375 DOI: 10.1016/j.ejps.2014.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 11/19/2022]
Abstract
The prophylactic and neuroprotective impact of a transdermal patch containing eserine and pralidoxime chloride (2-PAM) against (±)-Anatoxin A poisoning was investigated using Wistar strain albino rats. Rats were smooth-shaved on the dorsal side, attached with a drug-in-adhesive matrix type prophylactic transdermal patch for 72 h and challenged with subcutaneous injection of three doses (1.0, 1.5 and 2.0×LD50) of (±)-Anatoxin A. The LD50 value of (±)-Anatoxin A was determined to be 1.25mg/kg, and at this particular dose (1.0×LD50) of toxin induced severe clinical symptom including extreme seizures in rats, resulting acute brain injuries in discrete brain regions, leading to 100% mortality within 5 min. The anticonvulsant effect, antiarrythmic effect, nerve conduction study, clinical observations and mortality, neuroprotective effect as well as skin histopathology of the prophylactic transdermal patch against (±)-Anatoxin A poisoning were investigated systematically. It was found that seizures, tachycardia, nerve damage, clinical symptoms, brain injuries and mortality induced by such lethal toxin were effectively prevented by the prophylactic patch treatment up to certain LD50 level. Hence, it could be a choice of potential therapeutic regimen against such lethal poisoning.
Collapse
Affiliation(s)
- Subham Banerjee
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur 784 001, Assam, India; Department of Pharmaceutical Sciences, Birla Institute of Technology, Mesra, 835 215 Ranchi, Jharkhand, India
| | - Pronobesh Chattopadhyay
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur 784 001, Assam, India.
| | - Animesh Ghosh
- Department of Pharmaceutical Sciences, Birla Institute of Technology, Mesra, 835 215 Ranchi, Jharkhand, India.
| | - Manash Pratim Pathak
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur 784 001, Assam, India
| | - Jyotchna Gogoi
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur 784 001, Assam, India
| | - Vijay Veer
- Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur 784 001, Assam, India
| |
Collapse
|