1
|
Harkins J, Langston J, Keith ZM, Munoz C, Acon-Chen C, Shih TM. Learning and memory function preserved by delayed A 1 adenosine receptor agonist treatment following soman intoxication in rats and a humanized esterase mouse model. Neuropharmacology 2024; 253:109983. [PMID: 38704023 PMCID: PMC11132435 DOI: 10.1016/j.neuropharm.2024.109983] [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: 01/09/2024] [Revised: 04/23/2024] [Accepted: 05/01/2024] [Indexed: 05/06/2024]
Abstract
Exposure to organophosphorus compounds, such as soman (GD), cause widespread toxic effects, sustained status epilepticus, neuropathology, and death. The A1 adenosine receptor agonist N-bicyclo-(2.2.1)-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA), when given 1 min after GD exposure, provides neuroprotection and prevents behavioral impairments. Here, we tested the ability of ENBA at delayed treatment times to improve behavioral outcomes via a two-way active avoidance task in two male animal models, each consisting of saline and GD exposure groups. In a rat model, animals received medical treatments (atropine sulfate [A], 2-PAM [P], and midazolam [MDZ]) or AP + MDZ + ENBA at 15 or 30 min after seizure onset and were subjected to behavioral testing for up to 14 days. In a human acetylcholinesterase knock-in serum carboxylesterase knock-out mouse model, animals received AP, AP + MDZ, AP + ENBA, or AP + MDZ + ENBA at 15 min post seizure onset and were subjected to the behavioral task on days 7 and 14. In rats, the GD/AP + MDZ + ENBA group recovered to saline-exposed avoidance levels while the GD/AP + MDZ group did not. In mice, in comparison with GD/AP + MDZ group, the GD/AP + MDZ + ENBA showed decreases in escape latency, response latency, and pre-session crossings, as well as increases in avoidances. In both models, only ENBA-treated groups showed control level inter-trial interval crossings by day 14. Our findings suggest that ENBA, alone and as an adjunct to medical treatments, can improve behavioral and cognitive outcomes when given at delayed time points after GD intoxication.
Collapse
Affiliation(s)
- Joshua Harkins
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Jeffrey Langston
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Zora-Maya Keith
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Crystal Munoz
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Cindy Acon-Chen
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Tsung-Ming Shih
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| |
Collapse
|
2
|
Munoz C, Acon-Chen C, Keith ZM, Shih TM. Hypothermia as potential therapeutic approach to attenuating soman-induced seizure, neuropathology, and mortality with an adenosine A 1 receptor agonist and body cooling. Neuropharmacology 2024; 253:109966. [PMID: 38677446 PMCID: PMC11197881 DOI: 10.1016/j.neuropharm.2024.109966] [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: 01/04/2024] [Revised: 04/14/2024] [Accepted: 04/19/2024] [Indexed: 04/29/2024]
Abstract
Organophosphorus nerve agents, such as soman (GD), produce excitotoxic effects resulting in sustained status epilepticus (SSE) and brain damage. Previous work shows that neuronal inhibitory effects of A1 adenosine receptor (A1AR) agonists, such as N6- Bicyclo (2.2.1)-hept-2-yl-5'-chloro-5'-deoxyadenosine (Cl-ENBA), suppresses GD-induced SSE and improves neuropathology. Some other physiologic effects of these agonists are hypothermia, hypotension, and sedation. Hypothermia may also shield the brain from injury by slowing down chemical insults, lessening inflammation, and contributing to improved neurological outcomes. Therefore, we attempted to isolate the hypothermic effect from ENBA by assessing the neuroprotective efficacy of direct surface body cooling in a rat GD-induced SSE model, and comparing the effects on seizure termination, neuropathology, and survival. Male rats implanted with a body temperature (Tb) transponder and electroencephalographic (EEG) electrodes were primed with asoxime (HI-6), exposed to GD 30 min later, and then treated with Cl-ENBA or had Tb lowered directly via body cooling at 30 min after the onset of seizure activity. Afterwards, they were either allowed to develop hypothermia as expected, or received thermal support to maintain normothermic Tb for a period of 6-h. Neuropathology was assessed at 24 h. Regardless of Cl-ENBA or surface cooling, all hypothermic GD-exposed groups had significantly improved 24-h survival compared to rats with normothermic Tb (81% vs. 39%, p < 0.001). Cl-ENBA offered neuroprotection independently of hypothermic Tb. While hypothermia enhanced the overall efficacy of Cl-ENBA by improving survival outcomes, body cooling didn't reduce seizure activity or neuropathology following GD-induced SSE.
Collapse
Affiliation(s)
- Crystal Munoz
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400, USA
| | - Cindy Acon-Chen
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400, USA
| | - Zora-Maya Keith
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400, USA
| | - 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
|
3
|
Keith ZM, Munoz C, Acon-Chen C, Shih TM. Seizure suppression and neuroprotection in soman-exposed rats following delayed intramuscular treatment of adenosine A 1 receptor agonist as an adjunct to standard medical treatment. Toxicol Appl Pharmacol 2024; 488:116970. [PMID: 38777098 DOI: 10.1016/j.taap.2024.116970] [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: 01/12/2024] [Revised: 05/01/2024] [Accepted: 05/11/2024] [Indexed: 05/25/2024]
Abstract
Soman produces excitotoxic effects by inhibiting acetylcholinesterase in the cholinergic synapses and neuromuscular junctions, resulting in soman-induced sustained status epilepticus (SSE). Our previous work showed delayed intramuscular (i.m.) treatment with A1 adenosine receptor agonist N-bicyclo-[2.2.1]-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA) alone suppressed soman-induced SSE and prevented neuropathology. Using this same rat soman seizure model, we tested if delayed therapy with ENBA (60 mg/kg, i.m.) would terminate seizure, protect neuropathology, and aid in survival when given in conjunction with current standard medical countermeasures (MCMs): atropine sulfate, 2-PAM, and midazolam (MDZ). Either 15- or 30-min following soman-induced SSE onset, male rats received atropine and 2-PAM plus either MDZ or MDZ + ENBA. Electroencephalographic (EEG) activity, physiologic parameters, and motor function were recorded. Either 2- or 14-days following exposure surviving rats were euthanized and perfused for histology. All animals treated with MDZ + ENBA at both time points had 100% EEG seizure termination and reduced total neuropathology compared to animals treated with MDZ (2-day, p = 0.015 for 15-min, p = 0.002 for 30-min; 14-day, p < 0.001 for 15-min, p = 0.006 for 30-min), showing ENBA enhanced MDZ's anticonvulsant and neuroprotectant efficacy. However, combined MDZ + ENBA treatment, when compared to MDZ treatment groups, had a reduction in the 14-day survival rate regardless of treatment time, indicating possible enhancement of MDZ's neuronal inhibitory effects by ENBA. Based on our findings, ENBA shows promise as an anticonvulsant and neuroprotectant in a combined treatment regimen following soman exposure; when given as an adjunct to standard MCMs, the dose of ENBA needs to be adjusted.
Collapse
Affiliation(s)
- Zora-Maya Keith
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, USA.
| | - Crystal Munoz
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, USA.
| | - Cindy Acon-Chen
- Neuroscience Department, Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, USA.
| | - 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
|
4
|
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
|
5
|
Charalambous M, Muñana K, Patterson EE, Platt SR, Volk HA. ACVIM Consensus Statement on the management of status epilepticus and cluster seizures in dogs and cats. J Vet Intern Med 2024; 38:19-40. [PMID: 37921621 PMCID: PMC10800221 DOI: 10.1111/jvim.16928] [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: 10/04/2023] [Accepted: 10/19/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND Seizure emergencies (ie, status epilepticus [SE] and cluster seizures [CS]), are common challenging disorders with complex pathophysiology, rapidly progressive drug-resistant and self-sustaining character, and high morbidity and mortality. Current treatment approaches are characterized by considerable variations, but official guidelines are lacking. OBJECTIVES To establish evidence-based guidelines and an agreement among board-certified specialists for the appropriate management of SE and CS in dogs and cats. ANIMALS None. MATERIALS AND METHODS A panel of 5 specialists was formed to assess and summarize evidence in the peer-reviewed literature with the aim to establish consensus clinical recommendations. Evidence from veterinary pharmacokinetic studies, basic research, and human medicine also was used to support the panel's recommendations, especially for the interventions where veterinary clinical evidence was lacking. RESULTS The majority of the evidence was on the first-line management (ie, benzodiazepines and their various administration routes) in both species. Overall, there was less evidence available on the management of emergency seizure disorders in cats in contrast to dogs. Most recommendations made by the panel were supported by a combination of a moderate level of veterinary clinical evidence and pharmacokinetic data as well as studies in humans and basic research studies. CONCLUSIONS AND CLINICAL RELEVANCE Successful management of seizure emergencies should include an early, rapid, and stage-based treatment approach consisting of interventions with moderate to preferably high ACVIM recommendations; management of complications and underlying causes related to seizure emergencies should accompany antiseizure medications.
Collapse
Affiliation(s)
| | - Karen Muñana
- North Carolina State UniversityRaleighNorth CarolinaUSA
| | | | | | - Holger A. Volk
- University of Veterinary Medicine HannoverHannoverGermany
| |
Collapse
|
6
|
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
|
7
|
Du K, He M, Zhao D, Wang Y, Ma C, Liang H, Wang W, Min D, Xue L, Guo F. Mechanism of cell death pathways in status epilepticus and related therapeutic agents. Biomed Pharmacother 2022; 149:112875. [PMID: 35367755 DOI: 10.1016/j.biopha.2022.112875] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/15/2022] [Accepted: 03/23/2022] [Indexed: 11/30/2022] Open
Abstract
The most severe form of epilepsy, status epilepticus (SE), causes brain damage and results in the development of recurring seizures. Currently, the management of SE remains a clinical challenge because patients do not respond adequately to conventional treatments. Evidence suggests that neural cell death worsens the occurrence and progression of SE. The main forms of cell death are apoptosis, necroptosis, pyroptosis, and ferroptosis. Herein, these mechanisms of neuronal death in relation to SE and the alleviation of SE by potential modulators that target neuronal death have been reviewed. An understanding of these pathways and their possible roles in SE may assist in the development of SE therapies and in the discovery of new agents.
Collapse
Affiliation(s)
- Ke Du
- Department of Pharmacology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China
| | - Miao He
- Department of Pharmaceutical Toxicology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China
| | - Dongyi Zhao
- Department of Pharmaceutical Toxicology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China
| | - Yuting Wang
- Department of Pharmaceutical Toxicology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China
| | - Chao Ma
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Hongyue Liang
- Department of Pharmaceutical Toxicology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China
| | - Wuyang Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, 209Tongshan Rd, Xuzhou 221002, China
| | - Dongyu Min
- Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications, Liaoning University of Traditional Chinese Medicine, Shenyang 110032, China.
| | - Lei Xue
- China Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University, Shenyang, China.
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmaceutical Science, China Medical University, Shenyang 110001, China.
| |
Collapse
|
8
|
Defining and overcoming the therapeutic obstacles in canine refractory status epilepticus. Vet J 2022; 283-284:105828. [DOI: 10.1016/j.tvjl.2022.105828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 11/20/2022]
|
9
|
Morgan JE, Wilson SC, Travis BJ, Bagri KH, Pagarigan KT, Belski HM, Jackson C, Bounader KM, Coppola JM, Hornung EN, Johnson JE, McCarren HS. Refractory and Super-Refractory Status Epilepticus in Nerve Agent-Poisoned Rats Following Application of Standard Clinical Treatment Guidelines. Front Neurosci 2021; 15:732213. [PMID: 34566572 PMCID: PMC8462486 DOI: 10.3389/fnins.2021.732213] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/16/2021] [Indexed: 12/24/2022] Open
Abstract
Nerve agents (NAs) induce a severe cholinergic crisis that can lead to status epilepticus (SE). Current guidelines for treatment of NA-induced SE only include prehospital benzodiazepines, which may not fully resolve this life-threatening condition. This study examined the efficacy of general clinical protocols for treatment of SE in the specific context of NA poisoning in adult male rats. Treatment with both intramuscular and intravenous benzodiazepines was entirely insufficient to control SE. Second line intervention with valproate (VPA) initially terminated SE in 35% of rats, but seizures always returned. Phenobarbital (PHB) was more effective, with SE terminating in 56% of rats and 19% of rats remaining seizure-free for at least 24 h. The majority of rats demonstrated refractory SE (RSE) and required treatment with a continuous third-line anesthetic. Both ketamine (KET) and propofol (PRO) led to high levels of mortality, and nearly all rats on these therapies had breakthrough seizure activity, demonstrating super-refractory SE (SRSE). For the small subset of rats in which SE was fully resolved, significant improvements over controls were observed in recovery metrics, behavioral assays, and brain pathology. Together these data suggest that NA-induced SE is particularly severe, but aggressive treatment in the intensive care setting can lead to positive functional outcomes for casualties.
Collapse
Affiliation(s)
- Julia E Morgan
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Sara C Wilson
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Benjamin J Travis
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Kathryn H Bagri
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Kathleen T Pagarigan
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Hannah M Belski
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Cecelia Jackson
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Kevin M Bounader
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Jessica M Coppola
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Eden N Hornung
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - James E Johnson
- Comparative Pathology Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Hilary S McCarren
- Neuroscience Department, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| |
Collapse
|
10
|
Abstract
The canonical mechanism of organophosphate (OP) neurotoxicity is the inhibition of acetylcholinesterase (AChE). However, multiple lines of evidence suggest that mechanisms in addition to or other than AChE inhibition contribute to the neurotoxic effects associated with acute and chronic OP exposures. Characterizing the role(s) of AChE inhibition versus noncholinergic mechanisms in OP neurotoxicity remains an active area of research with significant diagnostic and therapeutic implications. Here, we review recently published studies that provide mechanistic insights regarding (1) OP-induced status epilepticus, (2) long-term neurologic consequences of acute OP exposures, and (3) neurotoxic effects associated with repeated low-level OP exposures. Key data gaps and challenges are also discussed.
Collapse
Affiliation(s)
- Yi-Hua Tsai
- Department of Molecular Sciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Sciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| |
Collapse
|
11
|
Rojas A, McCarren HS, Wang J, Wang W, Abreu-Melon J, Wang S, McDonough JH, Dingledine R. Comparison of neuropathology in rats following status epilepticus induced by diisopropylfluorophosphate and soman. Neurotoxicology 2021; 83:14-27. [PMID: 33352274 PMCID: PMC7987879 DOI: 10.1016/j.neuro.2020.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/29/2022]
Abstract
The increasing number of cases involving the use of nerve agents as deadly weapons has spurred investigation into the molecular mechanisms underlying nerve agent-induced pathology. The highly toxic nature of nerve agents restrict their use in academic research laboratories. Less toxic organophosphorus (OP) based agents including diisopropylfluorophosphate (DFP) are used as surrogates in academic research laboratories to mimic nerve agent poisoning. However, neuropathology resulting from DFP-induced status epilepticus (SE) has not been compared directly to neuropathology observed following nerve agent poisoning in the same study. Here, the hypothesis that neuropathology measured four days after SE is the same for rats exposed to DFP and soman was tested. Adult Sprague-Dawley rats were injected with soman or DFP to induce SE. Cortical electroencephalography (EEG) was recorded prior to and during soman-induced SE. EEG power analysis of rats administered soman revealed prolonged electrographic SE similar to that of rats that endure uninterrupted SE following injection of DFP. Rats that experienced soman-induced SE displayed less hippocampal neuroinflammation and gliosis compared to rats administered DFP. Seizure-induced weight change, blood-brain barrier (BBB) leakiness and neurodegeneration in most seizure sensitive limbic brain regions were similar for rats that endured SE following soman or DFP. The amalgamated pathology score calculated by combining pathological measures (weight loss, hippocampal neuroinflammation, gliosis, BBB integrity and neurodegeneration) was similar in rats administered the OP agents. These findings support use of the rat DFP model of SE as a suitable surrogate for investigating some, but not all delayed consequences produced by nerve agents.
Collapse
Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States.
| | - Hilary S McCarren
- Neuroscience Department, Medical Toxicology Research Division, United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, United States
| | - Jennifer Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - Wenyi Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - JuanMartin Abreu-Melon
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - Sarah Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - John H McDonough
- Neuroscience Department, Medical Toxicology Research Division, United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, United States
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| |
Collapse
|
12
|
Coluzzi F, Angelini A, Simmaco M, Alampi D, Alessandri E, Grassi E, Monina MG, Rocco M. The effect of dexmedetomidine on status epilepticus in a patient with anti-NMDA receptor encephalitis. Can J Anaesth 2020; 67:1677-1679. [DOI: 10.1007/s12630-020-01753-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 10/23/2022] Open
|
13
|
Spampanato J, Bealer SL, Smolik M, Dudek FE. Delayed Adjunctive Treatment of Organophosphate-Induced Status Epilepticus in Rats with Phenobarbital, Memantine, or Dexmedetomidine. J Pharmacol Exp Ther 2020; 375:59-68. [PMID: 32873622 DOI: 10.1124/jpet.120.000175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
Organophosphate (OP) exposure induces status epilepticus (SE), a medical emergency with high morbidity and mortality. Current standard medical countermeasures lose efficacy with time so that treatment delays, in the range of tens of minutes, result in increasingly poor outcomes. As part of the Countermeasures Against Chemical Threats Neurotherapeutics Screening Program, we previously developed a realistic model of delayed treatment of OP-induced SE using the OP diisopropyl fluorophosphate (DFP) to screen compounds for efficacy in the termination of SE and elimination of neuronal death. Male rats were implanted for electroencephalogram (EEG) recordings 7 days prior to experimentation. Rats were then exposed to DFP, and SE was induced for 60 minutes and then treated with midazolam (MDZ) plus one of three antiseizure drugs (ASDs)-phenobarbital (PHB), memantine (MEM), or dexmedetomidine (DMT)-in conjunction with antidotes. EEG was recorded for 24 hours, and brains were stained with Fluoro-Jade B for quantification of degenerating neurons. We found that PHB + MDZ induced a prolonged suppression of SE and reduced neuronal death. MEM + MDZ treatment exacerbated SE and increased mortality; however, surviving rats had fewer degenerating neurons. DMT + MDZ significantly suppressed SE with only a minimal reduction in neuronal death. These data demonstrate that delayed treatment of OP-induced SE with other ASDs, when added to MDZ, can achieve greater seizure suppression with additional reduction in degenerating neurons throughout the brain compared with MDZ alone. The effect of a drug on the severity of seizure activity did not necessarily determine the drug's effect on neuronal death under these conditions. SIGNIFICANCE STATEMENT: This study assesses the relative effectiveness of three different delayed-treatment regimens for the control of organophosphate-induced status epilepticus and reduction of subsequent neuronal death. The data demonstrate the potential for highly effective therapies despite significant treatment delay and a potential disconnect between seizure severity and neuronal death.
Collapse
Affiliation(s)
- Jay Spampanato
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - Steven L Bealer
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - Melissa Smolik
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| |
Collapse
|
14
|
Gioeni D, Di Cesare F, D'Urso ES, Rabbogliatti V, Ravasio G. Ketamine-dexmedetomidine combination and controlled mild hypothermia for the treatment of long-lasting and super-refractory status epilepticus in 3 dogs suffering from idiopathic epilepsy. J Vet Emerg Crit Care (San Antonio) 2020; 30:455-460. [PMID: 32372564 DOI: 10.1111/vec.12956] [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] [Received: 04/07/2018] [Revised: 10/04/2018] [Accepted: 10/31/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To describe the use of a ketamine-dexmedetomidine combination and mild hypothermia for the treatment of status epilepticus in 3 dogs that did not respond to GABAergic medication. CASE SERIES SUMMARY Three dogs, each with a diagnosis of idiopathic epilepsy, were presented to the emergency department in a state of status epilepticus. The dogs were treated unsuccessfully with benzodiazepine as a first-line therapy that was followed by IV propofol anesthesia maintained for at least 12 hours. When general anesthesia was discontinued, seizures reoccurred. All 3 dogs then received a bolus of ketamine (1 mg/kg, IV) over a period of 5 minutes that was followed by a bolus of dexmedetomidine (3 μg/kg, IV) over the same time period and then followed by a continuous infusion for 12 hours of ketamine at a constant rate of 1 mg/kg/h and dexmedetomidine at a variable rate of 3-7 μg/kg/h. Body temperature was maintained between 36.7 and 37.7°C at a state of mild hypothermia throughout treatment. The dogs recovered uneventfully over 48 hours after treatment was discontinued with no evidence of seizures. No notable alterations in physiological parameters were observed during the drug infusions. All dogs were discharged following examinations that showed normal neurological function. NEW OR UNIQUE INFORMATION PROVIDED This case series highlights the potential benefits of a ketamine-dexmedetomidine infusion combined with mild hypothermia for the treatment of status epilepticus refractory to GABAergic therapy in dogs suffering from idiopathic epilepsy. After the dogs were weaned from the ketamine-dexmedetomidine infusion, all dogs experienced complete recovery. Thus, this case series introduces a novel approach to treat this intense condition.
Collapse
Affiliation(s)
- Daniela Gioeni
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| | - Federica Di Cesare
- Department of Health, Animal Science and Food safety, Università degli Studi di Milano, Milan, Italy
| | - Elisa Silvia D'Urso
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| | - Vanessa Rabbogliatti
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| | - Giuliano Ravasio
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| |
Collapse
|
15
|
McCarren HS, Eisen MR, Nguyen DL, Dubée PB, Ardinger CE, Dunn EN, Haines KM, Santoro AN, Bodner PM, Ondeck CA, Honnold CL, McDonough JH, Beske PH, McNutt PM. Characterization and treatment of spontaneous recurrent seizures following nerve agent-induced status epilepticus in mice. Epilepsy Res 2020; 162:106320. [PMID: 32182542 PMCID: PMC7156324 DOI: 10.1016/j.eplepsyres.2020.106320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/21/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To develop and characterize a mouse model of spontaneous recurrent seizures following nerve agent-induced status epilepticus (SE) and test the efficacy of existing antiepileptic drugs. METHODS SE was induced in telemeterized male C57Bl6/J mice by soman exposure, and electroencephalographic activity was recorded for 4-6 weeks. Mice were treated with antiepileptic drugs (levetiracetam, valproic acid, phenobarbital) or corresponding vehicles for 14 d after exposure, followed by 14 d of drug washout. Survival, body weight, seizure characteristics, and histopathology were used to characterize the acute and chronic effects of nerve agent exposure and to evaluate the efficacy of treatments in mitigating or preventing neurological effects. RESULTS Spontaneous recurrent seizures manifested in all survivors, but the number and frequency of seizures varied considerably among mice. In untreated mice, seizures became longer over time. Moderate to severe histopathology was observed in the amygdala, piriform cortex, and CA1. Levetiracetam provided modest improvements in neurological parameters such as reduced spike rate and improved histopathology scores, whereas valproic acid and phenobarbital were largely ineffective. CONCLUSIONS This model of post-SE spontaneous recurrent seizures differs from other experimental models in the brief latency to seizure development, the occurrence of seizures in 100 % of exposed animals, and the lack of damage to CA4/dentate gyrus. It may serve as a useful tool for rapidly and efficiently screening novel therapies that would be effective against severe epilepsy cases.
Collapse
Affiliation(s)
- Hilary S McCarren
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States.
| | - Margaret R Eisen
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Dominique L Nguyen
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Parker B Dubée
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Cherish E Ardinger
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Emily N Dunn
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Kari M Haines
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Antonia N Santoro
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Paige M Bodner
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Celinia A Ondeck
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Cary L Honnold
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - John H McDonough
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Phillip H Beske
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| | - Patrick M McNutt
- United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd Aberdeen Proving Ground, MD, 21010, United States
| |
Collapse
|
16
|
Moffett MC, Rauscher NA, Rice NC, Myers TM. Survey of drug therapies against acute oral tetramethylenedisulfotetramine poisoning in a rat voluntary consumption model. Neurotoxicology 2019; 74:264-271. [DOI: 10.1016/j.neuro.2019.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/30/2019] [Accepted: 08/05/2019] [Indexed: 12/12/2022]
|
17
|
Mishra R, Geiling J. Chemical Agents in Disaster: Care and Management in the Intensive Care Unit. Crit Care Clin 2019; 35:633-645. [PMID: 31445610 DOI: 10.1016/j.ccc.2019.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Chemical agents of warfare are divided into lung agents, blood agents, vesicants, and nerve agents. Intensivists must familiarize themselves with the clinical presentation and management principles in the event of a chemical attack. Key principles in management include aggressive supportive care and early administration of specific antidotes, if available. Management includes proper personal protection for critical care providers. Patients may make complete recovery with aggressive supportive care, even if they appear to have a poor prognosis. Hospitals must have an emergency response disaster plan in place to deal with all potential causes of disasters, including illnesses resulting from chemical agents.
Collapse
Affiliation(s)
- Rashmi Mishra
- The Lung Center, Penn Highlands Healthcare, 100 Hospital Avenue, DuBois, PA 15801, USA.
| | - James Geiling
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Medical Service, VA Medical Center, White River Junction, VT 05009, USA
| |
Collapse
|
18
|
Malta JR, Greco J, Lodolo M, Ghosh S. A school-aged boy with super-refractory status epilepticus secondary to cortical dysplasia treated with dexmedetomidine. J Clin Neurosci 2019; 64:21-22. [DOI: 10.1016/j.jocn.2019.03.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/25/2019] [Indexed: 12/22/2022]
|
19
|
Thompson CM, Gerdes JM, VanBrocklin HF. Positron emission tomography studies of organophosphate chemical threats and oxime countermeasures. Neurobiol Dis 2019; 133:104455. [PMID: 31022458 DOI: 10.1016/j.nbd.2019.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/28/2019] [Accepted: 04/19/2019] [Indexed: 01/31/2023] Open
Abstract
There is a unique in vivo interplay involving the mechanism of inactivation of acetylcholinesterase (AChE) by toxic organophosphorus (OP) compounds and the restoration of AChE activity by oxime antidotes. OP compounds form covalent adducts to this critical enzyme target and oximes are introduced to directly displace the OP from AChE. For the most part, the in vivo inactivation of AChE leading to neurotoxicity and antidote-based therapeutic reversal of this mechanism are well understood, however, these molecular-level events have not been evaluated by dynamic imaging in living systems at millimeter resolution. A deeper understanding of these critically, time-dependent mechanisms is needed to develop new countermeasures. To address this void and to help accelerate the development of new countermeasures, positron-emission tomography (PET) has been investigated as a unique opportunity to create platform technologies to directly examine the interdependent toxicokinetic/pharmacokinetic and toxicodynamic/pharmacodynamic features of OPs and oximes in real time within live animals. This review will cover two first-in-class PET tracers representing an OP and an oxime antidote, including their preparation, requisite pharmacologic investigations, mechanistic interpretations, biodistribution and imaging.
Collapse
Affiliation(s)
- Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA.
| | - John M Gerdes
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA
| | - Henry F VanBrocklin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco 185 Berry St. Suite 350, San Francisco, CA 94107, USA
| |
Collapse
|
20
|
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
|