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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.
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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.
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Lin YS, Lange D, Baur DM, Foerges A, Chu C, Li C, Elmenhorst EM, Neumaier B, Bauer A, Aeschbach D, Landolt HP, Elmenhorst D. Repeated caffeine intake suppresses cerebral grey matter responses to chronic sleep restriction in an A 1 adenosine receptor-dependent manner: a double-blind randomized controlled study with PET-MRI. Sci Rep 2024; 14:12724. [PMID: 38830861 PMCID: PMC11148136 DOI: 10.1038/s41598-024-61421-8] [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: 12/27/2023] [Accepted: 05/03/2024] [Indexed: 06/05/2024] Open
Abstract
Evidence has shown that both sleep loss and daily caffeine intake can induce changes in grey matter (GM). Caffeine is frequently used to combat sleepiness and impaired performance caused by insufficient sleep. It is unclear (1) whether daily use of caffeine could prevent or exacerbate the GM alterations induced by 5-day sleep restriction (i.e. chronic sleep restriction, CSR), and (2) whether the potential impact on GM plasticity depends on individual differences in the availability of adenosine receptors, which are involved in mediating effects of caffeine on sleep and waking function. Thirty-six healthy adults participated in this double-blind, randomized, controlled study (age = 28.9 ± 5.2 y/; F:M = 15:21; habitual level of caffeine intake < 450 mg; 29 homozygous C/C allele carriers of rs5751876 of ADORA2A, an A2A adenosine receptor gene variant). Each participant underwent a 9-day laboratory visit consisting of one adaptation day, 2 baseline days (BL), 5-day sleep restriction (5 h time-in-bed), and a recovery day (REC) after an 8-h sleep opportunity. Nineteen participants received 300 mg caffeine in coffee through the 5 days of CSR (CAFF group), while 17 matched participants received decaffeinated coffee (DECAF group). We examined GM changes on the 2nd BL Day, 5th CSR Day, and REC Day using magnetic resonance imaging and voxel-based morphometry. Moreover, we used positron emission tomography with [18F]-CPFPX to quantify the baseline availability of A1 adenosine receptors (A1R) and its relation to the GM plasticity. The results from the voxel-wise multimodal whole-brain analysis on the Jacobian-modulated T1-weighted images controlled for variances of cerebral blood flow indicated a significant interaction effect between caffeine and CSR in four brain regions: (a) right temporal-occipital region, (b) right dorsomedial prefrontal cortex (DmPFC), (c) left dorsolateral prefrontal cortex (DLPFC), and (d) right thalamus. The post-hoc analyses on the signal intensity of these GM clusters indicated that, compared to BL, GM on the CSR day was increased in the DECAF group in all clusters but decreased in the thalamus, DmPFC, and DLPFC in the CAFF group. Furthermore, lower baseline subcortical A1R availability predicted a larger GM reduction in the CAFF group after CSR of all brain regions except for the thalamus. In conclusion, our data suggest an adaptive GM upregulation after 5-day CSR, while concomitant use of caffeine instead leads to a GM reduction. The lack of consistent association with individual A1R availability may suggest that CSR and caffeine affect thalamic GM plasticity predominantly by a different mechanism. Future studies on the role of adenosine A2A receptors in CSR-induced GM plasticity are warranted.
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Affiliation(s)
- Yu-Shiuan Lin
- Centre for Chronobiology, University Psychiatric Clinics Basel, Wilhelm Kleinstr. 27, 4002, Basel, Switzerland.
- Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland.
- Athinoula. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachussetts General Hospital, Harvard Medical School, Boston, USA.
| | - Denise Lange
- Department of Sleep and Human Factors, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Diego Manuel Baur
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - Anna Foerges
- Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, North Rhine-Westphalia, Germany
- Department of Neurophysiology, Institute of Zoology (Bio-II), RWTH Aachen University, Aachen, Germany
| | - Congying Chu
- Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, North Rhine-Westphalia, Germany
| | - Changhong Li
- Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, North Rhine-Westphalia, Germany
| | - Eva-Maria Elmenhorst
- Department of Sleep and Human Factors, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
- Institute for Occupational, Social, and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine, INM-5, Forschungszentrum Jülich, Jülich, Germany
| | - Andreas Bauer
- Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, North Rhine-Westphalia, Germany
| | - Daniel Aeschbach
- Department of Sleep and Human Factors, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
- Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Center, Bonn, Germany
| | - Hans-Peter Landolt
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - David Elmenhorst
- Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, North Rhine-Westphalia, Germany.
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, University Hospital Cologne, Cologne, Germany.
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Sahay S, Devine EA, McCullumsmith RE, O’Donovan SM. Adenosine Receptor mRNA Expression in Frontal Cortical Neurons in Schizophrenia. Cells 2023; 13:32. [PMID: 38201235 PMCID: PMC10778287 DOI: 10.3390/cells13010032] [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: 11/01/2023] [Revised: 12/14/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Schizophrenia is a devastating neuropsychiatric disorder associated with the dysregulation of glutamate and dopamine neurotransmitter systems. The adenosine system is an important neuroregulatory system in the brain that modulates glutamate and dopamine signaling via the ubiquitously expressed adenosine receptors; however, adenosine A1 and A2A receptor (A1R and A2AR) mRNA expression is poorly understood in specific cell subtypes in the frontal cortical brain regions implicated in this disorder. In this study, we assayed A1R and A2AR mRNA expression via qPCR in enriched populations of pyramidal neurons, which were isolated from postmortem anterior cingulate cortex (ACC) tissue from schizophrenia (n = 20) and control (n = 20) subjects using laser microdissection (LMD). A1R expression was significantly increased in female schizophrenia subjects compared to female control subjects (t(13) = -4.008, p = 0.001). A1R expression was also significantly decreased in female control subjects compared to male control subjects, suggesting sex differences in basal A1R expression (t(17) = 2.137, p = 0.047). A significant, positive association was found between dementia severity (clinical dementia rating (CDR) scores) and A2AR mRNA expression (Spearman's r = 0.424, p = 0.009). A2AR mRNA expression was significantly increased in unmedicated schizophrenia subjects, suggesting that A2AR expression may be normalized by chronic antipsychotic treatment (F(1,14) = 9.259, p = 0.009). Together, these results provide novel insights into the neuronal expression of adenosine receptors in the ACC in schizophrenia and suggest that receptor expression changes may be sex-dependent and associated with cognitive decline in these subjects.
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Affiliation(s)
- Smita Sahay
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (S.S.); (R.E.M.)
| | - Emily A. Devine
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
| | - Robert E. McCullumsmith
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (S.S.); (R.E.M.)
- Neuroscience Institute Promedica, Toledo, OH 43606, USA
| | - Sinead M. O’Donovan
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (S.S.); (R.E.M.)
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Tichelman NL, Foerges AL, Elmenhorst EM, Lange D, Hennecke E, Baur DM, Beer S, Kroll T, Neumaier B, Bauer A, Landolt HP, Aeschbach D, Elmenhorst D. A genetic variation in the adenosine A2A receptor gene contributes to variability in oscillatory alpha power in wake and sleep EEG and A 1 adenosine receptor availability in the human brain. Neuroimage 2023; 280:120345. [PMID: 37625500 DOI: 10.1016/j.neuroimage.2023.120345] [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: 03/31/2023] [Revised: 07/25/2023] [Accepted: 08/22/2023] [Indexed: 08/27/2023] Open
Abstract
The EEG alpha rhythm (∼ 8-13 Hz) is one of the most salient human brain activity rhythms, modulated by the level of attention and vigilance and related to cerebral energy metabolism. Spectral power in the alpha range in wakefulness and sleep strongly varies among individuals based on genetic predisposition. Knowledge about the underlying genes is scarce, yet small studies indicated that the variant rs5751876 of the gene encoding A2A adenosine receptors (ADORA2A) may contribute to the inter-individual variation. The neuromodulator adenosine is directly linked to energy metabolism as product of adenosine tri-phosphate breakdown and acts as a sleep promoting molecule by activating A1 and A2A adenosine receptors. We performed sleep and positron emission tomography studies in 59 healthy carriers of different rs5751876 alleles, and quantified EEG oscillatory alpha power in wakefulness and sleep, as well as A1 adenosine receptor availability with 18F-CPFPX. Oscillatory alpha power was higher in homozygous C-allele carriers (n = 27, 11 females) compared to heterozygous and homozygous carriers of the T-allele (n(C/T) = 23, n(T/T) = 5, 13 females) (F(18,37) = 2.35, p = 0.014, Wilk's Λ = 0.487). Furthermore, a modulatory effect of ADORA2A genotype on A1 adenosine receptor binding potential was found across all considered brain regions (F(18,40) = 2.62, p = 0.006, Wilk's Λ = 0.459), which remained significant for circumscribed occipital region of calcarine fissures after correction for multiple comparisons. In female participants, a correlation between individual differences in oscillatory alpha power and A1 receptor availability was observed. In conclusion, we confirmed that a genetic variant of ADORA2A affects individual alpha power, while a direct modulatory effect via A1 adenosine receptors in females is suggested.
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Affiliation(s)
- Naemi L Tichelman
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Anna L Foerges
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany; RWTH Aachen University, Department of Neurophysiology, Institute of Zoology (Bio-II), Worringerweg 3, Aachen, North Rhine-Westphalia 52074, Germany
| | - Eva-Maria Elmenhorst
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany; Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen, North Rhine-Westphalia 52074, Germany
| | - Denise Lange
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany
| | - Eva Hennecke
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany
| | - Diego M Baur
- University of Zurich, Institute of Pharmacology & Toxicology, Winterthurerstrasse 190, Zurich 8057, Switzerland and Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - Simone Beer
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Tina Kroll
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-5), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Andreas Bauer
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Hans-Peter Landolt
- University of Zurich, Institute of Pharmacology & Toxicology, Winterthurerstrasse 190, Zurich 8057, Switzerland and Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - Daniel Aeschbach
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany; Harvard Medical School, Division of Sleep Medicine, Suite BL-438, 221 Longwood Avenue, Boston, Massachusetts 02115, United States of America; Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Center, Sigmund-Freud Str. 25, Bonn, North Rhine-Westphalia 53127, Germany
| | - David Elmenhorst
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany; Rheinische Friedrich-Wilhelms-Universität Bonn, Division of Medical Psychology, Venusberg-Campus 1, Bonn, North Rhine-Westphalia 53127, Germany; University Hospital Cologne, Multimodal Neuroimaging Group, Department of Nuclear Medicine, Kerpener Strasse 62, Cologne, North Rhine-Westphalia 50937, Germany.
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Janse van Rensburg HD, Terre'Blanche G, Van der Walt MM. On the basis of sex: male vs. female rat adenosine A 1/A 2A receptor affinity. BMC Res Notes 2023; 16:165. [PMID: 37563689 PMCID: PMC10413537 DOI: 10.1186/s13104-023-06346-7] [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: 08/11/2022] [Accepted: 04/28/2023] [Indexed: 08/12/2023] Open
Abstract
OBJECTIVE To ensure reproducibility in biomedical research, the biological variable sex must be reported; yet a reason for using male (instead of female) rodents is seldom given. In our search for novel adenosine receptor ligands, our research group routinely determines a test compound's binding affinities at male Sprague-Dawley rat (r) adenosine A1 and A2A receptors via in vitro radioligand binding studies. This pilot study compared the binding affinities of four adenosine receptor ligands (frequently used as reference standards) at male and female adenosine rA1 and rA2A receptors. RESULTS The inhibition constant (Ki) values determined using female rats correspond well to the values obtained using male rats and no markable difference could be observed in affinity and selectivity of reference standards. For example, DPCPX the selective adenosine A1 receptor antagonist: male rA1Ki: 0.5 ± 0.1 nM versus female rA1Ki: 0.5 ± 0.03 nM; male rA2AKi: 149 ± 23 nM versus female rA2AKi: 135 ± 29 nM. From the limited data at hand, we conclude that even when using female rats for in vitro studies without regard for the oestrous cycle, the obtained data did not vary much from their male counterparts.
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Affiliation(s)
- Helena D Janse van Rensburg
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
| | - Gisella Terre'Blanche
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
- Department of Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South Africa
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Andrade-Talavera Y, Pérez-Rodríguez M, Prius-Mengual J, Rodríguez-Moreno A. Neuronal and astrocyte determinants of critical periods of plasticity. Trends Neurosci 2023:S0166-2236(23)00105-4. [PMID: 37202300 DOI: 10.1016/j.tins.2023.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023]
Abstract
Windows of plasticity allow environmental experiences to produce intense activity-dependent changes during postnatal development. The reordering and refinement of neural connections occurs during these periods, significantly influencing the formation of brain circuits and physiological processes in adults. Recent advances have shed light on factors that determine the onset and duration of sensitive and critical periods of plasticity. Although GABAergic inhibition has classically been implicated in closing windows of plasticity, astrocytes and adenosinergic inhibition have also emerged more recently as key determinants of the duration of these periods of plasticity. Here, we review novel aspects of the involvement of GABAergic inhibition, the possible role of presynaptic NMDARs, and the emerging roles of astrocytes and adenosinergic inhibition in determining the duration of windows of plasticity in different brain regions.
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Affiliation(s)
- Yuniesky Andrade-Talavera
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Mikel Pérez-Rodríguez
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - José Prius-Mengual
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain.
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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.
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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..
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Reichert CF, Deboer T, Landolt HP. Adenosine, caffeine, and sleep-wake regulation: state of the science and perspectives. J Sleep Res 2022; 31:e13597. [PMID: 35575450 PMCID: PMC9541543 DOI: 10.1111/jsr.13597] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 01/11/2023]
Abstract
For hundreds of years, mankind has been influencing its sleep and waking state through the adenosinergic system. For ~100 years now, systematic research has been performed, first started by testing the effects of different dosages of caffeine on sleep and waking behaviour. About 70 years ago, adenosine itself entered the picture as a possible ligand of the receptors where caffeine hooks on as an antagonist to reduce sleepiness. Since the scientific demonstration that this is indeed the case, progress has been fast. Today, adenosine is widely accepted as an endogenous sleep‐regulatory substance. In this review, we discuss the current state of the science in model organisms and humans on the working mechanisms of adenosine and caffeine on sleep. We critically investigate the evidence for a direct involvement in sleep homeostatic mechanisms and whether the effects of caffeine on sleep differ between acute intake and chronic consumption. In addition, we review the more recent evidence that adenosine levels may also influence the functioning of the circadian clock and address the question of whether sleep homeostasis and the circadian clock may interact through adenosinergic signalling. In the final section, we discuss the perspectives of possible clinical applications of the accumulated knowledge over the last century that may improve sleep‐related disorders. We conclude our review by highlighting some open questions that need to be answered, to better understand how adenosine and caffeine exactly regulate and influence sleep.
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Affiliation(s)
- Carolin Franziska Reichert
- Centre for Chronobiology, University Psychiatric Clinics Basel, Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland.,Center for Affective, Stress, and Sleep Disorders, University Psychiatric Clinics Basel, Basel, Switzerland
| | - Tom Deboer
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Hans-Peter Landolt
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland.,Sleep & Health Zürich, University Center of Competence, University of Zürich, Zürich, Switzerland
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