1
|
Bale R, Doshi G. Deciphering the role of siRNA in anxiety and depression. Eur J Pharmacol 2024; 981:176868. [PMID: 39128805 DOI: 10.1016/j.ejphar.2024.176868] [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: 01/04/2024] [Revised: 07/02/2024] [Accepted: 08/05/2024] [Indexed: 08/13/2024]
Abstract
Anxiety and depression are central nervous system illnesses that are among the most prevalent medical concerns of the twenty-first century. Patients with this condition and their families bear psychological, financial, and societal hardship. There are currently restrictions when utilizing the conventional course of treatment. RNA interference is expected to become an essential approach in anxiety and depression due to its potent and targeted gene silencing. Silencing of genes by post-transcriptional modification is the mechanism of action of small interfering RNA (siRNA). The suppression of genes linked to disease is typically accomplished by siRNA molecules in an efficient and targeted manner. Unfavourable immune responses, off-target effects, naked siRNA instability, nuclease vulnerability, and the requirement to create an appropriate delivery method are some of the challenges facing the clinical application of siRNA. This review focuses on the use of siRNA in the treatment of anxiety and depression.
Collapse
Affiliation(s)
- Rajeshwari Bale
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, V L M Road, Vile Parle (w), Mumbai, 400056, India
| | - Gaurav Doshi
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, V L M Road, Vile Parle (w), Mumbai, 400056, India.
| |
Collapse
|
2
|
Merenick DR, Munro BA, Gee JM, Pang DSJ. Assessing Susceptibility to Carbon Dioxide Gas in Three Rat Strains Using the Loss of Righting Reflex. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2024; 63:310-315. [PMID: 38325835 PMCID: PMC11193416 DOI: 10.30802/aalas-jaalas-23-000104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/28/2023] [Accepted: 01/16/2024] [Indexed: 02/09/2024]
Abstract
Overdose of carbon dioxide gas (CO₂) is a common euthanasia method for rodents; however, CO₂ exposure activates nociceptors in rats at concentrations equal to or greater than 37% and is reported to be painful in humans at concentrations equal to or greater than 32.5%. Exposure of rats to CO₂ could cause pain before loss of consciousness. We used 2 standardized loss of righting reflex (LORR) methods to identify CO₂ concentrations associated with unconsciousness in Wistar, Long???Evans, and Sprague???Dawley rats (n = 28 animals per strain). A rotating, motorized cylinder was used to test LORR while the rat was being exposed to increasing concentrations of CO₂. LORR was defined based on a 15-second observation period. The 2 methods were 1) a 1-Paw assessment (the righting reflex was considered to be present if one or more paws contacted the cylinder after the rat was positioned in dorsal recumbency), and 2) a 4-Paw assessment (the righting reflex was considered to be present if all 4 paws contacted the cylinder after the rat was positioned in dorsal recumbency). Data were analyzed with Probit regression, and dose-response curves were plotted. 1-Paw EC95 values (CO₂ concentration at which LORR occurred for 95% of the population) were Wistar, 27.2%; Long???Evans, 29.2%; and Sprague???Dawley, 35.0%. 4-Paw EC95 values were Wistar, 26.2%; Long???Evans, 25.9%, and Sprague???Dawley, 31.1%. Sprague???Dawley EC95 values were significantly higher in both 1- and 4-Paw tests as compared with Wistar and Long???Evans rats. No differences were detected between sexes for any strain. The 1-Paw EC95 was significantly higher than the 4-Paw EC95 only for Sprague-Dawley rats. These results suggest that a low number of individual rats from the strains studied may experience pain during CO₂ euthanasia.
Collapse
Affiliation(s)
- Dexter R Merenick
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Brittany A Munro
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Julia M Gee
- College of Engineering and Physical Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - Daniel SJ Pang
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| |
Collapse
|
3
|
Puthillathu N, Moffett JR, Korotcov A, Bosomtwi A, Vengilote R, Krishnan JKS, Johnson EA, Arun P, Namboodiri AM. Brief isoflurane administration as an adjunct treatment to control organophosphate-induced convulsions and neuropathology. Front Pharmacol 2023; 14:1293280. [PMID: 38230376 PMCID: PMC10790757 DOI: 10.3389/fphar.2023.1293280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/21/2023] [Indexed: 01/18/2024] Open
Abstract
Organophosphate-based chemical agents (OP), including nerve agents and certain pesticides such as paraoxon, are potent acetylcholinesterase inhibitors that cause severe convulsions and seizures, leading to permanent central nervous system (CNS) damage if not treated promptly. The current treatment regimen for OP poisoning is intramuscular injection of atropine sulfate with an oxime such as pralidoxime (2-PAM) to mitigate cholinergic over-activation of the somatic musculature and autonomic nervous system. This treatment does not provide protection against CNS cholinergic overactivation and therefore convulsions require additional medication. Benzodiazepines are the currently accepted treatment for OP-induced convulsions, but the convulsions become refractory to these GABAA agonists and repeated dosing has diminishing effectiveness. As such, adjunct anticonvulsant treatments are needed to provide improved protection against recurrent and prolonged convulsions and the associated excitotoxic CNS damage that results from them. Previously we have shown that brief, 4-min administration of 3%-5% isoflurane in 100% oxygen has profound anticonvulsant and CNS protective effects when administered 30 min after a lethal dose of paraoxon. In this report we provide an extended time course of the effectiveness of 5% isoflurane delivered for 5 min, ranging from 60 to 180 min after a lethal dose of paraoxon in rats. We observed substantial effectiveness in preventing neuronal loss as shown by Fluoro-Jade B staining when isoflurane was administered 1 h after paraoxon, with diminishing effectiveness at 90, 120 and 180 min. In vivo magnetic resonance imaging (MRI) derived T2 and mean diffusivity (MD) values showed that 5-min isoflurane administration at a concentration of 5% prevents brain edema and tissue damage when administered 1 h after a lethal dose of paraoxon. We also observed reduced astrogliosis as shown by GFAP immunohistochemistry. Studies with continuous EEG monitoring are ongoing to demonstrate effectiveness in animal models of soman poisoning.
Collapse
Affiliation(s)
- Narayanan Puthillathu
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - John R. Moffett
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Alexandru Korotcov
- Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, United States
| | - Asamoah Bosomtwi
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), Bethesda, MD, United States
| | - Ranjini Vengilote
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Jishnu K. S. Krishnan
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Erik A. Johnson
- Department of Neuroscience, United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Peethambaran Arun
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Aryan M. Namboodiri
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program and Molecular and Cell Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| |
Collapse
|
4
|
Munro BA, Merenick DR, Gee JM, Pang DSJ. Use of Loss of Righting Reflex to Assess Susceptibility to Carbon Dioxide Gas in Three Mouse Strains. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2023; 62:553-558. [PMID: 37770194 PMCID: PMC10772915 DOI: 10.30802/aalas-jaalas-23-000035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/20/2023] [Accepted: 07/24/2023] [Indexed: 09/30/2023]
Abstract
Exposure to CO₂ gas is a common rodent euthanasia method. CO₂ activates nociceptors in rats and is painful to humans at concentrations equal to or greater than 32.5% The concentration of CO₂ at which rodents become unconsciousness is inadequately defined. We used loss of righting reflex (LORR) to identify the concentration at which CO₂ caused loss of consciousness in C57Bl/6, CD1 and 129P3J mice (16 females and 16 males per strain). We used a custom built, rotating, motorized cylinder to determine LORR as CO₂ concentrations were increased. Two LORR assessment methods were used: 1) a 1-Paw assessment in which the righting reflex was considered to be present if one or more paws contacted the cylinder after rotation into dorsal recumbency and 2) a 4-Paw assessment in which the righting reflex was considered to be present only if all 4 paws contacted the cylinder. LORR test data were analyzed with Probit regression and dose response curves were plotted. 1-Paw EC95 values (CO₂ concentration at which LORR occurred for 95% of the population) were: C57Bl/6; 30.7%, CD1; 26.2%, 129P3J; 20.1%. The EC95 for C57Bl/6 was significantly higher than that of the 129P3J mice, with no significant differences between other strains. Four-Paw EC95 values were: C57Bl/6; 22.8%, CD1; 25.3%, 129P3J; 20.1%. Values for 129P3J mice were significantly lower than those of CD1 mice), with no significant difference between other strains. The EC95 varied significantly between 1-Paw and 4-Paw methods only for C57Bl/6 mice. These results suggest a potential for nociception and pain to occur in some individuals of some mouse strains during CO₂ euthanasia.
Collapse
Affiliation(s)
- Brittany A Munro
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
| | - Dexter R Merenick
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
| | - Julia M Gee
- College of Engineering and Physical Sciences, University of Guelph, Ontario, Canada
| | - Daniel SJ Pang
- Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada
- Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| |
Collapse
|
5
|
Que M, Li Y, Wang X, Zhan G, Luo X, Zhou Z. Role of astrocytes in sleep deprivation: accomplices, resisters, or bystanders? Front Cell Neurosci 2023; 17:1188306. [PMID: 37435045 PMCID: PMC10330732 DOI: 10.3389/fncel.2023.1188306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/05/2023] [Indexed: 07/13/2023] Open
Abstract
Sleep plays an essential role in all studied animals with a nervous system. However, sleep deprivation leads to various pathological changes and neurobehavioral problems. Astrocytes are the most abundant cells in the brain and are involved in various important functions, including neurotransmitter and ion homeostasis, synaptic and neuronal modulation, and blood-brain barrier maintenance; furthermore, they are associated with numerous neurodegenerative diseases, pain, and mood disorders. Moreover, astrocytes are increasingly being recognized as vital contributors to the regulation of sleep-wake cycles, both locally and in specific neural circuits. In this review, we begin by describing the role of astrocytes in regulating sleep and circadian rhythms, focusing on: (i) neuronal activity; (ii) metabolism; (iii) the glymphatic system; (iv) neuroinflammation; and (v) astrocyte-microglia cross-talk. Moreover, we review the role of astrocytes in sleep deprivation comorbidities and sleep deprivation-related brain disorders. Finally, we discuss potential interventions targeting astrocytes to prevent or treat sleep deprivation-related brain disorders. Pursuing these questions would pave the way for a deeper understanding of the cellular and neural mechanisms underlying sleep deprivation-comorbid brain disorders.
Collapse
Affiliation(s)
- Mengxin Que
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Department of Anesthesiology, Tongji Medical College, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Yujuan Li
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Department of Anesthesiology, Tongji Medical College, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xuan Wang
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Department of Anesthesiology, Tongji Medical College, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Gaofeng Zhan
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Department of Anesthesiology, Tongji Medical College, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoxiao Luo
- Department of Oncology, Tongji Medical College, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiqiang Zhou
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Department of Anesthesiology, Tongji Medical College, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
6
|
Brock O, Gelegen C, Sully P, Salgarella I, Jager P, Menage L, Mehta I, Jęczmień-Łazur J, Djama D, Strother L, Coculla A, Vernon AC, Brickley S, Holland P, Cooke SF, Delogu A. A Role for Thalamic Projection GABAergic Neurons in Circadian Responses to Light. J Neurosci 2022; 42:9158-9179. [PMID: 36280260 PMCID: PMC9761691 DOI: 10.1523/jneurosci.0112-21.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/07/2022] Open
Abstract
The thalamus is an important hub for sensory information and participates in sensory perception, regulation of attention, arousal and sleep. These functions are executed primarily by glutamatergic thalamocortical neurons that extend axons to the cortex and initiate cortico-thalamocortical connectional loops. However, the thalamus also contains projection GABAergic neurons that do not extend axons toward the cortex. Here, we have harnessed recent insight into the development of the intergeniculate leaflet (IGL) and the ventral lateral geniculate nucleus (LGv) to specifically target and manipulate thalamic projection GABAergic neurons in female and male mice. Our results show that thalamic GABAergic neurons of the IGL and LGv receive retinal input from diverse classes of retinal ganglion cells (RGCs) but not from the M1 intrinsically photosensitive retinal ganglion cell (ipRGC) type. We describe the synergistic role of the photoreceptor melanopsin and the thalamic neurons of the IGL/LGv in circadian entrainment to dim light. We identify a requirement for the thalamic IGL/LGv neurons in the rapid changes in vigilance states associated with circadian light transitions.SIGNIFICANCE STATEMENT The intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus (LGv) are part of the extended circadian system and mediate some nonimage-forming visual functions. Here, we show that each of these structures has a thalamic (dorsal) as well as prethalamic (ventral) developmental origin. We map the retinal input to thalamus-derived cells in the IGL/LGv complex and discover that while RGC input is dominant, this is not likely to originate from M1ipRGCs. We implicate thalamic cells in the IGL/LGv in vigilance state transitions at circadian light changes and in overt behavioral entrainment to dim light, the latter exacerbated by concomitant loss of melanopsin expression.
Collapse
Affiliation(s)
- Olivier Brock
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Cigdem Gelegen
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Peter Sully
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Irene Salgarella
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Polona Jager
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Lucy Menage
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Ishita Mehta
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Jagoda Jęczmień-Łazur
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Deyl Djama
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
- Department of Life Sciences and Centre for Neurotechnology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Lauren Strother
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Angelica Coculla
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| | - Anthony C Vernon
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom
| | - Stephen Brickley
- Department of Life Sciences and Centre for Neurotechnology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Philip Holland
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
- Wolfson Centre for Age Related Disease, King's College London, London SE1 1UL, United Kingdom
| | - Samuel F Cooke
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom
| | - Alessio Delogu
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
| |
Collapse
|
7
|
Fan X, Lu Y, Du G, Liu J. Advances in the Understanding of Two-Pore Domain TASK Potassium Channels and Their Potential as Therapeutic Targets. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238296. [PMID: 36500386 PMCID: PMC9736439 DOI: 10.3390/molecules27238296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/09/2022] [Accepted: 11/15/2022] [Indexed: 11/29/2022]
Abstract
TWIK-related acid-sensitive K+ (TASK) channels, including TASK-1, TASK-3, and TASK-5, are important members of the two-pore domain potassium (K2P) channel family. TASK-5 is not functionally expressed in the recombinant system. TASK channels are very sensitive to changes in extracellular pH and are active during all membrane potential periods. They are similar to other K2P channels in that they can create and use background-leaked potassium currents to stabilize resting membrane conductance and repolarize the action potential of excitable cells. TASK channels are expressed in both the nervous system and peripheral tissues, including excitable and non-excitable cells, and are widely engaged in pathophysiological phenomena, such as respiratory stimulation, pulmonary hypertension, arrhythmia, aldosterone secretion, cancers, anesthesia, neurological disorders, glucose homeostasis, and visual sensitivity. Therefore, they are important targets for innovative drug development. In this review, we emphasized the recent advances in our understanding of the biophysical properties, gating profiles, and biological roles of TASK channels. Given the different localization ranges and biologically relevant functions of TASK-1 and TASK-3 channels, the development of compounds that selectively target TASK-1 and TASK-3 channels is also summarized based on data reported in the literature.
Collapse
Affiliation(s)
- Xueming Fan
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Department of Anesthesiology, Guizhou Provincial People’s Hospital, Guiyang 550002, China
| | - Yongzhi Lu
- Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510700, China
| | - Guizhi Du
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (G.D.); (J.L.)
| | - Jin Liu
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (G.D.); (J.L.)
| |
Collapse
|
8
|
Gain and loss of TASK3 channel function and its regulation by novel variation cause KCNK9 imprinting syndrome. Genome Med 2022; 14:62. [PMID: 35698242 PMCID: PMC9195326 DOI: 10.1186/s13073-022-01064-4] [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: 11/23/2021] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genomics enables individualized diagnosis and treatment, but large challenges remain to functionally interpret rare variants. To date, only one causative variant has been described for KCNK9 imprinting syndrome (KIS). The genotypic and phenotypic spectrum of KIS has yet to be described and the precise mechanism of disease fully understood. METHODS This study discovers mechanisms underlying KCNK9 imprinting syndrome (KIS) by describing 15 novel KCNK9 alterations from 47 KIS-affected individuals. We use clinical genetics and computer-assisted facial phenotyping to describe the phenotypic spectrum of KIS. We then interrogate the functional effects of the variants in the encoded TASK3 channel using sequence-based analysis, 3D molecular mechanic and dynamic protein modeling, and in vitro electrophysiological and functional methodologies. RESULTS We describe the broader genetic and phenotypic variability for KIS in a cohort of individuals identifying an additional mutational hotspot at p.Arg131 and demonstrating the common features of this neurodevelopmental disorder to include motor and speech delay, intellectual disability, early feeding difficulties, muscular hypotonia, behavioral abnormalities, and dysmorphic features. The computational protein modeling and in vitro electrophysiological studies discover variability of the impact of KCNK9 variants on TASK3 channel function identifying variants causing gain and others causing loss of conductance. The most consistent functional impact of KCNK9 genetic variants, however, was altered channel regulation. CONCLUSIONS This study extends our understanding of KIS mechanisms demonstrating its complex etiology including gain and loss of channel function and consistent loss of channel regulation. These data are rapidly applicable to diagnostic strategies, as KIS is not identifiable from clinical features alone and thus should be molecularly diagnosed. Furthermore, our data suggests unique therapeutic strategies may be needed to address the specific functional consequences of KCNK9 variation on channel function and regulation.
Collapse
|
9
|
Speigel IA, Hemmings Jr. HC. Relevance of Cortical and Hippocampal Interneuron Functional Diversity to General Anesthetic Mechanisms: A Narrative Review. Front Synaptic Neurosci 2022; 13:812905. [PMID: 35153712 PMCID: PMC8825374 DOI: 10.3389/fnsyn.2021.812905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/30/2021] [Indexed: 01/04/2023] Open
Abstract
General anesthetics disrupt brain processes involved in consciousness by altering synaptic patterns of excitation and inhibition. In the cerebral cortex and hippocampus, GABAergic inhibition is largely mediated by inhibitory interneurons, a heterogeneous group of specialized neuronal subtypes that form characteristic microcircuits with excitatory neurons. Distinct interneuron subtypes regulate specific excitatory neuron networks during normal behavior, but how these interneuron subtypes are affected by general anesthetics is unclear. This narrative review summarizes current principles of the synaptic architecture of cortical and interneuron subtypes, their contributions to different forms of inhibition, and their roles in distinct neuronal microcircuits. The molecular and cellular targets in these circuits that are sensitive to anesthetics are reviewed in the context of how anesthetics impact interneuron function in a subtype-specific manner. The implications of this functional interneuron diversity for mechanisms of anesthesia are discussed, as are their implications for anesthetic-induced changes in neural plasticity and overall brain function.
Collapse
Affiliation(s)
- Iris A. Speigel
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States
- *Correspondence: Iris A. Speigel
| | - Hugh C. Hemmings Jr.
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, United States
| |
Collapse
|
10
|
Han L, Zhao S, Xu F, Wang Y, Zhou R, Huang S, Ding Y, Deng D, Mao W, Chen X. Sevoflurane Increases Hippocampal Theta Oscillations and Impairs Memory Via TASK-3 Channels. Front Pharmacol 2021; 12:728300. [PMID: 34776954 PMCID: PMC8581481 DOI: 10.3389/fphar.2021.728300] [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: 06/21/2021] [Accepted: 10/12/2021] [Indexed: 11/21/2022] Open
Abstract
Sevoflurane can induce memory impairment during clinical anesthesia; however, the underlying mechanisms are largely unknown. TASK-3 channels are one of the potential targets of sevoflurane. Accumulating evidence supports a negative role of intracranial theta rhythms (4–12 Hz) in memory formation. Here, we investigated whether TASK-3 channels contribute to sevoflurane-induced memory impairment by regulating hippocampal theta rhythms. In this study, the memory performance of mice was tested by contextual fear conditioning and inhibitory avoidance experiments. The hippocampal local field potentials (LFPs) were recorded from chronically implanted electrodes located in CA3 region. The results showed that sevoflurane concentration-dependently impaired the memory function of mice, as evidenced by the decreased time mice spent on freezing and reduced latencies for mice to enter the shock compartment. Our electrophysiological results revealed that sevoflurane also enhanced the spectral power of hippocampal LFPs (1–30 Hz), particularly in memory-related theta rhythms (4–12 Hz). These effects were mitigated by viral-mediated knockdown of TASK-3 channels in the hippocampal CA3 region. The knockdown of hippocampal TASK-3 channels significantly reduced the enhancing effect of sevoflurane on hippocampal theta rhythms and alleviated sevoflurane-induced memory impairment. Our data indicate that sevoflurane can increase hippocampal theta oscillations and impair memory function via TASK-3 channels.
Collapse
Affiliation(s)
- Linlin Han
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuai Zhao
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Feng Xu
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yafeng Wang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ruihui Zhou
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shiqian Huang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanyuan Ding
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Daling Deng
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weike Mao
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiangdong Chen
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
11
|
Contribution of Neuronal and Glial Two-Pore-Domain Potassium Channels in Health and Neurological Disorders. Neural Plast 2021; 2021:8643129. [PMID: 34434230 PMCID: PMC8380499 DOI: 10.1155/2021/8643129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/03/2021] [Indexed: 02/05/2023] Open
Abstract
Two-pore-domain potassium (K2P) channels are widespread in the nervous system and play a critical role in maintaining membrane potential in neurons and glia. They have been implicated in many stress-relevant neurological disorders, including pain, sleep disorder, epilepsy, ischemia, and depression. K2P channels give rise to leaky K+ currents, which stabilize cellular membrane potential and regulate cellular excitability. A range of natural and chemical effectors, including temperature, pressure, pH, phospholipids, and intracellular signaling molecules, substantially modulate the activity of K2P channels. In this review, we summarize the contribution of K2P channels to neuronal excitability and to potassium homeostasis in glia. We describe recently discovered functions of K2P channels in glia, such as astrocytic passive conductance and glutamate release, microglial surveillance, and myelin generation by oligodendrocytes. We also discuss the potential role of glial K2P channels in neurological disorders. In the end, we discuss current limitations in K2P channel researches and suggest directions for future studies.
Collapse
|
12
|
Platholi J, Hemmings HC. Effects of general anesthetics on synaptic transmission and plasticity. Curr Neuropharmacol 2021; 20:27-54. [PMID: 34344292 PMCID: PMC9199550 DOI: 10.2174/1570159x19666210803105232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
General anesthetics depress excitatory and/or enhance inhibitory synaptic transmission principally by modulating the function of glutamatergic or GABAergic synapses, respectively, with relative anesthetic agent-specific mechanisms. Synaptic signaling proteins, including ligand- and voltage-gated ion channels, are targeted by general anesthetics to modulate various synaptic mechanisms, including presynaptic neurotransmitter release, postsynaptic receptor signaling, and dendritic spine dynamics to produce their characteristic acute neurophysiological effects. As synaptic structure and plasticity mediate higher-order functions such as learning and memory, long-term synaptic dysfunction following anesthesia may lead to undesirable neurocognitive consequences depending on the specific anesthetic agent and the vulnerability of the population. Here we review the cellular and molecular mechanisms of transient and persistent general anesthetic alterations of synaptic transmission and plasticity.
Collapse
Affiliation(s)
- Jimcy Platholi
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| | - Hugh C Hemmings
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| |
Collapse
|
13
|
Abudoureyimu R, Heizhati M, Wang L, Li M, Zhang D, Wang Z, Yang Z, Hong J, Li N. Lower 24-h urinary potassium excretion is negatively associated with excessive daytime sleepiness in the general population. Sleep Breath 2021; 26:733-741. [PMID: 34331198 DOI: 10.1007/s11325-021-02444-7] [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: 04/11/2021] [Revised: 07/11/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Uncertainty remains about the association of potassium (K) intake and sleepiness. Therefore, we aimed to explore the relationship between K excretion using 24-h urine samples and excessive daytime sleepiness (EDS) in the general population. METHODS In a cross-sectional study, we used multi-stage proportional random sampling to obtain a study sample aged ≥ 18 years from Emin, China between March and June 2019. We collected timed 24-h urine specimens and conducted EDS assessments using the Epworth Sleepiness Scale (ESS) questionnaire. Subjects were divided into two groups by the median of 24-h urinary potassium (24-h UK). EDS was defined as ESS score ≥ 10. Multi-variable linear regression was used to examine the association between the 24-h UK and the odds of prevalent EDS. We performed a sensitivity analysis by excluding subjects under anti-hypertensive treatment and those with sleep disordered breathing by the NoSAS scale. RESULTS A total of 470 participants with complete 24-h urine samples and ESS data (62% women, mean age 49.6 years, mean ESS score of 9.0 ± 5.2) were enrolled. The mean ESS score was significantly lower in the upper half of 24-h UK group than in the lower half (9.5 ± 5.3 vs 8.5 ± 5.1, P = 0.044), and accordingly, prevalent EDS was significantly greater in the lower half than in the higher half (49% vs 40%, P = 0.039). In further improving the propensity matching score, the results remained consistent with the overall results. In multiple linear regression, 24-h UK was negatively correlated with ESS score (β = - 0.180 (- 0.276, - 0.085), < 0.001). Sensitivity analysis demonstrated augmented results in those without anti-hypertensive treatment. CONCLUSION Lower potassium intake, as suggested by lower UK excretion, may be implicated in the presence of EDS in the general population.
Collapse
Affiliation(s)
- Reyila Abudoureyimu
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Mulalibieke Heizhati
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Lin Wang
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Mei Li
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Delian Zhang
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Zhongrong Wang
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Zhikang Yang
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Jing Hong
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China
| | - Nanfang Li
- Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region, National Health Committee Key Laboratory of Hypertension Clinical Research China, No. 91 Tianchi Road, Urumqi, 830001, Xinjiang, China.
| |
Collapse
|
14
|
Huang L, Xu G, Jiang R, Luo Y, Zuo Y, Liu J. Development of Non-opioid Analgesics Targeting Two-pore Domain Potassium Channels. Curr Neuropharmacol 2021; 20:16-26. [PMID: 33827408 PMCID: PMC9199554 DOI: 10.2174/1570159x19666210407152528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/14/2021] [Accepted: 03/24/2021] [Indexed: 02/08/2023] Open
Abstract
Two-pore domain potassium (K2P) channels are a diverse family of potassium channels. K2P channels generate background leak potassium currents to regulate cellular excitability and are thereby involved in a wide range of neurological disorders. K2P channels are modulated by a variety of physicochemical factors such as mechanical stretch, temperature, and pH. In the the peripheral nervous system (PNS), K2P channels are widely expressed in nociceptive neurons and play a critical roles in pain perception. In this review, we summarize the recent advances in the pharmacological properties of K2P channels, with a focus on the exogenous small-molecule activators targeting K2P channels. We emphasize the subtype-selectivity, cellular and in vivo pharmacological properties of all the reported small-molecule activators. The key underlying analgesic mechanisms mediated by K2P are also summarized based on the data in the literature from studies using small-molecule activators and genetic knock-out animals. We discuss advantages and limitations of the translational perspectives of K2P in pain medicine and provide outstanding questions for future studies in the end.
Collapse
Affiliation(s)
- Lu Huang
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Guangyin Xu
- Department of Physiology and Neurobiology, Institute of Neuroscience, Medical College of Soochow University, Suzhou, 215123, Jiangsu. China
| | - Ruotian Jiang
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Yuncheng Luo
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Yunxia Zuo
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Jin Liu
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| |
Collapse
|
15
|
Luppi AI, Spindler LRB, Menon DK, Stamatakis EA. The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia. Front Neurosci 2021; 15:643871. [PMID: 33737863 PMCID: PMC7960927 DOI: 10.3389/fnins.2021.643871] [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: 12/19/2020] [Accepted: 02/05/2021] [Indexed: 12/13/2022] Open
Abstract
"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.
Collapse
Affiliation(s)
- Andrea I. Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Lennart R. B. Spindler
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - David K. Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Emmanuel A. Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
16
|
Zhou W, Guan Z. Ion Channels in Anesthesia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:401-413. [DOI: 10.1007/978-981-16-4254-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
17
|
Luppi AI, Spindler LRB, Menon DK, Stamatakis EA. The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia. Front Neurosci 2021; 15:643871. [PMID: 33737863 DOI: 10.3389/fnins.2021.64387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/05/2021] [Indexed: 05/20/2023] Open
Abstract
"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.
Collapse
Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Lennart R B Spindler
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
18
|
Wague A, Joseph TT, Woll KA, Bu W, Vaidya KA, Bhanu NV, Garcia BA, Nimigean CM, Eckenhoff RG, Riegelhaupt PM. Mechanistic insights into volatile anesthetic modulation of K2P channels. eLife 2020; 9:59839. [PMID: 33345771 PMCID: PMC7781597 DOI: 10.7554/elife.59839] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/19/2020] [Indexed: 01/01/2023] Open
Abstract
K2P potassium channels are known to be modulated by volatile anesthetic (VA) drugs and play important roles in clinically relevant effects that accompany general anesthesia. Here, we utilize a photoaffinity analog of the VA isoflurane to identify a VA-binding site in the TREK1 K2P channel. The functional importance of the identified site was validated by mutagenesis and biochemical modification. Molecular dynamics simulations of TREK1 in the presence of VA found multiple neighboring residues on TREK1 TM2, TM3, and TM4 that contribute to anesthetic binding. The identified VA-binding region contains residues that play roles in the mechanisms by which heat, mechanical stretch, and pharmacological modulators alter TREK1 channel activity and overlaps with positions found to modulate TASK K2P channel VA sensitivity. Our findings define molecular contacts that mediate VA binding to TREK1 channels and suggest a mechanistic basis to explain how K2P channels are modulated by VAs.
Collapse
Affiliation(s)
- Aboubacar Wague
- Department of Anesthesiology, Weill Cornell Medical College, New York City, United States
| | - Thomas T Joseph
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Kellie A Woll
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Weiming Bu
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Kiran A Vaidya
- Department of Anesthesiology, Weill Cornell Medical College, New York City, United States
| | - Natarajan V Bhanu
- Epigenetics Program, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Benjamin A Garcia
- Epigenetics Program, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medical College, New York City, United States.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York City, United States.,Department of Biochemistry, Weill Cornell Medical College, New York City, United States
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, United States
| | - Paul M Riegelhaupt
- Department of Anesthesiology, Weill Cornell Medical College, New York City, United States
| |
Collapse
|
19
|
Abstract
General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.
Collapse
Affiliation(s)
- Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, 3620 Hamilton Walk, 334 John Morgan Building, Philadelphia, PA 19104, USA; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Translational Research Laboratories, 125 S. 31st St., Philadelphia, PA 19104-3403, USA; Mahoney Institute for Neuroscience, University of Pennsylvania, Clinical Research Building, 415 Curie Blvd, Philadelphia, PA 19104, USA.
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| |
Collapse
|
20
|
Inhibition of histone deacetylation rescues phenotype in a mouse model of Birk-Barel intellectual disability syndrome. Nat Commun 2020; 11:480. [PMID: 31980599 PMCID: PMC6981138 DOI: 10.1038/s41467-019-13918-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/05/2019] [Indexed: 01/10/2023] Open
Abstract
Mutations in the actively expressed, maternal allele of the imprinted KCNK9 gene cause Birk-Barel intellectual disability syndrome (BBIDS). Using a BBIDS mouse model, we identify here a partial rescue of the BBIDS-like behavioral and neuronal phenotypes mediated via residual expression from the paternal Kcnk9 (Kcnk9pat) allele. We further demonstrate that the second-generation HDAC inhibitor CI-994 induces enhanced expression from the paternally silenced Kcnk9 allele and leads to a full rescue of the behavioral phenotype suggesting CI-994 as a promising molecule for BBIDS therapy. Thus, these findings suggest a potential approach to improve cognitive dysfunction in a mouse model of an imprinting disorder. Birk-Barel intellectual disability is an imprinting syndrome due to maternally-only transmitted mutations of KCNK9/TASK3. Here authors are using a heterozygous deletion of the active maternal Kcnk9 allele to model the disease and show phenotypic rescue by HDAC inhibition.
Collapse
|
21
|
|
22
|
Thamban T, Agarwaal V, Khosla S. Role of genomic imprinting in mammalian development. J Biosci 2020; 45:20. [PMID: 31965998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Non-mendelian inheritance refers to the group of phenomena and observations related to the inheritance of genetic information that cannot be merely explained by Mendel's laws of inheritance. Phenomenon including Genomic imprinting, X-chromosome Inactivation, Paramutations are some of the best studied examples of non-mendelian inheritance. Genomic imprinting is a process that reversibly marks one of the two homologous loci, chromosome or chromosomal sets during development, resulting in functional non-equivalence of gene expression. Genomic imprinting is known to occur in a few insect species, plants, and placental mammals. Over the years, studies on imprinted genes have contributed immensely to highlighting the role of epigenetic modifications and the epigenetic circuitry during gene expression and development. In this review, we discuss the phenomenon of genomic imprinting in mammals and the role it plays especially during fetoplacental growth and early development.
Collapse
Affiliation(s)
- Thushara Thamban
- Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | | | | |
Collapse
|
23
|
Bedoya M, Rinné S, Kiper AK, Decher N, González W, Ramírez D. TASK Channels Pharmacology: New Challenges in Drug Design. J Med Chem 2019; 62:10044-10058. [PMID: 31260312 DOI: 10.1021/acs.jmedchem.9b00248] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rational drug design targeting ion channels is an exciting and always evolving research field. New medicinal chemistry strategies are being implemented to explore the wild chemical space and unravel the molecular basis of the ion channels modulators binding mechanisms. TASK channels belong to the two-pore domain potassium channel family and are modulated by extracellular acidosis. They are extensively distributed along the cardiovascular and central nervous systems, and their expression is up- and downregulated in different cancer types, which makes them an attractive therapeutic target. However, TASK channels remain unexplored, and drugs designed to target these channels are poorly selective. Here, we review TASK channels properties and their known blockers and activators, considering the new challenges in ion channels drug design and focusing on the implementation of computational methodologies in the drug discovery process.
Collapse
Affiliation(s)
- Mauricio Bedoya
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud , Universidad Autónoma de Chile , El Llano Subercaseaux 2801, Piso 6 , 8900000 Santiago , Chile
| |
Collapse
|
24
|
Iqbal F, Thompson AJ, Riaz S, Pehar M, Rice T, Syed NI. Anesthetics: from modes of action to unconsciousness and neurotoxicity. J Neurophysiol 2019; 122:760-787. [PMID: 31242059 DOI: 10.1152/jn.00210.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Modern anesthetic compounds and advanced monitoring tools have revolutionized the field of medicine, allowing for complex surgical procedures to occur safely and effectively. Faster induction times and quicker recovery periods of current anesthetic agents have also helped reduce health care costs significantly. Moreover, extensive research has allowed for a better understanding of anesthetic modes of action, thus facilitating the development of more effective and safer compounds. Notwithstanding the realization that anesthetics are a prerequisite to all surgical procedures, evidence is emerging to support the notion that exposure of the developing brain to certain anesthetics may impact future brain development and function. Whereas the data in support of this postulate from human studies is equivocal, the vast majority of animal research strongly suggests that anesthetics are indeed cytotoxic at multiple brain structure and function levels. In this review, we first highlight various modes of anesthetic action and then debate the evidence of harm from both basic science and clinical studies perspectives. We present evidence from animal and human studies vis-à-vis the possible detrimental effects of anesthetic agents on both the young developing and the elderly aging brain while discussing potential ways to mitigate these effects. We hope that this review will, on the one hand, invoke debate vis-à-vis the evidence of anesthetic harm in young children and the elderly, and on the other hand, incentivize the search for better and less toxic anesthetic compounds.
Collapse
Affiliation(s)
- Fahad Iqbal
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew J Thompson
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Saba Riaz
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marcus Pehar
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tiffany Rice
- Department of Anesthesiology, Perioperative and Pain Medicine, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada
| | - Naweed I Syed
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
25
|
Heizhati M, Zhang Y, Shao L, Wang Y, Yao X, Abulikemu S, Zhang D, Chang G, Zhou L, Li N. Decreased serum potassium may disturb sleep homeostasis in essential hypertensives. Hypertens Res 2018; 42:174-181. [PMID: 30446708 PMCID: PMC8075976 DOI: 10.1038/s41440-018-0131-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 05/08/2018] [Accepted: 05/24/2018] [Indexed: 11/09/2022]
Abstract
The aim is to investigate the association between alterations in the serum potassium (K+) concentration and sleep architecture parameters in essential hypertensives. Two hundred ninety-two hypertensives undergoing polysomnography and providing blood samples were recruited. The sleep architecture was composed of sleep stages 1 (N1), 2 (N2), 3 (N3), 4 (N4) and REM. The light sleep stage (LST) was composed of N1 + N2, and the deep sleep stage (DST) was composed of N3 + N4. The potentialrelationships between electrolytes and sleep parameters were determined via univariate and multivariate analyses. The subjects were divided into two groups via the serum K+ median (3.86 mmol/L). The K+ < 3.86 mmol/L group showed significantly decreased N1 (7.10 ± 4.55% vs 8.61 ± 5.23%, p = 0.002), LST (71.48 ± 11.33% vs 75.92 ± 17.08%, p = 0.013), and periodic leg movement during sleep related to microarousals (MA) /arousal (PLMS-A) [4 (1~10) vs 8 (3~15)/night, p < 0.001] and increased REM (17.38 ± 6.43% vs 15.37 ± 6.18%, p = 0.007) compared to the K+ ≥ 3.86 mmol/L group. A subdivided analysis by gender showed that these changes were more statistically significant in men than in women. Significant positive correlations were identified between K+ and N1 (r = 0.169, p = 0.004), as well as PLMS-A (r = 0.222, p < 0.001) in subjects. Compared to women, a significantly strong correlation was identified between K+ and REM sleep in men (r = 0.158, p = 0.028 vs. r = 0.078, p = 0.442). Multiple linear regression analysis indicated that K+ is significantly associated with N1 in all subjects (p = 0.03) and with REM in men (p = 0.008), even after adjusting for confounders. Decreased K+ may disturb the homeostasis of the sleep architecture, and gender may interfere with their links in the hypertensive population.
Collapse
Affiliation(s)
- Mulalibieke Heizhati
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Yu Zhang
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Liang Shao
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Yingchun Wang
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Xiaoguang Yao
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Suofeiya Abulikemu
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Delian Zhang
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Guijuan Chang
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Ling Zhou
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China
| | - Nanfang Li
- The Center of Hypertension of People's Hospital of Xinjiang Uygur Autonomous Region China; The Center of Diagnosis, Treatment and Research of Hypertension in Xinjiang, China. No. 91 Tianchi Road, Tianshan District, Urumqi, Xinjiang, CN, 830001, China.
| |
Collapse
|
26
|
Abstract
A primary goal of sleep research is to understand the molecular basis of sleep. Although some sleep/wake-promoting circuits and secreted substances have been identified, the detailed molecular mechanisms underlying the regulation of sleep duration have been elusive. Here, to address these mechanisms, we developed a simple computational model of a cortical neuron with five channels and a pump, which recapitulates the cortical electrophysiological characteristics of slow-wave sleep (SWS) and wakefulness. Comprehensive bifurcation and detailed mathematical analyses predicted that leak K+ channels play a role in generating the electrophysiological characteristics of SWS, leading to a hypothesis that leak K+ channels play a role in the regulation of sleep duration. To test this hypothesis experimentally, we comprehensively generated and analyzed 14 KO mice, and found that impairment of the leak K+ channel (Kcnk9) decreased sleep duration. Based on these results, we hypothesize that leak K+ channels regulate sleep duration in mammals.
Collapse
|
27
|
Identifying the genetic risk factors for treatment response to lurasidone by genome-wide association study: A meta-analysis of samples from three independent clinical trials. Schizophr Res 2018; 199:203-213. [PMID: 29730043 DOI: 10.1016/j.schres.2018.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/22/2018] [Accepted: 04/03/2018] [Indexed: 01/05/2023]
Abstract
A genome-wide association study (GWAS) of response of schizophrenia patients to the atypical antipsychotic drug, lurasidone, based on two double-blind registration trials, identified SNPs from four classes of genes as predictors of efficacy, but none were genome wide significant (GWS). After inclusion of data from a third lurasidone trial, meta-analysis identified a GWS marker and other findings consistent with our first study. The primary end-point was change in Total Positive and Negative Syndrome Scale (PANSS) between baseline and last observation carried forward. rs4736253, a genetic locus near KCNK9, encoding the K2P9.1 potassium channel, with a role in cognition and neurodevelopment, was the top marker in patients of European ancestry (EUR) (n = 264), reaching GWS (p = 4.78 × 10-8). rs10180106 (p = 4.92 × 10-7), located at an intron region of CTNNA2, a SCZ risk gene important for dendritic spine stabilization, was one of other best response markers for EUR patients. SNPs at STXBP5L (rs511841, p = 2.63 × 10-7) were the top markers for patients of African ancestry (n = 158). The association between PTPRD, NRG1, and MAGI1 previously reported to be related to response to lurasidone in the first two trials, showed a trend of significant association in the third trial. None of these genetic loci showed significant associations with clinical response in the corresponding placebo groups (n = 107 for EUR; n = 58 for AFR). This meta-analysis yielded the first GWAS-based GWS biomarker for lurasidone response and additional support for the conclusion that genes related to synaptic biology and/or risk for SCZ are the strongest predictors of response to lurasidone in schizophrenia patients.
Collapse
|
28
|
Gent TC, Detotto C, Vyssotski AL, Bettschart-Wolfensberger R. Epileptiform activity during inert gas euthanasia of mice. PLoS One 2018; 13:e0195872. [PMID: 29672545 PMCID: PMC5908136 DOI: 10.1371/journal.pone.0195872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 03/30/2018] [Indexed: 02/04/2023] Open
Abstract
Carbon dioxide (CO2) is one of the most commonly used euthanasia agents for mice, yet it is highly aversive and nociceptive. Inert gases are a possible alternative, however there are qualitative reports of seizures resulting from exposure. Here we evaluate epileptiform activity caused by inert gases (N2, He, Ar and Xe) and CO2 in mice chronically instrumented for EEG/EMG undergoing single-gas euthanasia. We found that N2, He and Ar caused epileptiform activity in all animals, CO2 in half of animals and no epileptiform activity produced by Xe. Atmospheric O2 concentrations at epileptiform activity onset were significantly higher for CO2 than for all other gases and occurred soon after loss of motion, whereas N2 and Ar epileptiform activity occurred at cessation of neocortical activity. Helium caused the longest epileptiform activity and these commenced significantly before isoelectric EEG. We did not detect any epileptiform activity during active behaviour. Taken together, these results demonstrate that whilst epileptiform activity from inert gases and particularly Ar and N2 are more prevalent than for CO2, their occurrence at the onset of an isoelectric EEG is unlikely to impact on the welfare of the animal. Epileptiform activity from these gases should not preclude them from further investigation as euthanasia agents. The genesis of epileptiform activity from CO2 is unlikely to result from hypoxia as with the inert gases. Helium caused epileptiform activity before cessation of neocortical activity and for a longer duration and is therefore less suitable as an alternative to CO2.
Collapse
Affiliation(s)
- Thomas C. Gent
- Anaesthesiology Section, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- * E-mail:
| | - Carlotta Detotto
- Anaesthesiology Section, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | | | | |
Collapse
|
29
|
Gelegen C, Miracca G, Ran MZ, Harding EC, Ye Z, Yu X, Tossell K, Houston CM, Yustos R, Hawkins ED, Vyssotski AL, Dong HL, Wisden W, Franks NP. Excitatory Pathways from the Lateral Habenula Enable Propofol-Induced Sedation. Curr Biol 2018; 28:580-587.e5. [PMID: 29398217 PMCID: PMC5835141 DOI: 10.1016/j.cub.2017.12.050] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/12/2017] [Accepted: 12/21/2017] [Indexed: 12/30/2022]
Abstract
The lateral habenula has been widely studied for its contribution in generating reward-related behaviors [1, 2]. We have found that this nucleus plays an unexpected role in the sedative actions of the general anesthetic propofol. The lateral habenula is a glutamatergic, excitatory hub that projects to multiple targets throughout the brain, including GABAergic and aminergic nuclei that control arousal [3-5]. When glutamate release from the lateral habenula in mice was genetically blocked, the ability of propofol to induce sedation was greatly diminished. In addition to this reduced sensitivity to propofol, blocking output from the lateral habenula caused natural non-rapid eye movement (NREM) sleep to become highly fragmented, especially during the rest ("lights on") period. This fragmentation was largely reversed by the dual orexinergic antagonist almorexant. We conclude that the glutamatergic output from the lateral habenula is permissive for the sedative actions of propofol and is also necessary for the consolidation of natural sleep.
Collapse
Affiliation(s)
- Cigdem Gelegen
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Giulia Miracca
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Mingzi Z Ran
- Department of Anesthesiology & Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi 710032, China
| | - Edward C Harding
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Zhiwen Ye
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Xiao Yu
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Kyoko Tossell
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Catriona M Houston
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Raquel Yustos
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Edwin D Hawkins
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zürich/ETH Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Hailong L Dong
- Department of Anesthesiology & Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi 710032, China
| | - William Wisden
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK; Centre of Excellence in Neurotechnology and UK Dementia Research Institute, Imperial College London, South Kensington SW7 2AZ, UK.
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK; Centre of Excellence in Neurotechnology and UK Dementia Research Institute, Imperial College London, South Kensington SW7 2AZ, UK.
| |
Collapse
|
30
|
Abstract
The mechanisms regulating the control of consciousness in both spontaneous sleep–wake behaviour and general anaesthesia remain poorly understood and are a fundamental question in neuroscience. The last 30 years have identified numerous molecular substrates and more recently important monoaminergic neuronal substrates. Future work now needs to concentrate on elucidating the convergence of these neuronal circuits to build a unifying mechanism of consciousness control.
Collapse
Affiliation(s)
- Thomas Gent
- Inselspital Universitatsspital Bern, Inselspital University Hospital, University of Bern, Bern, Switzerland
| | - Antoine Adamantidis
- Inselspital Universitatsspital Bern, Inselspital University Hospital, University of Bern, Bern, Switzerland
| |
Collapse
|
31
|
Golowasch J, Bose A, Guan Y, Salloum D, Roeser A, Nadim F. A balance of outward and linear inward ionic currents is required for generation of slow-wave oscillations. J Neurophysiol 2017; 118:1092-1104. [PMID: 28539398 DOI: 10.1152/jn.00240.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/19/2017] [Accepted: 05/19/2017] [Indexed: 01/21/2023] Open
Abstract
Regenerative inward currents help produce slow oscillations through a negative-slope conductance region of their current-voltage relationship that is well approximated by a linear negative conductance. We used dynamic-clamp injections of a linear current with such conductance, INL, to explore why some neurons can generate intrinsic slow oscillations whereas others cannot. We addressed this question in synaptically isolated neurons of the crab Cancer borealis after blocking action potentials. The pyloric network consists of a distinct pacemaker and follower neurons, all of which express the same complement of ionic currents. When the pyloric dilator (PD) neuron, a member of the pacemaker group, was injected with INL with dynamic clamp, it consistently produced slow oscillations. In contrast, all follower neurons failed to oscillate with INL To understand these distinct behaviors, we compared outward current levels of PD with those of follower lateral pyloric (LP) and ventral pyloric (VD) neurons. We found that LP and VD neurons had significantly larger high-threshold potassium currents (IHTK) than PD and LP had lower-transient potassium current (IA). Reducing IHTK pharmacologically enabled both LP and VD neurons to produce INL-induced oscillations, whereas modifying IA levels did not affect INL-induced oscillations. Using phase-plane and bifurcation analysis of a simplified model cell, we demonstrate that large levels of IHTK can block INL-induced oscillatory activity whereas generation of oscillations is almost independent of IA levels. These results demonstrate the general importance of a balance between inward pacemaking currents and high-threshold K+ current levels in determining slow oscillatory activity.NEW & NOTEWORTHY Pacemaker neuron-generated rhythmic activity requires the activation of at least one inward and one outward current. We have previously shown that the inward current can be a linear current (with negative conductance). Using this simple mechanism, here we demonstrate that the inward current conductance must be in relative balance with the outward current conductances to generate oscillatory activity. Surprisingly, an excess of outward conductances completely precludes the possibility of achieving such a balance.
Collapse
Affiliation(s)
- Jorge Golowasch
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey; and .,Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Amitabha Bose
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Yinzheng Guan
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey; and
| | - Dalia Salloum
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey; and
| | - Andrea Roeser
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey; and.,Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey; and.,Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| |
Collapse
|
32
|
Hughes S, Foster RG, Peirson SN, Hankins MW. Expression and localisation of two-pore domain (K2P) background leak potassium ion channels in the mouse retina. Sci Rep 2017; 7:46085. [PMID: 28443635 PMCID: PMC5405414 DOI: 10.1038/srep46085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
Two-pore domain (K2P) potassium channels perform essential roles in neuronal function. These channels produce background leak type potassium currents that act to regulate resting membrane potential and levels of cellular excitability. 15 different K2P channels have been identified in mammals and these channels perform important roles in a wide number of physiological systems. However, to date there is only limited data available concerning the expression and role of K2P channels in the retina. In this study we conduct the first comprehensive study of K2P channel expression in the retina. Our data show that K2P channels are widely expressed in the mouse retina, with variations in expression detected at different times of day and throughout postnatal development. The highest levels of K2P channel expression are observed for Müller cells (TWIK-1, TASK-3, TRAAK, and TREK-2) and retinal ganglion cells (TASK-1, TREK-1, TWIK-1, TWIK-2 and TWIK-3). These data offer new insight into the channels that regulate the resting membrane potential and electrical activity of retinal cells, and suggests that K2P channels are well placed to act as central regulators of visual signalling pathways. The prominent role of K2P channels in neuroprotection offers novel avenues of research into the treatment of common retinal diseases.
Collapse
Affiliation(s)
- Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Russell G. Foster
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N. Peirson
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Mark W. Hankins
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| |
Collapse
|
33
|
Luethy A, Boghosian JD, Srikantha R, Cotten JF. Halogenated Ether, Alcohol, and Alkane Anesthetics Activate TASK-3 Tandem Pore Potassium Channels Likely through a Common Mechanism. Mol Pharmacol 2017; 91:620-629. [PMID: 28325748 DOI: 10.1124/mol.117.108290] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 03/20/2017] [Indexed: 01/10/2023] Open
Abstract
The TWIK-related acid-sensitive potassium channel 3 (TASK-3; KCNK9) tandem pore potassium channel function is activated by halogenated anesthetics through binding at a putative anesthetic-binding cavity. To understand the pharmacologic requirements for TASK-3 activation, we studied the concentration-response of TASK-3 to several anesthetics (isoflurane, desflurane, sevoflurane, halothane, α-chloralose, 2,2,2-trichloroethanol [TCE], and chloral hydrate), to ethanol, and to a panel of halogenated methanes and alcohols. We used mutagenesis to probe the anesthetic-binding cavity as observed in a TASK-3 homology model. TASK-3 activation was quantified by Ussing chamber voltage clamp analysis. We mutagenized the residue Val-136, which lines the anesthetic-binding cavity, its flanking residues (132 to 140), and Leu-122, a pore-gating residue. The 2-halogenated ethanols activate wild-type TASK-3 with the following rank order efficacy (normalized current [95% confidence interval]): 2,2,2-tribromo-(267% [240-294]) > 2,2,2-trichloro-(215% [196-234]) > chloral hydrate (165% [161-176]) > 2,2-dichloro- > 2-chloro ≈ 2,2,2-trifluoroethanol > ethanol. Similarly, carbon tetrabromide (296% [245-346]), carbon tetrachloride (180% [163-196]), and 1,1,1,3,3,3-hexafluoropropanol (200% [194-206]) activate TASK-3, whereas the larger carbon tetraiodide and α-chloralose inhibit. Clinical agents activate TASK-3 with the following rank order efficacy: halothane (207% [202-212]) > isoflurane (169% [161-176]) > sevoflurane (164% [150-177]) > desflurane (119% [109-129]). Mutations at and near residue-136 modify TCE activation of TASK-3, and interestingly M159W, V136E, and L122D were resistant to both isoflurane and TCE activation. TASK-3 function is activated by a multiple agents and requires a halogenated substituent between ∼30 and 232 cm3/mol volume with potency increased by halogen polarizeability. Val-136 and adjacent residues may mediate anesthetic binding and stabilize an open state regulated by pore residue Leu-122. Isoflurane and TCE likely share commonalities in their mechanism of TASK-3 activation.
Collapse
Affiliation(s)
- Anita Luethy
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (A.L., J.D.B., and J.F.C.); Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.); Carver College of Medicine, University of Iowa, Iowa City, Iowa (R.S.)
| | - James D Boghosian
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (A.L., J.D.B., and J.F.C.); Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.); Carver College of Medicine, University of Iowa, Iowa City, Iowa (R.S.)
| | - Rithu Srikantha
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (A.L., J.D.B., and J.F.C.); Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.); Carver College of Medicine, University of Iowa, Iowa City, Iowa (R.S.)
| | - Joseph F Cotten
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (A.L., J.D.B., and J.F.C.); Department of Anesthesia, Kantonsspital Aarau, Aarau, Switzerland (A.L.); Carver College of Medicine, University of Iowa, Iowa City, Iowa (R.S.)
| |
Collapse
|
34
|
TASK channels contribute to neuroprotective action of inhalational anesthetics. Sci Rep 2017; 7:44203. [PMID: 28276488 PMCID: PMC5343576 DOI: 10.1038/srep44203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/06/2017] [Indexed: 01/13/2023] Open
Abstract
Postconditioning with inhalational anesthetics can reduce ischemia-reperfusion brain injury, although the cellular mechanisms for this effect have not been determined. The current study was designed to test if TASK channels contribute to their neuroprotective actions. Whole cell recordings were used to examine effects of volatile anesthetic on TASK currents in cortical neurons and to verify loss of anesthetic-activated TASK currents from TASK−/− mice. A transient middle cerebral artery occlusion (tMCAO) model was used to establish brain ischemia-reperfusion injury. Quantitative RT-PCR analysis revealed that TASK mRNA was reduced by >90% in cortex and hippocampus of TASK−/− mice. The TASK−/− mice showed a much larger region of infarction than C57BL/6 J mice after tMCAO challenge. Isoflurane or sevoflurane administered after the ischemic insult reduced brain infarct percentage and neurological deficit scores in C57BL/6 J mice, these effect were reduced in TASK−/− mice. Whole cell recordings revealed that the isoflurane-activated background potassium current observed in cortical pyramidal neurons from wild type mice was conspicuously reduced in TASK−/− mice. Our studies demonstrate that TASK channels can limit ischemia-reperfusion damage in the cortex, and postconditioning with volatile anesthetics provides neuroprotective actions that depend, in part, on activation of TASK currents in cortical neurons.
Collapse
|
35
|
Lu TZ, Kostelecki W, Sun CLF, Dong N, Pérez Velázquez JL, Feng ZP. High sensitivity of spontaneous spike frequency to sodium leak current in a Lymnaea pacemaker neuron. Eur J Neurosci 2016; 44:3011-3022. [PMID: 27711993 DOI: 10.1111/ejn.13426] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/25/2016] [Accepted: 09/30/2016] [Indexed: 11/28/2022]
Abstract
The spontaneous rhythmic firing of action potentials in pacemaker neurons depends on the biophysical properties of voltage-gated ion channels and background leak currents. The background leak current includes a large K+ and a small Na+ component. We previously reported that a Na+ -leak current via U-type channels is required to generate spontaneous action potential firing in the identified respiratory pacemaker neuron, RPeD1, in the freshwater pond snail Lymnaea stagnalis. We further investigated the functional significance of the background Na+ current in rhythmic spiking of RPeD1 neurons. Whole-cell patch-clamp recording and computational modeling approaches were carried out in isolated RPeD1 neurons. The whole-cell current of the major ion channel components in RPeD1 neurons were characterized, and a conductance-based computational model of the rhythmic pacemaker activity was simulated with the experimental measurements. We found that the spiking rate is more sensitive to changes in the Na+ leak current as compared to the K+ leak current, suggesting a robust function of Na+ leak current in regulating spontaneous neuronal firing activity. Our study provides new insight into our current understanding of the role of Na+ leak current in intrinsic properties of pacemaker neurons.
Collapse
Affiliation(s)
- T Z Lu
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - W Kostelecki
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - C L F Sun
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - N Dong
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - J L Pérez Velázquez
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Z-P Feng
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| |
Collapse
|
36
|
Perez JD, Rubinstein ND, Dulac C. New Perspectives on Genomic Imprinting, an Essential and Multifaceted Mode of Epigenetic Control in the Developing and Adult Brain. Annu Rev Neurosci 2016; 39:347-84. [PMID: 27145912 DOI: 10.1146/annurev-neuro-061010-113708] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mammalian evolution entailed multiple innovations in gene regulation, including the emergence of genomic imprinting, an epigenetic regulation leading to the preferential expression of a gene from its maternal or paternal allele. Genomic imprinting is highly prevalent in the brain, yet, until recently, its central roles in neural processes have not been fully appreciated. Here, we provide a comprehensive survey of adult and developmental brain functions influenced by imprinted genes, from neural development and wiring to synaptic function and plasticity, energy balance, social behaviors, emotions, and cognition. We further review the widespread identification of parental biases alongside monoallelic expression in brain tissues, discuss their potential roles in dosage regulation of key neural pathways, and suggest possible mechanisms underlying the dynamic regulation of imprinting in the brain. This review should help provide a better understanding of the significance of genomic imprinting in the normal and pathological brain of mammals including humans.
Collapse
Affiliation(s)
- Julio D Perez
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Nimrod D Rubinstein
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Catherine Dulac
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| |
Collapse
|
37
|
TASK Channels on Basal Forebrain Cholinergic Neurons Modulate Electrocortical Signatures of Arousal by Histamine. J Neurosci 2016; 35:13555-67. [PMID: 26446210 DOI: 10.1523/jneurosci.1445-15.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED Basal forebrain cholinergic neurons are the main source of cortical acetylcholine, and their activation by histamine elicits cortical arousal. TWIK-like acid-sensitive K(+) (TASK) channels modulate neuronal excitability and are expressed on basal forebrain cholinergic neurons, but the role of TASK channels in the histamine-basal forebrain cholinergic arousal circuit is unknown. We first expressed TASK channel subunits and histamine Type 1 receptors in HEK cells. Application of histamine in vitro inhibited the acid-sensitive K(+) current, indicating a functionally coupled signaling mechanism. We then studied the role of TASK channels in modulating electrocortical activity in vivo using freely behaving wild-type (n = 12) and ChAT-Cre:TASK(f/f) mice (n = 12), the latter lacking TASK-1/3 channels on cholinergic neurons. TASK channel deletion on cholinergic neurons significantly altered endogenous electroencephalogram oscillations in multiple frequency bands. We then identified the effect of TASK channel deletion during microperfusion of histamine into the basal forebrain. In non-rapid eye movement sleep, TASK channel deletion on cholinergic neurons significantly attenuated the histamine-induced increase in 30-50 Hz activity, consistent with TASK channels contributing to histamine action on basal forebrain cholinergic neurons. In contrast, during active wakefulness, histamine significantly increased 30-50 Hz activity in ChAT-Cre:TASK(f/f) mice but not wild-type mice, showing that the histamine response depended upon the prevailing cortical arousal state. In summary, we identify TASK channel modulation in response to histamine receptor activation in vitro, as well as a role of TASK channels on cholinergic neurons in modulating endogenous oscillations in the electroencephalogram and the electrocortical response to histamine at the basal forebrain in vivo. SIGNIFICANCE STATEMENT Attentive states and cognitive function are associated with the generation of γ EEG activity. Basal forebrain cholinergic neurons are important modulators of cortical arousal and γ activity, and in this study we investigated the mechanism by which these neurons are activated by the wake-active neurotransmitter histamine. We found that histamine inhibited a class of K(+) leak channels called TASK channels and that deletion of TASK channels selectively on cholinergic neurons modulated baseline EEG activity as well as histamine-induced changes in γ activity. By identifying a discrete brain circuit where TASK channels can influence γ activity, these results represent new knowledge that enhances our understanding of how subcortical arousal systems may contribute to the generation of attentive states.
Collapse
|
38
|
Chokshi RH, Larsen AT, Bhayana B, Cotten JF. Breathing Stimulant Compounds Inhibit TASK-3 Potassium Channel Function Likely by Binding at a Common Site in the Channel Pore. Mol Pharmacol 2015; 88:926-34. [PMID: 26268529 DOI: 10.1124/mol.115.100107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022] Open
Abstract
Compounds PKTHPP (1-{1-[6-(biphenyl-4-ylcarbonyl)-5,6,7,8-tetrahydropyrido[4,3-d]-pyrimidin-4-yl]piperidin-4-yl}propan-1-one), A1899 (2''-[(4-methoxybenzoylamino)methyl]biphenyl-2-carboxylic acid 2,4-difluorobenzylamide), and doxapram inhibit TASK-1 (KCNK3) and TASK-3 (KCNK9) tandem pore (K2P) potassium channel function and stimulate breathing. To better understand the molecular mechanism(s) of action of these drugs, we undertook studies to identify amino acid residues in the TASK-3 protein that mediate this inhibition. Guided by homology modeling and molecular docking, we hypothesized that PKTHPP and A1899 bind in the TASK-3 intracellular pore. To test our hypothesis, we mutated each residue in or near the predicted PKTHPP and A1899 binding site (residues 118-128 and 228-248), individually, to a negatively charged aspartate. We quantified each mutation's effect on TASK-3 potassium channel concentration response to PKTHPP. Studies were conducted on TASK-3 transiently expressed in Fischer rat thyroid epithelial monolayers; channel function was measured in an Ussing chamber. TASK-3 pore mutations at residues 122 (L122D, E, or K) and 236 (G236D) caused the IC50 of PKTHPP to increase more than 1000-fold. TASK-3 mutants L122D, G236D, L239D, and V242D were resistant to block by PKTHPP, A1899, and doxapram. Our data are consistent with a model in which breathing stimulant compounds PKTHPP, A1899, and doxapram inhibit TASK-3 function by binding at a common site within the channel intracellular pore region, although binding outside the channel pore cannot yet be excluded.
Collapse
Affiliation(s)
- Rikki H Chokshi
- Department of Anesthesia, Critical Care, and Pain Medicine (R.H.C., J.F.C.), Center for Computational and Integrative Biology, and Department of Molecular Biology (A.T.L.), and Department of Dermatology (B.B.), Massachusetts General Hospital, Boston, Massachusetts
| | - Aaron T Larsen
- Department of Anesthesia, Critical Care, and Pain Medicine (R.H.C., J.F.C.), Center for Computational and Integrative Biology, and Department of Molecular Biology (A.T.L.), and Department of Dermatology (B.B.), Massachusetts General Hospital, Boston, Massachusetts
| | - Brijesh Bhayana
- Department of Anesthesia, Critical Care, and Pain Medicine (R.H.C., J.F.C.), Center for Computational and Integrative Biology, and Department of Molecular Biology (A.T.L.), and Department of Dermatology (B.B.), Massachusetts General Hospital, Boston, Massachusetts
| | - Joseph F Cotten
- Department of Anesthesia, Critical Care, and Pain Medicine (R.H.C., J.F.C.), Center for Computational and Integrative Biology, and Department of Molecular Biology (A.T.L.), and Department of Dermatology (B.B.), Massachusetts General Hospital, Boston, Massachusetts
| |
Collapse
|
39
|
Fullagar B, Boysen SR, Toy M, Makwana C, Pang DSJ. Sound Pressure Levels in 2 Veterinary Intensive Care Units. J Vet Intern Med 2015; 29:1013-21. [PMID: 26113147 PMCID: PMC4895367 DOI: 10.1111/jvim.13574] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/13/2015] [Accepted: 05/14/2015] [Indexed: 12/16/2022] Open
Abstract
Background Intensive care units (ICUs) in human hospitals are consistently noisy environments with sound levels sufficient to substantially decrease sleep quality. Sound levels in veterinary ICUs have not been studied previously, but environmental sound has been shown to alter activity in healthy dogs. Hypothesis Veterinary ICUs, like those in human medicine, will exceed international guidelines for hospital noise. Animals NA. Methods Prospective, observational study performed consecutively and simultaneously over 4 weeks in 2 veterinary ICUs. Conventional A‐weighted sound pressure levels (equivalent continuous level [a reflection of average sound], the sound level that is exceeded 90% of the recording period time [reflective of background noise], and maximum sound levels) were continuously recorded and the number of spikes in sound >80 dBA were manually counted. Results Noise levels were comparable to ICUs in human hospitals. The equivalent continuous sound level was higher in ICU1 than in ICU2 at every time point compared, with greatest differences observed on week day (ICU1, 60.1 ± 3.7 dBA; ICU2, 55.9 ± 2.5 dBA, P < .001) and weekend nights (ICU1, 59.9 ± 2.4 dBA; ICU2, 53.4 ± 1.7 dBA, P < .0001) reflecting a 50% difference in loudness. Similar patterns were observed for the maximum and background noise levels. The number of sound spikes was up to 4 times higher in ICU1 (162.3 ± 84.9 spikes) than in ICU2 (40.4 ± 12.2 spikes, P = .001). Conclusions and Clinical Importance These findings show that sound in veterinary ICUs is loud enough to potentially disrupt sleep in critically ill veterinary patients.
Collapse
Affiliation(s)
- B Fullagar
- CARE Centre Animal Hospital, Calgary, Alberta, Canada.,The Ohio State University Veterinary Medical Center, Columbus, Ohio, USA
| | - S R Boysen
- Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - M Toy
- Western Veterinary Specialist and Emergency Centre, Calgary, Alberta, Canada
| | - C Makwana
- Western Veterinary Specialist and Emergency Centre, Calgary, Alberta, Canada
| | - D S J Pang
- Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
40
|
Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
Collapse
Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
| | | | | |
Collapse
|
41
|
Altered activity in the central medial thalamus precedes changes in the neocortex during transitions into both sleep and propofol anesthesia. J Neurosci 2015; 34:13326-35. [PMID: 25274812 DOI: 10.1523/jneurosci.1519-14.2014] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
How general anesthetics cause loss of consciousness is unknown. Some evidence points toward effects on the neocortex causing "top-down" inhibition, whereas other findings suggest that these drugs act via subcortical mechanisms, possibly selectively stimulating networks promoting natural sleep. To determine whether some neuronal circuits are affected before others, we used Morlet wavelet analysis to obtain high temporal resolution in the time-varying power spectra of local field potentials recorded simultaneously in discrete brain regions at natural sleep onset and during anesthetic-induced loss of righting reflex in rats. Although we observed changes in the local field potentials that were anesthetic-specific, there were some common changes in high-frequency (20-40 Hz) oscillations (reductions in frequency and increases in power) that could be detected at, or before, sleep onset and anesthetic-induced loss of righting reflex. For propofol and natural sleep, these changes occur first in the thalamus before changes could be detected in the neocortex. With dexmedetomidine, the changes occurred simultaneously in the thalamus and neocortex. In addition, the phase relationships between the low-frequency (1-4 Hz) oscillations in thalamic nuclei and neocortical areas are essentially the same for natural sleep and following dexmedetomidine administration, but a sudden change in phase, attributable to an effect in the central medial thalamus, occurs at the point of dexmedetomidine loss of righting reflex. Our data are consistent with the central medial thalamus acting as a key hub through which general anesthesia and natural sleep are initiated.
Collapse
|
42
|
Bertaccini EJ, Dickinson R, Trudell JR, Franks NP. Molecular modeling of a tandem two pore domain potassium channel reveals a putative binding site for general anesthetics. ACS Chem Neurosci 2014; 5:1246-52. [PMID: 25340635 PMCID: PMC4306477 DOI: 10.1021/cn500172e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
![]()
Anesthetics are thought
to mediate a portion of their activity
via binding to and modulation of potassium channels. In particular,
tandem pore potassium channels (K2P) are transmembrane ion channels
whose current is modulated by the presence of general anesthetics
and whose genetic absence has been shown to confer a level of anesthetic
resistance. While the exact molecular structure of all K2P forms remains
unknown, significant progress has been made toward understanding their
structure and interactions with anesthetics via the methods of molecular
modeling, coupled with the recently released higher resolution structures
of homologous potassium channels to act as templates. Such models
reveal the convergence of amino acid regions that are known to modulate
anesthetic activity onto a common three- dimensional cavity that forms
a putative anesthetic binding site. The model successfully predicts
additional important residues that are also involved in the putative
binding site as validated by the results of suggested experimental
mutations. Such a model can now be used to further predict other amino
acid residues that may be intimately involved in the target-based
structure–activity relationships that are necessary for anesthetic
binding.
Collapse
Affiliation(s)
- Edward J. Bertaccini
- Department
of Anesthesia and Perioperative Medicine, Palo Alto VA Health Care System, Palo Alto, California 94304, United States
| | | | | | | |
Collapse
|
43
|
The role of K₂p channels in anaesthesia and sleep. Pflugers Arch 2014; 467:907-16. [PMID: 25482669 PMCID: PMC4428837 DOI: 10.1007/s00424-014-1654-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
Tandem two-pore potassium channels (K2Ps) have widespread expression in the central nervous system and periphery where they contribute to background membrane conductance. Some general anaesthetics promote the opening of some of these channels, enhancing potassium currents and thus producing a reduction in neuronal excitability that contributes to the transition to unconsciousness. Similarly, these channels may be recruited during the normal sleep-wake cycle as downstream effectors of wake-promoting neurotransmitters such as noradrenaline, histamine and acetylcholine. These transmitters promote K2P channel closure and thus an increase in neuronal excitability. Our understanding of the roles of these channels in sleep and anaesthesia has been largely informed by the study of mouse K2P knockout lines and what is currently predicted by in vitro electrophysiology and channel structure and gating.
Collapse
|
44
|
Borsotto M, Veyssiere J, Moha Ou Maati H, Devader C, Mazella J, Heurteaux C. Targeting two-pore domain K(+) channels TREK-1 and TASK-3 for the treatment of depression: a new therapeutic concept. Br J Pharmacol 2014; 172:771-84. [PMID: 25263033 DOI: 10.1111/bph.12953] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/20/2014] [Accepted: 09/22/2014] [Indexed: 12/17/2022] Open
Abstract
Depression is a disease that is particularly frequent, affecting up to 20% of the population in Western countries. The origins of this pathology involve multiple genes as well as environmental and developmental factors leading to a disorder that remains difficult to treat. Several therapies for depression have been developed and these mainly target monoamine neurotransmitters. However, these treatments are not only associated with numerous adverse effects, but they are also ineffective for more than one-third of patients. Therefore, the need to develop new concepts to treat depression is crucial. Recently, studies using knockout mouse models have provided evidence for a crucial role of two members of the two-pore domain potassium channel (K2P ) family, tandem P-domain weak inward rectifying K(+) (TWIK)-related K(+) channel 1 (TREK-1) and TWIK-related acid-sensitive K(+) channel 3 (TASK-3) in the pathophysiology of depression. It is believed that TREK-1 and TASK-3 antagonists could lead to the development of new antidepressants. Herein, we describe the discovery of spadin, a natural peptide released from the maturation of the neurotensin receptor-3 (also known as sortilin), which specifically blocks the activity of the TREK-1 channel and displays particular antidepressant properties, with a rapid onset of action and the absence of adverse effects. The development of such molecules may open a new era in the field of psychiatry.
Collapse
Affiliation(s)
- M Borsotto
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (CNRS) UMR 7275, Université Nice Sophia Antipolis, Valbonne, France
| | | | | | | | | | | |
Collapse
|
45
|
Leung LS, Luo T, Ma J, Herrick I. Brain areas that influence general anesthesia. Prog Neurobiol 2014; 122:24-44. [PMID: 25172271 DOI: 10.1016/j.pneurobio.2014.08.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 08/03/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
This document reviews the literature on local brain manipulation of general anesthesia in animals, focusing on behavioral and electrographic effects related to hypnosis or loss of consciousness. Local inactivation or lesion of wake-active areas, such as locus coeruleus, dorsal raphe, pedunculopontine tegmental nucleus, perifornical area, tuberomammillary nucleus, ventral tegmental area and basal forebrain, enhanced general anesthesia. Anesthesia enhancement was shown as a delayed emergence (recovery of righting reflex) from anesthesia or a decrease in the minimal alveolar concentration that induced loss of righting. Local activation of various wake-active areas, including pontis oralis and centromedial thalamus, promoted behavioral or electrographic arousal during maintained anesthesia and facilitated emergence. Lesion of the sleep-active ventrolateral preoptic area resulted in increased wakefulness and decreased isoflurane sensitivity, but only for 6 days after lesion. Inactivation of any structure within limbic circuits involving the medial septum, hippocampus, nucleus accumbens, ventral pallidum, and ventral tegmental area, amygdala, entorhinal and piriform cortex delayed emergence from anesthesia, and often reduced anesthetic-induced behavioral excitation. In summary, the concept that anesthesia works on the sleep-wake system has received strong support from studies that inactivated/lesioned or activated wake-active areas, and weak support from studies that lesioned sleep-active areas. In addition to the conventional wake-sleep areas, limbic structures such as the medial septum, hippocampus and prefrontal cortex are also involved in the behavioral response to general anesthesia. We suggest that hypnosis during general anesthesia may result from disrupting the wake-active neuronal activities in multiple areas and suppressing an atropine-resistant cortical activation associated with movements.
Collapse
Affiliation(s)
- L Stan Leung
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5C1.
| | - Tao Luo
- Department of Anesthesiology, Peking University, Shenzhen Hospital, China
| | - Jingyi Ma
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5C1
| | - Ian Herrick
- Department of Anaesthesiology and Perioperative Medicine, The University of Western Ontario, London, Ontario, Canada N6A 5C1
| |
Collapse
|
46
|
Novel approach identifies SNPs in SLC2A10 and KCNK9 with evidence for parent-of-origin effect on body mass index. PLoS Genet 2014; 10:e1004508. [PMID: 25078964 PMCID: PMC4117451 DOI: 10.1371/journal.pgen.1004508] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/14/2014] [Indexed: 01/12/2023] Open
Abstract
The phenotypic effect of some single nucleotide polymorphisms (SNPs) depends on their parental origin. We present a novel approach to detect parent-of-origin effects (POEs) in genome-wide genotype data of unrelated individuals. The method exploits increased phenotypic variance in the heterozygous genotype group relative to the homozygous groups. We applied the method to >56,000 unrelated individuals to search for POEs influencing body mass index (BMI). Six lead SNPs were carried forward for replication in five family-based studies (of ∼4,000 trios). Two SNPs replicated: the paternal rs2471083-C allele (located near the imprinted KCNK9 gene) and the paternal rs3091869-T allele (located near the SLC2A10 gene) increased BMI equally (beta = 0.11 (SD), P<0.0027) compared to the respective maternal alleles. Real-time PCR experiments of lymphoblastoid cell lines from the CEPH families showed that expression of both genes was dependent on parental origin of the SNPs alleles (P<0.01). Our scheme opens new opportunities to exploit GWAS data of unrelated individuals to identify POEs and demonstrates that they play an important role in adult obesity.
Collapse
|
47
|
Bose A, Golowasch J, Guan Y, Nadim F. The role of linear and voltage-dependent ionic currents in the generation of slow wave oscillations. J Comput Neurosci 2014; 37:229-42. [PMID: 24668241 DOI: 10.1007/s10827-014-0498-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 01/08/2023]
Abstract
Neuronal oscillatory activity is generated by a combination of ionic currents, including at least one inward regenerative current that brings the cell towards depolarized voltages and one outward current that repolarizes the cell. Such currents have traditionally been assumed to require voltage-dependence. Here we test the hypothesis that the voltage dependence of the regenerative inward current is not necessary for generating oscillations. Instead, a current I NL that is linear in the biological voltage range and has negative conductance is sufficient to produce regenerative activity. The current I NL can be considered a linear approximation to the negative-conductance region of the current-voltage relationship of a regenerative inward current. Using a simple conductance-based model, we show that I NL , in conjunction with a voltage-gated, non-inactivating outward current, can generate oscillatory activity. We use phase-plane and bifurcation analyses to uncover a rich variety of behaviors as the conductance of I NL is varied, and show that oscillations emerge as a result of destabilization of the resting state of the model neuron. The model shows the need for well-defined relationships between the inward and outward current conductances, as well as their reversal potentials, in order to produce stable oscillatory activity. Our analysis predicts that a hyperpolarization-activated inward current can play a role in stabilizing oscillatory activity by preventing swings to very negative voltages, which is consistent with what is recorded in biological neurons in general. We confirm this prediction of the model experimentally in neurons from the crab stomatogastric ganglion.
Collapse
Affiliation(s)
- Amitabha Bose
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | | | | | | |
Collapse
|
48
|
Gelegen C, Gent TC, Ferretti V, Zhang Z, Yustos R, Lan F, Yang Q, Overington DWU, Vyssotski AL, van Lith HA, Wisden W, Franks NP. Staying awake--a genetic region that hinders α2 adrenergic receptor agonist-induced sleep. Eur J Neurosci 2014; 40:2311-9. [PMID: 24674448 PMCID: PMC4215598 DOI: 10.1111/ejn.12570] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/21/2014] [Accepted: 02/24/2014] [Indexed: 11/29/2022]
Abstract
How external stimuli prevent the onset of sleep has been little studied. This is usually considered to be a non-specific type of phenomenon. However, the hypnotic drug dexmedetomidine, an agonist at α2 adrenergic receptors, has unusual properties that make it useful for investigating this question. Dexmedetomidine is considered to produce an ‘arousable’ sleep-like state, so that patients or animals given dexmedetomidine become alert following modest stimulation. We hypothesized that it might be more difficult to make mice unconscious with dexmedetomidine if there was a sufficient external stimulus. Employing a motorized rotating cylinder, which provided a continuous and controlled arousal stimulus, we quantitatively measured the ability of such a stimulus to prevent dexmedetomidine loss of righting reflex in two inbred strains of mice (C57BL/6 and 129X1). We found that whereas the C57BL/6 strain required a strong stimulus to prevent dexmedetomidine-induced hypnosis, the 129X1 strain stayed awake even with minimal stimuli. Remarkably, this could be calibrated as a simple threshold trait, i.e. a binary ‘yes–no’ response, which after crossing the two mouse strains behaved as a dominant-like trait. We carried out a genome-wide linkage analysis on the F2 progeny to determine if the ability of a stimulus to prevent dexmedetomidine hypnosis could be mapped to one or more chromosomal regions. We identified a locus on chromosome 4 with an associated Logarithm of Odds score exceeding the pre-established threshold level. These results show that complex traits, such as the ability of a stimulus to reverse drug-induced hypnosis, may have precise genetic determinants.
Collapse
Affiliation(s)
- Cigdem Gelegen
- Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Noriega-Navarro R, Lopez-Charcas O, Hernández-Enríquez B, Reyes-Gutiérrez PE, Martínez R, Landa A, Morán J, Gomora JC, Garcia-Valdes J. Novel TASK channels inhibitors derived from dihydropyrrolo[2,1-a]isoquinoline. Neuropharmacology 2013; 79:28-36. [PMID: 24212057 DOI: 10.1016/j.neuropharm.2013.10.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 10/22/2013] [Accepted: 10/27/2013] [Indexed: 01/12/2023]
Abstract
TASK channels belong to the family of K(+) channels with 4 transmembrane segments and 2 pore domains (4TM/2P) per subunit. These channels have been related to apoptosis in cerebellar granule neurons (CGN), as well as cancer in other tissues. TASK current is regulated by hormones, neurotransmitters, anesthetics and divalent cations, which are not selective. Recently, there has been found some organic compounds that inhibit TASK current selectively. In order to find other modulators, we report here a group of five dihydropyrrolo[2,1-a]isoquinolines (DPIs), four of them with putative anticancer activity, that were evaluated on TASK-1 and TASK-3 channels. The compounds 1, 2 and 3 showed IC50 < 320 μM on TASK-1 and TASK-3, intermediate activity on TASK-1/TASK-3 heterodimer, moderate effect over hslo and TREK-1 (500 μM), and practically not inhibition on Shaker-IR, herg and IRK2.1 potassium channels, when they were expressed heterologously in Xenopus laevis oocytes. In rat CGN, 500 μM of these three compounds induced a decrement by >39% of the TASK-carried leak current. Finally, only compound 1 showed significant protection (∼36%) against apoptotic death of CGN induced by K(+) deprivation. These results suggest that DPI compounds could be potential candidates for designing new selective inhibitors of TASK channels.
Collapse
Affiliation(s)
- R Noriega-Navarro
- Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - O Lopez-Charcas
- Departamento de Neuropatología Molecular, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - B Hernández-Enríquez
- Departamento de Neurodesarrollo y Fisiología, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - P E Reyes-Gutiérrez
- Departamento de Química Orgánica, Instituto de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - R Martínez
- Departamento de Química Orgánica, Instituto de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - A Landa
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - J Morán
- Departamento de Neurodesarrollo y Fisiología, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - J C Gomora
- Departamento de Neuropatología Molecular, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico
| | - J Garcia-Valdes
- Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, México City 04510, Mexico.
| |
Collapse
|
50
|
TASK-1 (KCNK3) and TASK-3 (KCNK9) tandem pore potassium channel antagonists stimulate breathing in isoflurane-anesthetized rats. Anesth Analg 2013; 116:810-6. [PMID: 23460565 DOI: 10.1213/ane.0b013e318284469d] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND TASK-1 and TASK-3 tandem pore potassium channel subunits provide a constitutive acidic pH- and hypoxia-inhibited potassium conductance. TASK channels are expressed in a number of tissues involved in regulation of breathing, and the TASK-1/TASK-3 heterodimer provides the predominant hypoxia-sensitive potassium conductance in carotid body type 1 glomus chemosensing cells. The carotid bodies have an important role in regulation of breathing. Doxapram is a potent TASK-1 and TASK-3 potassium channel antagonist and a carotid body and breathing stimulant. PK-THPP and A1899 are potent and selective TASK-1 and TASK-3 antagonists. I hypothesized PK-THPP and A1899 are, like doxapram, breathing stimulants. METHODS I studied rat TASK-3 potassium channel function by Ussing chamber using Fischer rat thyroid monolayers. To quantify breathing effects, I studied male Sprague-Dawley rats spontaneously breathing 1.5% isoflurane in room air by noninvasive plethysmography and by arterial blood gas analysis. RESULTS PK-THPP, A1899, and doxapram inhibit rat TASK-3 potassium channel function with IC50s of 42 nM (33-52), 1.6 μM (0.8-3.3), and 22 μM (18-28) (n = 4-6; 95% confidence limits). IV PK-THPP, A1899, and doxapram stimulated breathing by plethysmography with a peak change in minute ventilation relative to baseline of 84% ± 19% and 226% ± 56% (for PK-THPP at 0.5 and 5 mg/kg; mean ± SEM; n = 3-4; P < 0.05 and P < 0.001, respectively, relative to vehicle); 46% ± 2% and 236% ± 48% (for A1899 at 5 and 25 mg/kg; n = 3-4; P > 0.05 and P < 0.001, respectively); 103% ± 20% (for doxapram at 25 mg/kg; n = 4), and 33% ± 9% (for dimethylsulfoxide vehicle at 1 mL/kg; n = 4). PK-THPP and A1899, unlike doxapram, induced a profound and lasting respiratory alkalosis by arterial blood gas analysis. Thirty minutes after IV drug administration, I observed an arterial pH and carbon dioxide partial pressure of 7.62 ± 0.02 and 23 ± 0.8 mm Hg (for PK-THPP after 5 mg/kg; n = 4; P < 0.001 for both relative to vehicle), 7.49 ± 0.02 and 31 ± 2 mm Hg (for A1899 at 25 mg/kg; n = 6; P < 0.05 and 0.001, respectively), 7.43 ± 0.03 and 39 ± 4 mm Hg (for doxapram after 25 mg/kg; n = 4; P > 0.05 for both), and 7.38 ± 0.03 and 48 ± 4 mm Hg (for dimethylsulfoxide vehicle after 1 mL/kg; n = 3). CONCLUSIONS PK-THPP and A1899 are potent rat TASK-3 antagonists and effective breathing stimulants. PK-THPP and A1899 effects on breathing were of greater magnitude and/or duration relative to that of doxapram. PK-THPP and A1899 or related compounds may have therapeutic potential for treating breathing disorders.
Collapse
|