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Monteil A, Guérineau NC, Gil-Nagel A, Parra-Diaz P, Lory P, Senatore A. New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN. Physiol Rev 2024; 104:399-472. [PMID: 37615954 DOI: 10.1152/physrev.00014.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.
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Affiliation(s)
- Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Antonio Gil-Nagel
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Paloma Parra-Diaz
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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Hao X, Yang Y, Liu J, Zhang D, Ou M, Ke B, Zhu T, Zhou C. The Modulation by Anesthetics and Analgesics of Respiratory Rhythm in the Nervous System. Curr Neuropharmacol 2024; 22:217-240. [PMID: 37563812 PMCID: PMC10788885 DOI: 10.2174/1570159x21666230810110901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/27/2023] [Accepted: 02/28/2023] [Indexed: 08/12/2023] Open
Abstract
Rhythmic eupneic breathing in mammals depends on the coordinated activities of the neural system that sends cranial and spinal motor outputs to respiratory muscles. These outputs modulate lung ventilation and adjust respiratory airflow, which depends on the upper airway patency and ventilatory musculature. Anesthetics are widely used in clinical practice worldwide. In addition to clinically necessary pharmacological effects, respiratory depression is a critical side effect induced by most general anesthetics. Therefore, understanding how general anesthetics modulate the respiratory system is important for the development of safer general anesthetics. Currently used volatile anesthetics and most intravenous anesthetics induce inhibitory effects on respiratory outputs. Various general anesthetics produce differential effects on respiratory characteristics, including the respiratory rate, tidal volume, airway resistance, and ventilatory response. At the cellular and molecular levels, the mechanisms underlying anesthetic-induced breathing depression mainly include modulation of synaptic transmission of ligand-gated ionotropic receptors (e.g., γ-aminobutyric acid, N-methyl-D-aspartate, and nicotinic acetylcholine receptors) and ion channels (e.g., voltage-gated sodium, calcium, and potassium channels, two-pore domain potassium channels, and sodium leak channels), which affect neuronal firing in brainstem respiratory and peripheral chemoreceptor areas. The present review comprehensively summarizes the modulation of the respiratory system by clinically used general anesthetics, including the effects at the molecular, cellular, anatomic, and behavioral levels. Specifically, analgesics, such as opioids, which cause respiratory depression and the "opioid crisis", are discussed. Finally, underlying strategies of respiratory stimulation that target general anesthetics and/or analgesics are summarized.
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Affiliation(s)
- Xuechao Hao
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yaoxin Yang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Mengchan Ou
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Bowen Ke
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
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Yarana C, Maneechote C, Khuanjing T, Ongnok B, Prathumsap N, Thanasrisuk S, Pattanapanyasat K, Chattipakorn SC, Chattipakorn N. Potential roles of 4HNE-adducted protein in serum extracellular vesicles as an early indicator of oxidative response against doxorubicin-induced cardiomyopathy in rats. Curr Res Toxicol 2023; 5:100134. [PMID: 37964944 PMCID: PMC10641738 DOI: 10.1016/j.crtox.2023.100134] [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: 06/28/2023] [Revised: 10/18/2023] [Accepted: 10/31/2023] [Indexed: 11/16/2023] Open
Abstract
Late-onset cardiomyopathy is becoming more common among cancer survivors, particularly those who received doxorubicin (DOXO) treatment. However, few clinically available cardiac biomarkers can predict an unfavorable cardiac outcome before cell death. Extracellular vesicles (EVs) are emerging as biomarkers for cardiovascular diseases and others. This study aimed to measure dynamic 4-hydroxynonenal (4HNE)-adducted protein levels in rats treated chronically with DOXO and examine their link with oxidative stress, antioxidant gene expression in cardiac tissues, and cardiac function. Twenty-two male Wistar rats were randomly assigned to receive intraperitoneal injection of normal saline (n = 8) or DOXO (3 mg/kg, 6 doses, n = 14). Before and after therapy, serum EVs and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were determined. Tunable resistive pulse sensing was used to measure EV size and concentration. ELISA was used to assess 4HNE-adducted protein in EVs and cardiac tissues. Differential-display reverse transcription-PCR was used to quantitate cardiac Cat and Gpx1 gene expression. Potential correlations between 4HNE-adducted protein levels in EVs, cardiac oxidative stress, antioxidant gene expression, and cardiac function were determined. DOXO-treated rats showed more serum EV 4HNE-adducted protein than NSS-treated rats at day 9 and later endpoints, whereas NT-proBNP levels were not different between groups. Moreover, on day 9, surviving rats' EVs had higher levels of 4HNE-adducted protein, and these correlated positively with concentrations of heart tissue 4HNE adduction and copy numbers of Cat and Gpx1, while at endpoint correlated negatively with cardiac functions. Therefore, 4HNE-adducted protein in serum EVs could be an early, minimally invasive biomarker of the oxidative response and cardiac function in DOXO-induced cardiomyopathy.
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Affiliation(s)
- Chontida Yarana
- Center for Research Innovation and Biomedical Informatics, Faculty of Medical Technology, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand
| | - Chayodom Maneechote
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Thawatchai Khuanjing
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Benjamin Ongnok
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Nanthip Prathumsap
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Sirasa Thanasrisuk
- Faculty of Medical Technology, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand
| | - Kovit Pattanapanyasat
- Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Siriporn C. Chattipakorn
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
- Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
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Fyneface-Ogan S, Fiebai PO, Orazulike NC. Effect of Carbetocin on Uterine Tone during Cesarean Section: A Comparison between Subarachnoid Block and General Anesthesia. Ann Afr Med 2023; 22:321-326. [PMID: 37417020 PMCID: PMC10445711 DOI: 10.4103/aam.aam_72_22] [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: 04/23/2022] [Accepted: 03/09/2023] [Indexed: 07/08/2023] Open
Abstract
Background Postpartum hemorrhage remains a challenge in obstetric practice in developing climes and contributes immensely to the horrendous figures of maternal mortality worldwide. Aim The aim was to compare the effect of intravenous (IV) carbetocin on uterine tone under different anesthetic techniques for elective cesarean section. Methods Four hundred and seventy-eight consecutive women scheduled for elective cesarean section were recruited into two groups by convenience. While 445 parturients received subarachnoid block (SAB), 33 had general anesthesia (GA). At delivery, IV carbetocin was administered. The uterine tone was assessed manually and blood loss from intraoperative period to the 24th h was determined. Other variables such as hemodynamic profiles and Apgar scores were determined and recorded. Results The bio-characteristics between the two groups were essentially the same in terms of age, weight, height, body mass index, preoperative hemoglobin, and gestational age. While the response to the administered carbetocin was slower in the GA group, there was no need for additional dose. The mean estimated intraoperative blood loss under SAB was 250.44 ± 50.59 ml and that under GA was 470.89 ± 35.70 ml, P = 0.000000. The ephedrine consumption was 6.25 ± 2.05 mg in the SAB group while it was 11.25 ± 2.49 mg, P = 0.000000. There was no further maternal blood loss observed after the intraoperative period until the end of 24-h period. The hemodynamic profiles were significantly different in terms of mean systolic blood pressure, mean diastolic blood pressure, and mean arterial blood pressure, P = 0.006, P = 0.002, and P = 0.003, respectively. However, the difference in the mean heart rate was not statistically significant, P = 0.304. While the Apgar scores between groups were not statistically significant, the mean umbilical pH was 7.34 ± 0.09 in the SAB group, it was 7.35 ± 0.02 in the GA group, P = 0.071. Conclusion Intraoperative maternal blood loss was more among the parturients who received GA than subarachnoid blood. This could probably be due to the effect of the halogenated vapor used for the GA on the uterine tone. There was no further blood loss after the intraoperative period. The hemodynamic profile was better under SAB as evidenced by the total ephedrine consumption.
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Affiliation(s)
- Sotonye Fyneface-Ogan
- Obstetric Anaesthesia Unit, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
| | - Preye O. Fiebai
- Department of Obstetrics and Gynaecology, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
| | - Ngozi Clare Orazulike
- Department of Obstetrics and Gynaecology, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
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Jung J, Kim T. General anesthesia and sleep: like and unlike. Anesth Pain Med (Seoul) 2022; 17:343-351. [DOI: 10.17085/apm.22227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/17/2022] [Indexed: 11/05/2022] Open
Abstract
General anesthesia and sleep have long been discussed in the neurobiological context owingto their commonalities, such as unconsciousness, immobility, non-responsiveness to externalstimuli, and lack of memory upon returning to consciousness. Sleep is regulated bycomplex interactions between wake-promoting and sleep-promoting neural circuits. Anestheticsexert their effects partly by inhibiting wake-promoting neurons or activating sleep-promotingneurons. Unconscious but arousable sedation is more related to sleep-wake circuitries,whereas unconscious and unarousable anesthesia is independent of them. Generalanesthesia is notable for its ability to decrease sleep propensity. Conversely, increasedsleep propensity due to insufficient sleep potentiates anesthetic effects. Taken together, it isplausible that sleep and anesthesia are closely related phenomena but not the same ones.Further investigations on the relationship between sleep and anesthesia are warranted.
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Müller CP. Serotonin and Consciousness-A Reappraisal. Behav Brain Res 2022; 432:113970. [PMID: 35716774 DOI: 10.1016/j.bbr.2022.113970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 11/02/2022]
Abstract
The serotonergic system of the brain is a major modulator of behaviour. Here we describe a re-appraisal of its function for consciousness based on anatomical, functional and pharmacological data. For a better understanding, the current model of consciousness is expanded. Two parallel streams of conscious flow are distinguished. A flow of conscious content and an affective consciousness flow. While conscious content flow has its functional equivalent in the activity of higher cortico-cortical and cortico-thalamic networks, affective conscious flow originates in segregated deeper brain structures for single emotions. It is hypothesized that single emotional networks converge on serotonergic and other modulatory transmitter neurons in the brainstem where a bound percept of an affective conscious flow is formed. This is then dispersed to cortical and thalamic networks, where it is time locked with conscious content flow at the level of these networks. Serotonin acts in concert with other modulatory systems of the brain stem with some possible specialization on single emotions. Together, these systems signal a bound percept of affective conscious flow. Dysfunctions in the serotonergic system may not only give rise to behavioural and somatic symptoms, but also essentially affect the coupling of conscious affective flow with conscious content flow, leading to the affect-stained subjective side of mental disorders like anxiety, depression, or schizophrenia. The present model is an attempt to integrate the growing insights into serotonergic system function. However, it is acknowledged, that several key claims are still at a heuristic level that need further empirical support.
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Affiliation(s)
- Christian P Müller
- Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany; Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
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Ou M, Kuo FS, Chen X, Kahanovitch U, Olsen ML, Du G, Mulkey DK. Isoflurane inhibits a Kir4.1/5.1-like conductance in neonatal rat brainstem astrocytes and recombinant Kir4.1/5.1 channels in a heterologous expression system. J Neurophysiol 2020; 124:740-749. [PMID: 32727273 PMCID: PMC7509298 DOI: 10.1152/jn.00358.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 02/08/2023] Open
Abstract
All inhalation anesthetics used clinically including isoflurane can suppress breathing; since this unwanted side effect can persist during the postoperative period and complicate patient recovery, there is a need to better understand how isoflurane affects cellular and molecular elements of respiratory control. Considering that astrocytes in a brainstem region known as the retrotrapezoid nucleus (RTN) contribute to the regulation of breathing in response to changes in CO2/H+ (i.e., function as respiratory chemoreceptors), and astrocytes in other brain regions are highly sensitive to isoflurane, we wanted to determine whether and how RTN astrocytes respond to isoflurane. We found that RTN astrocytes in slices from neonatal rat pups (7-12 days postnatal) respond to clinically relevant levels of isoflurane by inhibition of a CO2/H+-sensitive Kir4.1/5.1-like conductance [50% effective concentration (EC50) = 0.8 mM or ~1.7%]. We went on to confirm that similar levels of isoflurane (EC50 = 0.53 mM or 1.1%) inhibit recombinant Kir4.1/5.1 channels but not homomeric Kir4.1 channels expressed in HEK293 cells. We also found that exposure to CO2/H+ occluded subsequent effects of isoflurane on both native and recombinant Kir4.1/5.1 currents. These results identify Kir4.1/5.1 channels in astrocytes as novel targets of isoflurane. These results suggest astrocyte Kir4.1/5.1 channels contribute to certain aspects of general anesthesia including altered respiratory control.NEW & NOTEWORTHY An unwanted side effect of isoflurane anesthesia is suppression of breathing. Despite this clinical significance, effects of isoflurane on cellular and molecular elements of respiratory control are not well understood. Here, we show that isoflurane inhibits heteromeric Kir4.1/5.1 channels in a mammalian expression system and a Kir4.1/5.1-like conductance in astrocytes in a brainstem respiratory center. These results identify astrocyte Kir4.1/5.1 channels as novel targets of isoflurane and potential substrates for altered respiratory control during isoflurane anesthesia.
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Affiliation(s)
- Mengchan Ou
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu City, China
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Fu-Shan Kuo
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Xinnian Chen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Uri Kahanovitch
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia
| | - Michelle L Olsen
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia
| | - Guizhi Du
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu City, China
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
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Advances in precision anaesthesia may be found by testing our resistance to change. Br J Anaesth 2020; 125:235-237. [DOI: 10.1016/j.bja.2020.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/03/2020] [Indexed: 12/29/2022] Open
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Kelemen B, Lisztes E, Vladár A, Hanyicska M, Almássy J, Oláh A, Szöllősi AG, Pénzes Z, Posta J, Voets T, Bíró T, Tóth BI. Volatile anaesthetics inhibit the thermosensitive nociceptor ion channel transient receptor potential melastatin 3 (TRPM3). Biochem Pharmacol 2020; 174:113826. [PMID: 31987857 DOI: 10.1016/j.bcp.2020.113826] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/22/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Volatile anaesthetics (VAs) are the most widely used compounds to induce reversible loss of consciousness and maintain general anaesthesia during surgical interventions. Although the mechanism of their action is not yet fully understood, it is generally believed, that VAs depress central nervous system functions mainly through modulation of ion channels in the neuronal membrane, including 2-pore-domain K+ channels, GABA and NMDA receptors. Recent research also reported their action on nociceptive and thermosensitive TRP channels expressed in the peripheral nervous system, including TRPV1, TRPA1, and TRPM8. Here, we investigated the effect of VAs on TRPM3, a less characterized member of the thermosensitive TRP channels playing a central role in noxious heat sensation. METHODS We investigated the effect of VAs on the activity of recombinant and native TRPM3, by monitoring changes in the intracellular Ca2+ concentration and measuring TRPM3-mediated transmembrane currents. RESULTS All the investigated VAs (chloroform, halothane, isoflurane, sevoflurane) inhibited both the agonist-induced (pregnenolone sulfate, CIM0216) and heat-activated Ca2+ signals and transmembrane currents in a concentration dependent way in HEK293T cells overexpressing recombinant TRPM3. Among the tested VAs, halothane was the most potent blocker (IC50 = 0.52 ± 0.05 mM). We also investigated the effect of VAs on native TRPM3 channels expressed in sensory neurons of the dorsal root ganglia. While VAs activated certain sensory neurons independently of TRPM3, they strongly and reversibly inhibited the agonist-induced TRPM3 activity. CONCLUSIONS These data provide a better insight into the molecular mechanism beyond the analgesic effect of VAs and propose novel strategies to attenuate TRPM3 dependent nociception.
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Affiliation(s)
- Balázs Kelemen
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Erika Lisztes
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Anita Vladár
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Martin Hanyicska
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - János Almássy
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Oláh
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Gábor Szöllősi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsófia Pénzes
- Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary; Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Posta
- Laboratory of Toxicology, Department of Forensic Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Thomas Voets
- Laboratory of Ion Channel Research, VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; Department of Cellular and Molecular Medicine and TRP Research Platform Leuven (TRPLe), KU Leuven, Leuven, Belgium
| | - Tamás Bíró
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Hungarian Center of Excellence for Molecular Medicine, Szeged, Hungary
| | - Balázs István Tóth
- Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
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Hao X, Ou M, Zhang D, Zhao W, Yang Y, Liu J, Yang H, Zhu T, Li Y, Zhou C. The Effects of General Anesthetics on Synaptic Transmission. Curr Neuropharmacol 2020; 18:936-965. [PMID: 32106800 PMCID: PMC7709148 DOI: 10.2174/1570159x18666200227125854] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/20/2020] [Accepted: 02/26/2020] [Indexed: 02/08/2023] Open
Abstract
General anesthetics are a class of drugs that target the central nervous system and are widely used for various medical procedures. General anesthetics produce many behavioral changes required for clinical intervention, including amnesia, hypnosis, analgesia, and immobility; while they may also induce side effects like respiration and cardiovascular depressions. Understanding the mechanism of general anesthesia is essential for the development of selective general anesthetics which can preserve wanted pharmacological actions and exclude the side effects and underlying neural toxicities. However, the exact mechanism of how general anesthetics work is still elusive. Various molecular targets have been identified as specific targets for general anesthetics. Among these molecular targets, ion channels are the most principal category, including ligand-gated ionotropic receptors like γ-aminobutyric acid, glutamate and acetylcholine receptors, voltage-gated ion channels like voltage-gated sodium channel, calcium channel and potassium channels, and some second massager coupled channels. For neural functions of the central nervous system, synaptic transmission is the main procedure for which information is transmitted between neurons through brain regions, and intact synaptic function is fundamentally important for almost all the nervous functions, including consciousness, memory, and cognition. Therefore, it is important to understand the effects of general anesthetics on synaptic transmission via modulations of specific ion channels and relevant molecular targets, which can lead to the development of safer general anesthetics with selective actions. The present review will summarize the effects of various general anesthetics on synaptic transmissions and plasticity.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Yu Li
- Address correspondence to these authors at the Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; E-mail: and Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, P.R. China; E-mail:
| | - Cheng Zhou
- Address correspondence to these authors at the Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; E-mail: and Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, P.R. China; E-mail:
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Denomme N, Hull JM, Mashour GA. Role of Voltage-Gated Sodium Channels in the Mechanism of Ether-Induced Unconsciousness. Pharmacol Rev 2019; 71:450-466. [PMID: 31471460 DOI: 10.1124/pr.118.016592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite continuous clinical use for more than 170 years, the mechanism of general anesthetics has not been completely characterized. In this review, we focus on the role of voltage-gated sodium channels in the sedative-hypnotic actions of halogenated ethers, describing the history of anesthetic mechanisms research, the basic neurobiology and pharmacology of voltage-gated sodium channels, and the evidence for a mechanistic interaction between halogenated ethers and sodium channels in the induction of unconsciousness. We conclude with a more integrative perspective of how voltage-gated sodium channels might provide a critical link between molecular actions of the halogenated ethers and the more distributed network-level effects associated with the anesthetized state across species.
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Affiliation(s)
- Nicholas Denomme
- Departments of Pharmacology (N.D.) and Anesthesiology (G.A.M.), Center for Consciousness Science (N.D., G.A.M.), and Neuroscience Graduate Program (J.M.H., G.A.M.), University of Michigan, Ann Arbor, Michigan
| | - Jacob M Hull
- Departments of Pharmacology (N.D.) and Anesthesiology (G.A.M.), Center for Consciousness Science (N.D., G.A.M.), and Neuroscience Graduate Program (J.M.H., G.A.M.), University of Michigan, Ann Arbor, Michigan
| | - George A Mashour
- Departments of Pharmacology (N.D.) and Anesthesiology (G.A.M.), Center for Consciousness Science (N.D., G.A.M.), and Neuroscience Graduate Program (J.M.H., G.A.M.), University of Michigan, Ann Arbor, Michigan
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12
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Ou M, Zhao W, Liu J, Liang P, Huang H, Yu H, Zhu T, Zhou C. The General Anesthetic Isoflurane Bilaterally Modulates Neuronal Excitability. iScience 2019; 23:100760. [PMID: 31926429 PMCID: PMC6956953 DOI: 10.1016/j.isci.2019.100760] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/16/2019] [Accepted: 12/06/2019] [Indexed: 02/05/2023] Open
Abstract
Volatile anesthetics induce hyperactivity during induction while producing anesthesia at higher concentrations. They also bidirectionally modulate many neuronal functions. However, the neuronal mechanism is unclear. The effects of isoflurane on sodium channel currents were analyzed in acute mouse brain slices, including sodium leak (NALCN) currents and voltage-gated sodium channels (Nav) currents. Isoflurane at sub-anesthetic concentrations increased the spontaneous firing rate of CA3 pyramidal neurons, whereas anesthetic concentrations of isoflurane decreased the firing rate. Isoflurane at sub-anesthetic concentrations enhanced NALCN conductance but minimally inhibited Nav currents. Isoflurane at anesthetic concentrations depressed Nav currents and action potential amplitudes. Isoflurane at sub-anesthetic concentrations depolarized resting membrane potential (RMP) of neurons, whereas hyperpolarized the RMP at anesthetic concentrations. Isoflurane at low concentrations induced hyperactivity in vivo, which was diminished in NALCN knockdown mice. In conclusion, enhancement of NALCN by isoflurane contributes to its bidirectional modulation of neuronal excitability and the hyperactivity during induction. Volatile anesthetic isoflurane exerts bidirectional modulation of neuronal excitability Isoflurane enhances NALCN conductance at sub-anesthetic concentration NALCN knockdown diminishes behavioral hyperactivity during isoflurane induction
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Affiliation(s)
- Mengchan Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Wenling Zhao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Jin Liu
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Han Huang
- Department of Anesthesiology, West China Second Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Hai Yu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, P.R. China.
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13
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Salimi R, Haddadi R, Moradi A, Jalilvand F, Firozian F. Local Anesthetic Effect of Amitriptyline versus Lidocaine in Isolated Lesion of the Limb Requiring Primary Suturing; Assessing a Novel Therapeutic Agent. Bull Emerg Trauma 2019; 7:240-244. [PMID: 31392222 DOI: 10.29252/beat-070305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Objective To compare the anesthetic effects of topical amitriptyline 2% with lidocaine 2% in isolated limb wound repair with suturing. Methods In a randomized clinical trial, 90 patients with a complaint of isolated ulcer and require a preliminary repair by suturing were selected from patients referred to emergency department of Beast Hospital in Hamadan. First, the scars were washed and anesthetized with lidocaine 2%. If after the peak period effect of lidocaine, the pain score of patients did not decrease, they randomly assigned to two groups, Lidocaine or Amitriptyline gel. After the intervention and during the suturing, the patient's pain score was measured at the intervals specified time by the visual analogous scale (VAS) and results recorded on the checklist. Finally, the collected data were analyzed by SPSS software version 20 at 95% confidence level. Results In the lidocaine and amitriptyline group, the mean age of the patients was 29.08 and 27.34 years, and male gender frequency was 71.1% and 80% respectively. Both groups were matched for age and sex. Mean score of pain in both groups decreased from the score of 10 before the intervention to 7.33 in the lidocaine group and 0.53 in amitriptyline group. Based on the results of the ANOVA repeated measure test, there was a statistically significant difference between the mean score of pain in the two groups (p<0.001). Conclusion In patients with isolated limbs ulcers, requiring initial repair with suturing, numbness and analgesia effect of amitriptyline 2% gel, with dose 2 mg/kg is better than lidocaine 2%.
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Affiliation(s)
- Rasoul Salimi
- Department of Emergency Medicine, Besat Hospital, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rasool Haddadi
- Department of Pharmacology, Faculty of Pharmacy, Hamadan University of Medical Sciences, Hamadan , Iran.,Medical Plants And Natural Products Research Center, Hamadan University Of Medical Sciences, Hamadan , Iran
| | - Abbas Moradi
- Department of Social Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Farnoush Jalilvand
- Department of Emergency Medicine, Besat Hospital, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Farzin Firozian
- Department of Pharmaceutics, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
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14
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Zhao P, Liu XM, Sun QC, Cui YF. Overactivation of the sodium-calcium exchanger and transient receptor potential in anesthesia-induced malignant hyperthermia. IUBMB Life 2019; 71:2048-2054. [PMID: 31381266 DOI: 10.1002/iub.2138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 07/11/2019] [Indexed: 11/09/2022]
Abstract
Malignant hyperthermia is a pharmacogenetic disorder, which is an uncommon but frequently fatal intricacy of inhalation anesthesia in man. It causes a quick rise in body temperature to highly irreversible levels, which causes death in around three of four cases. The trigger anesthetics cause an anomalous, continued ascent in myoplasmic calcium levels. Possible mechanisms by which continuous release of sodium, calcium from skeletal muscle plasma membrane and sarcoplasmic reticulum stores respectively can produce the profound hyperthermia are discussed.
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Affiliation(s)
- Peng Zhao
- Department of Anesthesiology, The Second Hospital of Jilin University, Changchun, Jilin, China
| | - Xiu-Min Liu
- Department of Clinical Laboratory, The Second Hospital of Jilin University, Changchun, Jilin, China
| | - Qian-Chuang Sun
- Department of Anesthesiology, The Second Hospital of Jilin University, Changchun, Jilin, China
| | - Yun-Feng Cui
- Department of Anesthesiology, The Second Hospital of Jilin University, Changchun, Jilin, China
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15
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Zhou C, Johnson KW, Herold KF, Hemmings HC. Differential Inhibition of Neuronal Sodium Channel Subtypes by the General Anesthetic Isoflurane. J Pharmacol Exp Ther 2019; 369:200-211. [PMID: 30792243 DOI: 10.1124/jpet.118.254938] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/19/2019] [Indexed: 02/05/2023] Open
Abstract
Volatile anesthetics depress neurotransmitter release in a brain region- and neurotransmitter-selective manner by unclear mechanisms. Voltage-gated sodium channels (Navs), which are coupled to synaptic vesicle exocytosis, are inhibited by volatile anesthetics through reduction of peak current and modulation of gating. Subtype-selective effects of anesthetics on Nav might contribute to observed neurotransmitter-selective anesthetic effects on release. We analyzed anesthetic effects on Na+ currents mediated by the principal neuronal Nav subtypes Nav1.1, Nav1.2, and Nav1.6 heterologously expressed in ND7/23 neuroblastoma cells using whole-cell patch-clamp electrophysiology. Isoflurane at clinically relevant concentrations induced a hyperpolarizing shift in the voltage dependence of steady-state inactivation and slowed recovery from fast inactivation in all three Nav subtypes, with the voltage of half-maximal steady-state inactivation significantly more positive for Nav1.1 (-49.7 ± 3.9 mV) than for Nav1.2 (-57.5 ± 1.2 mV) or Nav1.6 (-58.0 ± 3.8 mV). Isoflurane significantly inhibited peak Na+ current (I Na) in a voltage-dependent manner: at a physiologically relevant holding potential of -70 mV, isoflurane inhibited peak I Na of Nav1.2 (16.5% ± 5.5%) and Nav1.6 (18.0% ± 7.8%), but not of Nav1.1 (1.2% ± 0.8%). Since Nav subtypes are differentially expressed both between neuronal types and within neurons, greater inhibition of Nav1.2 and Nav1.6 compared with Nav1.1 could contribute to neurotransmitter-selective effects of isoflurane on synaptic transmission.
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Affiliation(s)
- Cheng Zhou
- Departments of Anesthesiology (C.Z., K.W.J., K.F.H., H.C.H.) and Pharmacology (H.C.H.), Weill Cornell Medicine, New York, New York; and Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, People's Republic of China (C.Z.)
| | - Kenneth W Johnson
- Departments of Anesthesiology (C.Z., K.W.J., K.F.H., H.C.H.) and Pharmacology (H.C.H.), Weill Cornell Medicine, New York, New York; and Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, People's Republic of China (C.Z.)
| | - Karl F Herold
- Departments of Anesthesiology (C.Z., K.W.J., K.F.H., H.C.H.) and Pharmacology (H.C.H.), Weill Cornell Medicine, New York, New York; and Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, People's Republic of China (C.Z.)
| | - Hugh C Hemmings
- Departments of Anesthesiology (C.Z., K.W.J., K.F.H., H.C.H.) and Pharmacology (H.C.H.), Weill Cornell Medicine, New York, New York; and Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, People's Republic of China (C.Z.)
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16
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Time-Resolved Neutron Interferometry and the Mechanism of Electromechanical Coupling in Voltage-Gated Ion Channels. Methods Enzymol 2018. [PMID: 29673535 DOI: 10.1016/bs.mie.2018.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The mechanism of electromechanical coupling for voltage-gated ion channels (VGICs) involved in neurological signal transmission, primarily Nav- and Kv-channels, remains unresolved. Anesthetics have been shown to directly impact this mechanism, at least for Kv-channels. Molecular dynamics computer simulations can now predict the structures of VGICs embedded within a hydrated phospholipid bilayer membrane as a function of the applied transmembrane voltage, but significant assumptions are still necessary. Nevertheless, these simulations are providing new insights into the mechanism of electromechanical coupling at the atomic level in 3-D. We show that time-resolved neutron interferometry can be used to investigate directly the profile structure of a VGIC, vectorially oriented within a single hydrated phospholipid bilayer membrane at the solid-liquid interface, as a function of the applied transmembrane voltage in the absence of any assumptions or potentially perturbing modifications of the VGIC protein and/or the host membrane. The profile structure is a projection of the membrane's 3-D structure onto the membrane normal and, in the absence of site-directed deuterium labeling, is provided at substantially lower spatial resolution than the atomic level. Nevertheless, this novel approach can be used to directly test the validity of the predictions from molecular dynamics simulations. We describe the key elements of our novel experimental approach, including why each is necessary and important to providing the essential information required for this critical comparison of "simulation" vs "experiment." In principle, the approach could be extended to higher spatial resolution and to include the effects of anesthetics on the electromechanical coupling mechanism in VGICs.
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17
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Lin SH, Lai HY, Lo YC, Chou C, Chou YT, Yang SH, Sun I, Chen BW, Wang CF, Liu GT, Jaw FS, Chen SY, Chen YY. Decreased Power but Preserved Bursting Features of Subthalamic Neuronal Signals in Advanced Parkinson's Patients under Controlled Desflurane Inhalation Anesthesia. Front Neurosci 2017; 11:701. [PMID: 29311782 PMCID: PMC5733027 DOI: 10.3389/fnins.2017.00701] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/28/2017] [Indexed: 11/13/2022] Open
Abstract
Deep brain stimulation (DBS) surgery of the subthalamic nucleus (STN) under general anesthesia (GA) had been used in Parkinson's disease (PD) patients who are unable tolerate awake surgery. The effect of anesthetics on intraoperative microelectrode recording (MER) remains unclear. Understanding the effect of anesthetics on MER is important in performing STN DBS surgery with general anesthesia. In this study, we retrospectively performed qualitive and quantitative analysis of STN MER in PD patients received STN DBS with controlled desflurane anesthesia or LA and compared their clinical outcome. From January 2005 to March 2006, 19 consecutive PD patients received bilateral STN DBS surgery in Hualien Tzu-Chi hospital under either desflurane GA (n = 10) or LA (n = 9). We used spike analysis (frequency and modified burst index [MBI]) and the Hilbert transform to obtain signal power measurements for background and spikes, and compared the characterizations of intraoperative microelectrode signals between the two groups. Additionally, STN firing pattern characteristics were determined using a combined approach based on the autocorrelogram and power spectral analysis, which was employed to investigate differences in the oscillatory activities between the groups. Clinical outcomes were assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) before and after surgery. The results revealed burst firing was observed in both groups. The firing frequencies were greater in the LA group and MBI was comparable in both groups. Both the background and spikes were of significantly greater power in the LA group. The power spectra of the autocorrelograms were significantly higher in the GA group between 4 and 8 Hz. Clinical outcomes based on the UPDRS were comparable in both groups before and after DBS surgery. Under controlled light desflurane GA, burst features of the neuronal firing patterns are preserved in the STN, but power is reduced. Enhanced low-frequency (4–8 Hz) oscillations in the MERs for the GA group could be a characteristic signature of desflurane's effect on neurons in the STN.
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Affiliation(s)
- Sheng-Huang Lin
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.,Department of Neurology, Tzu Chi General Hospital, Tzu Chi University, Hualien, Taiwan
| | - Hsin-Yi Lai
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China
| | - Yu-Chun Lo
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Chin Chou
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Yi-Ting Chou
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Shih-Hung Yang
- Department of Mechanical and Computer Aided Engineering, Feng Chia University, Taichung, Taiwan
| | - I Sun
- Department of Life Sciences, Institute of Genome Sciences, National Yang Ming University, Taipei, China
| | - Bo-Wei Chen
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Ching-Fu Wang
- Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
| | - Guan-Tze Liu
- Department of Medicine, National Yang Ming University, Taipei, Taiwan
| | - Fu-Shan Jaw
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Shin-Yuan Chen
- Department of Neurosurgery, Tzu Chi General Hospital, Tzu Chi University, Hualien, Taiwan
| | - You-Yin Chen
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Department of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan
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18
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Fong R, Khokhar S, Chowdhury AN, Xie KG, Wong JHY, Fox AP, Xie Z. Caffeine accelerates recovery from general anesthesia via multiple pathways. J Neurophysiol 2017; 118:1591-1597. [PMID: 28659466 PMCID: PMC5596131 DOI: 10.1152/jn.00393.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 12/19/2022] Open
Abstract
Various studies have explored different ways to speed emergence from anesthesia. Previously, we have shown that three drugs that elevate intracellular cAMP (forskolin, theophylline, and caffeine) accelerate emergence from anesthesia in rats. However, our earlier studies left two main questions unanswered. First, were cAMP-elevating drugs effective at all anesthetic concentrations? Second, given that caffeine was the most effective of the drugs tested, why was caffeine more effective than forskolin since both drugs elevate cAMP? In our current study, emergence time from anesthesia was measured in adult rats exposed to 3% isoflurane for 60 min. Caffeine dramatically accelerated emergence from anesthesia, even at the high level of anesthetic employed. Caffeine has multiple actions including blockade of adenosine receptors. We show that the selective A2a adenosine receptor antagonist preladenant or the intracellular cAMP ([cAMP]i)-elevating drug forskolin, accelerated recovery from anesthesia. When preladenant and forskolin were tested together, the effect on anesthesia recovery time was additive indicating that these drugs operate via different pathways. Furthermore, the combination of preladenant and forskolin was about as effective as caffeine suggesting that both A2A receptor blockade and [cAMP]i elevation play a role in caffeine's ability to accelerate emergence from anesthesia. Because anesthesia in rodents is thought to be similar to that in humans, these results suggest that caffeine might allow for rapid and uniform emergence from general anesthesia in humans at all anesthetic concentrations and that both the elevation of [cAMP]i and adenosine receptor blockade play a role in this response.NEW & NOTEWORTHY Currently, there is no method to accelerate emergence from anesthesia. Patients "wake" when they clear the anesthetic from their systems. Previously, we have shown that caffeine can accelerate emergence from anesthesia. In this study, we show that caffeine is effective even at high levels of anesthetic. We also show that caffeine operates by both elevating intracellular cAMP levels and by blocking adenosine receptors. This complicated pharmacology makes caffeine especially effective in accelerating emergence from anesthesia.
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Affiliation(s)
- Robert Fong
- Department of Anesthesia and Critical Care, The University of Chicago, Chicago, Illinois
| | - Suhail Khokhar
- College of Medicine, University of Illinois, School of Life Sciences, Chicago, Illinois
| | - Atif N Chowdhury
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Kelvin G Xie
- School of Engineering and Applied Science, Washington University, St Louis, Missouri
| | | | - Aaron P Fox
- Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, Illinois
| | - Zheng Xie
- Department of Anesthesia and Critical Care, The University of Chicago, Chicago, Illinois;
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19
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Devoto JC, Alcalde JL, Otayza F, Sepulveda W. Anesthesia for myelomeningocele surgery in fetus. Childs Nerv Syst 2017; 33:1169-1175. [PMID: 28547209 DOI: 10.1007/s00381-017-3437-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/28/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND Administering anesthesia for prenatal repair of myelomeningocele reveals several issues that are unique to this new form of treatment. This includes issues such as fetal well-being, surgical conditions and monitoring, among others. Exploring, analyzing, and understanding the different variables that are involved will help us reduce the high level of risk associated with this surgery. OBJECTIVE This review provides a systematic approach to the issues that are faced by anesthesiologists during fetal surgery.
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Affiliation(s)
- Juan Carlos Devoto
- Department of Anesthesiology, Fetal Surgery Program, Clínica las Condes, Lo fontecilla 441 Las Condes, 7591046, Santiago, Chile.
| | - Juan Luis Alcalde
- Department of Gynecology and Obstetrics, Fetal Surgery Program, Clínica Las Condes, Santiago, Chile
| | - Felipe Otayza
- Department of Neurosurgery, Fetal Surgery Program, Clínica Las Condes, Santiago, Chile
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20
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Wu TL, Mishra A, Wang F, Yang PF, Gore JC, Chen LM. Effects of isoflurane anesthesia on resting-state fMRI signals and functional connectivity within primary somatosensory cortex of monkeys. Brain Behav 2016; 6:e00591. [PMID: 28032008 PMCID: PMC5167001 DOI: 10.1002/brb3.591] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/15/2016] [Accepted: 09/06/2016] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Correlated low-frequency fluctuations of resting-state functional magnetic resonance imaging (rsfMRI) signals have been widely used for inferring intrinsic brain functional connectivity (FC). In animal studies, accurate estimate of anesthetic effects on rsfMRI signals is demanded for reliable interpretations of FC changes. We have previously shown that inter-regional FC can reliably delineate local millimeter-scale circuits within digit representations of primary somatosensory cortex (S1) subregions (areas 3a, 3b, and 1) in monkeys under isoflurane anesthesia. The goals of this study are to determine (1) the general effects of isoflurane on rsfMRI signals in the S1 circuit and (2) whether the effects are functional- and regional- dependent, by quantifying the relationships between isoflurane levels, power and inter-regional correlation coefficients in digit and face regions of distinct S1 subregions. METHODS Functional MRI data were collected from male adult squirrel monkeys at three different isoflurane levels (1.25%, 0.875%, and 0.5%). All scans were acquired on a 9.4T magnet with a 3-cm-diameter surface transmit-receive coil centered over the S1 cortex. Power and seed-based inter-regional functional connectivity analyses were subsequently performed. RESULTS As anesthesia level increased, we observed (1) diminishing amplitudes of signal fluctuations, (2) reduced power of fluctuations in the low-frequency band used for connectivity measurements, (3) decreased inter-voxel connectivity around seed regions, and (4) weakened inter-regional FC across all pairs of regions of interest (digit-to-digit). The low-frequency power measures derived from rsfMRI signals from control muscle regions, however, did not exhibit any isoflurane level-related changes. Within the isoflurane dosage range we tested, the inter-regional functional connectivity differences were still detectable, and the effects of isoflurane did not differ across region-of-interest (ROI) pairs. CONCLUSION Our data demonstrate that isoflurane induced similar dose-dependent suppressive effects on the power of rsfMRI signals and local fine-scale FC across functionally related but distinct S1 subregions.
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Affiliation(s)
- Tung-Lin Wu
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Biomedical Engineering Vanderbilt University Nashville TN USA
| | - Arabinda Mishra
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Radiology and Radiological Sciences Vanderbilt University Nashville TN USA
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Radiology and Radiological Sciences Vanderbilt University Nashville TN USA
| | - Pai-Feng Yang
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Radiology and Radiological Sciences Vanderbilt University Nashville TN USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Biomedical Engineering Vanderbilt University Nashville TN USA; Radiology and Radiological Sciences Vanderbilt University Nashville TN USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science Nashville TN USA; Radiology and Radiological Sciences Vanderbilt University Nashville TN USA
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22
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Covarrubias M, Barber AF, Carnevale V, Treptow W, Eckenhoff RG. Mechanistic Insights into the Modulation of Voltage-Gated Ion Channels by Inhalational Anesthetics. Biophys J 2016; 109:2003-11. [PMID: 26588560 DOI: 10.1016/j.bpj.2015.09.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/31/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022] Open
Abstract
General anesthesia is a relatively safe medical procedure, which for nearly 170 years has allowed life saving surgical interventions in animals and people. However, the molecular mechanism of general anesthesia continues to be a matter of importance and debate. A favored hypothesis proposes that general anesthesia results from direct multisite interactions with multiple and diverse ion channels in the brain. Neurotransmitter-gated ion channels and two-pore K+ channels are key players in the mechanism of anesthesia; however, new studies have also implicated voltage-gated ion channels. Recent biophysical and structural studies of Na+ and K+ channels strongly suggest that halogenated inhalational general anesthetics interact with gates and pore regions of these ion channels to modulate function. Here, we review these studies and provide a perspective to stimulate further advances.
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Affiliation(s)
- Manuel Covarrubias
- Department of Neuroscience and Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania.
| | - Annika F Barber
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania
| | - Werner Treptow
- Laboratorio de Biologia Teorica e Computacional, Universidade de Brasilia, Brazil
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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23
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Zimin PI, Woods CB, Quintana A, Ramirez JM, Morgan PG, Sedensky MM. Glutamatergic Neurotransmission Links Sensitivity to Volatile Anesthetics with Mitochondrial Function. Curr Biol 2016; 26:2194-201. [PMID: 27498564 DOI: 10.1016/j.cub.2016.06.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/28/2016] [Accepted: 06/14/2016] [Indexed: 12/31/2022]
Abstract
An enigma of modern medicine has persisted for over 150 years. The mechanisms by which volatile anesthetics (VAs) produce their effects (loss of consciousness, analgesia, amnesia, and immobility) remain an unsolved mystery. Many attractive putative molecular targets have failed to produce a significant effect when genetically tested in whole-animal models [1-3]. However, mitochondrial defects increase VA sensitivity in diverse organisms from nematodes to humans [4-6]. Ndufs4 knockout (KO) mice lack a subunit of mitochondrial complex I and are strikingly hypersensitive to VAs yet resistant to the intravenous anesthetic ketamine [7]. The change in VA sensitivity is the largest reported for a mammal. Limiting NDUFS4 loss to a subset of glutamatergic neurons recapitulates the VA hypersensitivity of Ndufs4(KO) mice, while loss in GABAergic or cholinergic neurons does not. Baseline electrophysiologic function of CA1 pyramidal neurons does not differ between Ndufs4(KO) and control mice. Isoflurane concentrations that anesthetize only Ndufs4(KO) mice (0.6%) decreased the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) only in Ndufs4(KO) CA1 neurons, while concentrations effective in control mice (1.2%) decreased sEPSC frequencies in both control and Ndufs4(KO) CA1 pyramidal cells. Spontaneous inhibitory postsynaptic currents (sIPSCs) were not differentially affected between genotypes. The effects of isoflurane were similar on evoked field excitatory postsynaptic potentials (fEPSPs) and paired pulse facilitation (PPF) in KO and control hippocampal slices. We propose that CA1 presynaptic excitatory neurotransmission is hypersensitive to isoflurane in Ndufs4(KO) mice due to the inhibition of pre-existing reduced complex I function, reaching a critical reduction that can no longer meet metabolic demands.
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Affiliation(s)
- Pavel I Zimin
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA.
| | - Christian B Woods
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Albert Quintana
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Philip G Morgan
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Margaret M Sedensky
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
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Positive Allosteric Modulation of Kv Channels by Sevoflurane: Insights into the Structural Basis of Inhaled Anesthetic Action. PLoS One 2015; 10:e0143363. [PMID: 26599217 PMCID: PMC4657974 DOI: 10.1371/journal.pone.0143363] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 11/04/2015] [Indexed: 11/19/2022] Open
Abstract
Inhalational general anesthesia results from the poorly understood interactions of haloethers with multiple protein targets, which prominently includes ion channels in the nervous system. Previously, we reported that the commonly used inhaled anesthetic sevoflurane potentiates the activity of voltage-gated K+ (Kv) channels, specifically, several mammalian Kv1 channels and the Drosophila K-Shaw2 channel. Also, previous work suggested that the S4-S5 linker of K-Shaw2 plays a role in the inhibition of this Kv channel by n-alcohols and inhaled anesthetics. Here, we hypothesized that the S4-S5 linker is also a determinant of the potentiation of Kv1.2 and K-Shaw2 by sevoflurane. Following functional expression of these Kv channels in Xenopus oocytes, we found that converse mutations in Kv1.2 (G329T) and K-Shaw2 (T330G) dramatically enhance and inhibit the potentiation of the corresponding conductances by sevoflurane, respectively. Additionally, Kv1.2-G329T impairs voltage-dependent gating, which suggests that Kv1.2 modulation by sevoflurane is tied to gating in a state-dependent manner. Toward creating a minimal Kv1.2 structural model displaying the putative sevoflurane binding sites, we also found that the positive modulations of Kv1.2 and Kv1.2-G329T by sevoflurane and other general anesthetics are T1-independent. In contrast, the positive sevoflurane modulation of K-Shaw2 is T1-dependent. In silico docking and molecular dynamics-based free-energy calculations suggest that sevoflurane occupies distinct sites near the S4-S5 linker, the pore domain and around the external selectivity filter. We conclude that the positive allosteric modulation of the Kv channels by sevoflurane involves separable processes and multiple sites within regions intimately involved in channel gating.
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Purtell K, Gingrich KJ, Ouyang W, Herold KF, Hemmings HC. Activity-dependent depression of neuronal sodium channels by the general anaesthetic isoflurane. Br J Anaesth 2015; 115:112-21. [PMID: 26089447 DOI: 10.1093/bja/aev203] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The mechanisms by which volatile anaesthetics such as isoflurane alter neuronal function are poorly understood, in particular their presynaptic mechanisms. Presynaptic voltage-gated sodium channels (Na(v)) have been implicated as a target for anaesthetic inhibition of neurotransmitter release. We hypothesize that state-dependent interactions of isoflurane with Na(v) lead to increased inhibition of Na(+) current (I(Na)) during periods of high-frequency neuronal activity. METHODS The electrophysiological effects of isoflurane, at concentrations equivalent to those used clinically, were measured on recombinant brain-type Na(v)1.2 expressed in ND7/23 neuroblastoma cells and on endogenous Na(v) in isolated rat neurohypophysial nerve terminals. Rate constants determined from experiments on the recombinant channel were used in a simple model of Na(v) gating. RESULTS At resting membrane potentials, isoflurane depressed peak I(Na) and shifted steady-state inactivation in a hyperpolarizing direction. After membrane depolarization, isoflurane accelerated entry (τ(control)=0.36 [0.03] ms compared with τ(isoflurane)=0.33 [0.05] ms, P<0.05) and slowed recovery (τ(control)=6.9 [1.1] ms compared with τ(isoflurane)=9.0 [1.9] ms, P<0.005) from apparent fast inactivation, resulting in enhanced depression of I(Na), during high-frequency stimulation of both recombinant and endogenous nerve terminal Na(v). A simple model of Na(v) gating involving stabilisation of fast inactivation, accounts for this novel form of activity-dependent block. CONCLUSIONS Isoflurane stabilises the fast-inactivated state of neuronal Na(v) leading to greater depression of I(Na) during high-frequency stimulation, consistent with enhanced inhibition of fast firing neurones.
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Affiliation(s)
- K Purtell
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA
| | - K J Gingrich
- Department of Anesthesiology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - W Ouyang
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA Present address: College of Physical Education and Health Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - K F Herold
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
| | - H C Hemmings
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
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Castro Fonseca MD, Da Silva JH, Ferraz VP, Gomez RS, Guatimosim C. Comparative presynaptic effects of the volatile anesthetics sevoflurane and isoflurane at the mouse neuromuscular junction. Muscle Nerve 2015; 52:876-84. [DOI: 10.1002/mus.24589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Matheus De Castro Fonseca
- Departamento de Morfologia, Instituto de Ciências Biológicas; Universidade Federal de Minas Gerais; Av. Antônio Carlos, 6627 Belo Horizonte MG 31270-901 Brasil
| | - Janice Henriques Da Silva
- Departamento de Morfologia, Instituto de Ciências Biológicas; Universidade Federal de Minas Gerais; Av. Antônio Carlos, 6627 Belo Horizonte MG 31270-901 Brasil
| | - Vany Perpetua Ferraz
- Departamento de Química, Instituto de Ciências Exatas; Universidade Federal de Minas Gerais; MG Brasil
| | - Renato Santiago Gomez
- Departamento de Cirurgia, Faculdade de Medicina; Universidade Federal de Minas Gerais; Belo Horizonte MG Brasil
| | - Cristina Guatimosim
- Departamento de Morfologia, Instituto de Ciências Biológicas; Universidade Federal de Minas Gerais; Av. Antônio Carlos, 6627 Belo Horizonte MG 31270-901 Brasil
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Johansen SL, Iceman KE, Iceman CR, Taylor BE, Harris MB. Isoflurane causes concentration-dependent inhibition of medullary raphé 5-HT neurons in situ. Auton Neurosci 2015. [PMID: 26213357 DOI: 10.1016/j.autneu.2015.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Anesthetics have a profound influence on a myriad of autonomic processes. Mechanisms of general anesthesia, and how these mechanisms give rise to the multifaceted state of anesthesia, are largely unknown. The ascending and descending serotonin (5-HT) networks are key modulators of autonomic pathways, and are critically involved in homeostatic reflexes across the motor, somatosensory, limbic and autonomic systems. These 5-HT networks are thought to contribute to anesthetic effects, but how anesthetics affect 5-HT neuron function remains a pertinent question. We hypothesized that the volatile anesthetic isoflurane inhibits action potential discharge of medullary raphé 5-HT neurons. METHODS We conducted extracellular recordings on individual neurons in the medullary raphé region of the unanesthetized in situ perfused brainstem preparation to determine how exposure to isoflurane affects 5-HT neurons. We examined changes in 5-HT neuron baseline firing in response to treatment with either 1, 1.5, or 2% isoflurane. We measured isoflurane concentrations by gas chromatography-mass spectrometry (GC-MS) analysis. RESULTS Exposure to isoflurane inhibited action potential discharge in raphé 5-HT neurons. We document a concentration-dependent inhibition over a range of concentrations approximating isoflurane MAC (minimum alveolar concentration required for surgical anesthesia). Delivered concentrations of isoflurane were confirmed using GC-MS analysis. CONCLUSIONS These findings illustrate that halogenated anesthetics greatly affect 5-HT neuron firing and suggest 5-HT neuron contributions to mechanisms of general anesthesia.
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Affiliation(s)
- S L Johansen
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - K E Iceman
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - C R Iceman
- Department of Chemistry and Biochemistry, University of Alaska, Fairbanks, AK 99775, USA
| | - B E Taylor
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - M B Harris
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA.
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Sellers KK, Bennett DV, Hutt A, Williams JH, Fröhlich F. Awake vs. anesthetized: layer-specific sensory processing in visual cortex and functional connectivity between cortical areas. J Neurophysiol 2015; 113:3798-815. [PMID: 25833839 DOI: 10.1152/jn.00923.2014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/30/2015] [Indexed: 01/03/2023] Open
Abstract
During general anesthesia, global brain activity and behavioral state are profoundly altered. Yet it remains mostly unknown how anesthetics alter sensory processing across cortical layers and modulate functional cortico-cortical connectivity. To address this gap in knowledge of the micro- and mesoscale effects of anesthetics on sensory processing in the cortical microcircuit, we recorded multiunit activity and local field potential in awake and anesthetized ferrets (Mustela putoris furo) during sensory stimulation. To understand how anesthetics alter sensory processing in a primary sensory area and the representation of sensory input in higher-order association areas, we studied the local sensory responses and long-range functional connectivity of primary visual cortex (V1) and prefrontal cortex (PFC). Isoflurane combined with xylazine provided general anesthesia for all anesthetized recordings. We found that anesthetics altered the duration of sensory-evoked responses, disrupted the response dynamics across cortical layers, suppressed both multimodal interactions in V1 and sensory responses in PFC, and reduced functional cortico-cortical connectivity between V1 and PFC. Together, the present findings demonstrate altered sensory responses and impaired functional network connectivity during anesthesia at the level of multiunit activity and local field potential across cortical layers.
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Affiliation(s)
- Kristin K Sellers
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Davis V Bennett
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Axel Hutt
- INRIA CR Nancy-Grand Est, Team Neurosys, Villers-les-Nancy, France
| | - James H Williams
- Department of Anesthesiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Flavio Fröhlich
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Asadollah S, Vahdat M, Yazdkhasti P, Nikravan N. The effect of magnesium sulphate on postoperative analgesia requirements in gynecological surgeries. Turk J Obstet Gynecol 2015; 12:34-37. [PMID: 28913038 PMCID: PMC5558402 DOI: 10.4274/tjod.02439] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/31/2014] [Indexed: 12/15/2022] Open
Abstract
Objective: Recent studies have shown the positive effect of magnesium sulphate (MgSO4) on pain reduction and postoperative analgesic requirements in patients undergoing surgery. We assessed the effect of MgSO4 on intra-operative and postoperative analgesic requirements in patients undergoing lower abdominal gynecological laparotomy. Materials and Methods: This randomized clinical trial was conducted on 30 female patients at Rasool-e-Akram (referral and academic) hospital in Tehran from August 2012 to March 2013. The patients who were candidates for gynecologic surgeries (hysterectomy and/or myomectomy) were randomized into study (n=15) and control (n=15) groups. Same anesthetic technique was used in all patients. Besides induction of the anesthesia in the study group, we administered MgSO4 50 mg/kg/hr intravenously (IV) for analgesic purposes as a bolus dose and then 8 mg/kg IV as maintenance dose. Control group received the same anesthetic agents and the same amount of isotonic saline instead of MgSO4. Analgesic consumption was measured in both groups postoperatively within 24 hours. The visual analog scale (VAS) was used for the evaluation of postoperative pain in both groups. Results: There was a decrease in analgesic consumption and pain in the group receiving MgSO4, in comparison to control group. Pain severity assessment, 24 hours post operatively showed similar results in both groups. There was a statistically significant difference in prescribed dose of pethidine between study and control groups (p=<0.0001). Conclusion: Intra-operative MgSO4 is effective in postoperative pain control following lower abdominal laparotomy. Further studies with larger sample sizes and longer follow-up should be performed to obtain more information about safety and to determine whether doses of MgSO4 can provide postoperative analgesic benefits.
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Affiliation(s)
- Sara Asadollah
- Iran University Faculty of Medicine, Rasool-e-Akram Hospital, Clinic of Obstetrics and Gynecology, Tehran, Iran
| | - Mansoureh Vahdat
- Iran University Faculty of Medicine, Rasool-e-Akram Hospital, Clinic of Obstetrics and Gynecology, Tehran, Iran
| | - Payman Yazdkhasti
- Iran University Faculty of Medicine, Rasool-e-Akram Hospital, Clinic of Anesthesiology and Pain, Tehran, Iran
| | - Nasrin Nikravan
- Iran University Faculty of Medicine, Rasool-e-Akram Hospital, Clinic of Obstetrics and Gynecology, Tehran, Iran
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McDavid S, Bauer MB, Brindley RL, Jewell ML, Currie KPM. Butanol isomers exert distinct effects on voltage-gated calcium channel currents and thus catecholamine secretion in adrenal chromaffin cells. PLoS One 2014; 9:e109203. [PMID: 25275439 PMCID: PMC4183593 DOI: 10.1371/journal.pone.0109203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Accepted: 09/08/2014] [Indexed: 12/20/2022] Open
Abstract
Butanol (C4H10OH) has been used both to dissect the molecular targets of alcohols/general anesthetics and to implicate phospholipase D (PLD) signaling in a variety of cellular functions including neurotransmitter and hormone exocytosis. Like other primary alcohols, 1-butanol is a substrate for PLD and thereby disrupts formation of the intracellular signaling lipid phosphatidic acid. Because secondary and tertiary butanols do not undergo this transphosphatidylation, they have been used as controls for 1-butanol to implicate PLD signaling. Recently, selective pharmacological inhibitors of PLD have been developed and, in some cases, fail to block cellular functions previously ascribed to PLD using primary alcohols. For example, exocytosis of insulin and degranulation of mast cells are blocked by primary alcohols, but not by the PLD inhibitor FIPI. In this study we show that 1-butanol reduces catecholamine secretion from adrenal chromaffin cells to a much greater extent than tert-butanol, and that the PLD inhibitor VU0155056 has no effect. Using fluorescent imaging we show the effect of these drugs on depolarization-evoked calcium entry parallel those on secretion. Patch-clamp electrophysiology confirmed the peak amplitude of voltage-gated calcium channel currents (ICa) is inhibited by 1-butanol, with little or no block by secondary or tert-butanol. Detailed comparison shows for the first time that the different butanol isomers exert distinct, and sometimes opposing, effects on the voltage-dependence and gating kinetics of ICa. We discuss these data with regard to PLD signaling in cellular physiology and the molecular targets of general anesthetics.
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Affiliation(s)
- Sarah McDavid
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Mary Beth Bauer
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Rebecca L. Brindley
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Mark L. Jewell
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Kevin P. M. Currie
- Department of Anesthesiology, Department of Pharmacology, and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Giles EK, Lawrence AJ, Duncan JR. Exploring the Modulation of Hypoxia-Inducible Factor (HIF)-1α by Volatile Anesthetics as a Possible Mechanism Underlying Volatile Anesthetic-Induced CNS Injury. Neurochem Res 2014; 39:1640-7. [DOI: 10.1007/s11064-014-1379-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/26/2014] [Accepted: 06/30/2014] [Indexed: 12/11/2022]
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Wang Q, Fong R, Mason P, Fox AP, Xie Z. Caffeine accelerates recovery from general anesthesia. J Neurophysiol 2014; 111:1331-40. [PMID: 24375022 PMCID: PMC3949308 DOI: 10.1152/jn.00792.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 12/26/2013] [Indexed: 11/22/2022] Open
Abstract
General anesthetics inhibit neurotransmitter release from both neurons and secretory cells. If inhibition of neurotransmitter release is part of an anesthetic mechanism of action, then drugs that facilitate neurotransmitter release may aid in reversing general anesthesia. Drugs that elevate intracellular cAMP levels are known to facilitate neurotransmitter release. Three cAMP elevating drugs (forskolin, theophylline, and caffeine) were tested; all three drugs reversed the inhibition of neurotransmitter release produced by isoflurane in PC12 cells in vitro. The drugs were tested in isoflurane-anesthetized rats. Animals were injected with either saline or saline containing drug. All three drugs dramatically accelerated recovery from isoflurane anesthesia, but caffeine was most effective. None of the drugs, at the concentrations tested, had significant effects on breathing rates, O2 saturation, heart rate, or blood pressure in anesthetized animals. Caffeine alone was tested on propofol-anesthetized rats where it dramatically accelerated recovery from anesthesia. The ability of caffeine to accelerate recovery from anesthesia for different chemical classes of anesthetics, isoflurane and propofol, opens the possibility that it will do so for all commonly used general anesthetics, although additional studies will be required to determine whether this is in fact the case. Because anesthesia in rodents is thought to be similar to that in humans, these results suggest that caffeine might allow for rapid and uniform emergence from general anesthesia in human patients.
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Affiliation(s)
- Qiang Wang
- Department of Neurobiology, Pharmacology and Physiology, University of Chicago, Chicago, Illinois
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Marinov V, Valic M, Pecotic R, Karanovic N, Dodig IP, Carev M, Valic Z, Dogas Z. Sevoflurane and isoflurane monoanesthesia abolished the phrenic long-term facilitation in rats. Respir Physiol Neurobiol 2013; 189:607-13. [DOI: 10.1016/j.resp.2013.07.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/30/2013] [Accepted: 07/31/2013] [Indexed: 01/06/2023]
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Stuth EAE, Stucke AG, Zuperku EJ. Effects of anesthetics, sedatives, and opioids on ventilatory control. Compr Physiol 2013; 2:2281-367. [PMID: 23720250 DOI: 10.1002/cphy.c100061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This article provides a comprehensive, up to date summary of the effects of volatile, gaseous, and intravenous anesthetics and opioid agonists on ventilatory control. Emphasis is placed on data from human studies. Further mechanistic insights are provided by in vivo and in vitro data from other mammalian species. The focus is on the effects of clinically relevant agonist concentrations and studies using pharmacological, that is, supraclinical agonist concentrations are de-emphasized or excluded.
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Affiliation(s)
- Eckehard A E Stuth
- Medical College of Wisconsin, Anesthesia Research Service, Zablocki VA Medical Center, Milwaukee, Wisconsin, USA.
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Park GY, Kwon DR. Platelet-rich plasma limits the nerve injury caused by 10% dextrose in the rabbit median nerve. Muscle Nerve 2013; 49:56-60. [DOI: 10.1002/mus.23863] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Gi-Young Park
- Department of Rehabilitation Medicine; Catholic University of Daegu School of Medicine; 33 Duryugongwon-ro 17-gil Nam-Gu Daegu 705-718 Korea
| | - Dong Rak Kwon
- Department of Rehabilitation Medicine; Catholic University of Daegu School of Medicine; 33 Duryugongwon-ro 17-gil Nam-Gu Daegu 705-718 Korea
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Postoperative Analgesic Effect of Transcranial Direct Current Stimulation in Lumbar Spine Surgery. Clin J Pain 2013; 29:696-701. [DOI: 10.1097/ajp.0b013e31826fb302] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Eckle VS, Hauser S, Drexler B, Antkowiak B, Grasshoff C. Opposing actions of sevoflurane on GABAergic and glycinergic synaptic inhibition in the spinal ventral horn. PLoS One 2013; 8:e60286. [PMID: 23565218 PMCID: PMC3614984 DOI: 10.1371/journal.pone.0060286] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 01/28/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The ventral horn is a major substrate in mediating the immobilizing properties of the volatile anesthetic sevoflurane in the spinal cord. In this neuronal network, action potential firing is controlled by GABA(A) and glycine receptors. Both types of ion channels are sensitive to volatile anesthetics, but their role in mediating anesthetic-induced inhibition of spinal locomotor networks is not fully understood. METHODOLOGY/PRINCIPAL FINDINGS To compare the effects of sevoflurane on GABAergic and glycinergic inhibitory postsynaptic currents (IPSCs) whole-cell voltage-clamp recordings from ventral horn interneurons were carried out in organotypic spinal cultures. At concentrations close to MAC (minimum alveolar concentration), decay times of both types of IPSCs were significantly prolonged. However, at 1.5 MAC equivalents, GABAergic IPSCs were decreased in amplitude and reduced in frequency. These effects counteracted the prolongation of the decay time, thereby decreasing the time-averaged GABAergic inhibition. In contrast, amplitudes and frequency of glycinergic IPSCs were not significantly altered by sevoflurane. Furthermore, selective GABA(A) and glycine receptor antagonists were tested for their potency to reverse sevoflurane-induced inhibition of spontaneous action potential firing in the ventral horn. These experiments confirmed a weak impact of GABA(A) receptors and a prominent role of glycine receptors at a high sevoflurane concentration. CONCLUSIONS At high concentrations, sevoflurane mediates neuronal inhibition in the spinal ventral horn primarily via glycine receptors, and less via GABA(A) receptors. Our results support the hypothesis that the impact of GABA(A) receptors in mediating the immobilizing properties of volatile anesthetics is less essential in comparison to glycine receptors.
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Affiliation(s)
- Veit-Simon Eckle
- Experimental Anesthesiology Section, Department of Anesthesiology & Intensive Care, Tübingen University Hospital, Eberhard-Karls-University, Tübingen, Germany
| | - Sabrina Hauser
- Experimental Anesthesiology Section, Department of Anesthesiology & Intensive Care, Tübingen University Hospital, Eberhard-Karls-University, Tübingen, Germany
| | - Berthold Drexler
- Experimental Anesthesiology Section, Department of Anesthesiology & Intensive Care, Tübingen University Hospital, Eberhard-Karls-University, Tübingen, Germany
- * E-mail:
| | - Bernd Antkowiak
- Experimental Anesthesiology Section, Department of Anesthesiology & Intensive Care, Tübingen University Hospital, Eberhard-Karls-University, Tübingen, Germany
| | - Christian Grasshoff
- Experimental Anesthesiology Section, Department of Anesthesiology & Intensive Care, Tübingen University Hospital, Eberhard-Karls-University, Tübingen, Germany
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Dawson AG, Heidari P, Gadagkar SR, Murray MJ, Call GB. An airtight approach to the inebriometer: from construction to application with volatile anesthetics. Fly (Austin) 2013; 7:112-7. [PMID: 23579237 DOI: 10.4161/fly.24142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The mechanism by which inhaled anesthetics work is not fully understood, although they have been extensively used. Much research has been done showing the likelihood that there is more than one pathway or mechanism of action. A long-term goal of our laboratory is to decipher these mechanisms using Drosophila melanogaster, an excellent model organism for this purpose. In order to do this, we have modified and constructed an apparatus called the inebriometer to quantitatively analyze the response of flies to inhaled anesthetics. While the inebriometer is not new to the fly community, our updated design provides a relatively low-labor, high-throughput means for performing screens in search of genes involved in the anesthetic mechanism. Here we describe our construction of an airtight inebriometer that we have designed for this purpose. We also provide data that validates this apparatus and establishes a procedure for its use.
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Affiliation(s)
- Adam G Dawson
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
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Vanden Abeele F, Kondratskyi A, Dubois C, Shapovalov G, Gkika D, Busserolles J, Shuba Y, Skryma R, Prevarskaya N. Complex modulation of TRPM8 cold receptor by volatile anaesthetics and role in complications of general anaesthesia. J Cell Sci 2013; 126:4479-89. [DOI: 10.1242/jcs.131631] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanisms by which volatile general anaesthetics (VAs) produce a depression of central nervous system are beginning to be better understood, but little is known about a number of side effects. Here, we show that the cold receptor, TRPM8, is complexly modulated by clinical concentration of VAs in dorsal root ganglion neurons and HEK-293 cells heterologously expressing TRPM8. VAs produced transient enhancement of TRPM8 via a depolarizing shift of its activation towards physiological membrane potentials, followed by a sustained TRPM8 inhibition. Stimulatory action of VAs engaged molecular determinants distinct from those used by the TRPM8 agonist. Transient TRPM8 activation by VAs could explain such side effects as inhibition of respiratory drive, shivering and cooling sensation during the beginning of anaesthesia, whereas the second phase of VA action associated with sustained TRPM8 inhibition may be responsible for hypothermia. Consistent with this, both hypothermia and inhibition of respiratory drive induced by VAs are partially abolished in TRPM8-null animals. Thus, we propose TRPM8 as a new clinical target for diminishing common and serious complications of general anaesthesia.
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Westphalen RI, Desai KM, Hemmings HC. Presynaptic inhibition of the release of multiple major central nervous system neurotransmitter types by the inhaled anaesthetic isoflurane. Br J Anaesth 2012; 110:592-9. [PMID: 23213036 DOI: 10.1093/bja/aes448] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Presynaptic effects of general anaesthetics are not well characterized. We tested the hypothesis that isoflurane exhibits transmitter-specific effects on neurotransmitter release from neurochemically and functionally distinct isolated mammalian nerve terminals. METHODS Nerve terminals from adult male rat brain were prelabelled with [(3)H]glutamate and [(14)C]GABA (cerebral cortex), [(3)H]norepinephrine (hippocampus), [(14)C]dopamine (striatum), or [(3)H]choline (precursor of [(3)H]acetylcholine; striatum). Release evoked by depolarizing pulses of 4-aminopyridine (4AP) or elevated KCl was quantified using a closed superfusion system. RESULTS Isoflurane at clinical concentrations (<0.7 mM; ~2 times median anaesthetic concentration) inhibited Na(+) channel-dependent 4AP-evoked release of the five neurotransmitters tested in a concentration-dependent manner. Isoflurane was a more potent inhibitor [expressed as IC(50) (SEM)] of glutamate release [0.37 (0.03) mM; P<0.05] compared with the release of GABA [0.52 (0.03) mM], norepinephrine [0.48 (0.03) mM], dopamine [0.48 (0.03) mM], or acetylcholine [0.49 (0.02) mM]. Inhibition of Na(+) channel-independent release evoked by elevated K(+) was not significant at clinical concentrations of isoflurane, with the exception of dopamine release [IC(50)=0.59 (0.03) mM]. CONCLUSIONS Isoflurane inhibited the release of the major central nervous system neurotransmitters with selectivity for glutamate release, consistent with both widespread inhibition and nerve terminal-specific presynaptic effects. Glutamate release was most sensitive to inhibition compared with GABA, acetylcholine, dopamine, and norepinephrine release due to presynaptic specializations in ion channel expression, regulation, and/or coupling to exocytosis. Reductions in neurotransmitter release by volatile anaesthetics could contribute to altered synaptic transmission, leading to therapeutic and toxic effects involving all major neurotransmitter systems.
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Affiliation(s)
- R I Westphalen
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
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Lecker I, Wang DS, Romaschin AD, Peterson M, Mazer CD, Orser BA. Tranexamic acid concentrations associated with human seizures inhibit glycine receptors. J Clin Invest 2012. [PMID: 23187124 DOI: 10.1172/jci63375] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Antifibrinolytic drugs are widely used to reduce blood loss during surgery. One serious adverse effect of these drugs is convulsive seizures; however, the mechanisms underlying such seizures remain poorly understood. The antifibrinolytic drugs tranexamic acid (TXA) and ε-aminocaproic acid (EACA) are structurally similar to the inhibitory neurotransmitter glycine. Since reduced function of glycine receptors causes seizures, we hypothesized that TXA and EACA inhibit the activity of glycine receptors. Here we demonstrate that TXA and EACA are competitive antagonists of glycine receptors in mice. We also showed that the general anesthetic isoflurane, and to a lesser extent propofol, reverses TXA inhibition of glycine receptor-mediated current, suggesting that these drugs could potentially be used to treat TXA-induced seizures. Finally, we measured the concentration of TXA in the cerebrospinal fluid (CSF) of patients undergoing major cardiovascular surgery. Surprisingly, peak TXA concentration in the CSF occurred after termination of drug infusion and in one patient coincided with the onset of seizures. Collectively, these results show that concentrations of TXA equivalent to those measured in the CSF of patients inhibited glycine receptors. Furthermore, isoflurane or propofol may prevent or reverse TXA-induced seizures.
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Affiliation(s)
- Irene Lecker
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Cederholm JME, Froud KE, Wong ACY, Ko M, Ryan AF, Housley GD. Differential actions of isoflurane and ketamine-based anaesthetics on cochlear function in the mouse. Hear Res 2012; 292:71-9. [PMID: 22960466 DOI: 10.1016/j.heares.2012.08.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/13/2012] [Accepted: 08/21/2012] [Indexed: 10/28/2022]
Abstract
Isoflurane is a volatile inhaled anaesthetic widely used in animal research, with particular utility for hearing research. Isoflurane has been shown to blunt hearing sensitivity compared with the awake state, but little is known about how isoflurane compares with other anaesthetics with regard to hair cell transduction and auditory neurotransmission. The current study was undertaken in C57Bl/6J and C129/SvEv strains of mice to determine whether isoflurane anaesthesia affects hearing function relative to ketamine-based anaesthesia. Cochlear function and central auditory transmission were assessed using auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE), comparing thresholds and input/output functions over time, for isoflurane vs. ketamine/xylazine/acepromazine anaesthesia. ABR thresholds at the most sensitive region of hearing (16 kHz) were initially higher under isoflurane anaesthesia. This reduced hearing sensitivity worsened over the 1 h study period, and also became evident with broadband click stimulus. Ketamine anaesthesia provided stable ABR thresholds. Although the growth functions were unchanged over time for both anaesthetics, the slopes under isoflurane anaesthesia were significantly less. Cubic (2f(1)-f(2)) DPOAE thresholds and growth functions were initially similar for both anaesthetics. After 60 min, DPOAE thresholds increased for both groups, but this effect was significantly greater with ketamine anaesthesia. The isoflurane-mediated increase in ABR thresholds over time is attributable to action on cochlear nerve activation, evident as a right-shift in the P1-N1 input/output function compared to K/X/A. The ketamine-based anaesthetic produced stable ABR thresholds and gain over time, despite a right-shift in the outer hair cell - mediated DPOAE input/output function.
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Affiliation(s)
- Jennie M E Cederholm
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales, UNSW Kensington Campus, Sydney, NSW Australia
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Inhibition of voltage-gated sodium channels by emulsified isoflurane may contribute to its subarachnoid anesthetic effect in beagle dogs. Reg Anesth Pain Med 2012; 36:553-9. [PMID: 21989153 DOI: 10.1097/aap.0b013e3182324d18] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Volatile anesthetics, in addition to their general anesthesia action, have been proven to produce regional anesthetic effect in various animal models. The major aim of this study was to examine whether emulsified isoflurane (EI) could also produce subarachnoid anesthesia and to investigate its possible mechanism. METHODS Beagle dogs were randomly assigned into 5 groups (n = 6/group): intrathecally receiving 1% lidocaine 0.1 mL/kg, 30% intralipid 0.1 mL/kg (control), or 8% EI at doses of 0.05, 0.075, or 0.1 mL/kg, respectively. Consciousness state, motor function of limbs, and response to nociceptive stimulus were observed after drug administration. The effect of EI on voltage-gated Na channel was recorded from isolated spinal neurons of rats, using the whole-cell patch-clamp technique. Inhibition of peak sodium currents and effect of EI on Na channel gating were analyzed. RESULTS Emulsified isoflurane produced subarachnoid anesthesia in a dose-dependent manner, and at the dose of 0.1 mL/kg, the effect of 8% EI was similar to 1% lidocaine. Sodium channel currents were inhibited by EI at clinically relevant concentrations, with the IC50 (median inhibitory concentration) at 0.69 ± 0.08 mM. Voltage activation of Na channels was positive, shifted by isoflurane at the concentration of 0.77 mM, and V½ of activation (voltage for half-maximal activation) shifted from -12.4 ± 2.7 mV to -7.3 ± 2.3 mV (P < 0.01). CONCLUSIONS Emulsified isoflurane produced dose-dependent subarachnoid anesthesia, and this effect might be mediated by inhibition of EI on voltage-gated Na channels in the spinal cord.
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Abstract
Anesthesia has broad actions that include changing neuronal excitability, vascular reactivity, and other baseline physiologies and eventually modifies the neurovascular coupling relationship. Here, we review the effects of anesthesia on the spatial propagation, temporal dynamics, and quantitative relationship between the neural and vascular responses to cortical stimulation. Previous studies have shown that the onset latency of evoked cerebral blood flow (CBF) changes is relatively consistent across anesthesia conditions compared with variations in the time-to-peak. This finding indicates that the mechanism of vasodilation onset is less dependent on anesthesia interference, while vasodilation dynamics are subject to this interference. The quantitative coupling relationship is largely influenced by the type and dosage of anesthesia, including the actions on neural processing, vasoactive signal transmission, and vascular reactivity. The effects of anesthesia on the spatial gap between the neural and vascular response regions are not fully understood and require further attention to elucidate the mechanism of vascular control of CBF supply to the underlying focal and surrounding neural activity. The in-depth understanding of the anesthesia actions on neurovascular elements allows for better decision-making regarding the anesthetics used in specific models for neurovascular experiments and may also help elucidate the signal source issues in hemodynamic-based neuroimaging techniques.
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Affiliation(s)
- Kazuto Masamoto
- Center for Frontier Science and Engineering, University of Electro-Communications, Tokyo, Japan.
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Hinge-bending motions in the pore domain of a bacterial voltage-gated sodium channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2120-5. [PMID: 22579978 DOI: 10.1016/j.bbamem.2012.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 04/11/2012] [Accepted: 05/02/2012] [Indexed: 12/20/2022]
Abstract
Computational methods and experimental data are used to provide structural models for NaChBac, the homo-tetrameric voltage-gated sodium channel from the bacterium Bacillus halodurans, with a closed and partially open pore domain. Molecular dynamic (MD) simulations on membrane-bound homo-tetrameric NaChBac structures, each comprising six helical transmembrane segments (labeled S1 through S6), reveal that the shape of the lumen, which is defined by the bundle of four alpha-helical S6 segments, is modulated by hinge bending motions around the S6 glycine residues. Mutation of these glycine residues into proline and alanine affects, respectively, the structure and conformational flexibility of the S6 bundle. In the closed channel conformation, a cluster of stacked phenylalanine residues from the four S6 helices hinders diffusion of water molecules and Na(+) ions. Activation of the voltage sensor domains causes destabilization of the aforementioned cluster of phenylalanines, leading to a more open structure. The conformational change involving the phenylalanine cluster promotes a kink in S6, suggesting that channel gating likely results from the combined action of hinge-bending motions of the S6 bundle and concerted reorientation of the aromatic phenylalanine side-chains.
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Oose Y, Miura M, Inoue R, Andou N, Aosaki T, Nishimura K. Imbalanced suppression of excitatory and inhibitory synaptic transmission onto mouse striatal projection neurons during induction of anesthesia with sevoflurane in vitro. Eur J Neurosci 2012; 35:1396-405. [DOI: 10.1111/j.1460-9568.2012.08065.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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A gain-of-function mutation in adenylate cyclase confers isoflurane resistance in Caenorhabditis elegans. Anesthesiology 2012; 115:1162-71. [PMID: 22024713 DOI: 10.1097/aln.0b013e318239355d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Volatile general anesthetics inhibit neurotransmitter release by a mechanism not fully understood. Genetic evidence in Caenorhabditis elegans has shown that a major mechanism of action of volatile anesthetics acting at clinical concentrations in this animal is presynaptic inhibition of neurotransmission. To define additional components of this presynaptic volatile anesthetic mechanism, C. elegans mutants isolated as phenotypic suppressors of a mutation in syntaxin, an essential component of the neurotransmitter release machinery, were screened for anesthetic sensitivity phenotypes. METHODS Sensitivity to isoflurane concentrations was measured in locomotion assays on adult C. elegans. Sensitivity to the acetylcholinesterase inhibitor aldicarb was used as an assay for the global level of C. elegans acetylcholine release. Comparisons of isoflurane sensitivity (measured by the EC₅₀) were made by simultaneous curve-fitting and F test. RESULTS Among the syntaxin suppressor mutants, js127 was the most isoflurane resistant, with an EC₅₀ more than 3-fold that of wild type. Genetic mapping, sequencing, and transformation phenocopy showed that js127 was an allele of acy-1, which encodes an adenylate cyclase expressed throughout the C. elegans nervous system and in muscle. js127 behaved as a gain-of-function mutation in acy-1 and had increased concentrations of cyclic adenosine monophosphate. Testing of single and double mutants along with selective tissue expression of the js127 mutation revealed that acy-1 acts in neurons within a Gαs-PKA-UNC-13-dependent pathway to regulate behavior and isoflurane sensitivity. CONCLUSIONS Activation of neuronal adenylate cyclase antagonizes isoflurane inhibition of locomotion in C. elegans.
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Müller CP, Pum ME, Amato D, Schüttler J, Huston JP, De Souza Silva MA. The in vivo neurochemistry of the brain during general anesthesia. J Neurochem 2011; 119:419-46. [DOI: 10.1111/j.1471-4159.2011.07445.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Yokoyama T, Minami K, Sudo Y, Horishita T, Ogata J, Yanagita T, Uezono Y. Effects of sevoflurane on voltage-gated sodium channel Na(v)1.8, Na(v)1.7, and Na(v)1.4 expressed in Xenopus oocytes. J Anesth 2011; 25:609-13. [PMID: 21656091 DOI: 10.1007/s00540-011-1167-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/28/2011] [Indexed: 12/19/2022]
Abstract
Sevoflurane is widely used as a volatile anesthetic in clinical practice. However, its mechanism is still unclear. Recently, it has been reported that voltage-gated sodium channels have important roles in anesthetic mechanisms. Much attention has been paid to the effects of sevoflurane on voltage-dependent sodium channels. To elucidate this, we examined the effects of sevoflurane on Na(v) 1.8, Na(v) 1.4, and Na(v) 1.7 expressed in Xenopus oocytes. The effects of sevoflurane on Na(v) 1.8, Na(v) 1.4, and Na(v) 1.7 sodium channels were studied by an electrophysiology method using whole-cell, two-electrode voltage-clamp techniques in Xenopus oocytes. Sevoflurane at 1.0 mM inhibited the voltage-gated sodium channels Na(v)1.8, Na(v)1.4, and Na(v)1.7, but sevoflurane (0.5 mM) had little effect. This inhibitory effect of 1 mM sevoflurane was completely abolished by pretreatment with protein kinase C (PKC) inhibitor, bisindolylmaleimide I. Sevoflurane appears to have inhibitory effects on Na(v)1.8, Na(v)1.4, and Na(v) 1.7 by PKC pathways. However, these sodium channels might not be related to the clinical anesthetic effects of sevoflurane.
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Affiliation(s)
- Toru Yokoyama
- Department of Anesthesiology and Critical Care Medicine, Jichi Medical University, Tochigi 329-0483, Japan
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Westphalen RI, Kwak NB, Daniels K, Hemmings HC. Regional differences in the effects of isoflurane on neurotransmitter release. Neuropharmacology 2011; 61:699-706. [PMID: 21651920 DOI: 10.1016/j.neuropharm.2011.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Revised: 02/04/2011] [Accepted: 05/16/2011] [Indexed: 11/18/2022]
Abstract
Stimulus evoked neurotransmitter release requires that Na(+) channel-dependent nerve terminal depolarization be transduced into synaptic vesicle exocytosis. Inhaled anesthetics block presynaptic Na(+) channels and selectively inhibit glutamate over GABA release from isolated nerve terminals, indicating mechanistic differences between excitatory and inhibitory transmitter release. We compared the effects of isoflurane on depolarization-evoked [(3)H]glutamate and [(14)C]GABA release from isolated nerve terminals prepared from four regions of rat CNS evoked by 4-aminopyridine (4AP), veratridine (VTD), or elevated K(+). These mechanistically distinct secretegogues distinguished between Na(+) channel- and/or Ca(2+) channel-mediated presynaptic effects. Isoflurane completely inhibited total 4AP-evoked glutamate release (IC(50) = 0.42 ± 0.03 mM) more potently than GABA release (IC(50) = 0.56 ± 0.02 mM) from cerebral cortex (1.3-fold greater potency), hippocampus and striatum, but inhibited glutamate and GABA release from spinal cord terminals equipotently. Na(+) channel-specific VTD-evoked glutamate release from cortex was also significantly more sensitive to inhibition by isoflurane than was GABA release. Na(+) channel-independent K(+)-evoked release was insensitive to isoflurane at clinical concentrations in all four regions, consistent with a target upstream of Ca(2+) entry. Isoflurane inhibited Na(+) channel-mediated (tetrodotoxin-sensitive) 4AP-evoked glutamate release (IC(50) = 0.30 ± 0.03 mM) more potently than GABA release (IC(50) = 0.67 ± 0.04 mM) from cortex (2.2-fold greater potency). The magnitude of inhibition of Na(+) channel-mediated 4AP-evoked release by a single clinical concentration of isoflurane (0.35 mM) varied by region and transmitter: Inhibition of glutamate release from spinal cord was greater than from the three brain regions and greater than GABA release for each CNS region. These findings indicate that isoflurane selectively inhibits glutamate release compared to GABA release via Na(+) channel-mediated transduction in the four CNS regions tested, and that differences in presynaptic Na(+) channel involvement determine differences in anesthetic pharmacology.
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Affiliation(s)
- Robert I Westphalen
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, United States
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