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Butiulca M, Farczadi L, Vari CE, Imre S, Pui M, Lazar A. LC-MS/MS assisted biomonitoring of ropivacaine and 3-OH-ropivacaine after plane block anesthesia for cardiac device implantation. Front Mol Biosci 2023; 10:1243103. [PMID: 37828919 PMCID: PMC10566374 DOI: 10.3389/fmolb.2023.1243103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/08/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction: Ropivacaine is a popular local anesthetic used for regional anesthesia or for pain management. Although designed as an enantiomerically pure drug, an aspect that reduces the adverse effects, its toxicological effects are still a risk. As such, biomonitoring to assure appropriate dosage and bioavailability are essential to avoid complications during or post-surgery. Methods: The study focused on developing a sensitive, selective, and accurate liquid chromatography-mass spectrometry (LCMS/MS) method which facilitates the biomonitoring of ropivacaine and its main metabolite in plasma after regional anesthesia using ropivacaine. Results and Discussion: The method was validated with regards to all relevant parameters, such as sensitivity, selectivity, accuracy, precision, and the effect of sample matrix. The method was successfully used in a pilot study, which included one patient undergoing plane block anesthesia for cardiac device implantation. The results showed the method is appropriate for its intended purpose and could even be used in other, similar applications.
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Affiliation(s)
- Mihaela Butiulca
- Department of Anesthesiology and Intensive Care Medicine, Faculty of General Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
- Department of Anesthesiology and Intensive Care Medicine, Emergency County Hospital, Târgu Mureș, Romania
| | - Lenard Farczadi
- Chromatography and Mass Spectrometry Laboratory, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
| | - Camil Eugen Vari
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
| | - Silvia Imre
- Chromatography and Mass Spectrometry Laboratory, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
- Department of Analytical Chemistry and Drug Analysis, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
| | - Mihai Pui
- Department of Anesthesiology and Intensive Care Medicine, Emergency County Hospital, Târgu Mureș, Romania
| | - Alexandra Lazar
- Department of Anesthesiology and Intensive Care Medicine, Faculty of General Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology, Târgu Mureș, Romania
- Department of Anesthesiology and Intensive Care Medicine, Emergency County Hospital, Târgu Mureș, Romania
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Synergistic effects of agonists and two-pore-domain potassium channels on secretory responses of human pancreatic duct cells Capan-1. Pflugers Arch 2023; 475:361-379. [PMID: 36534232 PMCID: PMC9908661 DOI: 10.1007/s00424-022-02782-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
Mechanisms of synergistic agonist stimulation and modulation of the electrochemical driving force for anion secretion are still not fully explored in human pancreatic duct epithelial cells. The first objective of this study was therefore to test whether combined agonist stimulation augments anion transport responses in the Capan-1 monolayer model of human pancreatic duct epithelium. The second objective was to test the influence of H+,K+-ATPase inhibition on anion transport in Capan-1 monolayers. The third objective was to analyze the expression and function of K+ channels in Capan-1, which could support anion secretion and cooperate with H+,K+-ATPases in pH and potassium homeostasis. The human pancreatic adenocarcinoma cell line Capan-1 was cultured conventionally or as polarized monolayers that were analyzed by Ussing chamber electrophysiological recordings. Single-cell intracellular calcium was assayed with Fura-2. mRNA isolated from Capan-1 was analyzed by use of the nCounter assay or RT-PCR. Protein expression was assessed by immunofluorescence and western blot analyses. Combined stimulation with different physiological agonists enhanced anion transport responses compared to single agonist stimulation. The responsiveness of Capan-1 cells to histamine was also revealed in these experiments. The H+,K+-ATPase inhibitor omeprazole reduced carbachol- and riluzole-induced anion transport responses. Transcript analyses revealed abundant TASK-2, TWIK-1, TWIK-2, TASK-5, KCa3.1, and KCNQ1 mRNA expression. KCNE1 mRNA and TREK-1, TREK-2, TASK-2, and KCNQ1 protein expression were also shown. This study shows that the Capan-1 model recapitulates key physiological aspects of a bicarbonate-secreting epithelium and constitutes a valuable model for functional studies on human pancreatic duct epithelium.
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Russell T, Gangotia D, Barry G. Assessing the potential of repurposing ion channel inhibitors to treat emerging viral diseases and the role of this host factor in virus replication. Biomed Pharmacother 2022; 156:113850. [DOI: 10.1016/j.biopha.2022.113850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/25/2022] [Accepted: 10/06/2022] [Indexed: 12/03/2022] Open
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Khoubza L, Gilbert N, Kim EJ, Chatelain FC, Feliciangeli S, Abelanet S, Kang D, Lesage F, Bichet D. Alkaline-sensitive two-pore domain potassium channels form functional heteromers in pancreatic β-cells. J Biol Chem 2022; 298:102447. [PMID: 36063992 PMCID: PMC9520024 DOI: 10.1016/j.jbc.2022.102447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/15/2022] Open
Abstract
Two-pore domain K+ channels (K2P channels), active as dimers, produce inhibitory currents regulated by a variety of stimuli. Among them, TWIK1-related alkalinization-activated K+ channel 1 (TALK1), TWIK1-related alkalinization-activated K+ channel 2 (TALK2), and TWIK1-related acid-sensitive K+ channel 2 (TASK2) form a subfamily of structurally related K2P channels stimulated by extracellular alkalosis. The human genes encoding these proteins are clustered at chromosomal region 6p21 and coexpressed in multiple tissues, including the pancreas. The question whether these channels form functional heteromers remained open. By analyzing single-cell transcriptomic data, we show that these channels are coexpressed in insulin-secreting pancreatic β-cells. Using in situ proximity ligation assay and electrophysiology, we show that they form functional heterodimers both upon heterologous expression and under native conditions in human pancreatic β-cells. We demonstrate that heteromerization of TALK2 with TALK1 or with TASK2 endows TALK2 with sensitivity to extracellular alkalosis in the physiological range. We further show that the association of TASK2 with TALK1 and TALK2 increases their unitary conductance. These results provide a new example of heteromerization in the K2P channel family expanding the range of the potential physiological and pathophysiological roles of TALK1/TALK2/TASK2 channels, not only in insulin-secreting cells but also in the many other tissues in which they are coexpressed.
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Affiliation(s)
- Lamyaa Khoubza
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France
| | - Nicolas Gilbert
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France
| | - Eun-Jin Kim
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, South Korea
| | - Franck C Chatelain
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France
| | - Sylvain Feliciangeli
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France; Inserm, Paris, France
| | - Sophie Abelanet
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France
| | - Dawon Kang
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, South Korea
| | - Florian Lesage
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France; Inserm, Paris, France.
| | - Delphine Bichet
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, Valbonne, France
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Weinschenk S, Weiss C, Benrath J, von Baehr V, Strowitzki T, Feißt M. Anti-Inflammatory Characteristics of Local Anesthetics: Inhibition of TNF-α Secretion of Lipopolysaccharide-Stimulated Leucocytes in Human Blood Samples. Int J Mol Sci 2022; 23:ijms23063283. [PMID: 35328706 PMCID: PMC8949497 DOI: 10.3390/ijms23063283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 02/04/2023] Open
Abstract
Background. Local anesthetics (LAs) have potent anti-inflammatory properties. Inflammatory down-regulation is crucial in diseases with overactive immune reactions, such as acute respiratory distress syndrome (ARDS) and chronic inflammation. We investigated the influence of four LAs, procaine, lidocaine, mepivacaine, and bupivacaine, on the reduction of tumor necrosis factor-alpha (TNF-α) secretion in lipopolysaccharide (LPS)-activated human leucocytes. Methods. Blood samples of 28 individuals were stimulated with LPS. The reduction of TNF-α production by each of the four LAs added (0.5 mg/mL) was measured and correlated with biometric variables. A response was defined as reduction to <85% of initial levels. Results. All four LAs down-regulated the TNF-α secretion in 44−61%: Bupivacaine (44.4%), lidocaine (61.5%), mepivacaine (44.4%), and procaine (50% of the individuals, “responders”). The TNF-α secretion was reduced to 67.4, 68.0, 63.6, and 67.1% of the initial values in responders. The effects in both patients and healthy persons were the same. Interindividual responses to LAs were not correlated with the duration or type of complaints, basal TNF-α serum level, sex, BMI, or age of responders. Conclusions. Four clinically relevant LAs (amid-LA and ester-LA) attenuate the inflammatory response provoked by LPS. They are potential candidates for drug repositioning in treating overactive immune reactions and chronic inflammation.
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Affiliation(s)
- Stefan Weinschenk
- Department of Gynecological Endocrinology and Fertility Disorders, Women’s Hospital, University of Heidelberg, D-69120 Heidelberg, Germany;
- Correspondence:
| | - Carsten Weiss
- Institute of Biological and Chemical Systems, Biological Information Processing, Karlsruhe Institute of Technology (KIT), Campus North, D-76133 Karlsruhe, Germany;
| | - Justus Benrath
- Pain Clinic, Mannheim University Hospital, Faculty of Heidelberg University, D-68167 Mannheim, Germany;
| | - Volker von Baehr
- Institute of Medical Diagnostics, Nicolaistraße 22, D-12247 Berlin, Germany;
| | - Thomas Strowitzki
- Department of Gynecological Endocrinology and Fertility Disorders, Women’s Hospital, University of Heidelberg, D-69120 Heidelberg, Germany;
| | - Manuel Feißt
- Institute of Medical Biometry (IMBI), Heidelberg University, Im Neuenheimer Feld 130.3, D-69120 Heidelberg, Germany;
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David SN, Varghese DC, Valiaveedan S. What is the minimum effective anesthetic volume (MEAV90) of 0.2% ropivacaine required for ultrasound-guided popliteal-sciatic nerve block? J Anaesthesiol Clin Pharmacol 2021; 37:402-405. [PMID: 34759551 PMCID: PMC8562438 DOI: 10.4103/joacp.joacp_34_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 10/21/2020] [Accepted: 12/02/2020] [Indexed: 11/30/2022] Open
Abstract
Background and Aims: Popliteal-Sciatic nerve block under Ultrasound Guidance (USG) using a local anesthetic agent like Ropivacaine is an established technique for providing analgesia and muscle relaxation for lower limb surgeries with minimal untoward events. Establishing the minimal volume of 0.2% ropivacaine required to provide intraoperative and postoperative analgesia will further reduce the drug requirements and adverse effects toward the patient. Material and Methods: This randomized prospective observational blinded study was done in a tertiary care referral hospital in South India over 9 months from August 2017 till April 2018. The block was performed on all recruited patients under ultrasound guidance with a starting volume of 16 ml 0.2% ropivacaine. Duration of time for loss of pin-prick sensation around the sole of the foot (tibial nerve) and the lateral malleolus (common peroneal nerve) was noted. If successful, the volume of the drug for subsequent patients was randomized by lottery method to either be kept the same or reduced. If the block failed, the subsequent patient recruited would have an increased volume of drug injected. Results: By Probit regression analysis using the biased coin up-and-down method we found that 9.3 ml (MEAV90) of 0.2% ropivacaine was sufficient for providing adequate analgesia. Factors such as patient age or weight had no role in efficacy of the block. There were no adverse effects such as allergy to the drug or systemic toxicity noted in the studied patients. Conclusion: 9.3 ml of 0.2% ropivacaine is sufficient to provide analgesia (assessed by pin-prick) in 90% of patients undergoing popliteal-sciatic block for lower limb surgeries.
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Affiliation(s)
- Sandeep N David
- Department of Anaesthesiology, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
| | - Davies C Varghese
- Department of Anaesthesiology, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
| | - Sebastian Valiaveedan
- Department of Anaesthesiology, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
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Two-Pore-Domain Potassium (K 2P-) Channels: Cardiac Expression Patterns and Disease-Specific Remodelling Processes. Cells 2021; 10:cells10112914. [PMID: 34831137 PMCID: PMC8616229 DOI: 10.3390/cells10112914] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/23/2022] Open
Abstract
Two-pore-domain potassium (K2P-) channels conduct outward K+ currents that maintain the resting membrane potential and modulate action potential repolarization. Members of the K2P channel family are widely expressed among different human cell types and organs where they were shown to regulate important physiological processes. Their functional activity is controlled by a broad variety of different stimuli, like pH level, temperature, and mechanical stress but also by the presence of lipids or pharmacological agents. In patients suffering from cardiovascular diseases, alterations in K2P-channel expression and function have been observed, suggesting functional significance and a potential therapeutic role of these ion channels. For example, upregulation of atrial specific K2P3.1 (TASK-1) currents in atrial fibrillation (AF) patients was shown to contribute to atrial action potential duration shortening, a key feature of AF-associated atrial electrical remodelling. Therefore, targeting K2P3.1 (TASK-1) channels might constitute an intriguing strategy for AF treatment. Further, mechanoactive K2P2.1 (TREK-1) currents have been implicated in the development of cardiac hypertrophy, cardiac fibrosis and heart failure. Cardiovascular expression of other K2P channels has been described, functional evidence in cardiac tissue however remains sparse. In the present review, expression, function, and regulation of cardiovascular K2P channels are summarized and compared among different species. Remodelling patterns, observed in disease models are discussed and compared to findings from clinical patients to assess the therapeutic potential of K2P channels.
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Huang W, Ke Y, Zhu J, Liu S, Cong J, Ye H, Guo Y, Wang K, Zhang Z, Meng W, Gao TM, Luhmann HJ, Kilb W, Chen R. TRESK channel contributes to depolarization-induced shunting inhibition and modulates epileptic seizures. Cell Rep 2021; 36:109404. [PMID: 34289346 DOI: 10.1016/j.celrep.2021.109404] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/19/2021] [Accepted: 06/23/2021] [Indexed: 11/18/2022] Open
Abstract
Glutamatergic and GABAergic synaptic transmission controls excitation and inhibition of postsynaptic neurons, whereas activity of ion channels modulates neuronal intrinsic excitability. However, it is unclear how excessive neuronal excitation affects intrinsic inhibition to regain homeostatic stability under physiological or pathophysiological conditions. Here, we report that a seizure-like sustained depolarization can induce short-term inhibition of hippocampal CA3 neurons via a mechanism of membrane shunting. This depolarization-induced shunting inhibition (DShI) mediates a non-synaptic, but neuronal intrinsic, short-term plasticity that is able to suppress action potential generation and postsynaptic responses by activated ionotropic receptors. We demonstrate that the TRESK channel significantly contributes to DShI. Disruption of DShI by genetic knockout of TRESK exacerbates the sensitivity and severity of epileptic seizures of mice, whereas overexpression of TRESK attenuates seizures. In summary, these results uncover a type of homeostatic intrinsic plasticity and its underlying mechanism. TRESK might represent a therapeutic target for antiepileptic drugs.
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Affiliation(s)
- Weiyuan Huang
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yue Ke
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jianping Zhu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shuai Liu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jin Cong
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hailin Ye
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yanwu Guo
- The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Kewan Wang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhenhai Zhang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Center for Precision Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou 510030, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China
| | - Wenxiang Meng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tian-Ming Gao
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China; State Key Laboratory of Organ Failure Research, Collaborative Innovation Center for Brain Science, Southern Medical University, Guangzhou 510515, China
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany.
| | - Rongqing Chen
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China.
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Gaur S, Marimuthu M, Wahab A, Krishnan N, Ramasubbu S. Twin Mixed Local Anesthesia in Third Molar Surgery - Randomized Controlled Trial. J Oral Maxillofac Surg 2021; 80:63-69. [PMID: 34363764 DOI: 10.1016/j.joms.2021.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 06/18/2021] [Accepted: 07/09/2021] [Indexed: 01/23/2023]
Abstract
PURPOSE The aim of this study was to compare the clinical efficacy of injection of 2 long-acting amide local anesthetic agents - bupivacaine and ropivacaine with and without 4 mg dexamethasone in patients undergoing third molar extraction. METHODS A prospective randomized double blind controlled trial was conducted among 68 patients with impacted mandibular third molars. Group A and B were the control groups and received 1.8 mL of 0.5% bupivacaine hydrochloride and 0.75% ropivacaine hydrochloride, respectively. Group A1 and B1 were experimental groups and received modified twin mixes which were 1.8 mL of 0.5% bupivacaine hydrochloride + 1mL/4mg dexamethasone and 0.75% ropivacaine hydrochloride + 1 mL/4mg dexamethasone, respectively. Visual analog pain scale, mouth opening measurement and facial swelling were assessed at the time of injection and postoperative days 1, 3, and 7. RESULTS The mean visual analogue scale score for pain on local anesthesia injection was found to be less in both experimental groups- Group A1 (2.94) and B1 (2.41) as compared to control groups- Group A (3.59) and B (3.06). The durations of soft tissue anesthesia were higher as compared to their respective controls for both Group A1 and B1. Patients in both control groups A and B had an increased postoperative swelling, pain and trismus. CONCLUSIONS Intraoperative and postoperative comfort in both the experimental groups were higher than those for control groups, thereby establishing the clinical efficacy of both modified twin mixes for use in surgical extraction of mandibular third molars.
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Affiliation(s)
- Shivangi Gaur
- Post graduate Resident, Department of Oral & Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai India
| | - Madhulaxmi Marimuthu
- Professor, Department of Oral & Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai India.
| | - Abdul Wahab
- Professor, Department of Oral & Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai India
| | - Navaneetha Krishnan
- Professor, Department of Anesthesia, Saveetha Medical College and Hospitals, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai India
| | - Subhashini Ramasubbu
- Post graduate Resident, Department of Oral & Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai India
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Ropivacaine: A Novel Local Anaesthetic Drug to Use in Otorhinolaryngology Practice. Indian J Otolaryngol Head Neck Surg 2021; 73:267-270. [PMID: 34150604 DOI: 10.1007/s12070-020-02309-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/07/2020] [Indexed: 10/22/2022] Open
Abstract
Ropivacaine is a long-acting amide local anaesthetic agent which has a significant vasoconstrictive property, long duration of action, least central nervous system and cardiac complications due to the pure (S)-enantiomer property by reversible inhibition of sodium ion influx in nerve fibres. By using additives the duration of analgesia may be prolonged. Ropivacaine has been used routinely in our otorhinolaryngology procedures since 2010 (10 years). The present article details the clinical applications of ropivacaine and its current place as a local anaesthetic in otorhinolaryngology practice.
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Hermanns H, Hollmann MW, Stevens MF, Lirk P, Brandenburger T, Piegeler T, Werdehausen R. Molecular mechanisms of action of systemic lidocaine in acute and chronic pain: a narrative review. Br J Anaesth 2019; 123:335-349. [DOI: 10.1016/j.bja.2019.06.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 02/07/2023] Open
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Bedoya M, Rinné S, Kiper AK, Decher N, González W, Ramírez D. TASK Channels Pharmacology: New Challenges in Drug Design. J Med Chem 2019; 62:10044-10058. [PMID: 31260312 DOI: 10.1021/acs.jmedchem.9b00248] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rational drug design targeting ion channels is an exciting and always evolving research field. New medicinal chemistry strategies are being implemented to explore the wild chemical space and unravel the molecular basis of the ion channels modulators binding mechanisms. TASK channels belong to the two-pore domain potassium channel family and are modulated by extracellular acidosis. They are extensively distributed along the cardiovascular and central nervous systems, and their expression is up- and downregulated in different cancer types, which makes them an attractive therapeutic target. However, TASK channels remain unexplored, and drugs designed to target these channels are poorly selective. Here, we review TASK channels properties and their known blockers and activators, considering the new challenges in ion channels drug design and focusing on the implementation of computational methodologies in the drug discovery process.
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Affiliation(s)
- Mauricio Bedoya
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud , Universidad Autónoma de Chile , El Llano Subercaseaux 2801, Piso 6 , 8900000 Santiago , Chile
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Iqbal F, Thompson AJ, Riaz S, Pehar M, Rice T, Syed NI. Anesthetics: from modes of action to unconsciousness and neurotoxicity. J Neurophysiol 2019; 122:760-787. [PMID: 31242059 DOI: 10.1152/jn.00210.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Modern anesthetic compounds and advanced monitoring tools have revolutionized the field of medicine, allowing for complex surgical procedures to occur safely and effectively. Faster induction times and quicker recovery periods of current anesthetic agents have also helped reduce health care costs significantly. Moreover, extensive research has allowed for a better understanding of anesthetic modes of action, thus facilitating the development of more effective and safer compounds. Notwithstanding the realization that anesthetics are a prerequisite to all surgical procedures, evidence is emerging to support the notion that exposure of the developing brain to certain anesthetics may impact future brain development and function. Whereas the data in support of this postulate from human studies is equivocal, the vast majority of animal research strongly suggests that anesthetics are indeed cytotoxic at multiple brain structure and function levels. In this review, we first highlight various modes of anesthetic action and then debate the evidence of harm from both basic science and clinical studies perspectives. We present evidence from animal and human studies vis-à-vis the possible detrimental effects of anesthetic agents on both the young developing and the elderly aging brain while discussing potential ways to mitigate these effects. We hope that this review will, on the one hand, invoke debate vis-à-vis the evidence of anesthetic harm in young children and the elderly, and on the other hand, incentivize the search for better and less toxic anesthetic compounds.
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Affiliation(s)
- Fahad Iqbal
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew J Thompson
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Saba Riaz
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marcus Pehar
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tiffany Rice
- Department of Anesthesiology, Perioperative and Pain Medicine, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada
| | - Naweed I Syed
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Ben Soussia I, El Mouridi S, Kang D, Leclercq-Blondel A, Khoubza L, Tardy P, Zariohi N, Gendrel M, Lesage F, Kim EJ, Bichet D, Andrini O, Boulin T. Mutation of a single residue promotes gating of vertebrate and invertebrate two-pore domain potassium channels. Nat Commun 2019; 10:787. [PMID: 30770809 PMCID: PMC6377628 DOI: 10.1038/s41467-019-08710-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/23/2019] [Indexed: 01/28/2023] Open
Abstract
Mutations that modulate the activity of ion channels are essential tools to understand the biophysical determinants that control their gating. Here, we reveal the conserved role played by a single amino acid position (TM2.6) located in the second transmembrane domain of two-pore domain potassium (K2P) channels. Mutations of TM2.6 to aspartate or asparagine increase channel activity for all vertebrate K2P channels. Using two-electrode voltage-clamp and single-channel recording techniques, we find that mutation of TM2.6 promotes channel gating via the selectivity filter gate and increases single channel open probability. Furthermore, channel gating can be progressively tuned by using different amino acid substitutions. Finally, we show that the role of TM2.6 was conserved during evolution by rationally designing gain-of-function mutations in four Caenorhabditis elegans K2P channels using CRISPR/Cas9 gene editing. This study thus describes a simple and powerful strategy to systematically manipulate the activity of an entire family of potassium channels. Mutations that modulate the activity of ion channels are essential tools to understand the biophysical determinants that control their gating. Here authors reveal the role played by a single residue in the second transmembrane domain of vertebrate and invertebrate two-pore domain potassium channels.
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Affiliation(s)
- Ismail Ben Soussia
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Sonia El Mouridi
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Dawon Kang
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, 52727, South Korea
| | - Alice Leclercq-Blondel
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Lamyaa Khoubza
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Philippe Tardy
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Nora Zariohi
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Marie Gendrel
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Florian Lesage
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Eun-Jin Kim
- Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, 52727, South Korea
| | - Delphine Bichet
- Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, CNRS UMR 7275, Université de Nice Sophia Antipolis, Valbonne, 06560, France
| | - Olga Andrini
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France.
| | - Thomas Boulin
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France.
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Nagaraj P, Thalamkandathil N, Sadique H. ROPIVACAINE VERSUS LIDOCAINE FOR EPISIOTOMY-A RANDOMISED DOUBLE BLIND STUDY. ACTA ACUST UNITED AC 2017. [DOI: 10.18410/jebmh/2017/382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Telles CJ, Decker SE, Motley WW, Peters AW, Mehr AP, Frizzell RA, Forrest JN. Functional and molecular identification of a TASK-1 potassium channel regulating chloride secretion through CFTR channels in the shark rectal gland: implications for cystic fibrosis. Am J Physiol Cell Physiol 2016; 311:C884-C894. [PMID: 27653983 PMCID: PMC5206301 DOI: 10.1152/ajpcell.00030.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 09/18/2016] [Indexed: 11/22/2022]
Abstract
In the shark rectal gland (SRG), apical chloride secretion through CFTR channels is electrically coupled to a basolateral K+ conductance whose type and molecular identity are unknown. We performed studies in the perfused SRG with 17 K+ channel inhibitors to begin this search. Maximal chloride secretion was markedly inhibited by low-perfusate pH, bupivicaine, anandamide, zinc, quinidine, and quinine, consistent with the properties of an acid-sensitive, four-transmembrane, two-pore-domain K+ channel (4TM-K2P). Using PCR with degenerate primers to this family, we identified a TASK-1 fragment in shark rectal gland, brain, gill, and kidney. Using 5' and 3' rapid amplification of cDNA ends PCR and genomic walking, we cloned the full-length shark gene (1,282 bp), whose open reading frame encodes a protein of 375 amino acids that was 80% identical to the human TASK-1 protein. We expressed shark and human TASK-1 cRNA in Xenopus oocytes and characterized these channels using two-electrode voltage clamping. Both channels had identical current-voltage relationships (outward rectifying) and a reversal potential of -90 mV. Both were inhibited by quinine, bupivicaine, and acidic pH. The pKa for current inhibition was 7.75 for shark TASK-1 vs. 7.37 for human TASK-1, values similar to the arterial pH for each species. We identified this protein in SRG by Western blot and confocal immunofluorescent microscopy and detected the protein in SRG and human airway cells. Shark TASK-1 is the major K+ channel coupled to chloride secretion in the SRG, is the oldest 4TM 2P family member identified, and is the first TASK-1 channel identified to play a role in setting the driving force for chloride secretion in epithelia. The detection of this potassium channel in mammalian lung tissue has implications for human biology and disease.
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Affiliation(s)
- Connor J Telles
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Sarah E Decker
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - William W Motley
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Alexander W Peters
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Ali Poyan Mehr
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Raymond A Frizzell
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - John N Forrest
- Nephrology Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut;
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
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17
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Syeda F, Holmes AP, Yu TY, Tull S, Kuhlmann SM, Pavlovic D, Betney D, Riley G, Kucera JP, Jousset F, de Groot JR, Rohr S, Brown NA, Fabritz L, Kirchhof P. PITX2 Modulates Atrial Membrane Potential and the Antiarrhythmic Effects of Sodium-Channel Blockers. J Am Coll Cardiol 2016; 68:1881-1894. [PMID: 27765191 PMCID: PMC5075046 DOI: 10.1016/j.jacc.2016.07.766] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 07/05/2016] [Accepted: 07/20/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Antiarrhythmic drugs are widely used to treat patients with atrial fibrillation (AF), but the mechanisms conveying their variable effectiveness are not known. Recent data suggested that paired like homeodomain-2 transcription factor (PITX2) might play an important role in regulating gene expression and electrical function of the adult left atrium (LA). OBJECTIVES After determining LA PITX2 expression in AF patients requiring rhythm control therapy, the authors assessed the effects of Pitx2c on LA electrophysiology and the effect of antiarrhythmic drugs. METHODS LA PITX2 messenger ribonucleic acid (mRNA) levels were measured in 95 patients undergoing thoracoscopic AF ablation. The effects of flecainide, a sodium (Na+)-channel blocker, and d,l-sotalol, a potassium channel blocker, were studied in littermate mice with normal and reduced Pitx2c mRNA by electrophysiological study, optical mapping, and patch clamp studies. PITX2-dependent mechanisms of antiarrhythmic drug action were studied in human embryonic kidney (HEK) cells expressing human Na channels and by modeling human action potentials. RESULTS Flecainide 1 μmol/l was more effective in suppressing atrial arrhythmias in atria with reduced Pitx2c mRNA levels (Pitx2c+/-). Resting membrane potential was more depolarized in Pitx2c+/- atria, and TWIK-related acid-sensitive K+ channel 2 (TASK-2) gene and protein expression were decreased. This resulted in enhanced post-repolarization refractoriness and more effective Na-channel inhibition. Defined holding potentials eliminated differences in flecainide's effects between wild-type and Pitx2c+/- atrial cardiomyocytes. More positive holding potentials replicated the increased effectiveness of flecainide in blocking human Nav1.5 channels in HEK293 cells. Computer modeling reproduced an enhanced effectiveness of Na-channel block when resting membrane potential was slightly depolarized. CONCLUSIONS PITX2 mRNA modulates atrial resting membrane potential and thereby alters the effectiveness of Na-channel blockers. PITX2 and ion channels regulating the resting membrane potential may provide novel targets for antiarrhythmic drug development and companion therapeutics in AF.
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Affiliation(s)
- Fahima Syeda
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ting Y Yu
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Physical Sciences of Imaging in the Biomedical Sciences, School of Chemistry, University of Birmingham, Birmingham, United Kingdom
| | - Samantha Tull
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | - Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Daniel Betney
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Genna Riley
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Florian Jousset
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Joris R de Groot
- Heart Center, Department of Cardiology, Academisch Medisch Centrum, Amsterdam, the Netherlands
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Nigel A Brown
- St. George's Hospital Medical School, University of London, London, United Kingdom
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, United Kingdom.
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18
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Central Nervous System-Toxic Lidocaine Concentrations Unmask L-Type Ca²⁺ Current-Mediated Action Potentials in Rat Thalamocortical Neurons: An In Vitro Mechanism of Action Study. Anesth Analg 2016; 122:1360-9. [PMID: 26771269 DOI: 10.1213/ane.0000000000001158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND High systemic lidocaine concentrations exert well-known toxic effects on the central nervous system (CNS), including seizures, coma, and death. The underlying mechanisms are still largely obscure, and the actions of lidocaine on supraspinal neurons have received comparatively little study. We recently found that lidocaine at clinically neurotoxic concentrations increases excitability mediated by Na-independent, high-threshold (HT) action potential spikes in rat thalamocortical neurons. Our goal in this study was to characterize these spikes and test the hypothesis that they are generated by HT Ca currents, previously implicated in neurotoxicity. We also sought to identify and isolate the specific underlying subtype of Ca current. METHODS We investigated the actions of lidocaine in the CNS-toxic concentration range (100 μM-1 mM) on ventrobasal thalamocortical neurons in rat brain slices in vitro, using whole-cell patch-clamp recordings aided by differential interference contrast infrared videomicroscopy. Drugs were bath applied; action potentials were generated using current clamp protocols, and underlying currents were identified and isolated with ion channel blockers and electrolyte substitution. RESULTS Lidocaine (100 μM-1 mM) abolished Na-dependent tonic firing in all neurons tested (n = 46). However, in 39 of 46 (85%) neurons, lidocaine unmasked evoked HT action potentials with lower amplitudes and rates of de-/repolarization compared with control. These HT action potentials remained during the application of tetrodotoxin (600 nM), were blocked by Cd (50 μM), and disappeared after superfusion with an extracellular solution deprived of Ca. These features implied that the unmasked potentials were generated by high-voltage-activated Ca channels and not by Na channels. Application of the L-type Ca channel blocker, nifedipine (5 μM), completely blocked the HT potentials, whereas the N-type Ca channel blocker, ω-conotoxin GVIA (1 μM), had little effect. CONCLUSIONS At clinically CNS-toxic concentrations, lidocaine unmasked in thalamocortical neurons evoked HT action potentials mediated by the L-type Ca current while substantially suppressing Na-dependent excitability. On the basis of the known role of an increase in intracellular Ca in the pathogenesis of local anesthetic neurotoxicity, this novel action represents a plausible contributing candidate mechanism for lidocaine's CNS toxicity in vivo.
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Hu T, Liu N, Lv M, Ma L, Peng H, Peng S, Liu T. Lidocaine Inhibits HCN Currents in Rat Spinal Substantia Gelatinosa Neurons. Anesth Analg 2016; 122:1048-59. [PMID: 26756913 PMCID: PMC4791316 DOI: 10.1213/ane.0000000000001140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Lidocaine, which blocks voltage-gated sodium channels, is widely used in surgical anesthesia and pain management. Recently, it has been proposed that the hyperpolarization-activated cyclic nucleotide (HCN) channel is one of the other novel targets of lidocaine. Substantia gelatinosa in the spinal dorsal horn, which plays key roles in modulating nociceptive information from primary afferents, comprises heterogeneous interneurons that can be electrophysiologically categorized by firing pattern. Our previous study demonstrated that a substantial proportion of substantia gelatinosa neurons reveal the presence of HCN current (Ih); however, the roles of lidocaine and HCN channel expression in different types of substantia gelatinosa neurons remain unclear. METHODS By using the whole-cell patch-clamp technique, we investigated the effect of lidocaine on Ih in rat substantia gelatinosa neurons of acute dissociated spinal cord slices. RESULTS We found that lidocaine rapidly decreased the peak Ih amplitude with an IC50 of 80 μM. The inhibition rate on Ih was not significantly different with a second application of lidocaine in the same neuron. Tetrodotoxin, a sodium channel blocker, did not affect lidocaine's effect on Ih. In addition, lidocaine shifted the half-activation potential of Ih from -109.7 to -114.9 mV and slowed activation. Moreover, the reversal potential of Ih was shifted by -7.5 mV by lidocaine. In the current clamp, lidocaine decreased the resting membrane potential, increased membrane resistance, delayed rebound depolarization latency, and reduced the rebound spike frequency. We further found that approximately 58% of substantia gelatinosa neurons examined expressed Ih, in which most of them were tonically firing. CONCLUSIONS Our studies demonstrate that lidocaine strongly inhibits Ih in a reversible and concentration-dependent manner in substantia gelatinosa neurons, independent of tetrodotoxin-sensitive sodium channels. Thus, our study provides new insight into the mechanism underlying the central analgesic effect of the systemic administration of lidocaine.
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Affiliation(s)
- Tao Hu
- From the Departments of *Pediatrics and †Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China; and ‡Center for Laboratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
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20
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van der Wal SEI, van den Heuvel SAS, Radema SA, van Berkum BFM, Vaneker M, Steegers MAH, Scheffer GJ, Vissers KCP. The in vitro mechanisms and in vivo efficacy of intravenous lidocaine on the neuroinflammatory response in acute and chronic pain. Eur J Pain 2015; 20:655-74. [PMID: 26684648 DOI: 10.1002/ejp.794] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2015] [Indexed: 12/27/2022]
Abstract
INTRODUCTION The neuroinflammatory response plays a key role in several pain syndromes. Intravenous (iv) lidocaine is beneficial in acute and chronic pain. This review delineates the current literature concerning in vitro mechanisms and in vivo efficacy of iv lidocaine on the neuroinflammatory response in acute and chronic pain. DATABASES AND DATA TREATMENT We searched PUBMED and the Cochrane Library for in vitro and in vivo studies from July 1975 to August 2014. In vitro articles providing an explanation for the mechanisms of action of lidocaine on the neuroinflammatory response in pain were included. Animal or clinical studies were included concerning iv lidocaine for acute or chronic pain or during inflammation. RESULTS Eighty-eight articles regarding iv lidocaine were included: 36 in vitro studies evaluating the effect on ion channels and receptors; 31 animal studies concerning acute and chronic pain and inflammatory models; 21 clinical studies concerning acute and chronic pain. Low-dose lidocaine inhibits in vitro voltage-gated sodium channels, the glycinergic system, some potassium channels and Gαq-coupled protein receptors. Higher lidocaine concentrations block potassium and calcium channels, and NMDA receptors. Animal studies demonstrate lidocaine to have analgesic effects in acute and neuropathic pain syndromes and anti-inflammatory effects early in the inflammatory response. Clinical studies demonstrate lidocaine to have advantage in abdominal surgery and in some neuropathic pain syndromes. CONCLUSIONS Intravenous lidocaine has analgesic, anti-inflammatory and antihyperalgesic properties mediated by an inhibitory effect on ion channels and receptors. It attenuates the neuroinflammatory response in perioperative pain and chronic neuropathic pain.
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Affiliation(s)
- S E I van der Wal
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - S A S van den Heuvel
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - S A Radema
- Department of Medical Oncology, RUMC, Nijmegen, The Netherlands
| | - B F M van Berkum
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - M Vaneker
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - M A H Steegers
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - G J Scheffer
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
| | - K C P Vissers
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center (RUMC), Nijmegen, The Netherlands
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Li M, Wan L, Mei W, Tian Y. Update on the clinical utility and practical use of ropivacaine in Chinese patients. DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:1269-76. [PMID: 25246768 PMCID: PMC4166907 DOI: 10.2147/dddt.s57258] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We reviewed the Chinese and English literature for efficacy and tolerability data as well as pharmacological properties of ropivacaine in Chinese patients. Ropivacaine is a long-acting amide local anesthetic agent that elicits nerve block via reversible inhibition of sodium ion influx in nerve fibers. The available evidence in the literature on anesthesia practice indicates that ropivacaine produces equally surgical sensory block and postoperative and obstetrics analgesia with good maternal and fetal outcome to those of bupivacaine or levobupivacaine. It appears to be associated with comparable onset, quality, and duration of sensory block, but with a lower incidence or grade of motor block, compared to bupivacaine. The satisfaction of both patients and surgeons is high when ropivacaine is used. Thus, ropivacaine appears to be an important option for regional anesthesia and for the management of postoperative and labor pain, with its enhanced sensorimotor differentiation blockage at lower concentrations and enhanced safety at higher concentrations.
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Affiliation(s)
- Man Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Li Wan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wei Mei
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yuke Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Abstract
The pedigree of voltage-gated sodium channels spans the millennia from eukaryotic members that initiate the action potential firing in excitable tissues to primordial ancestors that act as enviro-protective complexes in bacterial extremophiles. Eukaryotic sodium channels (eNavs) are central to electrical signaling throughout the cardiovascular and nervous systems in animals and are established clinical targets for the therapeutic management of epilepsy, cardiac arrhythmia, and painful syndromes as they are inhibited by local anesthetic compounds. Alternatively, bacterial voltage-gated sodium channels (bNavs) likely regulate the survival response against extreme pH conditions, electrophiles, and hypo-osmotic shock and may represent a founder of the voltage-gated cation channel family. Despite apparent differences between eNav and bNav channel physiology, gating, and gene structure, the discovery that bNavs are amenable to crystallographic study opens the door for the possibility of structure-guided rational design of the next generation of therapeutics that target eNavs. Here we summarize the gating behavior of these disparate channel members and discuss mechanisms of local anesthetic inhibition in light of the growing number of bNav structures.
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Affiliation(s)
- Ben Corry
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
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Hayashi M, Novak I. Molecular basis of potassium channels in pancreatic duct epithelial cells. Channels (Austin) 2013; 7:432-41. [PMID: 23962792 PMCID: PMC4042478 DOI: 10.4161/chan.26100] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Potassium channels regulate excitability, epithelial ion transport, proliferation, and apoptosis. In pancreatic ducts, K+ channels hyperpolarize the membrane potential and provide the driving force for anion secretion. This review focuses on the molecular candidates of functional K+ channels in pancreatic duct cells, including KCNN4 (KCa3.1), KCNMA1 (KCa1.1), KCNQ1 (Kv7.1), KCNH2 (Kv11.1), KCNH5 (Kv10.2), KCNT1 (KCa4.1), KCNT2 (KCa4.2), and KCNK5 (K2P5.1). We will give an overview of K+ channels with respect to their electrophysiological and pharmacological characteristics and regulation, which we know from other cell types, preferably in epithelia, and, where known, their identification and functions in pancreatic ducts and in adenocarcinoma cells. We conclude by pointing out some outstanding questions and future directions in pancreatic K+ channel research with respect to the physiology of secretion and pancreatic pathologies, including pancreatitis, cystic fibrosis, and cancer, in which the dysregulation or altered expression of K+ channels may be of importance.
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Affiliation(s)
- Mikio Hayashi
- Department of Biology; University of Copenhagen; Copenhagen, Denmark
| | - Ivana Novak
- Department of Biology; University of Copenhagen; Copenhagen, Denmark
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The inhibitory effects of bupivacaine, levobupivacaine, and ropivacaine on K2P (two-pore domain potassium) channel TREK-1. J Anesth 2013; 28:81-6. [DOI: 10.1007/s00540-013-1661-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 06/13/2013] [Indexed: 12/18/2022]
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Giovannitti JA, Rosenberg MB, Phero JC. Pharmacology of local anesthetics used in oral surgery. Oral Maxillofac Surg Clin North Am 2013; 25:453-65, vi. [PMID: 23660127 DOI: 10.1016/j.coms.2013.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This article provides a comprehensive review of the pharmacology of local anesthetics as a class, and provides details of the individual drugs available in dental cartridges. Maximum recommended doses of local anesthetics and vasoconstrictors are presented for healthy adult and pediatric patients, and for patients with cardiovascular system impairments. Various complications and reasons for failure of local anesthesia effectiveness are discussed, and current and future trends in local anesthesia are presented to provide an overview of current research in local anesthesia.
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Affiliation(s)
- Joseph A Giovannitti
- Department of Dental Anesthesiology, Center for Patients with Special Needs, University of Pittsburgh School of Dental Medicine, 3501 Terrace Street, G-89 Salk Hall, Pittsburgh, PA 15261, USA.
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Synthesis, local anaesthetic and antiarrhythmic activities of N-alkyl derivatives of proline anilides. Eur J Med Chem 2013; 63:144-50. [DOI: 10.1016/j.ejmech.2013.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 01/25/2013] [Accepted: 02/04/2013] [Indexed: 11/18/2022]
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Abstract
Recent structural breakthroughs with the voltage-gated sodium channel from Arcobacter butzleri suggest that such bacterial channels may provide a structural platform to advance the understanding of eukaryotic sodium channel gating and pharmacology. We therefore set out to determine whether compounds known to interact with eukaryotic NaVs could also inhibit the bacterial channel from Bacillus halodurans and NaChBac and whether they did so through similar mechanisms as in their eukaryotic homologues. The data show that the archetypal local anesthetic (LA) lidocaine inhibits resting NaChBac channels with a dissociation constant (Kd) of 260 µM, and channels displayed a left-shifted steady-state inactivation gating relationship in the presence of the drug. Extracellular application of QX-314 to expressed NaChBac channels had no effect on sodium current, whereas internal exposure via injection of a bolus of the quaternary derivative rapidly reduced sodium conductance, consistent with a hydrophilic cytoplasmic access pathway to an internal binding site. However, the neutral derivative benzocaine applied externally inhibited NaChBac channels, suggesting that hydrophobic pathways can also provide drug access to inhibit channels. Alternatively, ranolazine, a putative preopen state blocker of eukaryotic NaVs, displayed a Kd of 60 µM and left-shifted the NaChBac activation-voltage relationship. In each case, block enhanced entry into the inactivated state of the channel, an effect that is well described by a simple kinetic scheme. The data suggest that although significant differences exist, LA block of eukaryotic NaVs also occurs in bacterial sodium channels and that NaChBac shares pharmacological homology to the resting state of vertebrate NaV homologues.
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Affiliation(s)
- Sora Lee
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Patel SK, Jackson L, Warren AY, Arya P, Shaw RW, Khan RN. A role for two-pore potassium (K2P) channels in endometrial epithelial function. J Cell Mol Med 2013; 17:134-46. [PMID: 23305490 PMCID: PMC3823143 DOI: 10.1111/j.1582-4934.2012.01656.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 10/15/2012] [Indexed: 11/20/2022] Open
Abstract
The human endometrial epithelium is pivotal to menstrual cycle progression, implantation and early pregnancy. Endometrial function is directly regulated by local factors that include pH, oxygen tension and ion concentrations to generate an environment conducive to fertilization. A superfamily of potassium channels characterized by two-pore domains (K2P) and encoded by KCNK genes is implicated in the control of the cell resting membrane potential through the generation of leak currents and modulation by various physicochemical stimuli. The aims of the study were to determine the expression and function of K2P channel subtypes in proliferative and secretory phase endometrium obtained from normo-ovulatory women and in an endometrial cancer cell line. Using immunochemical methods, real-time qRT-PCR proliferation assays and electrophysiology. Our results demonstrate mRNA for several K2P channel subtypes in human endometrium with molecular expression of TREK-1 shown to be higher in proliferative than secretory phase endometrium (P < 0.001). The K2P channel blockers methanandamide, lidocaine, zinc and curcumin had antiproliferative effects (P < 0.01) in an endometrial epithelial cancer cell line indicating a role for TASK and TREK-1 channels in proliferation. Tetraethylammonium- and 4-aminopyridine-insensitive outwards currents were inhibited at all voltages by reducing extracellular pH from 7.4 to 6.6. Higher expression of TREK-1 expression in proliferative phase endometrium may, in part, underlie linked to increased cell division. The effects of pH and a lack of effect of non-specific channel blockers of voltage-gated potassium channels imply a role for K2P channels in the regulation of human endometrial function.
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Affiliation(s)
- Suraj K Patel
- Academic Division of Obstetrics & Gynaecology, University of Nottingham, Derby, UK
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Kim S, Lee Y, Tak HM, Park HJ, Sohn YS, Hwang S, Han J, Kang D, Lee KW. Identification of blocker binding site in mouse TRESK by molecular modeling and mutational studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012. [PMID: 23200789 DOI: 10.1016/j.bbamem.2012.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
TWIK (tandem-pore domain weak inward rectifying K(+))-related spinal cord K(+) channel, TRESK, a member of the tandem-pore domain K(+) channel family, is the most recently cloned K(2P) channel. TRESK is highly expressed in dorsal root ganglion neuron, a pain sensing neuron, which is a target for analgesics. In this study, a reliable 3D structure for transmembrane (TM) region of mouse TRESK (mTRESK) was constructed, and then the reasonable blocker binding mode of the protein was investigated. The 3D structure of the mTRESK built by homology modeling method was validated with recommend value of stereochemical quality. Based on the validated structure, K(+) channel blocker-bound conformation was obtained by molecular docking and 5ns MD simulation with DPPC lipid bilayer. Our docking study provides the plausible binding mode of known blockers with key interacting residues, especially, F156 and F364. Finally, these modeling results were verified by experimental study with mutation from phenylalanine to alanine (F156A, F364A and F156A/F364A) at the TM2 and TM4. This is the first modeling study for TRESK that can provide structural information of the protein including ligand binding information. These results can be useful in structure based drug design for finding new blockers of the TRESK as potential therapeutic target of pain treatment.
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Affiliation(s)
- Songmi Kim
- Gyeongsang National University, Gazha-dong, Jinju, Republic of Korea
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Andronic J, Bobak N, Bittner S, Ehling P, Kleinschnitz C, Herrmann AM, Zimmermann H, Sauer M, Wiendl H, Budde T, Meuth SG, Sukhorukov VL. Identification of two-pore domain potassium channels as potent modulators of osmotic volume regulation in human T lymphocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:699-707. [PMID: 23041580 DOI: 10.1016/j.bbamem.2012.09.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 09/21/2012] [Accepted: 09/27/2012] [Indexed: 11/17/2022]
Abstract
Many functions of T lymphocytes are closely related to cell volume homeostasis and regulation, which utilize a complex network of membrane channels for anions and cations. Among the various potassium channels, the voltage-gated K(V)1.3 is well known to contribute greatly to the osmoregulation and particularly to the potassium release during the regulatory volume decrease (RVD) of T cells faced with hypotonic environment. Here we address a putative role of the newly identified two-pore domain (K(2P)) channels in the RVD of human CD4(+) T lymphocytes, using a series of potent well known channel blockers. In the present study, the pharmacological profiles of RVD inhibition revealed K(2P)5.1 and K(2P)18.1 as the most important K(2P) channels involved in the RVD of both naïve and stimulated T cells. The impact of chemical inhibition of K(2P)5.1 and K(2P)18.1 on the RVD was comparable to that of K(V)1.3. K(2P)9.1 also notably contributed to the RVD of T cells but the extent of this contribution and its dependence on the activation status could not be unambiguously resolved. In summary, our data provide first evidence that the RVD-related potassium efflux from human T lymphocytes relies on K(2P) channels.
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Affiliation(s)
- Joseph Andronic
- University of Wuerzburg, Lehrstuhl für Biotechnologie und Biophysik, Biozentrum, Am Hubland, 97074 Wuerzburg, Germany
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Lee S, Goodchild SJ, Ahern CA. Molecular and functional determinants of local anesthetic inhibition of NaChBac. Channels (Austin) 2012; 6:403-6. [PMID: 22992485 DOI: 10.4161/chan.21807] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In our recent publication, we describe the local anesthetic (LA) inhibition of the prokaryotic voltage gated sodium channel NaChBac. Despite the numerous functional and putative structural differences with the mammalian sodium channels, the data show that LA compounds effectively and reversibly inhibit NaChBac channels in a concentration range similar to resting blockade on eukaryotic Navs. In addition to current reduction, LA application accelerated channel inactivation kinetics of NaChBac which could be accounted for in a simple state-model whereby local anesthetics increase the probability of entering the inactivated state. We have further explored what state (or states) local anesthetic blockade of NaChBac could pertain to eukaryotic sodium channels, and what molecular similarities exist between these disparate channel families. Here we show that the rate of recovery from inactivation remains unaffected in the presence of local anesthetics. Further, we show that two sites that support use-dependent inhibition in eukaryotic channels, do not affect block to the same extent when mutated in NaChBac channels. The data indicate that the molecular determinants and the inherent mechanisms for LA block are likely to be divergent between bacterial and eukaryotic Navs, but future experiments will help define possible similarities.
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Affiliation(s)
- Sora Lee
- Department of Anesthesiology, University of British Columbia, Vancouver, BC, CA
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Abstract
BACKGROUND Local anesthetics (LAs) are typically used for regional anesthesia but can be given systemically to mitigate postoperative pain, supplement general anesthesia, or prevent cardiac arrhythmias. However, systemic application or inadvertent intravenous injection can be associated with substantial toxicity, including seizure induction. The molecular basis for this toxic action remains unclear. METHODS We characterized inhibition by different LAs of homomeric and heteromeric K channels containing TASK-1 (K2P3.1, KCNK3) and TASK-3 (K2P9.1, KCNK9) subunits in a mammalian expression system. In addition, we used TASK-1/TASK-3 knockout mice to test the possibility that TASK channels contribute to LA-evoked seizures. RESULTS LAs inhibited homomeric and heteromeric TASK channels in a range relevant for seizure induction; channels containing TASK-1 subunits were most sensitive and IC₅₀ values indicated a rank order potency of bupivacaine > ropivacaine >> lidocaine. LAs induced tonic-clonic seizures in mice with the same rank order potency, but higher LA doses were required to evoke seizures in TASK knockout mice. For bupivacaine, which produced the longest seizure times, seizure duration was significantly shorter in TASK knockout mice; bupivacaine-induced seizures were associated with an increase in electroencephalogram power at frequencies less than 5 Hz in both wild-type and TASK knockout mice. CONCLUSIONS These data suggest that increased neuronal excitability associated with TASK channel inhibition by LAs contributes to seizure induction. Because all LAs were capable of evoking seizures in TASK channel deleted mice, albeit at higher doses, the results imply that other molecular targets must also be involved in this toxic action.
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Clark RB, Kondo C, Belke DD, Giles WR. Two-pore domain K⁺ channels regulate membrane potential of isolated human articular chondrocytes. J Physiol 2011; 589:5071-89. [PMID: 21911614 DOI: 10.1113/jphysiol.2011.210757] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Potassium channels that regulate resting membrane potential (RMP) of human articular chondrocytes (HACs) of the tibial joint maintained in short-term (0-3 days) non-confluent cell culture were studied using patch-clamp techniques. Quantitative PCR showed that transcripts of genes for two-pore domain K(+) channels (KCNK1, KCNK5 and KCNK6), and 'BK' Ca(2+)-activated K(+) channels (KCNMA1) were abundantly expressed. Immunocytological methods detected α-subunits for BK and K(2p)5.1 (TASK-2) K(+) channels. Electrophysiological recordings identified three distinct K(+) currents in isolated HACs: (i) a voltage- and time-dependent 'delayed rectifier', blocked by 100 nM α-dendrotoxin, (ii) a large 'noisy' voltage-dependent current that was blocked by low concentrations of tetraethylammonium (TEA; 50% blocking dose = 0.15 mM) and iberiotoxin (52% block, 100 nM) and (iii) a voltage-independent 'background' K(+) current that was blocked by acidic pH (5.5-6), was increased by alkaline pH (8.5), and was not blocked by TEA, but was blocked by the local anaesthetic bupivacaine (0.25 mM). The RMP of isolated HACs was very slightly affected by 5 mM TEA, which was sufficient to block both voltage-dependent K(+) currents, suggesting that these currents probably contributed little to maintaining RMP under 'resting' conditions (i.e. low internal [Ca(2+)]). Increases in external K(+) concentration depolarized HACs by 30 mV in response to a 10-fold increase in [K(+)], indicating a significant but not exclusive role for K(+) current in determining RMP. Increases in external [K(+)] in voltage-clamped HACs revealed a voltage-independent K(+) current whose inward current magnitude increased with external [K(+)]. Block of this current by bupivacaine (0.25-1 mM) in 5 and 25 mM external [K(+)] resulted in a large (8-25 mV) depolarization of RMP. The biophysical and pharmacological properties of the background K(+) current, together with expression of mRNA and α-subunit protein for TASK-2, strongly suggest that these two-pore domain K(+) channels contribute significantly to stabilizing the RMP of HACs.
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Affiliation(s)
- Robert B Clark
- Roger Jackson Centre for Health and Wellness Research, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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Abstract
Ropivacaine is a long-acting amide local anaesthetic agent and first produced as a pure enantiomer. It produces effects similar to other local anaesthetics via reversible inhibition of sodium ion influx in nerve fibres. Ropivacaine is less lipophilic than bupivacaine and is less likely to penetrate large myelinated motor fibres, resulting in a relatively reduced motor blockade. Thus, ropivacaine has a greater degree of motor sensory differentiation, which could be useful when motor blockade is undesirable. The reduced lipophilicity is also associated with decreased potential for central nervous system toxicity and cardiotoxicity. The drug displays linear and dose proportional pharmacokinetics (up to 80 mg administered intravenously). It is metabolised extensively in the liver and excreted in urine. The present article details the clinical applications of ropivacaine and its current place as a local anaesthetic in the group.
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Affiliation(s)
- Gaurav Kuthiala
- Department of Anesthesia and Critical Care, SPS Apollo Hospitals, Ludhiana, India
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Wang HL, Zhang WH, Lei WF, Zhou CQ, Ye T. The Inhibitory Effect of Lidocaine on the Release of High Mobility Group Box 1 in Lipopolysaccharide-Stimulated Macrophages. Anesth Analg 2011; 112:839-44. [DOI: 10.1213/ane.0b013e31820dca9f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Nayak TK, Harinath S, Nama S, Somasundaram K, Sikdar SK. Inhibition of Human Two-Pore Domain K+ Channel TREK1 by Local Anesthetic Lidocaine: Negative Cooperativity and Half-of-Sites Saturation Kinetics. Mol Pharmacol 2009; 76:903-17. [DOI: 10.1124/mol.109.056838] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Yi JW, Lee BJ, Kim DO, Park SW, Choi YK, Chang HK, Kim CJ, Park JH. Effects of bupivacaine and ropivacaine on field potential in rat hippocampal slices. Br J Anaesth 2009; 102:673-9. [DOI: 10.1093/bja/aep023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim JE, Kwak SE, Kang TC. Upregulated TWIK-related acid-sensitive K+ channel-2 in neurons and perivascular astrocytes in the hippocampus of experimental temporal lobe epilepsy. Epilepsia 2009; 50:654-63. [PMID: 19220408 DOI: 10.1111/j.1528-1167.2008.01957.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To identify the modulation of Tandem of P-domains in a weak inwardly rectifying K(+) channel (TWIK)-related acid-sensitive K(+) (TASK)-2 channel expressions in epilepsy, we conducted a comparative analysis of TASK-2 channel immunoreactivity in the hippocampus of a pilocarpine-induced rat epilepsy model. METHODS We performed and immunohistochemical study for TASK-2 and double immunofluorescent staining for TASK-2 and glial fibrillary acidic protein (GFAP) in the rat hippocampus of pilocarpine-induced epilepsy models. RESULTS In control animals, TASK-2 immunoreactivity was strongly detected in CA1-3 pyramidal layers and dentate granule cell layer. After status epilepticus (SE), TASK-2 immunoreactivity was increased in dentate granule cell layer and CA3 pyramidal cell layer, whereas its immunoreactivity was reduced in CA1 pyramidal cell layer. In addition, TASK-2 immunoreactivity is gradually increased in perivascular regions following SE. Double immunofluorescent study revealed that the enhancement of TASK-2 immunoreactivity in perivascular regions is caused by increase in the number of TASK-2 immunoreactive endfeet of perivascular astrocytes. DISCUSSION Our findings suggest that elevated TASK-2 immunoreactivity in neurons may contribute to rapid adaptive responses (presumably for extracellular alkalinization), which result in hyperpolarization and regulate seizure activity. In contrast, upregulated TASK-2 immunoreactivity in perivascular regions may be involved in abnormalities of blood flow regulation or brain-blood barrier impairment. These changes may contribute to acquisition of the properties of the epileptic hippocampus.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology and Institute of Epilepsy Research, College of Medicine, Hallym University, Chunchon, South Korea
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Onizuka S, Kasaba T, Takasaki M. The Effect of Lidocaine on Cholinergic Neurotransmission in an Identified Reconstructed Synapse. Anesth Analg 2008; 107:1236-42. [DOI: 10.1213/ane.0b013e31818064f6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Beckett EAH, Han I, Baker SA, Han J, Britton FC, Koh SD. Functional and molecular identification of pH-sensitive K+ channels in murine urinary bladder smooth muscle. BJU Int 2008; 102:113-24. [PMID: 18394011 DOI: 10.1111/j.1464-410x.2008.07541.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To examine the role of pH-sensitive K(+) channels in setting the resting membrane potential in murine bladder smooth muscle, as bladder contractility is influenced by the resting membrane potential, which is mainly regulated by background K(+) conductances. MATERIALS AND METHODS Using conventional microelectrode recordings, isometric tension measurements, patch-clamp recordings, reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry, we assessed bladder smooth muscle cells and tissues. RESULTS Acidic pH (pH 6.5) depolarized the resting membrane potential of murine bladder smooth muscles and increased muscle tone and contractility. The pH-induced changes were not abolished by neuronal blockers or classical K(+)-channel antagonists. Lidocaine (1 mM) and bupivacaine (100 microm) mimicked the effects of acidifying the external solution, and in the presence of lidocaine no further increase in contractility was induced by reducing the pH to 6.5. Voltage-clamp experiments on freshly dispersed bladder myocytes showed that pH 6.5 decreased the outward current. Pre-treatment of bladder myocytes with the classical K(+) antagonists tetraethylammonium (10 mm), 4-aminopyridine (5 mM), glibenclamide (10 microm) or apamin (300 nM) did not inhibit the effects of low pH on outward current. However, treatment with lidocaine (1 mM) abolished the effects of acidic pH on outward current. RT-PCR showed the expression of the acid-sensitive K(+) channel (TASK)-1 and TASK-2 gene transcripts in murine bladder, and immunohistochemistry and Western blot analysis showed TASK-1 and TASK-2 channel expression and distribution in smooth muscle tissues and cells. CONCLUSION TASK channels are expressed in bladder smooth muscle and contribute to the basal K(+) conductances responsible for resting membrane potential.
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Affiliation(s)
- Elizabeth A H Beckett
- Department of Physiology and Cell Biology, University of Nevada Reno, School of Medicine, Reno, NV 89557, USA
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Lahat A, Ben-Horin S, Horin SB, Lang A, Fudim E, Picard O, Chowers Y. Lidocaine down-regulates nuclear factor-kappaB signalling and inhibits cytokine production and T cell proliferation. Clin Exp Immunol 2008; 152:320-7. [PMID: 18355353 DOI: 10.1111/j.1365-2249.2008.03636.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Lidocaine is a commonly used local anaesthetic agent which has also been found to possess anti-inflammatory activity in several disorders. However, the mechanism of this effect has been little explored. The aim of this study was to investigate the effect of lidocaine on stimulated human T cells. The effect of lidocaine on Jurkat T cells was examined by enzyme-linked immunosorbent assay (ELISA) to determine secretion of interleukin (IL)-2, and by the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] viability assay. Tumour necrosis factor (TNF)-alpha and IL-2 mRNA expression was determined by reverse transcription-polymerase chain reaction. In addition, the effect of lidocaine on the proliferation of freshly isolated peripheral blood (PB) CD3(+) T cells was examined by carboxyfluorescein succinimidyl ester dilution. Apoptosis induction and cytokine production and secretion were determined by annexin V/PI assay, intracellular immunostaining and ELISA respectively. The results showed that lidocaine exerts a dose-dependent inhibition of IL-2 and TNF-alpha secretion by Jurkat T cells at the protein and mRNA levels. Moreover, lidocaine reduced nuclear factor-kappaB (NF-kappaB) signalling in clinically relevant concentrations. Similarly, proliferation of anti-CD3 stimulated PB T cells was abrogated significantly by lidocaine, and the percentage of interferon-gamma- and TNF-alpha-producing T cells was diminished after culture with this agent. In both experimental systems, lidocaine's effect was not mediated by cytotoxic mechanism, as no significant apoptosis or necrosis was demonstrated following co-culture of T cells with this drug. In conclusion, lidocaine's anti-inflammatory effect may be mediated by a drug-induced abrogation of T cell proliferation and cytokine secretion independent of cell death. These effects are mediated at least partly by inhibition of NF-kappaB signalling.
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Affiliation(s)
- A Lahat
- Department of Gastroenterology, Chaim Sheba Medical Center affiliated with the Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Kang D, Kim GT, Kim EJ, La JH, Lee JS, Lee ES, Park JY, Hong SG, Han J. Lamotrigine inhibits TRESK regulated by G-protein coupled receptor agonists. Biochem Biophys Res Commun 2008; 367:609-15. [PMID: 18190784 DOI: 10.1016/j.bbrc.2008.01.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Accepted: 01/03/2008] [Indexed: 10/22/2022]
Abstract
Dorsal root ganglion (DRG) neurons express mRNAs for numerous two-pore domain K(+) (K(2P)) channels and G-protein coupled receptors (GPCR). Recent studies have shown that TRESK is a major background K(+) channel in DRG neurons. Here, we demonstrate the pharmacological properties of TRESK, including GPCR agonist-induced effects on DRG neurons. TRESK mRNA was highly expressed in DRG compared to brain and spinal cord. Similar to cloned TRESK, native TRESK was inhibited by acid and arachidonic acid (AA), but not zinc. Native TRESK was also activated by GPCR agonists such as acetylcholine, glutamate, and histamine. The glutamate-activated TRESK was blocked by lamotrigine in DRG neurons. In COS-7 cells transfected with mouse TRESK, 30 microM lamotrigine inhibited TRESK by approximately 50%. Since TRESK is target of modulation by acid, AA, GPCR agonists, and lamotrigine, it is likely to play an active role in the regulation of excitability in DRG neurons.
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Affiliation(s)
- Dawon Kang
- Medical Research Center for Neural Dysfunction and Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, 90 Chilam, Jinju 660-751, South Korea
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Lotshaw DP. Biophysical, pharmacological, and functional characteristics of cloned and native mammalian two-pore domain K+ channels. Cell Biochem Biophys 2007; 47:209-56. [PMID: 17652773 DOI: 10.1007/s12013-007-0007-8] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 12/12/2022]
Abstract
The mammalian family of two-pore domain K+ (K2P) channel proteins are encoded by 15 KCNK genes and subdivided into six subfamilies on the basis of sequence similarities: TWIK, TREK, TASK, TALK, THIK, and TRESK. K2P channels are expressed in cells throughout the body and have been implicated in diverse cellular functions including maintenance of the resting potential and regulation of excitability, sensory transduction, ion transport, and cell volume regulation, as well as metabolic regulation and apoptosis. In recent years K2P channel isoforms have been identified as important targets of several widely employed drugs, including: general anesthetics, local anesthetics, neuroprotectants, and anti-depressants. An important goal of future studies will be to identify the basis of drug actions and channel isoform selectivity. This goal will be facilitated by characterization of native K2P channel isoforms, their pharmacological properties and tissue-specific expression patterns. To this end the present review examines the biophysical, pharmacological, and functional characteristics of cloned mammalian K2P channels and compares this information with the limited data available for native K2P channels in order to determine criteria which may be useful in identifying ionic currents mediated by native channel isoforms and investigating their pharmacological and functional characteristics.
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Affiliation(s)
- David P Lotshaw
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
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44
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La JH, Kang D, Park JY, Hong SG, Han J. A novel acid-sensitive K+ channel in rat dorsal root ganglia neurons. Neurosci Lett 2006; 406:244-9. [PMID: 16904821 DOI: 10.1016/j.neulet.2006.07.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 07/07/2006] [Accepted: 07/19/2006] [Indexed: 02/02/2023]
Abstract
Recent studies have suggested that acid-sensitive background K+ channels such as TASK-1 and TASK-3, members of two-pore domain K+ (K2P) channel family, express and contribute to extracellular acidification-induced responses in dorsal root ganglia (DRG) neurons. However, it has remained to address whether other acid-sensitive background K+ channels are functionally expressed in DRG neurons. Here we characterized biophysical and pharmacological properties of a novel acid-sensitive background K+ channel in DRG neurons isolated from neonatal rats. We recorded an 80-pS K+ channel with a weak inward rectification current-voltage relationship in cell-attached patches in 150mM KCl bath solution. The 80-pS K+ channel was inhibited by extracellular low pH (pHo 6.3). Interestingly, the channel was similar to TASK-2 cloned from mouse and rat in biophysical and pharmacological properties. However, extracellular alkaline condition which activates TASK-2 channel, failed to activate the 80-pS K+ channel. Lidocaine and quinine more inhibited the channel activity of 80-pS K+ channel than that of TASK-2 channel. Our results suggest that the acid-sensitive 80-pS K+ channels may regulate resting membrane potential and may play a critical role in various processes such as cell metabolism, pH, and pain sensation in DRG neurons.
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Affiliation(s)
- Jun-Ho La
- Medical Research Center for Neural Dysfunction, Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, 90 Chilam-dong, Jinju, Gyeongnam, South Korea
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Simpson D, Curran MP, Oldfield V, Keating GM. Ropivacaine: a review of its use in regional anaesthesia and acute pain management. Drugs 2006; 65:2675-717. [PMID: 16392884 DOI: 10.2165/00003495-200565180-00013] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Ropivacaine (Naropin) is the pure S(-)-enantiomer of propivacaine, and is a long-acting amide local anaesthetic agent, eliciting nerve block via reversible inhibition of sodium ion influx in nerve fibres. Ropivacaine is a well tolerated regional anaesthetic effective for surgical anaesthesia as well as the relief of postoperative and labour pain. The efficacy of ropivacaine is similar to that of bupivacaine and levobupivacaine for peripheral nerve blocks and, although it may be slightly less potent than bupivacaine when administered epidurally or intrathecally, equi-effective doses have been established. Clinically adequate doses of ropivacaine appear to be associated with a lower incidence or grade of motor block than bupivacaine. Thus ropivacaine, with its efficacy, lower propensity for motor block and reduced potential for CNS toxicity and cardiotoxicity, appears to be an important option for regional anaesthesia and for the management of postoperative and labour pain.
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Affiliation(s)
- Dene Simpson
- Adis International Limited, Auckland, New Zealand.
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Urban BW, Bleckwenn M, Barann M. Interactions of anesthetics with their targets: non-specific, specific or both? Pharmacol Ther 2006; 111:729-70. [PMID: 16483665 DOI: 10.1016/j.pharmthera.2005.12.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 12/23/2005] [Indexed: 01/11/2023]
Abstract
What makes a general anesthetic a general anesthetic? We shall review first what general anesthesia is all about and which drugs are being used as anesthetics. There is neither a unique definition of general anesthesia nor any consensus on how to measure it. Diverse drugs and combinations of drugs generate general anesthetic states of sometimes very different clinical quality. Yet the principal drugs are still considered to belong to the same class of 'general anesthetics'. Effective concentrations of inhalation anesthetics are in the high micromolar range and above, and even for intravenous anesthetics they do not go below the micromolar range. At these concentrations, many molecular and higher level targets are affected by inhalation anesthetics, fewer probably by intravenous anesthetics. The only physicochemical characteristic shared by anesthetics is the correlation of their anesthetic potencies with hydrophobicity. These correlations depend on the group of general anesthetics considered. In this review, anesthetic potencies for many different targets are plotted against octanol/water partition coefficients as measure of hydrophobicity. Qualitatively, similar correlations result, suggesting several but weak interactions with proteins as being characteristic of anesthetic actions. The polar interactions involved are weak, being roughly equal in magnitude to hydrophobic interactions. Generally, intravenous anesthetics are noticeably more potent than inhalation anesthetics. They differ considerably more between each other in their interactions with various targets than inhalation anesthetics do, making it difficult to come to a decision which of these should be used in future studies as representative 'prototypical general anesthetics'.
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Affiliation(s)
- Bernd W Urban
- Klinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany.
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Brazier SP, Mason HS, Bateson AN, Kemp PJ. Cloning of the human TASK-2 (KCNK5) promoter and its regulation by chronic hypoxia. Biochem Biophys Res Commun 2005; 336:1251-8. [PMID: 16168386 DOI: 10.1016/j.bbrc.2005.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 09/02/2005] [Indexed: 10/25/2022]
Abstract
The tandem P domain potassium channel family includes five members of the acid-sensing subfamily, TASK. TASK channels are active at resting potential and are inhibited by extracellular protons, suggesting they function as acid sensors and control excitability/ion homeostasis. Indeed, TASK-2 (KCNK5) has been shown to control excitability, volume regulation, bicarbonate handling, and apoptosis in a variety of tissues. With such diverse functions being ascribed to TASK-2, it is important to understand long-term as well as short-term regulation of this important channel. Thus, we have cloned the TASK-2 promoter, demonstrated that its transcriptional activity is dependent upon pO(2), shown that deletion of overlapping consensus binding sites for NF-kappaB/Elk-1 ablates this O(2) sensitivity, and proved that Elk-1 binds preferentially to this site. Furthermore, the consequences of chronic hypoxia on natively expressed TASK-2 are decreased steady-state mRNA and cell depolarization showing that TASK-2 contributes to the excitability of this important lung cell type.
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Davis KA, Cowley EA. Two-pore-domain potassium channels support anion secretion from human airway Calu-3 epithelial cells. Pflugers Arch 2005; 451:631-41. [PMID: 16311719 DOI: 10.1007/s00424-005-1505-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 08/04/2005] [Indexed: 10/25/2022]
Abstract
Potassium channels are required for the absorption and secretion of fluids and electrolytes in epithelia. Calu-3 cells possess a secretory phenotype, and are a model human airway submucosal gland serous cell. Short-circuit current (I(sc)) recordings from Calu-3 cells indicated that basal anion secretion was reduced by apical application of the K+ channel inhibitors bupivicaine, lidocaine, clofilium, and quinidine. Application of riluzole resulted in a large increase in I(sc), inhibited by apical application of either bupivicane or the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel blocker DPC. These results suggested that one or more members of the two-pore-domain K+ (K(2P)) channel family could influence anion secretion. Using RT-PCR, we found that Calu-3 cells express mRNA transcripts for TASK-2 (KCNK5), TWIK-1 (KCNK1), TWIK-2 (KCNK6) and TREK-1 (KCNK2). TASK-2, TWIK-2 and TREK-1 protein were detected by Western blotting, while immunolocalization of polarized cells confirmed protein expression of TREK-1 and TWIK-2 at the plasma cell membrane. TASK-2 protein staining was localized to intracellular vesicles, located beneath the apical membrane. While the pro-secretory role of basolateral K+ channels is well established, we suggest that apically located K2P channels, not previously described in airway epithelial cells, also play an important role in controlling the rate of transepithelial anion secretion.
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Affiliation(s)
- Kellie A Davis
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, B3H 4H7, Canada
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Keshavaprasad B, Liu C, Au JD, Kindler CH, Cotten JF, Yost CS. Species-Specific Differences in Response to Anesthetics and Other Modulators by the K2P Channel TRESK. Anesth Analg 2005; 101:1042-1049. [PMID: 16192517 DOI: 10.1213/01.ane.0000168447.87557.5a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED TRESK (TWIK-related spinal cord K+ channel) is the most recently characterized member of the tandem-pore domain potassium channel (K2P) family. Human TRESK is potently activated by halothane, isoflurane, sevoflurane, and desflurane, making it the most sensitive volatile anesthetic-activated K2P channel yet described. Herein, we compare the anesthetic sensitivity and pharmacologic modulation of rodent versions of TRESK to their human orthologue. Currents passed by mouse and rat TRESK were enhanced by isoflurane at clinical concentrations but with significantly lower efficacy than human TRESK. Unlike human TRESK, the rodent TRESKs are strongly inhibited by acidic extracellular pH in the physiologic range. Zinc inhibited currents passed by both rodent TRESK in the low micromolar range but was without effect on human TRESK. Enantiomers of isoflurane that have stereoselective anesthetic potency in vivo produced stereospecific enhancement of the rodent TRESKs in vitro. Amide local anesthetics inhibited the rodent TRESKs at almost 10-fold smaller concentrations than that which inhibit human TRESK. These results identified interspecies differences and similarities in the pharmacology of TRESK. Further characterization of TRESK expression patterns is needed to understand their role in anesthetic mechanisms. IMPLICATIONS Mouse and rat TRESK (TWIK-related spinal cord K+ channel) have different pharmacologic responses compared with human TRESK. In particular, we found stereospecific differences in response to isoflurane by the rodent TRESKs but not by human TRESK. TRESK may be a target site for the mechanism of action of volatile anesthetics.
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Affiliation(s)
- Bharat Keshavaprasad
- *Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California; Department of Anesthesia, University Hospital Basel, Basel, Switzerland
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