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Guo J, Zhang C, Zhao H, Yan Y, Liu Z. The key mediator of diabetic kidney disease: Potassium channel dysfunction. Genes Dis 2024; 11:101119. [PMID: 38523672 PMCID: PMC10958065 DOI: 10.1016/j.gendis.2023.101119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 06/11/2022] [Accepted: 06/04/2023] [Indexed: 03/26/2024] Open
Abstract
Diabetic kidney disease is a leading cause of end-stage renal disease, making it a global public health concern. The molecular mechanisms underlying diabetic kidney disease have not been elucidated due to its complex pathogenesis. Thus, exploring these mechanisms from new perspectives is the current focus of research concerning diabetic kidney disease. Ion channels are important proteins that maintain the physiological functions of cells and organs. Among ion channels, potassium channels stand out, because they are the most common and important channels on eukaryotic cell surfaces and function as the basis for cell excitability. Certain potassium channel abnormalities have been found to be closely related to diabetic kidney disease progression and genetic susceptibility, such as KATP, KCa, Kir, and KV. In this review, we summarized the roles of different types of potassium channels in the occurrence and development of diabetic kidney disease to discuss whether the development of DKD is due to potassium channel dysfunction and present new ideas for the treatment of DKD.
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Affiliation(s)
- Jia Guo
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Chaojie Zhang
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Hui Zhao
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Yufan Yan
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Zhangsuo Liu
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
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Alam KA, Svalastoga P, Martinez A, Glennon JC, Haavik J. Potassium channels in behavioral brain disorders. Molecular mechanisms and therapeutic potential: A narrative review. Neurosci Biobehav Rev 2023; 152:105301. [PMID: 37414376 DOI: 10.1016/j.neubiorev.2023.105301] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
Potassium channels (K+-channels) selectively control the passive flow of potassium ions across biological membranes and thereby also regulate membrane excitability. Genetic variants affecting many of the human K+-channels are well known causes of Mendelian disorders within cardiology, neurology, and endocrinology. K+-channels are also primary targets of many natural toxins from poisonous organisms and drugs used within cardiology and metabolism. As genetic tools are improving and larger clinical samples are being investigated, the spectrum of clinical phenotypes implicated in K+-channels dysfunction is rapidly expanding, notably within immunology, neurosciences, and metabolism. K+-channels that previously were considered to be expressed in only a few organs and to have discrete physiological functions, have recently been found in multiple tissues and with new, unexpected functions. The pleiotropic functions and patterns of expression of K+-channels may provide additional therapeutic opportunities, along with new emerging challenges from off-target effects. Here we review the functions and therapeutic potential of K+-channels, with an emphasis on the nervous system, roles in neuropsychiatric disorders and their involvement in other organ systems and diseases.
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Affiliation(s)
| | - Pernille Svalastoga
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway; Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | | | - Jeffrey Colm Glennon
- Conway Institute for Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland.
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Norway.
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3
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Gómez-Herrera MA, Patlán E, Estrada-Garrido A, Hernández-Cruz A, Luis E. Fluorescent membrane potential assay for drug screening on Kv10.1 channel: identification of BL-1249 as a channel activator. Front Pharmacol 2023; 14:1238503. [PMID: 37554982 PMCID: PMC10404814 DOI: 10.3389/fphar.2023.1238503] [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: 06/11/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023] Open
Abstract
Resting membrane potential is a bioelectric property of all cells. Multiple players govern this property, the ion channels being the most important. Ion channel dysfunction can affect cells' resting membrane potential and could be associated with numerous diseases. Therefore, the drug discovery focus on ion channels has increased yearly. In addition to patch-clamp, cell-based fluorescent assays have shown a rapid and reliable method for searching new ion channel modulators. Here, we used a cell-based membrane potential assay to search for new blockers of the Kv10.1, a potassium channel strongly associated with cancer progression and a promising target in anticancer therapy. We found that fluoxetine and miconazole can inhibit the Kv10.1 channel in the micromolar range. In contrast, BL-1249 potentiates Kv10.1 currents in a dose-dependent manner, becoming the first molecule described as an activator of the channel. These results demonstrate that cell-based membrane potential assay can accelerate the discovery of new Kv10.1 modulators.
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Affiliation(s)
- Mirsha Aseret Gómez-Herrera
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Enikar Patlán
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Armando Estrada-Garrido
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Universidad Tecnológica de México (UNITEC)—Campus Ecatepec, Estado de México, Mexico
| | - Arturo Hernández-Cruz
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Enoch Luis
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Cátedras CONAHCYT—Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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4
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Szabo I, Szewczyk A. Mitochondrial Ion Channels. Annu Rev Biophys 2023; 52:229-254. [PMID: 37159294 DOI: 10.1146/annurev-biophys-092622-094853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Mitochondria are involved in multiple cellular tasks, such as ATP synthesis, metabolism, metabolite and ion transport, regulation of apoptosis, inflammation, signaling, and inheritance of mitochondrial DNA. The majority of the correct functioning of mitochondria is based on the large electrochemical proton gradient, whose component, the inner mitochondrial membrane potential, is strictly controlled by ion transport through mitochondrial membranes. Consequently, mitochondrial function is critically dependent on ion homeostasis, the disturbance of which leads to abnormal cell functions. Therefore, the discovery of mitochondrial ion channels influencing ion permeability through the membrane has defined a new dimension of the function of ion channels in different cell types, mainly linked to the important tasks that mitochondrial ion channels perform in cell life and death. This review summarizes studies on animal mitochondrial ion channels with special focus on their biophysical properties, molecular identity, and regulation. Additionally, the potential of mitochondrial ion channels as therapeutic targets for several diseases is briefly discussed.
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Affiliation(s)
- Ildiko Szabo
- Department of Biology, University of Padova, Italy;
| | - Adam Szewczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland;
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Quiñonez M, DiFranco M, Wu F, Cannon SC. Retigabine suppresses loss of force in mouse models of hypokalaemic periodic paralysis. Brain 2023; 146:1554-1560. [PMID: 36718088 PMCID: PMC10115351 DOI: 10.1093/brain/awac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recurrent episodes of weakness in periodic paralysis are caused by intermittent loss of muscle fibre excitability, as a consequence of sustained depolarization of the resting potential. Repolarization is favoured by increasing the fibre permeability to potassium. Based on this principle, we tested the efficacy of retigabine, a potassium channel opener, to suppress the loss of force induced by a low-K+ challenge in hypokalaemic periodic paralysis (HypoPP). Retigabine can prevent the episodic loss of force in HypoPP. Knock-in mutant mouse models of HypoPP (Cacna1s p.R528H and Scn4a p.R669H) were used to determine whether pre-treatment with retigabine prevented the loss of force, or post-treatment hastened recovery of force for a low-K+ challenge in an ex vivo contraction assay. Retigabine completely prevents the loss of force induced by a 2 mM K+ challenge (protection) in our mouse models of HypoPP, with 50% inhibitory concentrations of 0.8 ± 0.13 μM and 2.2 ± 0.42 μM for NaV1.4-R669H and CaV1.1-R528H, respectively. In comparison, the effective concentration for the KATP channel opener pinacidil was 10-fold higher. Application of retigabine also reversed the loss of force (rescue) for HypoPP muscle maintained in 2 mM K+. Our findings show that retigabine, a selective agonist of the KV7 family of potassium channels, is effective for the prevention of low-K+ induced attacks of weakness and to enhance recovery from an ongoing loss of force in mouse models of type 1 (Cacna1s) and type 2 (Scn4a) HypoPP. Substantial protection from the loss of force occurred in the low micromolar range, well within the therapeutic window for retigabine.
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Affiliation(s)
- Marbella Quiñonez
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Wigenstam E, Artursson E, Bucht A, Thors L. Supplemental treatment to atropine improves the efficacy to reverse nerve agent induced bronchoconstriction. Chem Biol Interact 2022; 364:110061. [PMID: 35872047 DOI: 10.1016/j.cbi.2022.110061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/23/2022] [Accepted: 07/13/2022] [Indexed: 12/29/2022]
Abstract
Exposure to highly toxic organophosphorus compounds causes inhibition of the enzyme acetylcholinesterase resulting in a cholinergic toxidrome and innervation of receptors in the neuromuscular junction may cause life-threatening respiratory effects. The involvement of several receptor systems was therefore examined for their impact on bronchoconstriction using an ex vivo rat precision-cut lung slice (PCLS) model. The ability to recover airways with therapeutics following nerve agent exposure was determined by quantitative analyses of muscle contraction. PCLS exposed to nicotine resulted in a dose-dependent bronchoconstriction. The neuromuscular nicotinic antagonist tubocurarine counteracted the nicotine-induced bronchoconstriction but not the ganglion blocker mecamylamine or the common muscarinic antagonist atropine. Correspondingly, atropine demonstrated a significant airway relaxation following ACh-exposure while tubocurarine did not. Atropine, the M3 muscarinic receptor antagonist 4-DAMP, tubocurarine, the β2-adrenergic receptor agonist formoterol, the Na+-channel blocker tetrodotoxin and the KATP-channel opener cromakalim all significantly decreased airway contractions induced by electric field stimulation. Following VX-exposure, treatment with atropine and the Ca2+-channel blocker magnesium sulfate resulted in significant airway relaxation. Formoterol, cromakalim and magnesium sulfate administered in combinations with atropine demonstrated an additive effect. In conclusion, the present study demonstrated improved airway function following nerve agent exposure by adjunct treatment to the standard therapy of atropine.
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Affiliation(s)
| | - Elisabet Artursson
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden
| | - Anders Bucht
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden
| | - Lina Thors
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden.
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Sherikar A, Dhavale R, Bhatia M. Vasorelaxant Effect of Novel Nitric Oxide-Hydrogen Sulfide Donor Chalcone in Isolated Rat Aorta: Involvement of cGMP Mediated sGC and Potassium Channel Activation. Curr Mol Pharmacol 2021; 13:126-136. [PMID: 31654520 DOI: 10.2174/1874467212666191025092346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/03/2019] [Accepted: 10/15/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVE Recently, nitric oxide (NO) and hydrogen sulfide (H2S) donating moieties were extensively studied for their role in the vasculature as they are responsible for many cellular and pathophysiological functioning. The objective of the present study is to evaluate novel NO and H2S donating chalcone moieties on isolated rat aorta for vasorelaxation, and to investigate the probable mechanism of action. METHODS To extend our knowledge of vasorelaxation by NO and H2S donor drugs, here we investigated the vasorelaxing activity of novel NO and H2S donating chalcone moieties on isolated rat aorta. The mechanism of vasorelaxation by these molecules was investigated by performing in vitro cGMP mediated sGC activation assay and using Tetraethylammonium chloride (TEA) as a potassium channel blocker and Methylene blue as NO blocker. RESULTS Both NO and H2S donating chalcone moieties were found to be potent vasorelaxant. The compound G4 and G5 produce the highest vasorelaxation with 3.716 and 3.789 M of pEC50, respectively. After the addition of TEA, G4 and G5 showed 2.772 and 2.796 M of pEC50, respectively. The compounds Ca1, Ca2, and D7 produced significant activation and release of cGMP mediated sGC which was 1.677, 1.769 and 1.768 M of pEC50, respectively. CONCLUSION The vasorelaxation by NO-donating chalcones was blocked by Methylene blue but it did not show any effect on H2S donating chalcones. The vasorelaxing potency of NO-donating molecules was observed to be less affected by the addition of TEA but H2S donors showed a decrease in both efficacy and potency. The cGMP release was more in the case of NO-donating molecules. The tested compounds were found potent for relaxing vasculature of rat aorta.
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Affiliation(s)
- Amol Sherikar
- Department of Pharmaceutical Chemistry, Tatyasaheb Kore College of Pharmacy, Warananagar, Tal-Panhala, Dist- Kolhapur-416 113 (MS), India
| | - Rakesh Dhavale
- Department of Pharmaceutical Chemistry, Bharati Vidyapeeth College of Pharmacy, Kolhapur, Near Chitranagri, Kolhapur-416 013 (MS), India
| | - Manish Bhatia
- Department of Pharmaceutical Chemistry, Bharati Vidyapeeth College of Pharmacy, Kolhapur, Near Chitranagri, Kolhapur-416 013 (MS), India
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8
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Nieves-Cintrón M, Flores-Tamez VA, Le T, Baudel MMA, Navedo MF. Cellular and molecular effects of hyperglycemia on ion channels in vascular smooth muscle. Cell Mol Life Sci 2021; 78:31-61. [PMID: 32594191 PMCID: PMC7765743 DOI: 10.1007/s00018-020-03582-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 06/10/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022]
Abstract
Diabetes affects millions of people worldwide. This devastating disease dramatically increases the risk of developing cardiovascular disorders. A hallmark metabolic abnormality in diabetes is hyperglycemia, which contributes to the pathogenesis of cardiovascular complications. These cardiovascular complications are, at least in part, related to hyperglycemia-induced molecular and cellular changes in the cells making up blood vessels. Whereas the mechanisms mediating endothelial dysfunction during hyperglycemia have been extensively examined, much less is known about how hyperglycemia impacts vascular smooth muscle function. Vascular smooth muscle function is exquisitely regulated by many ion channels, including several members of the potassium (K+) channel superfamily and voltage-gated L-type Ca2+ channels. Modulation of vascular smooth muscle ion channels function by hyperglycemia is emerging as a key contributor to vascular dysfunction in diabetes. In this review, we summarize the current understanding of how diabetic hyperglycemia modulates the activity of these ion channels in vascular smooth muscle. We examine underlying mechanisms, general properties, and physiological relevance in the context of myogenic tone and vascular reactivity.
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Affiliation(s)
- Madeline Nieves-Cintrón
- Department of Pharmacology, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Víctor A Flores-Tamez
- Department of Pharmacology, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Thanhmai Le
- Department of Pharmacology, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
| | | | - Manuel F Navedo
- Department of Pharmacology, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA.
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El-Ouady F, Eddouks M. Asteriscus graveolens exhibits Antihypertensive Activity through Activation of Vascular KATP Channels Activation in Rats. Endocr Metab Immune Disord Drug Targets 2020; 20:736-744. [DOI: 10.2174/1871530319666191016100851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 11/22/2022]
Abstract
Objective:
The objective of the study was to evaluate the antihypertensive activity of Asteriscus
graveolens.
Methods:
L-NAME hypertensive and normotensive rats have received orally the aqueous extract of
Asteriscus graveolens aerial parts (AGAPE) (100 mg/kg) during six hours for the acute experiment and
during seven days for the sub-chronic treatment. Thereafter, blood pressure parameters were evaluated.
Concerning the in vitro investigation, the vasorelaxant effect of AGAPE was tested in isolated thoracic
aortic rings.
Results:
AGAPE extract significantly decreased the blood pressure parameters in hypertensive rats.
Moreover, the results revealed that AGAPE exhibited antihypertensive effect through its vasorelaxant
properties. More interestingly, this vasorelaxant activity seems to be probably mediated through activation
of K+ ATP-sensitive (KATP) channels.
Conclusion:
The study demonstrates the antihypertensive activity of aqueous Asteriscus graveolens
extract in hypertensive rats through activation of vascular KATP channels. This finding supports the use
of this plant for the management of hypertension in Morocco.
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Affiliation(s)
- Fadwa El-Ouady
- Team of Ethnopharmacology and Pharmacognosy, Faculty of Sciences and Techniques Errachidia, Moulay Ismail University of Meknes, BP 509, Boutalamine, 52000 Errachidia, Morocco
| | - Mohamed Eddouks
- Team of Ethnopharmacology and Pharmacognosy, Faculty of Sciences and Techniques Errachidia, Moulay Ismail University of Meknes, BP 509, Boutalamine, 52000 Errachidia, Morocco
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Lin Z, Huang X, Zhou W, Zhang W, Liu Y, Bian T, Niu L, Meng L, Guo Y. Ultrasound Stimulation Modulates Voltage-Gated Potassium Currents Associated With Action Potential Shape in Hippocampal CA1 Pyramidal Neurons. Front Pharmacol 2019; 10:544. [PMID: 31178727 PMCID: PMC6538798 DOI: 10.3389/fphar.2019.00544] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/30/2019] [Indexed: 11/28/2022] Open
Abstract
Potassium channels (K+) play an important role in the regulation of cellular signaling. Dysfunction of potassium channels is associated with several severe ion channels diseases, such as long QT syndrome, episodic ataxia and epilepsy. Ultrasound stimulation has proven to be an effective non-invasive tool for the modulation of ion channels and neural activity. In this study, we demonstrate that ultrasound stimulation enables to modulate the potassium currents and has an impact on the shape modulation of action potentials (AP) in the hippocampal pyramidal neurons using whole-cell patch-clamp recordings in vitro. The results show that outward potassium currents in neurons increase significantly, approximately 13%, in response to 30 s ultrasound stimulation. Simultaneously, the increasing outward potassium currents directly decrease the resting membrane potential (RMP) from −64.67 ± 1.10 mV to −67.51 ± 1.35 mV. Moreover, the threshold current and AP fall rate increase while the reduction of AP half-width and after-hyperpolarization peak time is detected. During ultrasound stimulation, reduction of the membrane input resistance of pyramidal neurons can be found and shorter membrane time constant is achieved. Additionally, we verify that the regulation of potassium currents and shape of action potential is mainly due to the mechanical effects induced by ultrasound. Therefore, ultrasound stimulation may offer an alternative tool to treat some ion channels diseases related to potassium channels.
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Affiliation(s)
- Zhengrong Lin
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Xiaowei Huang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wei Zhou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wenjun Zhang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Key Laboratory of E&M, Ministry of Education and Zhejiang Province, Zhejiang University of Technology, Hangzhou, China
| | - Yingzhe Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
| | - Tianyuan Bian
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
| | - Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 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, China
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11
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Dogan MF, Yildiz O, Arslan SO, Ulusoy KG. Potassium channels in vascular smooth muscle: a pathophysiological and pharmacological perspective. Fundam Clin Pharmacol 2019; 33:504-523. [PMID: 30851197 DOI: 10.1111/fcp.12461] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/28/2019] [Accepted: 03/07/2019] [Indexed: 12/23/2022]
Abstract
Potassium (K+ ) ion channel activity is an important determinant of vascular tone by regulating cell membrane potential (MP). Activation of K+ channels leads to membrane hyperpolarization and subsequently vasodilatation, while inhibition of the channels causes membrane depolarization and then vasoconstriction. So far five distinct types of K+ channels have been identified in vascular smooth muscle cells (VSMCs): Ca+2 -activated K+ channels (BKC a ), voltage-dependent K+ channels (KV ), ATP-sensitive K+ channels (KATP ), inward rectifier K+ channels (Kir ), and tandem two-pore K+ channels (K2 P). The activity and expression of vascular K+ channels are changed during major vascular diseases such as hypertension, pulmonary hypertension, hypercholesterolemia, atherosclerosis, and diabetes mellitus. The defective function of K+ channels is commonly associated with impaired vascular responses and is likely to become as a result of changes in K+ channels during vascular diseases. Increased K+ channel function and expression may also help to compensate for increased abnormal vascular tone. There are many pharmacological and genotypic studies which were carried out on the subtypes of K+ channels expressed in variable amounts in different vascular beds. Modulation of K+ channel activity by molecular approaches and selective drug development may be a novel treatment modality for vascular dysfunction in the future. This review presents the basic properties, physiological functions, pathophysiological, and pharmacological roles of the five major classes of K+ channels that have been determined in VSMCs.
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Affiliation(s)
- Muhammed Fatih Dogan
- Department of Pharmacology, Ankara Yildirim Beyazit University, Bilkent, Ankara, 06010, Turkey
| | - Oguzhan Yildiz
- Department of Pharmacology, Gulhane Faculty of Medicine, University of Health Sciences, Etlik, Ankara, 06170, Turkey
| | - Seyfullah Oktay Arslan
- Department of Pharmacology, Ankara Yildirim Beyazit University, Bilkent, Ankara, 06010, Turkey
| | - Kemal Gokhan Ulusoy
- Department of Pharmacology, Gulhane Faculty of Medicine, University of Health Sciences, Etlik, Ankara, 06170, Turkey
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12
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Xu Y, Halievski K, Katsuno M, Adachi H, Sobue G, Breedlove SM, Jordan CL. Pre-clinical symptoms of SBMA may not be androgen-dependent: implications from two SBMA mouse models. Hum Mol Genet 2019; 27:2425-2442. [PMID: 29897452 DOI: 10.1093/hmg/ddy142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 04/16/2018] [Indexed: 12/31/2022] Open
Abstract
A distinguishing aspect of spinal and bulbar muscular atrophy (SBMA) is its androgen-dependence, possibly explaining why only males are clinically affected. This disease, which impairs neuromuscular function, is linked to a polyglutamine expansion mutation in the androgen receptor (AR). In mouse models of SBMA, motor dysfunction is associated with pronounced defects in neuromuscular transmission, including defects in evoked transmitter release (quantal content, QC) and fiber membrane excitability (based on the resting membrane potential, RMP). However, whether such defects are androgen-dependent is unknown. Thus, we recorded synaptic potentials intracellularly from adult muscle fibers of transgenic (Tg) AR97Q male mice castrated pre-symptomatically. Although castration largely protects both QC and the RMP of fibers, correlating with the protective effect of castration on motor function, significant deficits in QC and RMP remained. Surprisingly, comparable defects in QC and RMP were also observed in pre-symptomatic AR97Q males, indicating that such defects emerge early and are pre-clinical. Exposing asymptomatic Tg females to androgens also induces both motor dysfunction and comparable defects in QC and RMP. Notably, asymptomatic Tg females also showed significant deficits in QC and RMP, albeit less severe, supporting their pre-clinical nature, but also raising questions about the androgen-dependence of pre-clinical symptoms. In summary, current evidence indicates that disease progression depends on androgens, but early pathogenic events may be triggered by the mutant AR allele independent of androgens. Such early, androgen-independent disease mechanisms may also be relevant to females carrying the SBMA allele.
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Affiliation(s)
- Youfen Xu
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | | | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environment Health School of Medicine, Yahatanishi-ku, Kitakyushu Fukuoka, Japan
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - S Marc Breedlove
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Cynthia L Jordan
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
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13
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Kylat RI. Pulmonary hypertension occurring with diazoxide use in a preterm infant with hypoglycemia. DRUG HEALTHCARE AND PATIENT SAFETY 2019; 11:7-10. [PMID: 30881142 PMCID: PMC6407670 DOI: 10.2147/dhps.s198255] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pharmacologic modulation to open the KATP channels with diazoxide is useful in treating hyperinsulinemia. Diazoxide is being used more often in neonates with hyperinsulinemic hypoglycemia. This report highlights a case of severe pulmonary hypertension (PH) with re-opening of ductus arteriosus in an extremely premature infant after the use of diazoxide. The rapid onset of PH with respiratory failure was completely reversible. This case emphasizes the need for extreme caution with use of diazoxide in the premature infant population, especially those with chronic lung disease of prematurity. In addition, the use of diazoxide should be limited to the persistent form of congenital hyperinsulinism, after adequate work up has been completed to evaluate for other causes of hypoglycemia. It is postulated that development of PH could be related to KATP agonsim.
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Affiliation(s)
- Ranjit I Kylat
- Division of Neonatal-Perinatal Medicine and Developmental Biology, Department of Pediatrics, The University of Arizona, College of Medicine, Tucson, AZ, USA,
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14
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Bollinger WL, Sial N, Dawson-Scully K. BK channels and a cGMP-dependent protein kinase (PKG) function through independent mechanisms to regulate the tolerance of synaptic transmission to acute oxidative stress at the Drosophila larval neuromuscular junction. J Neurogenet 2018; 32:246-255. [DOI: 10.1080/01677063.2018.1500571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Wesley L. Bollinger
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
| | - Nadia Sial
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
- Brain Institute Research Scholars Program, Florida Atlantic University, Boca Raton, FL, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
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15
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Kim JE, Park JY, Kang TC. TRPC6-mediated ERK1/2 Activation Regulates Neuronal Excitability via Subcellular Kv4.3 Localization in the Rat Hippocampus. Front Cell Neurosci 2017; 11:413. [PMID: 29326557 PMCID: PMC5742353 DOI: 10.3389/fncel.2017.00413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/11/2017] [Indexed: 01/02/2023] Open
Abstract
Recently, we have reported that transient receptor potential channel-6 (TRPC6) plays an important role in the regulation of neuronal excitability and synchronization of spiking activity in the dentate granule cells (DGC). However, the underlying mechanisms of TRPC6 in these phenomena have been still unclear. In the present study, we investigated the role of TRPC6 in subcellular localization of Kv4.3 and its relevance to neuronal excitability in the rat hippocampus. TRPC6 knockdown increased excitability and inhibitory transmission in the DGC and the CA1 neurons in response to a paired-pulse stimulus. However, TRPC6 knockdown impaired γ-aminobutyric acid (GABA)ergic inhibition in the hippocampus during and after high-frequency stimulation (HFS). TRPC6 knockdown reduced the Kv4.3 clusters in membrane fractions and its dendritic localization on DGC and GABAergic interneurons. TRPC6 knockdown also decreased extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and the efficacy of 4-aminopyridine (4-AP) in neuronal excitability. An ERK1/2 inhibitor generated multiple population spikes in response to a paired-pulse stimulus, concomitant with reduced membrane Kv4.3 translocation. A TRPC6 activator (hyperforin) reversed the effects of TRPC knockdown, except paired-pulse inhibition. These findings provide valuable clues indicating that TRPC6-mediated ERK1/2 activation may regulate subcellular Kv4.3 localization in DGC and interneurons, which is cause-effect relationship between neuronal excitability and seizure susceptibility.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Jin-Young Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
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16
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Li L, Fan Y, Li Q, Sheng R, Si H, Fang J, Tong L, Tang B. Simultaneous Single-Cell Analysis of Na+, K+, Ca2+, and Mg2+ in Neuron-Like PC-12 Cells in a Microfluidic System. Anal Chem 2017; 89:4559-4565. [DOI: 10.1021/acs.analchem.6b05045] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Lu Li
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Yuanyuan Fan
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Qingling Li
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Renjie Sheng
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Haibin Si
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Juan Fang
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Lili Tong
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
| | - Bo Tang
- College of Chemistry, Chemical
Engineering and Materials Science, Collaborative Innovation Center
of Functionalized Probes for Chemical Imaging in Universities of Shandong,
Key Laboratory of Molecular and Nano Probes, Ministry of Education,
Institute of Molecular and Nano Science, Shandong Normal University, Jinan, Shandong 250014, P. R. China
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17
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Nelson PT, Trojanowski JQ, Abner EL, Al-Janabi OM, Jicha GA, Schmitt FA, Smith CD, Fardo DW, Wang WX, Kryscio RJ, Neltner JH, Kukull WA, Cykowski MD, Van Eldik LJ, Ighodaro ET. "New Old Pathologies": AD, PART, and Cerebral Age-Related TDP-43 With Sclerosis (CARTS). J Neuropathol Exp Neurol 2016; 75:482-98. [PMID: 27209644 PMCID: PMC6366658 DOI: 10.1093/jnen/nlw033] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 12/12/2022] Open
Abstract
The pathology-based classification of Alzheimer's disease (AD) and other neurodegenerative diseases is a work in progress that is important for both clinicians and basic scientists. Analyses of large autopsy series, biomarker studies, and genomics analyses have provided important insights about AD and shed light on previously unrecognized conditions, enabling a deeper understanding of neurodegenerative diseases in general. After demonstrating the importance of correct disease classification for AD and primary age-related tauopathy, we emphasize the public health impact of an underappreciated AD "mimic," which has been termed "hippocampal sclerosis of aging" or "hippocampal sclerosis dementia." This pathology affects >20% of individuals older than 85 years and is strongly associated with cognitive impairment. In this review, we provide an overview of current hypotheses about how genetic risk factors (GRN, TMEM106B, ABCC9, and KCNMB2), and other pathogenetic influences contribute to TDP-43 pathology and hippocampal sclerosis. Because hippocampal sclerosis of aging affects the "oldest-old" with arteriolosclerosis and TDP-43 pathologies that extend well beyond the hippocampus, more appropriate terminology for this disease is required. We recommend "cerebral age-related TDP-43 and sclerosis" (CARTS). A detailed case report is presented, which includes neuroimaging and longitudinal neurocognitive data. Finally, we suggest a neuropathology-based diagnostic rubric for CARTS.
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Affiliation(s)
- Peter T Nelson
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC).
| | - John Q Trojanowski
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Erin L Abner
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Omar M Al-Janabi
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Gregory A Jicha
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Frederick A Schmitt
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Charles D Smith
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - David W Fardo
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Wang-Xia Wang
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Richard J Kryscio
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Janna H Neltner
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Walter A Kukull
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Matthew D Cykowski
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Linda J Van Eldik
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
| | - Eseosa T Ighodaro
- From the Department of Pathology, Division of Neuropathology (PTN, JHN), Department of Neurology (GAJ, FAS, CDS), Department of Statistics (DWF, RJK), Department of Anatomy and Neurobiology (PTN, JHN, LJVE, ETI), Department of Epidemiology (ELA), and Sanders-Brown Center on Aging (PTN, ELA, OMA-J, GAJ, FAS, CDS, DWF, WXW, RJK, LJVE, ETI), University of Kentucky, Lexington, Kentucky; Department of Pathology & Laboratory Medicine and Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvannia (JQT); Department of Epidemiology, University of Washington, Seattle, Washington (WAK); and Department of Pathology, Houston Methodist Hospital, Houston, Texas (MDC)
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18
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Zou Z, Lu Y, Zha Y, Yang H. Endocannabinoid 2-Arachidonoylglycerol Suppresses LPS-Induced Inhibition of A-Type Potassium Channel Currents in Caudate Nucleus Neurons Through CB1 Receptor. J Mol Neurosci 2016; 59:493-503. [PMID: 27129498 DOI: 10.1007/s12031-016-0761-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/22/2016] [Indexed: 01/29/2023]
Abstract
Inflammation plays a pivotal role in the pathogenesis of many diseases in the central nervous system. Caudate nucleus (CN), the largest nucleus in the brain, is also implicated in many neurological disorders. 2-Arachidonoylglycerol (2-AG), the most abundant endogenous cannabinoid, has been shown to exhibit neuroprotective effects through its anti-inflammatory action from some proinflammatory stimuli. However, the neuroprotective mechanism of 2-AG is complex and has not been fully understood. A-type K(+) channels critically regulate neuronal excitability and have been demonstrated to be associated with some nervous system diseases. The aim of this study was to explore whether A-type K(+) channels were involved in neurotoxicity of lipopolysaccharides (LPS) and the neuroprotective mechanism of 2-AG in CN neurons. Whole cell patch clamp recording was used to investigate the influence of LPS on the function of A-type K(+) channels and its modulation by 2-AG in primary cultured rat CN neurons. Our findings showed that in cultured CN neurons, LPS significantly decreased the A-type potassium currents (I A) in a voltage-insensitive way. The further data demonstrated that an elevation of 2-AG levels by directly applying exogenous 2-AG or inhibiting monoacylglycerol lipase (MAGL) to prevent 2-AG hydrolysis was capable of suppressing the LPS-induced inhibition of IA and the action of 2-AG is mediated through CB1 receptor-dependant way. The study provides a better understanding of inflammation-related neurological disorders and suggests the therapeutic potential for 2-AG for the treatment of these diseases.
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Affiliation(s)
- Ziliang Zou
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China
| | - Yongli Lu
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China.,Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, China Three Gorges University, 443002, Yichang, Hubei, People's Republic of China
| | - Yunhong Zha
- Department of Neurology, The First Hospital of Yichang, Institute of Translational Neuroscience, Three Gorges University College of Medicine, 443000, Yichang, Hubei, People's Republic of China
| | - Hongwei Yang
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China. .,Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, China Three Gorges University, 443002, Yichang, Hubei, People's Republic of China.
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19
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Roy Chowdhury U, Dosa PI, Fautsch MP. ATP sensitive potassium channel openers: A new class of ocular hypotensive agents. Exp Eye Res 2016; 158:85-93. [PMID: 27130546 DOI: 10.1016/j.exer.2016.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 12/25/2022]
Abstract
ATP sensitive potassium (KATP) channels connect the metabolic and energetic state of cells due to their sensitivity to ATP and ADP concentrations. KATP channels have been identified in multiple tissues and organs of the body including heart, pancreas, vascular smooth muscles and skeletal muscles. These channels are obligatory hetero-octamers and contain four sulfonylurea (SUR) and four potassium inward rectifier (Kir) subunits. Based on the particular type of SUR and Kir present, there are several tissue specific subtypes of KATP channels, each with their own unique set of functions. Recently, KATP channels have been reported in human and mouse ocular tissues. In ex vivo and in vivo model systems, KATP channel openers showed significant ocular hypotensive properties with no appearance of toxic side effects. Additionally, when used in conjunction with known intraocular pressure lowering drugs, an additive effect on IOP reduction was observed. These KATP channel openers have also been reported to protect the retinal ganglion cells during ischemic stress and glutamate induced toxicity suggesting a neuroprotective property for this drug class. Medications that are currently used for treating ocular hypertensive diseases like glaucoma do not directly protect the affected retinal cells, are sometimes ineffective and may show significant side effects. In light of this, KATP channel openers with both ocular hypotensive and neuroprotective properties, have the potential to develop into a new class of glaucoma therapeutics.
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Affiliation(s)
- Uttio Roy Chowdhury
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN 55414, United States.
| | - Michael P Fautsch
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
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Roy Chowdhury U, Bahler CK, Holman BH, Dosa PI, Fautsch MP. Ocular Hypotensive Effects of the ATP-Sensitive Potassium Channel Opener Cromakalim in Human and Murine Experimental Model Systems. PLoS One 2015; 10:e0141783. [PMID: 26535899 PMCID: PMC4633217 DOI: 10.1371/journal.pone.0141783] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/13/2015] [Indexed: 11/17/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the most prevalent and only treatable risk factor for glaucoma, a leading cause of irreversible blindness worldwide. Unfortunately, all current therapeutics used to treat elevated IOP and glaucoma have significant and sometimes irreversible side effects necessitating the development of novel compounds. We evaluated the IOP lowering ability of the broad spectrum KATP channel opener cromakalim. Cultured human anterior segments when treated with 2 μM cromakalim showed a decrease in pressure (19.33 ± 2.78 mmHg at 0 hours to 13.22 ± 2.64 mmHg at 24 hours; p<0.001) when compared to vehicle treated controls (15.89 ± 5.33 mmHg at 0 h to 15.56 ± 4.88 mmHg at 24 hours; p = 0.89). In wild-type C57BL/6 mice, cromakalim reduced IOP by 18.75 ± 2.22% compared to vehicle treated contralateral eyes (17.01 ± 0.32 mmHg at 0 hours to 13.82 ± 0.37 mmHg at 24 hours; n = 10, p = 0.002). Cromakalim demonstrated an additive effect when used in conjunction with latanoprost free acid, a common ocular hypotensive drug prescribed to patients with elevated IOP. To examine KATP channel subunit specificity, Kir6.2(-/-) mice were treated with cromakalim, but unlike wild-type animals, no change in IOP was noted. Histologic analysis of treated and control eyes in cultured human anterior segments and in mice showed similar cell numbers and extracellular matrix integrity within the trabecular meshwork, with no disruptions in the inner and outer walls of Schlemm's canal. Together, these studies suggest that cromakalim is a potent ocular hypotensive agent that lowers IOP via activation of Kir6.2 containing KATP channels, its effect is additive when used in combination with the commonly used glaucoma drug latanoprost, and is not toxic to cells and tissues of the aqueous humor outflow pathway, making it a candidate for future therapeutic development.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Cindy K Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, United States of America
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
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Hippocampal Sclerosis of Aging Can Be Segmental: Two Cases and Review of the Literature. J Neuropathol Exp Neurol 2015; 74:642-52. [PMID: 26083567 DOI: 10.1097/nen.0000000000000204] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hippocampal sclerosis of aging (HS-Aging) is a neurodegenerative disease that mimics Alzheimer disease (AD) clinically and has a prevalence rivaling AD in advanced age. Whereas clinical biomarkers are not yet optimized, HS-Aging has distinctive pathological features that distinguish it from other diseases with "hippocampal sclerosis" pathology, such as epilepsy, cerebrovascular perturbations, and frontotemporal lobar degeneration. By definition, HS-Aging brains show neuronal cell loss and gliosis in the hippocampal formation out of proportion to AD-type pathology; it is strongly associated with aberrant TDP-43 pathology and arteriolosclerosis. Here, we describe 2 cases of "segmental" HS-Aging in which "sclerosis" in the hippocampus was evident only in a subset of brain sections by hematoxylin and eosin (H&E) stain. In these cases, TDP-43 pathology was more widespread on immunostained sections than the neuronal cell loss and gliosis seen in H&E stains. The 2 patients were cognitively intact at baseline and were tracked longitudinally over a decade using cognitive studies with at least 1 neuroimaging scan. We discuss the relevant HS-Aging literature, which indicates the need for a clearer consensus-based delineation of "hippocampal sclerosis" and TDP-43 pathologies in aged subjects.
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Umaru B, Pyriochou A, Kotsikoris V, Papapetropoulos A, Topouzis S. ATP-sensitive potassium channel activation induces angiogenesis in vitro and in vivo. J Pharmacol Exp Ther 2015; 354:79-87. [PMID: 25977483 DOI: 10.1124/jpet.114.222000] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/13/2015] [Indexed: 12/19/2022] Open
Abstract
Intense research is conducted to identify new molecular mechanisms of angiogenesis. Previous studies have shown that the angiogenic effects of hydrogen sulfide (H2S) depend on the activation of ATP-sensitive potassium channels (KATP) and that C-type natriuretic peptide (CNP), which can act through KATP, promotes endothelial cell growth. We therefore investigated whether direct KATP activation induces angiogenic responses and whether it is required for the endothelial responses to CNP or vascular endothelial growth factor (VEGF). Chick chorioallantoic membrane (CAM) angiogenesis was similarly enhanced by the direct KATP channel activator 2-nicotinamidoethyl acetate (SG-209) and by CNP or VEGF. The KATP inhibitors glibenclamide and 5-hydroxydecanoate (5-HD) reduced basal and abolished CNP-induced CAM angiogenesis. In vitro, the direct KATP openers nicorandil and SG-209 and the polypeptides VEGF and CNP increased proliferation and migration in bEnd.3 mouse endothelial cells. In addition, VEGF and CNP induced cord-like formation on Matrigel by human umbilical vein endothelial cells (HUVECs). All these in vitro endothelial responses were effectively abrogated by glibenclamide or 5-HD. In HUVECs, a small-interfering RNA-mediated decrease in the expression of the inwardly rectifying potassium channel (Kir) 6.1 subunit impaired cell migration and network morphogenesis in response to either SG-209 or CNP. We conclude that 1) direct pharmacologic activation of KATP induces angiogenic effects in vitro and in vivo, 2) angiogenic responses to CNP and VEGF depend on KATP activation and require the expression of the Kir6.1 KATP subunit, and 3) KATP activation may underpin angiogenesis to a variety of vasoactive stimuli, including H2S, VEGF, and CNP.
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Affiliation(s)
- Bukar Umaru
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Rio-Patras, Greece (B.U., A.Py., V.K., S.T.); and Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece (A.Pa.)
| | - Anastasia Pyriochou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Rio-Patras, Greece (B.U., A.Py., V.K., S.T.); and Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece (A.Pa.)
| | - Vasileios Kotsikoris
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Rio-Patras, Greece (B.U., A.Py., V.K., S.T.); and Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece (A.Pa.)
| | - Andreas Papapetropoulos
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Rio-Patras, Greece (B.U., A.Py., V.K., S.T.); and Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece (A.Pa.)
| | - Stavros Topouzis
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Rio-Patras, Greece (B.U., A.Py., V.K., S.T.); and Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece (A.Pa.)
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Liu YQ, Huang WX, Sanchez RM, Min JW, Hu JJ, He XH, Peng BW. Regulation of Kv4.2 A-Type Potassium Channels in HEK-293 Cells by Hypoxia. Front Cell Neurosci 2014; 8:329. [PMID: 25352783 PMCID: PMC4196569 DOI: 10.3389/fncel.2014.00329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/29/2014] [Indexed: 11/13/2022] Open
Abstract
We previously observed that A-type potassium currents were decreased and membrane excitability increased in hippocampal dentate granule cells after neonatal global hypoxia associated with seizures. Here, we studied the effects of hypoxia on the function and expression of Kv4.2 and Kv4.3 α subunit channels, which encode rapidly inactivating A-type K currents, in transfected HEK-293 cells to determine if hypoxia alone could regulate IAin vitro. Global hypoxia in neonatal rat pups resulted in early decreased hippocampal expression of Kv4.2 mRNA and protein with 6 or 12 h post-hypoxia. Whole-cell voltage-clamp recordings revealed that similar times after hypoxia (1%) in vitro decreased peak currents mediated by recombinant Kv4.2 but not Kv4.3 channels. Hypoxia had no significant effect on the voltage-dependencies of activation and inactivation of Kv4.2 channels, but increased the time constant of activation. The same result was observed when Kv4.2 and Kv4.3 channels were co-expressed in a 1:1 ratio. These data suggested that hypoxia directly modulates A-type potassium channels of the subfamily typically expressed in principal hippocampal neurons, and does so in a manner to decrease function. Given the role of IA to slow action potential firing, these data are consistent with a direct effect of hypoxia to decrease IA as a mechanism of increased neuronal excitability and promotion of seizures.
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Affiliation(s)
- Yu-Qiang Liu
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Wen-Xian Huang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Russell M Sanchez
- Department of Surgery, College of Medicine, Texas A&M Health Science Center, Neuroscience Institute, Scott and White Hospital, Central Texas Veterans Health Care System , Temple, TX , USA
| | - Jia-Wei Min
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Jiang-Jian Hu
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Xiao-Hua He
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Bi-Wen Peng
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
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Gündüz MG, İşli F, El-Khouly A, Yıldırım Ş, Öztürk Fincan GS, Şimşek R, Şafak C, Sarıoğlu Y, Öztürk Yıldırım S, Butcher RJ. Microwave-assisted synthesis and myorelaxant activity of 9-indolyl-1,8-acridinedione derivatives. Eur J Med Chem 2014; 75:258-66. [DOI: 10.1016/j.ejmech.2014.01.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/23/2014] [Accepted: 01/29/2014] [Indexed: 01/12/2023]
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Abstract
Urinary incontinence is a common and distressing condition that is known to adversely affect quality of life. Overactive bladder (OAB) is the term used to describe the symptom complex of urgency with or without urge incontinence, usually with frequency and nocturia. Drug therapy, in addition to behavioral modification, remains integral in the management of women with OAB, and the development of new drugs, treatment regimens and methods of delivery should improve patient compliance and acceptability. Developments over the last 10 years have led to the launch of several new drugs for the treatment of OAB that may offer greater efficacy while minimizing adverse effects. This article critically reviews the current pharmacological treatment of OAB in addition to providing a rationale for treatment.
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Affiliation(s)
- Dudley Robinson
- Kings College Hospital, Department of Urogynaecology, 3rd Floor, Golden Jubilee Wing, London, UK.
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Denton JS, Pao AC, Maduke M. Novel diuretic targets. Am J Physiol Renal Physiol 2013; 305:F931-42. [PMID: 23863472 PMCID: PMC3798746 DOI: 10.1152/ajprenal.00230.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/12/2013] [Indexed: 01/11/2023] Open
Abstract
As the molecular revolution continues to inform a deeper understanding of disease mechanisms and pathways, there exist unprecedented opportunities for translating discoveries at the bench into novel therapies for improving human health. Despite the availability of several different classes of antihypertensive medications, only about half of the 67 million Americans with hypertension manage their blood pressure appropriately. A broader selection of structurally diverse antihypertensive drugs acting through different mechanisms would provide clinicians with greater flexibility in developing effective treatment regimens for an increasingly diverse and aging patient population. An emerging body of physiological, genetic, and pharmacological evidence has implicated several renal ion-transport proteins, or regulators thereof, as novel, yet clinically unexploited, diuretic targets. These include the renal outer medullary potassium channel, ROMK (Kir1.1), Kir4.1/5.1 potassium channels, ClC-Ka/b chloride channels, UTA/B urea transporters, the chloride/bicarbonate exchanger pendrin, and the STE20/SPS1-related proline/alanine-rich kinase (SPAK). The molecular pharmacology of these putative targets is poorly developed or lacking altogether; however, recent efforts by a few academic and pharmaceutical laboratories have begun to lessen this critical barrier. Here, we review the evidence in support of the aforementioned proteins as novel diuretic targets and highlight examples where progress toward developing small-molecule pharmacology has been made.
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Affiliation(s)
- Jerod S Denton
- T4208 Medical Center North, 1161 21st Ave. South, Nashville, TN 37232.
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Involvement of Potassium Channels in Vasorelaxant Effect Induced by Valeriana prionophylla Standl. in Rat Mesenteric Artery. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:147670. [PMID: 24023569 PMCID: PMC3759249 DOI: 10.1155/2013/147670] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/07/2013] [Accepted: 07/08/2013] [Indexed: 11/17/2022]
Abstract
Assays in vitro and in vivo were performed on extract from roots and leaves from the Valeriana prionophylla Standl. (VPR and VPF, resp.). In phenylephrine (1 μM) precontracted rings, VPR (0.01–300 μg/mL) induced a concentration-dependent relaxation (maximum response (MR) = 75.4 ± 4.0%, EC50 = 5.97 (3.8–9.3) μg/mL, n = 6]); this effect was significantly modified after removal of the endothelium (EC50 = 39.6 (27.2–57.6) μg/mL, P < 0.05). However, VPF-induced vasorelaxation was less effective compared to VPR. When rings were preincubated with L-NAME (100 μM) or indomethacin (10 μM), the endothelium-dependent relaxation induced by VPR was significantly attenuated (MR = 20.9 ± 2.3%, 34.2 ± 2.9%, resp., P < 0.001). In rings denuded endothelium, precontracted with KCl (80 mM), or in preparations pretreated with KCl (20 mM) or tetraethylammonium (1 or 3 mM), the vasorelaxant activity of VPR was significantly attenuated (MR = 40.0 ± 8.2, n = 5; 50.5 ± 6.0%; 49.3 ± 6.4%; 46.8 ± 6.2%; resp., P < 0.01). In contrast, neither glibenclamide (10 μM), barium chloride (30 μM), nor 4-aminopyridine (1 mM) affected VPR-induced relaxation. Taken together, these results demonstrate that hypotension induced by VPR seems to involve, at least in part, a vascular component. Furthermore, endothelium-independent relaxation induced by VPR involves K+ channels activation, most likely due to BKCa channels, in the rat superior mesenteric artery.
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Chowdhury UR, Holman BH, Fautsch MP. ATP-sensitive potassium (K(ATP)) channel openers diazoxide and nicorandil lower intraocular pressure in vivo. Invest Ophthalmol Vis Sci 2013; 54:4892-9. [PMID: 23778875 DOI: 10.1167/iovs.13-11872] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To evaluate the expression of ATP-sensitive potassium (K(ATP)) channel subunits and study the effect of K(ATP) channel openers diazoxide and nicorandil on intraocular pressure (IOP) in an in vivo mouse model. METHODS Expression of K(ATP) channel subunits in normal C57BL/6 mouse eyes was studied by immunohistochemistry and confocal microscopy. Wild-type C57BL/6 mice were treated with K(ATP) channel openers diazoxide (n = 10) and nicorandil (n = 10) for 14 days. Similar treatments with diazoxide were performed on K(ir)6.2((-/-)) mice (n = 10). IOP was recorded with a handheld tonometer 1 hour, 4 hours, and 23 hours following daily treatment. Posttreatment histology was examined by light and transmission electron microscopy. RESULTS The K(ATP) channel subunits SUR2B, K(ir)6.1, and K(ir)6.2 were identified in all tissues within mouse eyes. Treatment with diazoxide in wild-type mice decreased IOP by 21.5 ± 3.2% with an absolute IOP reduction of 3.9 ± 0.6 mm Hg (P = 0.002). Nicorandil also decreased IOP (18.9 ± 1.8%) with an absolute IOP reduction of 3.4 ± 0.4 mm Hg (P = 0.002). Treatment with diazoxide in K(ir)6.2((-/-)) mice had no effect on IOP. No morphological abnormalities were observed in diazoxide- or nicorandil-treated eyes. CONCLUSIONS K(ATP) channel openers diazoxide and nicorandil are effective regulators of IOP in mouse eyes. K(ir)6.2 appears to be a major K(ATP) channel subunit through which IOP is lowered following treatment with diazoxide.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Sá RDCDSE, Almeida RND, Bhattacharyya J. Pharmaceutical properties and toxicology of Dioclea grandiflora. PHARMACEUTICAL BIOLOGY 2013; 51:659-667. [PMID: 23368936 DOI: 10.3109/13880209.2012.755208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT Since the beginning of civilization, herbal medicines have been an important source for human beings to treat their ailments. Despite the large number of synthetic remedies available in the market, the use of plants is seen as a great challenge in the search for new substances endowed with therapeutic properties. One example is Dioclea grandiflora Mart. ex Benth. (Leguminosae) employed in traditional medicine to treat prostate disorders and kidney stones. OBJECTIVES This work presents a brief overview of D. grandiflora, including a description of the plant, its chemical composition and pharmacological properties. METHODS This review gathers information available in the scientific literature compiled from databases such as Science Direct, PubMed, Dr. Dukes Phytochemical and Ethnobotany, Missouri Botanical Garden and The International Plant Names Index. RESULTS The information found in the literature showed that flavonoids are the major constituents of D. grandiflora that account for most of the pharmacological properties so far disclosed. Several studies have revealed that D. grandiflora possesses antinociceptive, cardiovascular, antioxidant and anti-inflammatory activities. CONCLUSION Research shows that D. grandiflora is a potential source of compounds pertaining medicinal applications. It provides an interesting subject in the search for new drugs of natural origin.
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Affiliation(s)
- Rita de Cássia da Silveira E Sá
- Department of Physiology and Pathology, Federal University of Paraíba (UFPB), Av Antonio Lira, 950, Cabo Branco, 58045-030, João Pessoa, Paraíba, Brasil.
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Excitotoxicity in the Pathogenesis of Autism. Neurotox Res 2012; 23:393-400. [DOI: 10.1007/s12640-012-9354-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/10/2012] [Accepted: 09/22/2012] [Indexed: 01/29/2023]
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Hu XQ, Zhang L. Function and regulation of large conductance Ca(2+)-activated K+ channel in vascular smooth muscle cells. Drug Discov Today 2012; 17:974-87. [PMID: 22521666 PMCID: PMC3414640 DOI: 10.1016/j.drudis.2012.04.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/06/2012] [Accepted: 04/05/2012] [Indexed: 12/23/2022]
Abstract
Large conductance Ca(2+)-activated K(+) (BK(Ca)) channels are abundantly expressed in vascular smooth muscle cells. Activation of BK(Ca) channels leads to hyperpolarization of cell membrane, which in turn counteracts vasoconstriction. Therefore, BK(Ca) channels have an important role in regulation of vascular tone and blood pressure. The activity of BK(Ca) channels is subject to modulation by various factors. Furthermore, the function of BK(Ca) channels are altered in both physiological and pathophysiological conditions, such as pregnancy, hypertension and diabetes, which has dramatic impacts on vascular tone and hemodynamics. Consequently, compounds and genetic manipulation that alter activity and expression of the channel might be of therapeutic interest.
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Affiliation(s)
- Xiang-Qun Hu
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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Niwa S, Ohya S, Kojima Y, Sasaki S, Yamamura H, Sakuragi M, Kohri K, Imaizumi Y. Down-Regulation of the Large-Conductance Ca 2+-Activated K + Channel, K Ca1.1 in the Prostatic Stromal Cells of Benign Prostate Hyperplasia. Biol Pharm Bull 2012; 35:737-44. [DOI: 10.1248/bpb.35.737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Satomi Niwa
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Susumu Ohya
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Yoshiyuki Kojima
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Shoichi Sasaki
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Hisao Yamamura
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | | | - Kenjiro Kohri
- Department of Nephro-urology, Graduate School of Medical Sciences, Nagoya City University
| | - Yuji Imaizumi
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
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Szabò I, Leanza L, Gulbins E, Zoratti M. Physiology of potassium channels in the inner membrane of mitochondria. Pflugers Arch 2011; 463:231-46. [PMID: 22089812 DOI: 10.1007/s00424-011-1058-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 10/30/2011] [Indexed: 02/06/2023]
Abstract
The inner membrane of the ATP-producing organelles of endosymbiotic origin, mitochondria, has long been considered to be poorly permeable to cations and anions, since the strict control of inner mitochondrial membrane permeability is crucial for efficient ATP synthesis. Over the past 30 years, however, it has become clear that various ion channels--along with antiporters and uniporters--are present in the mitochondrial inner membrane, although at rather low abundance. These channels are important for energy supply, and some are a decisive factor in determining whether a cell lives or dies. Their electrophysiological and pharmacological characterisations have contributed importantly to the ongoing elucidation of their pathophysiological roles. This review gives an overview of recent advances in our understanding of the functions of the mitochondrial potassium channels identified so far. Open issues concerning the possible molecular entities giving rise to the observed activities and channel protein targeting to mitochondria are also discussed.
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Affiliation(s)
- Ildikò Szabò
- Department of Biology, University of Padova, Padova, Italy.
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Investigation of myorelaxant activity of 9-aryl-3,4,6,7-tetrahydroacridine-1,8-(2H,5H,9H,10H)-diones in isolated rabbit gastric fundus. Med Chem Res 2011. [DOI: 10.1007/s00044-011-9698-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Chao CC, Mihic A, Tsushima RG, Gaisano HY. SNARE protein regulation of cardiac potassium channels and atrial natriuretic factor secretion. J Mol Cell Cardiol 2011; 50:401-7. [DOI: 10.1016/j.yjmcc.2010.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/17/2010] [Accepted: 11/19/2010] [Indexed: 01/28/2023]
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Rapposelli S. Novel adenosine 5'-triphosphate-sensitive potassium channel ligands: a patent overview (2005-2010). Expert Opin Ther Pat 2011; 21:355-79. [PMID: 21269236 DOI: 10.1517/13543776.2011.553601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION ATP-sensitive potassium channels are important metabolic regulators that link cellular metabolism to excitability. Their wide distribution in various tissues and organs makes them significant and topical targets in a large number of diseases. AREAS COVERED This review summarizes the current understanding of the molecular biology and pharmacology of K(ATP) channels, and the pathological states that result from aberrant expression or function of these proteins. In particular, relevant research, patents and patent applications of the past 5 years are discussed. EXPERT OPINION The tissue-specific K(ATP) channel modulation reflects an early discovery stage in drug design. The wide distribution of K(ATP) channels lets us consider them as valid targets for several pathologies, but on other hand the ubiquitous nature is a relevant drawback in developing an effective therapy because of the onset of side effects related to the lack of selectivity. On this basis, further investigations on both the structures and the localization of each receptor subtype should be carried out either exploring the structure-activity relationship of the already existing K(ATP) ligands or developing new selective fluorescent probes. To date, this research area still strives to design new tissue-targeted ligands that could pave the way to the development of innovative and effective drugs for clinical use.
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Affiliation(s)
- Simona Rapposelli
- Dipartimento di Scienze Farmaceutiche - Università di Pisa, Via Bonanno, 6, 56126 Pisa, Italy.
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Szewczyk A, Kajma A, Malinska D, Wrzosek A, Bednarczyk P, Zabłocka B, Dołowy K. Pharmacology of mitochondrial potassium channels: dark side of the field. FEBS Lett 2010; 584:2063-9. [PMID: 20178786 DOI: 10.1016/j.febslet.2010.02.048] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 01/25/2010] [Accepted: 02/15/2010] [Indexed: 11/25/2022]
Abstract
Mitochondrial potassium channels play an important role in cytoprotection. Potassium channels in the inner mitochondrial membrane are modulated by inhibitors and activators (potassium channel openers) previously described for plasma membrane potassium channels. The majority of mitochondrial potassium channel modulators exhibit a broad spectrum of off-target effects. These include uncoupling properties, inhibition of the respiratory chain and effects on cellular calcium homeostasis. Therefore, the rational application of channel inhibitors or activators is crucial to understanding the cellular consequences of mitochondrial channel inhibition or activation. Moreover, understanding their side-effects should facilitate the design of a specific mitochondrial channel opener with cytoprotective properties. In this review, we discuss the complex interactions of potassium channel inhibitors and activators with cellular structures.
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Affiliation(s)
- Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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38
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Savegnago L, Jesse CR, Santos ARS, Rocha JBT, Nogueira CW. Mechanisms involved in the antinociceptive effect caused by diphenyl diselenide in the formalin test. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.60.12.0015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
This study investigated the mechanisms involved in the antinociceptive action induced by diphenyl diselenide ((PhSe)2) in the formalin test. Mice were pre-treated with (PhSe)2 by the oral route (0.1–100 mg kg−1), 30 min before formalin injection. To address some of the mechanisms by which (PhSe)2 inhibits formalin-induced nociception mice were treated with different drugs. The antinociceptive effect of (PhSe)2 was shown in the first and second phases of the formalin test. The antinociceptive effect caused by (PhSe)2 (10 mg kg−1, p.o.) was prevented by intrathecal injection of K+ channel blockers such as apamin and charybdotoxin (small- and large-conductance Ca2+-activated K+ channel inhibitors, respectively) and tetraethylammonium (TEA, a non-selective voltage-dependent K+ channel inhibitor), but not glib-enclamide (an ATP-sensitive K+ channel inhibitor). The antinociceptive action caused by (PhSe)2 (10 mg kg−1, p.o.) was also blocked by a nitric oxide (NO) synthase inhibitor (Nω-nitro-l-arginine, L-NOARG) and the soluble guanylate cyclase inhibitors 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and methylene blue. These results suggest the participation of NO/cyclic GMP/Ca2+ and K+ channel pathways in the antinociceptive effect caused by (PhSe)2.
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Affiliation(s)
- Lucielli Savegnago
- Departamento de Quimica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, SM, RS, CEP 97105-900 Santa Maria, Brazil
- Universidade Federal do Pampa (UNIPAMPA), Campus Uruguaiana, BR472 KM 7, CEP 97500-970, Uruguaiana - RS, Brazil, Caixa Postal 118
| | - Cristiano R Jesse
- Departamento de Quimica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, SM, RS, CEP 97105-900 Santa Maria, Brazil
| | - Adair R S Santos
- Departamento de Ciências Fisiológicas, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC., Brazil
| | - João B T Rocha
- Departamento de Quimica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, SM, RS, CEP 97105-900 Santa Maria, Brazil
| | - Cristina W Nogueira
- Departamento de Quimica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, SM, RS, CEP 97105-900 Santa Maria, Brazil
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39
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Abstract
To date, most of the major types of Kir channels, Kir2s, Kir3s, Kir4s, and Kir6s, have been found to partition into cholesterol-rich membrane domains and/or to be regulated by changes in the level of membrane cholesterol. Surprisingly, however, in spite of the structural similarities between different Kirs, effects of cholesterol on different types of Kir channels vary from cholesterol-induced decrease in the current density (Kir2 channels) to the loss of channel activity by cholesterol depletion (Kir4 channels) and loss of channel coupling by different mediators (Kir3 and Kir6 channels). Recently, we have gained initial insights into the mechanisms responsible for cholesterol-induced suppression Kir2 channels, but mechanisms underlying cholesterol sensitivity of other Kir channels are mostly unknown. The goal of this review is to present a summary of the current knowledge of the distinct effects of cholesterol on different types of Kir channels in vitro and in vivo.
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Affiliation(s)
- Irena Levitan
- Department of Medicine, Pulmonary Section, University of Illinois at Chicago, Chicago, IL 60612, USA.
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40
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Yang Y, Murphy TV, Ella SR, Grayson TH, Haddock R, Hwang YT, Braun AP, Peichun G, Korthuis RJ, Davis MJ, Hill MA. Heterogeneity in function of small artery smooth muscle BKCa: involvement of the beta1-subunit. J Physiol 2009; 587:3025-44. [PMID: 19359368 DOI: 10.1113/jphysiol.2009.169920] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Arteriolar myogenic vasoconstriction occurs when increased stretch or membrane tension leads to smooth muscle cell depolarization and opening of voltage-gated Ca2+ channels. To prevent positive feedback and excessive pressure-induced vasoconstriction, studies in cerebral artery smooth muscle have suggested that activation of large conductance, Ca2+-activated K+ channels (BKCa) provides an opposing hyperpolarizing influence reducing Ca2+ channel activity. We have hypothesized that this mechanism may not equally apply to all vascular beds. To establish the existence of such heterogeneity in vascular reactivity, studies were performed on rat vascular smooth muscle (VSM) cells from cremaster muscle arterioles and cerebral arteries. Whole cell K+ currents were determined at pipette [Ca2+] of 100 nM or 5 microM in the presence and absence of the BKCa inhibitor, iberiotoxin (IBTX; 0.1 microM). Similar outward current densities were observed for the two cell preparations at the lower pipette Ca2+ levels. At 5 microM Ca2+, cremaster VSM showed a significantly (P < 0.05) lower current density compared to cerebral VSM (34.5 +/- 1.9 vs 45.5 +/- 1.7 pA pF(-1) at +70 mV). Studies with IBTX suggested that the differences in K+ conductance at 5 microM intracellular [Ca2+] were largely due to activity of BKCa. 17beta-Oestradiol (1 microM), reported to potentiate BKCa current via the channel's beta-subunit, caused a greater effect on whole cell K+ currents in cerebral vessel smooth muscle cells (SMCs) compared to those of cremaster muscle. In contrast, the alpha-subunit-selective BKCa opener, NS-1619 (20 microM), exerted a similar effect in both preparations. Spontaneously transient outward currents (STOCs) were more apparent (frequency and amplitude) and occurred at more negative membrane potentials in cerebral compared to cremaster SMCs. Also consistent with decreased STOC activity in cremaster SMCs was an absence of detectable Ca2+ sparks (0 of 76 cells) compared to that in cerebral SMCs (76 of 105 cells). Quantitative PCR showed decreased mRNA expression for the beta1 subunit and a decrease in the beta1:alpha ratio in cremaster arterioles compared to cerebral vessels. Similarly, cremaster arterioles showed a decrease in total BKCa protein and the beta1:alpha-subunit ratio. The data support vascular heterogeneity with respect to the activity of BKCa in terms of both beta-subunit regulation and interaction with SR-mediated Ca2+ signalling.
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Affiliation(s)
- Yan Yang
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211, USA
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41
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Wrzosek A, Łukasiak A, Gwóźdź P, Malińska D, Kozlovski VI, Szewczyk A, Chlopicki S, Dołowy K. Large-conductance K+ channel opener CGS7184 as a regulator of endothelial cell function. Eur J Pharmacol 2009; 602:105-11. [DOI: 10.1016/j.ejphar.2008.10.066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 09/19/2008] [Accepted: 10/29/2008] [Indexed: 01/08/2023]
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42
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Sundelacruz S, Levin M, Kaplan DL. Membrane potential controls adipogenic and osteogenic differentiation of mesenchymal stem cells. PLoS One 2008; 3:e3737. [PMID: 19011685 PMCID: PMC2581599 DOI: 10.1371/journal.pone.0003737] [Citation(s) in RCA: 181] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 10/28/2008] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Control of stem cell behavior is a crucial aspect of developmental biology and regenerative medicine. While the functional role of electrophysiology in stem cell biology is poorly understood, it has become clear that endogenous ion flows represent a powerful set of signals by means of which cell proliferation, differentiation, and migration can be controlled in regeneration and embryonic morphogenesis. METHODOLOGY/PRINCIPAL FINDINGS We examined the membrane potential (V(mem)) changes exhibited by human mesenchymal stem cells (hMSCs) undergoing adipogenic (AD) and osteogenic (OS) differentiation, and uncovered a characteristic hyperpolarization of differentiated cells versus undifferentiated cells. Reversal of the progressive polarization via pharmacological modulation of transmembrane potential revealed that depolarization of hMSCs prevents differentiation. In contrast, treatment with hyperpolarizing reagents upregulated osteogenic markers. CONCLUSIONS/SIGNIFICANCE Taken together, these data suggest that the endogenous hyperpolarization is a functional determinant of hMSC differentiation and is a tractable control point for modulating stem cell function.
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Affiliation(s)
- Sarah Sundelacruz
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, United States of America
| | - Michael Levin
- Biology Department, and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts, United States of America
| | - David L. Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, United States of America
- * E-mail:
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43
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Kicinska A, Skalska J, Szewczyk A. Mitochondria and Big-Conductance Potassium Channel Openers. Toxicol Mech Methods 2008; 14:63-5. [DOI: 10.1080/15376520490257491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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44
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Abstract
Epileptogenesis in mesial temporal lobe epilepsy is determined by several factors including abnormalities in the expression and function of ion channels. Here, we report a long-lasting deficit in gene expression of Kcnma1 coding for the large-conductance calcium-activated potassium (BK, MaxiK) channel alpha-subunits after pilocarpine-induced status epilepticus. By using comparative real-time PCR, Taqman gene expression assays, and the delta-delta comparative threshold method we detected a significant reduction in Kcnma1 expression in microdissected dentate gyrus at different intervals after status epilepticus (24 h, 10 days, 1 month, and more than 2 months). BK channels are key regulators of neuronal excitability and transmitter release. Hence, defective Kcnma1 expression may play a critical role in the pathogenesis of mesial temporal lobe epilepsy.
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Lee JH, Park SY, Shin HK, Kim CD, Lee WS, Hong KW. Protective effects of cilostazol against transient focal cerebral ischemia and chronic cerebral hypoperfusion injury. CNS Neurosci Ther 2008; 14:143-52. [PMID: 18482026 DOI: 10.1111/j.1527-3458.2008.00042.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cilostazol increases intracellular cyclic adenosine monophosphate (cyclic AMP) levels by inhibiting type III phosphodiesterase. It was approved by the Food and Drug Administration for the treatment of intermittent claudication. Its principal actions include inhibition of platelet aggregation, antithrombotic action in cerebral ischemia, and vasodilation, mediated by increased cyclic AMP levels. In a multicenter, randomized, placebo-controlled, double-blind clinical trial, cilostazol has been shown to protect patients from recurrent cerebral infarction. It has been recently suggested that cilastozol could be useful in the treatment of transient focal cerebral ischemic injury. Beneficial effects of cilostazol in cerebral ischemic infarction and edema formation has been confirmed in rats by the magnetic resonance imaging (MRI). The preventive effect was ascribed to cAMP-dependent protein kinase (PKA)-coupled maxi-K channel activation with additional antioxidant and poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitory actions. Most recently, cilostazol has been shown to prevent vacuolation and rarefaction in the white matter of the rats subjected to chronic cerebral hypoperfusion in association with suppression of astrocyte and microglial activation. Taken together, recent experimental studies with cilostazol showed promising results in cerebral ischemia and chronic cerebral hypoperfusion.
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Affiliation(s)
- Jeong Hyun Lee
- Department of Pharmacology, College of Medicine, Pusan National University, Busan, Korea
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46
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Diness TG, Yeh YH, Qi XY, Chartier D, Tsuji Y, Hansen RS, Olesen SP, Grunnet M, Nattel S. Antiarrhythmic properties of a rapid delayed-rectifier current activator in rabbit models of acquired long QT syndrome. Cardiovasc Res 2008; 79:61-9. [DOI: 10.1093/cvr/cvn075] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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47
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Abstract
Overactive bladder (OAB) syndrome is the term used to describe the symptom complex of urinary urgency with or without urge incontinence, usually with frequency and nocturia. Drug treatment continues to have an important role in the management of women with OAB. Other treatment options include conservative management with lifestyle interventions, modification of fluid intake, and physiotherapy including bladder retraining. Surgery remains the last resort in the treatment and is usually reserved for intractable detrusor overactivity, as it is associated with significant morbidity. This article reviews the management of the overactive bladder with specific focus on newer developments in the medical treatment of OAB in women.
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Affiliation(s)
- Sushma Srikrishna
- Department of Urogynaecology, King's College Hospital, Denmark Hill, London, UK.
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48
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Lu T, Ye D, Wang X, Seubert JM, Graves JP, Bradbury JA, Zeldin DC, Lee HC. Cardiac and vascular KATP channels in rats are activated by endogenous epoxyeicosatrienoic acids through different mechanisms. J Physiol 2006; 575:627-44. [PMID: 16793897 PMCID: PMC1819457 DOI: 10.1113/jphysiol.2006.113985] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We have reported that epoxyeicosatrienoic acids (EETs), the cytochrome P450 (CYP) epoxygenase metabolites of arachidonic acid (AA), are potent sarcolemmal ATP-sensitive K+ (KATP) channel activators. However, activation of cardiac and vascular KATP channels by endogenously produced EETs under physiological intracellular conditions has not been demonstrated and direct comparison of the mechanisms whereby EETs activate the KATP channels in cardiac myocytes versus vascular smooth muscle cells has not been made. In this study, we examined the effects of AA on KATP channels in freshly isolated cardiac myocytes from rats, wild-type (WT) and transgenic mice overexpressing CYP2J2 cDNA, and mesenteric arterial smooth muscle cells from rats. We also compared the activation of cardiac and vascular KATP channels by extracellularly and intracellularly applied 11,12-EET. We found that 1 microm AA enhanced KATP channel activities in both cardiac and vascular smooth muscle cells, and the AA effects were inhibited by preincubation with CYP epoxygenase inhibitors. Baseline cardiac KATP current densities in CYP2J2 transgenic mice were 190% higher than those of WT mice, and both were reduced to similar levels by CYP epoxygenase inhibition. Western blot analysis showed that expression of Kir6.2 and SUR2A was similar between WT and CYP2J2 transgenic hearts. 11,12-EET (5 microm) applied intracellularly enhanced the KATP currents by 850% in cardiac myocytes, but had no effect in vascular smooth muscle cells. In contrast, 11,12-EET (5 microm) applied extracellularly increased KATP currents by 520% in mesenteric arterial smooth muscle cells, but by only 209% in cardiac myocytes. Preincubation with 100 microm m-iodobenzylguanidine or 5 microm myristoylated PKI amide did not alter the activation of cardiac KATP channels by 5 microm 11,12-EET, but significantly inhibited activation of vascular KATP channels. Moreover, EET only enhanced the inward component of cardiac KATP currents, but activated both the inward and outward components of vascular KATP currents. Our results indicate that endogenously derived CYP metabolites of AA potently activate cardiac and vascular KATP channels. EETs regulate cardiac electrophysiology and vascular tone by KATP channel activation, albeit through different mechanisms: the cardiac KATP channels are directly activated by EETs, whereas activation of the vascular KATP channels by EETs is protein kinase A dependent.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacology
- Arteries/cytology
- Arteries/drug effects
- Arteries/metabolism
- Cyclic AMP-Dependent Protein Kinases/physiology
- Cytochrome P-450 CYP2J2
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Gene Expression Regulation, Enzymologic/genetics
- Male
- Mice
- Mice, Transgenic
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Oxygenases/genetics
- Oxygenases/metabolism
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Rats
- Rats, Sprague-Dawley
- Vasodilator Agents/metabolism
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Affiliation(s)
- Tong Lu
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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49
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Robinson D, Cardozo L. Pharmacological treatment for overactive bladder in women. WOMEN'S HEALTH (LONDON, ENGLAND) 2006; 2:239-250. [PMID: 19803896 DOI: 10.2217/17455057.2.2.239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Urinary incontinence is a common and distressing condition that is known to adversely affect quality of life. Overactive bladder is the term used to describe the symptom complex of urinary frequency and urgency, with or without urge incontinence. Drug therapy, in addition to behavioral modification, remains integral in the management of women with overactive bladder, and the development of new drugs, treatment regimens and methods of delivery should improve patient compliance and acceptability. This article critically reviews the current pharmacological treatment of overactive bladder in addition to providing a rationale for treatment.
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Affiliation(s)
- Dudley Robinson
- Department of Urogynaecology, King's College Hospital, Denmark Hill, London, UK.
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50
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Casis O, Olesen SP, Sanguinetti MC. Mechanism of Action of a Novel Humanether-a-go-go-Related Gene Channel Activator. Mol Pharmacol 2005; 69:658-65. [PMID: 16284303 DOI: 10.1124/mol.105.019943] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
1,3-Bis-(2-hydroxy-5-trifluoromethyl-phenyl)-urea (NS1643) is a newly discovered activator of human ether-a-go-go-related gene (hERG) K(+) channels. Here, we characterize the effects of this compound on cloned hERG channels heterologously expressed in Xenopus laevis oocytes. When assessed with 2-s depolarizations, NS1643 enhanced the magnitude of wild-type hERG current in a concentration- and voltage-dependent manner with an EC(50) of 10.4 microM at -10 mV. The fully activated current-voltage relationship revealed that the drug increased outward but not inward currents, consistent with altered inactivation gating. NS1643 shifted the voltage dependence of inactivation by +21 mV at 10 microM and +35 mV at 30 microM, but it did not alter the voltage dependence of activation of hERG channels. The effects of the drug on three inactivation-deficient hERG mutant channels (S620T, S631A, and G628C/S631C) were determined. In the absence of channel inactivation, NS1643 did not enhance hERG current magnitude. The agonist activity of NS1643 was facilitated by mutations (F656 to Val, Met, or Thr) that are known to greatly attenuate channel inhibition by hERG blockers. We conclude that NS1643 is a partial agonist of hERG channels and that the mechanism of activation is reduced channel inactivation.
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Affiliation(s)
- Oscar Casis
- Nora Eccles Harrison Cardiovascular Research and Training Institute and Department of Physiology, University of Utah, Salt Lake City, 84112, USA
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