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Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension. Biochem Pharmacol 2022; 206:115318. [PMID: 36283445 DOI: 10.1016/j.bcp.2022.115318] [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: 08/24/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.
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2
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Yang L, Wang Y, Chen Z. Central histaminergic signalling, neural excitability and epilepsy. Br J Pharmacol 2021; 179:3-22. [PMID: 34599508 DOI: 10.1111/bph.15692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 09/07/2021] [Accepted: 09/12/2021] [Indexed: 12/31/2022] Open
Abstract
Epilepsy is a common neurological disorder characterized by repeated and spontaneous epileptic seizures and is not well controlled by current medication. Traditional theory suggests that epilepsy results from an imbalance of excitatory glutamate neurons and inhibitory GABAergic neurons. However, new evidence from clinical and preclinical research suggests that histamine in the CNS plays an important role in the modulation of neural excitability and in the pathogenesis of epilepsy. Many histamine receptor ligands have achieved curative effects in animal epilepsy models, among which the histamine H3 receptor antagonist pitolisant has shown anti-epileptic effects in clinical trials. Recent studies, therefore, have focused on the potential action of histamine receptors to control and treat epilepsy. In this review, we summarize the findings from animal and clinical epilepsy research on the role of brain histamine and its receptors. We also identify current gaps in the research and suggest where further studies are most needed.
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Affiliation(s)
- Lin Yang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.,Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.,Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Naffaa MM, Al-Ewaidat OA. Ligand modulation of KCNQ-encoded (K V7) potassium channels in the heart and nervous system. Eur J Pharmacol 2021; 906:174278. [PMID: 34174270 DOI: 10.1016/j.ejphar.2021.174278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/06/2021] [Accepted: 06/18/2021] [Indexed: 10/21/2022]
Abstract
KCNQ-encoded (KV7) potassium channels are diversely distributed in the human tissues, associated with many physiological processes and pathophysiological conditions. These channels are increasingly used as drug targets for treating diseases. More selective and potent molecules on various types of the KV7 channels are desirable for appropriate therapies. The recent knowledge of the structure and function of human KCNQ-encoded channels makes it more feasible to achieve these goals. This review discusses the role and mechanism of action of many molecules in modulating the function of the KCNQ-encoded potassium channels in the heart and nervous system. The effects of these compounds on KV7 channels help to understand their involvement in many diseases, and to search for more selective and potent ligands to be used in the treatment of many disorders such as various types of cardiac arrhythmias, epilepsy, and pain.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
| | - Ola A Al-Ewaidat
- Faculty of Medicine, The University of Jordan, Amman, 11942, Jordan
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Sato A, Arichi S, Kojima F, Hayashi T, Ohba T, Cheung DL, Eto K, Narushima M, Murakoshi H, Maruo Y, Kadoya Y, Nabekura J, Ishibashi H. Histamine depolarizes rat intracardiac ganglion neurons through the activation of TRPC non-selective cation channels. Eur J Pharmacol 2020; 886:173536. [PMID: 32896550 DOI: 10.1016/j.ejphar.2020.173536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 08/27/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022]
Abstract
The cardiac plexus, which contains parasympathetic ganglia, plays an important role in regulating cardiac function. Histamine is known to excite intracardiac ganglion neurons, but the underlying mechanism is obscure. In the present study, therefore, the effect of histamine on rat intracardiac ganglion neurons was investigated using perforated patch-clamp recordings. Histamine depolarized acutely isolated neurons with a half-maximal effective concentration of 4.5 μM. This depolarization was markedly inhibited by the H1 receptor antagonist triprolidine and mimicked by the H1 receptor agonist 2-pyridylethylamine, thus implicating histamine H1 receptors. Consistently, reverse transcription-PCR (RT-PCR) and Western blot analyses confirmed H1 receptor expression in the intracardiac ganglia. Under voltage-clamp conditions, histamine evoked an inward current that was potentiated by extracellular Ca2+ removal and attenuated by extracellular Na+ replacement with N-methyl-D-glucamine. This implicated the involvement of non-selective cation channels, which given the link between H1 receptors and Gq/11-protein-phospholipase C signalling, were suspected to be transient receptor potential canonical (TRPC) channels. This was confirmed by the marked inhibition of the inward current through the pharmacological disruption of either Gq/11 signalling or intracellular Ca2+ release and by the application of the TRPC blockers Pyr3, Gd3+ and ML204. Consistently, RT-PCR analysis revealed the expression of several TRPC subtypes in the intracardiac ganglia. Whilst histamine was also separately found to inhibit the M-current, the histamine-induced depolarization was only significantly inhibited by the TRPC blockers Gd3+ and ML204, and not by the M-current blocker XE991. These results suggest that TRPC channels serve as the predominant mediator of neuronal excitation by histamine.
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Affiliation(s)
- Aya Sato
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan; Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan; Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Shiho Arichi
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Fumiaki Kojima
- Department of Pharmacology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Toru Hayashi
- Department of Anatomical Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tatsuko Ohba
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Dennis Lawrence Cheung
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Kei Eto
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Madoka Narushima
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Yuichi Kadoya
- Department of Anatomical Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Hitoshi Ishibashi
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan.
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Voltage-dependent modulation of TRPA1 currents by diphenhydramine. Cell Calcium 2020; 90:102245. [PMID: 32634675 DOI: 10.1016/j.ceca.2020.102245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 11/23/2022]
Abstract
Diphenhydramine (DPH) has been broadly used to treat allergy. When used as a topical medicine, DPH temporarily relieves itching and pain. Although transient receptor potential type A1 (TRPA1) channel is known to play roles in both acute and chronic itch and pain, whether DPH affects the activities of TRPA1 remains unclear. Using whole-cell patch clamp recordings, we demonstrated that DPH modulates the voltage-dependence of TRPA1. When co-applied with a TRPA1 agonist, DPH significantly enhanced the inward currents while suppressing the outward currents of TRPA1, converting the channel from outwardly rectifying to inwardly rectifying. This effect of DPH occurred no matter TRPA1 was activated by an electrophilic or non-electrophilic agonist and for both mouse and human TRPA1. The modulation of TRPA1 by DPH was maintained in the L906C mutant, which by itself also causes inward rectification of TRPA1, indicating that additional acting sites are present for the modulation of TRPA1 currents by DPH. Our recordings also revealed that DPH partially blocked capsaicin evoked TRPV1 currents. These data suggest that DPH may exert its therapeutic effects on itch and pain, through modulation of TRPA1 in a voltage-dependent fashion.
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Andersson R, Galter D, Papadia D, Fisahn A. Histamine induces KCNQ channel-dependent gamma oscillations in rat hippocampus via activation of the H1 receptor. Neuropharmacology 2017; 118:13-25. [PMID: 28274820 DOI: 10.1016/j.neuropharm.2017.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 11/30/2022]
Abstract
Histamine is an aminergic neurotransmitter, which regulates wakefulness, arousal and attention in the central nervous system. Histamine receptors have been the target of efforts to develop pro-cognitive drugs to treat disorders such as Alzheimer's disease and schizophrenia. Cognitive functions including attention are closely associated with gamma oscillations, a rhythmical electrical activity pattern in the 30-80 Hz range, which depends on the synchronized activity of excitatory pyramidal cells and inhibitory fast-spiking interneurons. We set out to explore whether histamine has a role in promoting gamma oscillations in the hippocampus. Using in-situ hybridization we demonstrate that histamine receptor subtypes 1, 2 and 3 are expressed in stratum pyramidale of area CA3 in rats. We show that both pyramidal cells and fast-spiking interneurons depolarize and increase action potential firing in response to histamine in vitro. The activation of histamine receptors generates dose-dependent, transient gamma oscillations in area CA3 of the hippocampus - the locus of the gamma rhythm generator. We also demonstrate that this histamine effect is independent of muscarinic receptors. Using specific antagonists we provide evidence that histamine gamma rhythmogenesis specifically depends on the H1 receptor. Histamine also depolarized both pyramidal cells and fast-spiking interneurons and increased membrane resistance in pyramidal cells. The increased membrane resistance is potentially mediated by the inhibition of potassium channels because application of the KCNQ channel opener ICA110381 abolished the oscillations. Taken together our data demonstrate a novel and physiological mechanism for generating gamma oscillations in hippocampus and suggest a role for KCNQ channels in this cognition-relevant brain activity.
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Affiliation(s)
- Richard Andersson
- Neuronal Oscillations Laboratory, Neurogeriatrics Division, Center for Alzheimer Research, Dept. of Neurobiology, Care Sciences and Society, Karolinska Institutet, 14186 Stockholm, Sweden
| | - Dagmar Galter
- Dept. of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Daniela Papadia
- Neuronal Oscillations Laboratory, Neurogeriatrics Division, Center for Alzheimer Research, Dept. of Neurobiology, Care Sciences and Society, Karolinska Institutet, 14186 Stockholm, Sweden
| | - André Fisahn
- Neuronal Oscillations Laboratory, Neurogeriatrics Division, Center for Alzheimer Research, Dept. of Neurobiology, Care Sciences and Society, Karolinska Institutet, 14186 Stockholm, Sweden.
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Zhang Y, Chu X, Liu L, Zhang N, Guo H, Yang F, Liu Z, Dong Y, Bao Y, Zhang X, Zhang J. Tannic acid activates the Kv7.4 and Kv7.3/7.5 K+ channels expressed in HEK293 cells and reduces tension in the rat mesenteric arteries. J Pharm Pharmacol 2016; 68:494-502. [PMID: 26969140 DOI: 10.1111/jphp.12527] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/14/2016] [Indexed: 12/13/2022]
Abstract
Abstract
Objectives
This study investigated the effect of tannic acid (TA), a plant-derived hydrolyzable polyphenol, on Kv7.4 and Kv7.5 K+ channels and rat mesenteric artery.
Methods
Whole-cell patch clamp experiments were used to record the Kv7.4 and Kv7.3/7.5 K+ currents expressed in HEK293 cells; and the tension changes of mesenteric arteries isolated from rats were recorded using small vessel myography apparatus.
Key findings
Tannic acid increases the Kv7.4 and Kv7.3/7.5 K+ currents in a concentration-dependent manner (median effective concentration (EC50) = 27.3 ± 3.6 μm and EC50 = 23.1 ± 3.9 μm, respectively). In addition, 30 μm TA shifts the G–V curve of Kv7.4 and Kv7.3/7.5 K+ currents to the left by 14.18 and 25.24 mV, respectively, and prolongs the deactivation time constants by 184.44 and 154.77 ms, respectively. Moreover, TA relaxes the vascular tension of rat mesenteric arteries in a concentration-dependent manner (half inhibitory concentration (IC50) = 148.7 ± 13.4 μm).
Conclusion
These results confirms the vasodilatory effects of TA on rat mesenteric artery and the activating effects on the Kv7.4 and Kv7.3/7.5 K+ channels, which may be a mechanism to explain the vasodilatory effect and this mechanism can be used in the research of antihypertension.
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Affiliation(s)
- Yuanyuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Xi Chu
- Department of Pharmacy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ling Liu
- Department of Pharmacy, Maternal and Child Health Hospital, Tangshan, Hebei, China
| | - Nan Zhang
- Vascular Surgery, The East Branch of Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Hui Guo
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Fan Yang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Zhenyi Liu
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Yongsheng Dong
- Intensive Care Unit, Air Force General Hospital, Beijing, Jiangsu, China
| | - Yifan Bao
- Key Laboratory of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Xuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Jianping Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
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Föhr KJ, Zeller K, Georgieff M, Köster S, Adolph O. Open channel block of NMDA receptors by diphenhydramine. Neuropharmacology 2015; 99:459-70. [PMID: 26284492 DOI: 10.1016/j.neuropharm.2015.08.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/28/2015] [Accepted: 08/13/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Diphenhydramine is a well known H1-receptor antagonist that plays a major role in clinical practice. Nowadays, diphenhydramine is primarily applied to prevent nausea but also its sedative and analgesic effects are of clinical importance. As other drugs mediating sedative and analgesic properties partly operate via the inhibition of glutamate receptors, we tested the hypothesis that diphenhydramine, as well interacts with excitatory ionotropic glutamate receptors. EXPERIMENTAL APPROACH Electrophysiological patch-clamp experiments were performed on glutamate receptors which were heterologously expressed in human TsA cells. KEY RESULTS Diphenhydramine inhibits NMDA-mediated membrane currents in a reversible and concentration-dependent manner at clinically relevant concentrations. The inhibition occurred in a noncompetitive manner. Diphenhydramine did not compete with NMDA or glycine for their binding sites and half-maximal inhibition was obtained around 25 μM diphenhydramine, independent of the subunit composition. The inhibition was caused by a classical open channel blocking mechanism and varied strongly with the membrane potential. Our results suggest that diphenhydramine most probably interacts with the Mg2+ binding site or a very closely related area of the channel pore. CONCLUSION AND IMPLICATIONS The data presented here provide evidence that the NMDA receptor antagonism of diphenhydramine contribute to its sedative and potentially LTP-related effects like analgesia and amnesia.
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Affiliation(s)
- Karl J Föhr
- University Hospital of Ulm, Department of Anesthesiology, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Kathrin Zeller
- University Hospital of Ulm, Department of Anesthesiology, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Michael Georgieff
- University Hospital of Ulm, Department of Anesthesiology, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - Sarah Köster
- Georg-August-Universität Göttingen, Institute for X-Ray Physics, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany.
| | - Oliver Adolph
- University Hospital of Ulm, Department of Anesthesiology, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
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Li H, Wang F, Wang X, Sun R, Chen J, Chen B, Zhang Y. Antinociceptive Efficacy of Retigabine in the Monosodium Lodoacetate Rat Model for Osteoarthritis Pain. Pharmacology 2015; 95:251-7. [PMID: 25997526 DOI: 10.1159/000381721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/15/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND The goal of pharmacological osteoarthritis (OA) treatments is to reduce pain and thus increase patient joint function and quality of life. Retigabine, a potent Kv7/M channel activator, shows analgesic efficacy in animal models of chronic inflammatory and neuropathic pain. We hypothesized that retigabine may also mitigate OA pain. To determine the effects of retigabine on pain behavior associated with monosodium iodoacetate (MIA)-induced OA. METHODS The OA model was established with an intra-articular injection of MIA through the right patellar ligament, animals were treated with retigabine, and pain-related behaviors were assessed. RESULTS Retigabine significantly increased the mechanical threshold and prolonged the withdrawal latency of OA rats at 3-14 days. Retigabine also increased the mechanical threshold and prolonged the withdrawal latency of OA pain in a dose-dependent manner, with the strongest antinociceptive effect occurring at 60 min. The antinociceptive effects of retigabine were fully antagonized by the Kv7/M channel blocker XE991. CONCLUSION Retigabine showed antinociceptive effects for OA pain in the MIA model at different times during pain development. Retigabine may be an alternative therapeutic treatment for OA.
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Affiliation(s)
- Han Li
- Department of Orthopaedic Surgery, Institute of Biomechanical Science, Biomechanical Key Laboratory of Hebei Province, Third Hospital of Hebei Medical University, Shijiazhuang, China
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Sadek B, Khanian SS, Ashoor A, Prytkova T, Ghattas MA, Atatreh N, Nurulain SM, Yang KHS, Howarth FC, Oz M. Effects of antihistamines on the function of human α7-nicotinic acetylcholine receptors. Eur J Pharmacol 2014; 746:308-16. [PMID: 25445036 DOI: 10.1016/j.ejphar.2014.10.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 01/16/2023]
Abstract
Effects of the histamine H₁ receptor (H1R) antagonists (antihistamines), promethazine (PMZ), orphenadrine (ORP), chlorpheniramine (CLP), pyrilamine (PYR), diphenhydramine (DPH), citerizine (CTZ), and triprolidine (TRP) on the functional properties of the cloned α7 subunit of the human nicotinic acetylcholine receptor expressed in Xenopus oocytes were investigated. Antihistamines inhibited the α7-nicotinic acetylcholine receptor in the order PYR>CLP>TRP>PMZ>ORP≥DPH≥CTZ. Among the antihistamines, PYR showed the highest reversible inhibition of acetylcholine (100 µM)-induced responses with IC₅₀ of 6.2 µM. PYR-induced inhibition was independent of the membrane potential and could not be reversed by increasing the concentration of acetylcholine. Specific binding of [¹²⁵I] α-bungarotoxin, a selective antagonist for α7-nicotinic acetylcholine receptor, was not changed in the presence of PYR suggesting a non-competitive inhibition of nicotinic receptors. In line with functional experiments, docking studies indicated that PYR can potentially bind allosterically with the α7 transmembrane domain. Our results indicate that the H₂-H₄ receptor antagonists tested in this study (10 µM) showed negligible inhibition of α7-nicotinic acetylcholine receptors. On the other hand, H₁ receptor antagonists inhibited the function of human α7-nicotinic acetylcholine receptor, with varying potencies. These results emphasize the importance of α7-nicotinic acetylcholine receptor for future pharmacological/toxicological profiling.
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Affiliation(s)
- Bassem Sadek
- Laboratory of Functional Lipidomics, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Abu Dhabi, Al Ain, United Arab Emirates
| | - Seyedeh Soha Khanian
- Laboratory of Functional Lipidomics, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Abu Dhabi, Al Ain, United Arab Emirates
| | - Abrar Ashoor
- Laboratory of Functional Lipidomics, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Abu Dhabi, Al Ain, United Arab Emirates
| | - Tatiana Prytkova
- Department of Biological Sciences, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - Mohammad A Ghattas
- College of Pharmacy, Al Ain University of Science and Technology, Al Ain, United Arab Emirates
| | - Noor Atatreh
- College of Pharmacy, Al Ain University of Science and Technology, Al Ain, United Arab Emirates
| | - Syed M Nurulain
- Laboratory of Functional Lipidomics, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Abu Dhabi, Al Ain, United Arab Emirates
| | - Keun-Hang Susan Yang
- Department of Biological Sciences, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - Frank Christopher Howarth
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Murat Oz
- Laboratory of Functional Lipidomics, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Abu Dhabi, Al Ain, United Arab Emirates.
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Zhang F, Mi Y, Qi JL, Li JW, Si M, Guan BC, Du XN, An HL, Zhang HL. Modulation of K(v)7 potassium channels by a novel opener pyrazolo[1,5-a]pyrimidin-7(4H)-one compound QO-58. Br J Pharmacol 2013; 168:1030-42. [PMID: 23013484 DOI: 10.1111/j.1476-5381.2012.02232.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/22/2012] [Accepted: 09/17/2012] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Modulation of K(v)7/M channel function represents a relatively new strategy to treat neuronal excitability disorders such as epilepsy and neuropathic pain. We designed and synthesized a novel series of pyrazolo[1,5-a] pyrimidin-7(4H)-one compounds, which activate K(v)7 channels. Here, we characterized the effects of the lead compound, QO-58, on K(v)7 channels and investigated its mechanism of action. EXPERIMENTAL APPROACH A perforated whole-cell patch technique was used to record K(v)7 currents expressed in mammalian cell lines and M-type currents from rat dorsal root ganglion neurons. The effects of QO-58 in a rat model of neuropathic pain, chronic constriction injury (CCI) of the sciatic nerve, were also examined. KEY RESULTS QO-58 increased the current amplitudes, shifted the voltage-dependent activation curve in a more negative direction and slowed the deactivation of K(v)7.2/K(v)7.3 currents. QO-58 activated K(v)7.1, K(v)7.2, K(v)7.4 and K(v)7.3/K(v)7.5 channels with a more selective effect on K(v)7.2 and K(v)7.4, but little effect on K(v)7.3. The mechanism of QO-58's activation of K(v)7 channels was clearly distinct from that used by retigabine. A chain of amino acids, Val(224)Val(225)Tyr(226), in K(v)7.2 was important for QO-58 activation of this channel. QO-58 enhanced native neuronal M currents, resulting in depression of evoked action potentials. QO-58 also elevated the pain threshold of neuropathic pain in the sciatic nerve CCI model. CONCLUSIONS AND IMPLICATIONS The results indicate that QO-58 is a potent modulator of K(v)7 channels with a mechanism of action different from those of known K(v)7 openers. Hence, QO-58 shows potential as a treatment for diseases associated with neuronal hyperexcitability.
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Affiliation(s)
- F Zhang
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.
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12
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Du XN, Zhang X, Qi JL, An HL, Li JW, Wan YM, Fu Y, Gao HX, Gao ZB, Zhan Y, Zhang HL. Characteristics and molecular basis of celecoxib modulation on K(v)7 potassium channels. Br J Pharmacol 2012; 164:1722-37. [PMID: 21564087 DOI: 10.1111/j.1476-5381.2011.01483.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor used for the treatment of pain and inflammation. Emerging and accumulating evidence suggests that celecoxib can affect cellular targets other than COX, such as ion channels. In this study, we characterized the effects of celecoxib on K(v)7 K(+) channels and compared its effects with the well-established K(v)7 channel opener retigabine. EXPERIMENTAL APPROACH A perforated whole-cell patch technique was used to record K(v)7currents expressed in HEK 293 cells and M-type currents from rat superior cervical ganglion neurons. KEY RESULTS Celecoxib enhanced K(v)7.2-7.4, K(v)7.2/7.3 and K(v)7.3/7.5 currents but inhibited K(v)7.1 and K(v)7.1/KCNE1 currents and these effects were concentration dependent. The IC(50) value for inhibition of K(v)7.1 channels was approximately 4 µM and the EC(50) values for activation of K(v)7.2-7.4, K(v)7.2/K(v)7.3 and K(v)7.3/K(v)7.5 channels were approximately 2-5 µM. The effects of celecoxib were manifested by increasing current amplitudes, shifting the voltage-dependent activation curve in a more negative direction and slowing the deactivation of K(v)7 currents. 2,5-Dimethyl-celecoxib, a celecoxib analogue devoid of COX inhibition activity, has similar but greater effects on K(v)7currents. K(v)7.2(A235T) and K(v) 7.2(W236L) mutant channels, which have greatly attenuated responses to retigabine, showed a reversed response to celecoxib, from activation to inhibition. CONCLUSIONS AND IMPLICATIONS These results suggest that K(v)7 channels are targets of celecoxib action and provide new mechanistic evidence for understanding the effects of celecoxib. They also provide a new approach to developing K(v)7 modulators and for studying the structure-function relationship of K(v)7 channels.
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Affiliation(s)
- X N Du
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Department of Pharmacology, Shijiazhuang, China
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Liu B, Liang H, Liu L, Zhang H. Phosphatidylinositol 4,5-bisphosphate hydrolysis mediates histamine-induced KCNQ/M current inhibition. Am J Physiol Cell Physiol 2008; 295:C81-91. [PMID: 18448631 DOI: 10.1152/ajpcell.00028.2008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The M-type potassium channel, of which its molecular basis is constituted by KCNQ2-5 homo- or heteromultimers, plays a key role in regulating neuronal excitability and is modulated by many G protein-coupled receptors. In this study, we demonstrate that histamine inhibits KCNQ2/Q3 currents in human embryonic kidney (HEK)293 cells via phosphatidylinositol 4,5-bisphosphate (PIP(2)) hydrolysis mediated by stimulation of H(1) receptor and phospholipase C (PLC). Histamine inhibited KCNQ2/Q3 currents in HEK293 cells coexpressing H(1) receptor, and this effect was totally abolished by H(1) receptor antagonist mepyramine but not altered by H(2) receptor antagonist cimetidine. The inhibition of KCNQ currents was significantly attenuated by a PLC inhibitor U-73122 but not affected by depletion of internal Ca(2+) stores or intracellular Ca(2+) concentration ([Ca(2+)](i)) buffering via pipette dialyzing BAPTA. Moreover, histamine also concentration dependently inhibited M current in rat superior cervical ganglion (SCG) neurons by a similar mechanism. The inhibitory effect of histamine on KCNQ2/Q3 currents was entirely reversible but became irreversible when the resynthesis of PIP(2) was impaired with phosphatidylinsitol-4-kinase inhibitors. Histamine was capable of producing a reversible translocation of the PIP(2) fluorescence probe PLC(delta1)-PH-GFP from membrane to cytosol in HEK293 cells by activation of H(1) receptor and PLC. We concluded that the inhibition of KCNQ/M currents by histamine in HEK293 cells and SCG neurons is due to the consumption of membrane PIP(2) by PLC.
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Affiliation(s)
- Boyi Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei Province, China
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