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Zhou J, Wang W, Liu D, Xu S, Wang X, Zhang X, Wang X, Li Y, Sheng L, Wang X, Xu B. Discovery of 2-Ethoxy-5-isobutyramido- N-1-substituted Benzamide Derivatives as Selective Kv2.1 Inhibitors with In Vivo Neuroprotective Effects. J Med Chem 2024; 67:213-233. [PMID: 38150670 DOI: 10.1021/acs.jmedchem.3c01245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Kv2.1 is involved in regulating neuronal excitability and neuronal cell apoptosis, and inhibiting Kv2.1 is a potential strategy to prevent cell death and achieve neuroprotection in ischemic stroke. In this work, a series of novel benzamide derivatives were designed and synthesized as Kv2.1 inhibitors, and extensive structure-activity relationships led to highly potent and selective Kv2.1 inhibitors having IC50 values of 10-8 M. Among them, compound 80 (IC50 = 0.07 μM, selectivity >130 fold over other K+, Na+, and Ca2+ ion channels) was able to decrease the apoptosis of HEK293/Kv2.1 cells induced by H2O2. Furthermore, its anti-ischemic efficacy was demonstrated as it markedly reduced the infarct volume in MCAO rat model. Additionally, compound 80 possessed appropriate plasma PK parameters. It could serve as a probe to investigate Kv2.1 pathological functions and deserved to be further explored.
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Affiliation(s)
- Jie Zhou
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Weiping Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Dong Liu
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Shaofeng Xu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xue Wang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xinyuan Zhang
- Information Center, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xiaoyu Wang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yan Li
- Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD Study, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Li Sheng
- Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD Study, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xiaoliang Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Bailing Xu
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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Wang X, Zhang X, Zhou J, Wang W, Wang X, Xu B. An in silico investigation of Kv2.1 potassium channel: Model building and inhibitors binding sites analysis. Mol Inform 2023; 42:e202300072. [PMID: 37793122 DOI: 10.1002/minf.202300072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 09/25/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Kv2.1 is widely expressed in brain, and inhibiting Kv2.1 is a potential strategy to prevent cell death and achieve neuroprotection in ischemic stroke. Herein, an in silico model of Kv2.1 tetramer structure was constructed by employing the AlphaFold-Multimer deep learning method to facilitate the rational discovery of Kv2.1 inhibitors. GaMD was utilized to create an ion transporting trajectory, which was analyzed with HMM to generate multiple representative receptor conformations. The binding site of RY785 and RY796(S) under the P-loop was defined with Fpocket program together with the competitive binding electrophysiology assay. The docking poses of the two inhibitors were predicted with the aid of the semi-empirical quantum mechanical calculation, and the IGMH results suggested that Met375, Thr376, and Thr377 of the P-helix and Ile405 of the S6 segment made significant contributions to the binding affinity. These results provided insights for rational molecular design to develop novel Kv2.1 inhibitors.
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Affiliation(s)
- Xiaoyu Wang
- Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Xinyuan Zhang
- Information Center, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Jie Zhou
- Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Weiping Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Xiaoliang Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Bailing Xu
- Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
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Stone TW. Does kynurenic acid act on nicotinic receptors? An assessment of the evidence. J Neurochem 2020; 152:627-649. [PMID: 31693759 PMCID: PMC7078985 DOI: 10.1111/jnc.14907] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023]
Abstract
As a major metabolite of kynurenine in the oxidative metabolism of tryptophan, kynurenic acid is of considerable biological and clinical importance as an endogenous antagonist of glutamate in the central nervous system. It is most active as an antagonist at receptors sensitive to N-methyl-D-aspartate (NMDA) which regulate neuronal excitability and plasticity, brain development and behaviour. It is also thought to play a causative role in hypo-glutamatergic conditions such as schizophrenia, and a protective role in several neurodegenerative disorders, notably Huntington's disease. An additional hypothesis, that kynurenic acid could block nicotinic receptors for acetylcholine in the central nervous system has been proposed as an alternative mechanism of action of kynurenate. However, the evidence for this alternative mechanism is highly controversial, partly because at least eight earlier studies concluded that kynurenic acid blocked NMDA receptors but not nicotinic receptors and five subsequent, independent studies designed to repeat the results have failed to do so. Many studies considered to support the alternative 'nicotinic' hypothesis have been based on the use of analogs of kynurenate such as 7-chloro-kynurenic acid, or putatively nicotinic modulators such as galantamine, but a detailed analysis of the pharmacology of these compounds suggests that the results have often been misinterpreted, especially since the pharmacology of galantamine itself has been disputed. This review examines the evidence in detail, with the conclusion that there is no confirmed, reliable evidence for an antagonist activity of kynurenic acid at nicotinic receptors. Therefore, since there is overwhelming evidence for kynurenate acting at ionotropic glutamate receptors, especially NMDAR glutamate and glycine sites, with some activity at GPR35 sites and Aryl Hydrocarbon Receptors, results with kynurenic acid should be interpreted only in terms of these confirmed sites of action.
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Affiliation(s)
- Trevor W. Stone
- Institute for Neuroscience and PsychologyUniversity of GlasgowGlasgowG12 8QQUK
- Present address:
Kennedy InstituteNDORMSUniversity of OxfordOxfordOX3 7FYUK
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Agrawal M, Saraf S, Saraf S, Antimisiaris SG, Chougule MB, Shoyele SA, Alexander A. Nose-to-brain drug delivery: An update on clinical challenges and progress towards approval of anti-Alzheimer drugs. J Control Release 2018; 281:139-177. [DOI: 10.1016/j.jconrel.2018.05.011] [Citation(s) in RCA: 203] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/10/2018] [Accepted: 05/10/2018] [Indexed: 01/02/2023]
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Paeonol promotes hippocampal synaptic transmission: The role of the Kv2.1 potassium channel. Eur J Pharmacol 2018; 827:227-237. [PMID: 29550337 DOI: 10.1016/j.ejphar.2018.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 12/30/2022]
Abstract
Paeonol is a major constituent of the Chinese herb Moutan cortex radices. Recent studies report that paeonol has neuroprotective effects and improves impaired learning and memory. However, its underlying mechanisms by which paeonol contributes to synaptic transmission remain unclear. In this study, we found that paeonol increased the frequency of miniature excitatory postsynaptic currents (mEPSCs) and spontaneous excitatory postsynaptic currents (sEPSCs), but had no effect on the amplitude in rat hippocampal CA1 neurons. Similarly, the acetylcholinesterase (AChE) inhibitor rivastigmine increased the frequency of mEPSCs, but had no effect upon amplitude in rat hippocampal neurons. Rivastigmine also inhibited the delayed outward K+ currents in rat hippocampal CA1 neurons, but had no effect in nucleus ambiguus (NA) neurons. The Kv2 blocker guangxitoxin-1E increased the frequency of both mEPSCs and sEPSCs of rat hippocampal CA1 neurons, without affecting their amplitude. Our results suggest that paeonol and rivastigmine enhance spontaneous presynaptic transmitter release, which may be associated with the inhibition of the hippocampal Kv2 current and with therapeutic potential in neurotransmitter deficits found in Alzheimer's disease (AD). Moreover, our data also show that paeonol protects against Aβ25-35-induced impairment of long-term potentiation (LTP) in mouse hippocampal neurons. However, guangxitoxin-1E failed to potentiate the evoked field excitatory postsynaptic potentials (fEPSPs), LTP and Aβ25-35-induced impairment of LTP. These results indicate that paeonol may has the potential to improve learning and memory in AD. Interestingly, this effect is not involved in the inhibition of the hippocampal Kv2 current.
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Yang CT, Leung YM, Hsu SF, MacDonald I, Wang ML, Lin JG, Hung SY, Chen YH. A comparison of the delayed outward potassium current between the nucleus ambiguus and hippocampus: sensitivity to paeonol. Eur J Pharmacol 2016; 784:49-60. [PMID: 27164420 DOI: 10.1016/j.ejphar.2016.04.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 01/31/2023]
Abstract
Whole-cell patch-clamp recordings investigated the electrophysiological effects of 2'-hydroxy-4'-methoxyacetophenone (paeonol), one of the major components of Moutan Cortex, in hippocampal CA1 neurons and nucleus ambiguus (NA) neurons from neonatal rats as well as in lung epithelial H1355 cells expressing Kv2.1 or Kv1.2. Extracellular application of paeonol at 100μM did not significantly affect the spontaneous action potential frequency, whereas paeonol at 300μM increased the frequency of spontaneous action potentials in hippocampal CA1 neurons. Paeonol (300μM) significantly decreased the tetraethylammonium-sensitive outward current in hippocampal CA1 neurons, but had no effect upon the fast-inactivating potassium current (IA). Extracellular application of paeonol at 300μM did not affect action potentials or the delayed outward currents in NA neurons. Paeonol (100μM) reduced the Kv2.1 current in H1355 cells, but not the Kv1.2 current. The inhibitor of Kv2, guangxitoxin-1E, reduced the delayed outward potassium currents in hippocampal neurons, but had only minimal effects in NA neurons. We demonstrated that paeonol decreased the delayed outward current and increased excitability in hippocampal CA1 neurons, whereas these effects were not observed in NA neurons. These effects may be associated with the inhibitory effects on Kv2.1 currents.
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Affiliation(s)
- Chin-Tsang Yang
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Sheng-Feng Hsu
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan
| | - Iona MacDonald
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan
| | - Mei-Ling Wang
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Jaung-Geng Lin
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Shih-Ya Hung
- Division of Colorectal Surgery, China Medical University Hospital, Taichung, Taiwan; Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan.
| | - Yi-Hung Chen
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan; Department of Photonics and Communication Engineering, Asia University, Taiwan.
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Zhou TT, Quan LL, Chen LP, Du T, Sun KX, Zhang JC, Yu L, Li Y, Wan P, Chen LL, Jiang BH, Hu LH, Chen J, Shen X. SP6616 as a new Kv2.1 channel inhibitor efficiently promotes β-cell survival involving both PKC/Erk1/2 and CaM/PI3K/Akt signaling pathways. Cell Death Dis 2016; 7:e2216. [PMID: 27148689 PMCID: PMC4917657 DOI: 10.1038/cddis.2016.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 12/31/2022]
Abstract
Kv2.1 as a voltage-gated potassium (Kv) channel subunit has a pivotal role in the regulation of glucose-stimulated insulin secretion (GSIS) and pancreatic β-cell apoptosis, and is believed to be a promising target for anti-diabetic drug discovery, although the mechanism underlying the Kv2.1-mediated β-cell apoptosis is obscure. Here, the small molecular compound, ethyl 5-(3-ethoxy-4-methoxyphenyl)-2-(4-hydroxy-3-methoxybenzylidene)-7-methyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate (SP6616) was discovered to be a new Kv2.1 inhibitor. It was effective in both promoting GSIS and protecting β cells from apoptosis. Evaluation of SP6616 on either high-fat diet combined with streptozocin-induced type 2 diabetic mice or db/db mice further verified its efficacy in the amelioration of β-cell dysfunction and glucose homeostasis. SP6616 treatment efficiently increased serum insulin level, restored β-cell mass, decreased fasting blood glucose and glycated hemoglobin levels, and improved oral glucose tolerance. Mechanism study indicated that the promotion of SP6616 on β-cell survival was tightly linked to its regulation against both protein kinases C (PKC)/extracellular-regulated protein kinases 1/2 (Erk1/2) and calmodulin(CaM)/phosphatidylinositol 3-kinase(PI3K)/serine/threonine-specific protein kinase (Akt) signaling pathways. To our knowledge, this may be the first report on the underlying pathway responsible for the Kv2.1-mediated β-cell protection. In addition, our study has also highlighted the potential of SP6616 in the treatment of type 2 diabetes.
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Affiliation(s)
- T T Zhou
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - L L Quan
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L P Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - T Du
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - K X Sun
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - J C Zhang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L Yu
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Y Li
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - P Wan
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L L Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - B H Jiang
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - L H Hu
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - J Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - X Shen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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McCord MC, Aizenman E. The role of intracellular zinc release in aging, oxidative stress, and Alzheimer's disease. Front Aging Neurosci 2014; 6:77. [PMID: 24860495 PMCID: PMC4028997 DOI: 10.3389/fnagi.2014.00077] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 04/02/2014] [Indexed: 01/26/2023] Open
Abstract
Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury.
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Affiliation(s)
- Meghan C McCord
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
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9
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Li W, Zhou Y, Zhao N, Hao B, Wang X, Kong P. Pharmacokinetic behavior and efficiency of acetylcholinesterase inhibition in rat brain after intranasal administration of galanthamine hydrobromide loaded flexible liposomes. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2012; 34:272-279. [PMID: 22613079 DOI: 10.1016/j.etap.2012.04.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 04/22/2012] [Accepted: 04/25/2012] [Indexed: 06/01/2023]
Abstract
Galanthamine hydrobromide (GH) has been approved for symptomatic treatment of Alzheimer's disease (AD) and vascular dementia. Hence, the effects of intranasal administration of GH loaded flexible liposomes have been investigated for the first time on the efficiency of acetylcholinesterase inhibition, as well as the pharmacokinetic behavior of GH in rat brain. The GH loaded flexible liposomes were characterized for shape, entrapment capacity, size distribution and zeta potential by transmission electron microscopy (TEM), ultracentrifugation and dynamic light scattering (DLS), respectively. The inhibition of acetylcholinesterase was investigated using rat brain homogenates as an enzyme resource and microdialysis was used to determine the pharmacokinetic behavior of GH in rats brain. The rat pheochromocytoma PC-12 cell line was used to evaluate the cytotoxicity of GH loaded flexible liposomes. The results revealed that: (i) the efficiency of acetylcholinesterase inhibition of GH was greatly enhanced by intranasal administration compared with oral administration, especially GH loaded in flexible liposomes; (ii) the C(max) and AUC(0→10) for intranasal administration of GH loaded flexible liposomes were 3.52 and 3.36 times higher than those of orally administered GH, moreover, the T(max) was greatly shortened from 1.5h for oral administration to 0.75h for intranasal administration of GH loaded flexible liposomes; and (iii) PC-12 cells viability tests showed that the flexible liposome carrier is not toxic to the cultured cells and the cytotoxicity of GH to cells was clearly decreased by loading in flexible liposomes. These results indicate that intranasal administration of GH loaded flexible liposomes could readily transport GH into brain tissues, suggesting some promise for this approach in successful brain-drug targeting in AD treatment.
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Affiliation(s)
- Weize Li
- College of Pharmacy, Xi'an Medical University, Xi'an 710021, PR China; Institute of Drug Research and Development, Fengyuan Pharmaceutical Limited Company, Ruicheng 044600, PR China
| | - Yongqiang Zhou
- Center of Nanjing Hailing R&D for Chinese Traditional Medicine Pharmaceutical Technology, Nanjing 210049, PR China.
| | - Ning Zhao
- College of Pharmacy, Xi'an Medical University, Xi'an 710021, PR China
| | - Baohua Hao
- School of Science and Life, Northwest University, Xi'an 710069, PR China
| | - Xiaoning Wang
- College of Pharmacy, Xi'an Medical University, Xi'an 710021, PR China
| | - Peng Kong
- Institute of Drug Research and Development, Fengyuan Pharmaceutical Limited Company, Ruicheng 044600, PR China
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10
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Hao S, Bao YM, An LJ, Cheng W, Zhao RG, Bi J, Wang HS, Sun CS, Liu JW, Jiang B. Effects of Resibufogenin and Cinobufagin on voltage-gated potassium channels in primary cultures of rat hippocampal neurons. Toxicol In Vitro 2011; 25:1644-53. [DOI: 10.1016/j.tiv.2011.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 05/29/2011] [Accepted: 07/04/2011] [Indexed: 10/17/2022]
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Vicente MI, Costa PF, Lima PA. Galantamine inhibits slowly inactivating K+ currents with a dual dose–response relationship in differentiated N1E-115 cells and in CA1 neurones. Eur J Pharmacol 2010; 634:16-25. [DOI: 10.1016/j.ejphar.2010.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 01/26/2010] [Accepted: 02/13/2010] [Indexed: 11/15/2022]
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Frolov RV, Bondarenko VE, Singh S. Mechanisms of Kv2.1 channel inhibition by celecoxib--modification of gating and channel block. Br J Pharmacol 2009; 159:405-18. [PMID: 20015088 DOI: 10.1111/j.1476-5381.2009.00539.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Selective cyclooxygenase-2 (COX-2) inhibitors such as rofecoxib (Vioxx) and celecoxib (Celebrex) were developed as NSAIDs with reduced gastric side effects. Celecoxib has now been shown to affect cellular physiology via an unexpected, COX-independent, pathway - by inhibiting K(v)2.1 and other ion channels. In this study, we investigated the mechanism of the action of celecoxib on K(v)2.1 channels. EXPERIMENTAL APPROACH The mode of action of celecoxib on rat K(v)2.1 channels was studied by whole-cell patch-clamping to record currents from channels expressed in HEK-293 cells. KEY RESULTS Celecoxib reduced current through K(v)2.1 channels when applied from the extracellular side. At low concentrations (<or=3 microM), celecoxib accelerated kinetics of activation, deactivation and inactivation. Recovery of rat K(v)2.1 channels from inactivation could be characterized by two components, with celecoxib selectively accelerating the slow component of recovery at <or=10 microM. At >3 microM, celecoxib led to closed-channel block with relative slowing of activation. At 30 microM, it additionally induced open-channel block that manifested in use-dependent inhibition and slower recovery from inactivation. CONCLUSIONS AND IMPLICATIONS Celecoxib reduced current through K(v)2.1 channels by modifying gating and inducing closed- and open-channel block, with the three effects manifesting at different concentrations. These data will help to elucidate the mechanisms of action of this widely prescribed drug on ion channels and those underlying its neurological, cardiovascular and other effects.
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Affiliation(s)
- R V Frolov
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214-3000, USA
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Alés E, Gullo F, Arias E, Olivares R, García AG, Wanke E, López MG. Blockade of Ca2+-activated K+ channels by galantamine can also contribute to the potentiation of catecholamine secretion from chromaffin cells. Eur J Pharmacol 2006; 548:45-52. [PMID: 16949070 DOI: 10.1016/j.ejphar.2006.07.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 07/14/2006] [Accepted: 07/19/2006] [Indexed: 11/30/2022]
Abstract
Galantamine is a drug in clinical use for the treatment of Alzheimer's disease, but its mechanism(s) of action remains controversial. Here we addressed the question whether galantamine could potentiate neurotransmitter release by inhibiting small conductance Ca2+ -activated K+ channels (KCa2). Galantamine potentiated catecholamine secretory responses induced by 10 s pulses of acetylcholine and high [K+]o applied to fast-superfused bovine adrenal chromaffin cell populations. Catecholamine release was significantly enhanced by galantamine although we did not find concentration dependence in the range 0.1-1 microM. The KCa2 channel blocker apamin (0.3 microM) occluded the potentiating effects of galantamine on acetylcholine-evoked secretion. Like apamin, galantamine also modified the firing of action potentials, but to a lesser extent. In addition, 1 microM galantamine reduced by 41% the KCa2 current without modifying the voltage-dependent Ca2+ currents. These results constitute the first direct evidence that galantamine can potentiate neurotransmitter release by blocking KCa2 channels, in addition to its already demonstrated capacity to mildly block acetylcholinesterase or potentiate allosterically nicotinic receptors.
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Affiliation(s)
- Eva Alés
- Instituto Teófilo Hernando. Departamento de Farmacología y Terapéutica, Facultad de Medicina, U.A.M., Universidad Autónoma de Madrid, C/, Arzobispo Morcillo 4, E-28029 Madrid - Spain
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Zhao YM, Sun LN, Zhou HY, Wang XL. Voltage-dependent potassium channels are involved in glutamate-induced apoptosis of rat hippocampal neurons. Neurosci Lett 2006; 398:22-7. [PMID: 16434141 DOI: 10.1016/j.neulet.2005.12.073] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2005] [Revised: 12/13/2005] [Accepted: 12/19/2005] [Indexed: 11/18/2022]
Abstract
The role of voltage-dependent potassium channel currents in glutamate-treated rat hippocampal neurons was investigated. Cell viability was evaluated by MTT reduction assay and morphological changes. Apoptosis was detected by Hoechst33342 staining with fluorescent microscopy and propidium iodide staining with flow cytometry. Membrane potassium channel currents were recorded with whole-cell patch clamp recordings. Results showed that after shortly exposed to glutamate, about 25 and 50% cells died in 3 h and 24 h, respectively. Meanwhile, the enhancement of IK was observed within 6 h after the glutamate insult. TEA selectively blocked IK and significantly reduced cell apoptosis. IA did not change in the insult though 4-AP, the blocker of this current, showed a protective effect against the injury. These data were in consistent with the hypothesis that K+ efflux contributed to glutamate-triggered apoptosis and IK channels might have a therapeutic effect on the treatment of cerebral ischemia.
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Affiliation(s)
- Yu-Ming Zhao
- Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050, China
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