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Xu HB, Zhu YY, Yang JH, Chai XY, Dong L. RhIII-Catalyzed one-pot cascade synthesis of quinazolines with N-alkoxyamide as an amidating reagent. Org Chem Front 2020. [DOI: 10.1039/d0qo00084a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Novel and efficient rhodium(iii)-catalyzed C–H bond activation and tandem annulation for the synthesis of structurally complex quinazolines have been successfully developed.
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Affiliation(s)
- Hui-Bei Xu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry
- Sichuan Research Center for Drug Precision Industrial Technology
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Yan-Ying Zhu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry
- Sichuan Research Center for Drug Precision Industrial Technology
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Jia-Hui Yang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry
- Sichuan Research Center for Drug Precision Industrial Technology
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Xin-Yue Chai
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry
- Sichuan Research Center for Drug Precision Industrial Technology
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
| | - Lin Dong
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry
- Sichuan Research Center for Drug Precision Industrial Technology
- West China School of Pharmacy
- Sichuan University
- Chengdu 610041
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2
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Lingayya R, Vellakkaran M, Nagaiah K, Tadikamalla PR, Nanubolu JB. Palladium(ii)-catalyzed direct O-alkenylation of 2-arylquinazolinones with N-tosylhydrazones: an efficient route to O-alkenylquinazolines. Chem Commun (Camb) 2017; 53:1672-1675. [PMID: 28101549 DOI: 10.1039/c6cc09445g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
An efficient Pd(ii)-catalyzed direct O-alkenylation of 2-arylquinazolinones with simple ketone-derived N-tosylhydrazones is reported. In this reaction, O-alkenylquinazolines were obtained in good yields, with excellent functional group tolerance. Pd-carbene migratory insertion is proposed as the key step in the reaction mechanism.
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Affiliation(s)
- Rajaka Lingayya
- Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad-500 007, India.
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3
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Abdullaeva OS, Schulz M, Balzer F, Parisi J, Lützen A, Dedek K, Schiek M. Photoelectrical Stimulation of Neuronal Cells by an Organic Semiconductor-Electrolyte Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8533-8542. [PMID: 27480642 DOI: 10.1021/acs.langmuir.6b02085] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
As a step toward the realization of neuroprosthetics for vision restoration, we follow an electrophysiological patch-clamp approach to study the fundamental photoelectrical stimulation mechanism of neuronal model cells by an organic semiconductor-electrolyte interface. Our photoactive layer consisting of an anilino-squaraine donor blended with a fullerene acceptor is supporting the growth of the neuronal model cell line (N2A cells) without an adhesion layer on it and is not impairing cell viability. The transient photocurrent signal upon illumination from the semiconductor-electrolyte layer is able to trigger a passive response of the neuronal cells under physiological conditions via a capacitive coupling mechanism. We study the dynamics of the capacitive transmembrane currents by patch-clamp recordings and compare them to the dynamics of the photocurrent signal and its spectral responsivity. Furthermore, we characterize the morphology of the semiconductor-electrolyte interface by atomic force microscopy and study the stability of the interface in dark and under illuminated conditions.
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Affiliation(s)
| | - Matthias Schulz
- Kekulé Institute of Organic Chemistry and Biochemistry, Rheinische-Friedrich-Wilhelms-University of Bonn , Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany
| | - Frank Balzer
- Mads Clausen Institute, University of Southern Denmark , Alsion 2, DK-6400 Sønderborg, Denmark
| | | | - Arne Lützen
- Kekulé Institute of Organic Chemistry and Biochemistry, Rheinische-Friedrich-Wilhelms-University of Bonn , Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany
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4
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Wang X, Lerchen A, Glorius F. A Comparative Investigation: Group 9 Cp*M(III)-Catalyzed Formal [4 + 2] Cycloaddition as an Atom-Economic Approach to Quinazolines. Org Lett 2016; 18:2090-3. [DOI: 10.1021/acs.orglett.6b00716] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Xiaoming Wang
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Andreas Lerchen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
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5
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Saitsu H, Akita T, Tohyama J, Goldberg-Stern H, Kobayashi Y, Cohen R, Kato M, Ohba C, Miyatake S, Tsurusaki Y, Nakashima M, Miyake N, Fukuda A, Matsumoto N. De novo KCNB1 mutations in infantile epilepsy inhibit repetitive neuronal firing. Sci Rep 2015; 5:15199. [PMID: 26477325 PMCID: PMC4609934 DOI: 10.1038/srep15199] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/21/2015] [Indexed: 11/09/2022] Open
Abstract
The voltage-gated Kv2.1 potassium channel encoded by KCNB1 produces the major delayed rectifier potassium current in pyramidal neurons. Recently, de novo heterozygous missense KCNB1 mutations have been identified in three patients with epileptic encephalopathy and a patient with neurodevelopmental disorder. However, the frequency of KCNB1 mutations in infantile epileptic patients and their effects on neuronal activity are yet unknown. We searched whole exome sequencing data of a total of 437 patients with infantile epilepsy, and found novel de novo heterozygous missense KCNB1 mutations in two patients showing psychomotor developmental delay and severe infantile generalized seizures with high-amplitude spike-and-wave electroencephalogram discharges. The mutation located in the channel voltage sensor (p.R306C) disrupted sensitivity and cooperativity of the sensor, while the mutation in the channel pore domain (p.G401R) selectively abolished endogenous Kv2 currents in transfected pyramidal neurons, indicating a dominant-negative effect. Both mutants inhibited repetitive neuronal firing through preventing production of deep interspike voltages. Thus KCNB1 mutations can be a rare genetic cause of infantile epilepsy, and insufficient firing of pyramidal neurons would disturb both development and stability of neuronal circuits, leading to the disease phenotypes.
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Affiliation(s)
- Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Jun Tohyama
- Department of Pediatrics, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | | | - Yu Kobayashi
- Department of Pediatrics, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Roni Cohen
- Epilepsy Center, Schneider's Children Medical Center, Petah Tiqwa, Israel
| | - Mitsuhiro Kato
- Department of Pediatrics, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yoshinori Tsurusaki
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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6
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Chen YH, Wu KC, Yang CT, Tu YK, Gong CL, Chao CC, Tsai MF, Kuo YH, Leung YM. Coumarsabin hastens C-type inactivation gating of voltage-gated K+ channels. Eur J Pharmacol 2013; 704:41-8. [DOI: 10.1016/j.ejphar.2013.01.062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 01/30/2013] [Accepted: 01/31/2013] [Indexed: 11/16/2022]
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7
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Garg V, Sachse FB, Sanguinetti MC. Tuning of EAG K(+) channel inactivation: molecular determinants of amplification by mutations and a small molecule. ACTA ACUST UNITED AC 2012; 140:307-24. [PMID: 22930803 PMCID: PMC3434097 DOI: 10.1085/jgp.201210826] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Ether-à-go-go (EAG) and EAG-related gene (ERG) K+ channels are close homologues but differ markedly in their gating properties. ERG1 channels are characterized by rapid and extensive C-type inactivation, whereas mammalian EAG1 channels were previously considered noninactivating. Here, we show that human EAG1 channels exhibit an intrinsic voltage-dependent slow inactivation that is markedly enhanced in rate and extent by 1–10 µM 3-nitro-N-(4-phenoxyphenyl) benzamide, or ICA105574 (ICA). This compound was previously reported to have the opposite effect on ERG1 channels, causing an increase in current magnitude by inhibition of C-type inactivation. The voltage dependence of 2 µM ICA-induced inhibition of EAG1 current was half-maximal at −73 mV, 62 mV negative to the half-point for channel activation. This finding suggests that current inhibition by the drug is mediated by enhanced inactivation and not open-channel block, where the voltage half-points for current inhibition and channel activation are predicted to overlap, as we demonstrate for clofilium and astemizole. The mutation Y464A in the S6 segment also induced inactivation of EAG1, with a time course and voltage dependence similar to that caused by 2 µM ICA. Several Markov models were investigated to describe gating effects induced by multiple concentrations of the drug and the Y464A mutation. Models with the smallest fit error required both closed- and open-state inactivation. Unlike typical C-type inactivation, the rate of Y464A- and ICA-induced inactivation was not decreased by external tetraethylammonium or elevated [K+]e. EAG1 channel inactivation introduced by Y464A was prevented by additional mutation of a nearby residue located in the S5 segment (F359A) or pore helix (L434A), suggesting a tripartite molecular model where interactions between single residues in S5, S6, and the pore helix modulate inactivation of EAG1 channels.
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Affiliation(s)
- Vivek Garg
- Department of Physiology, University of Utah, Salt Lake City, UT 84112, USA
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8
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Inhibition of voltage-gated K+ channels and Ca2+ channels by diphenidol. Pharmacol Rep 2012; 64:739-44. [PMID: 22814027 DOI: 10.1016/s1734-1140(12)70869-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 01/05/2012] [Indexed: 11/24/2022]
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9
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Leung YM. Involvement of C-type inactivation gating in the actions of voltage-gated K+ channel inhibitors. Pharmacol Ther 2012; 133:151-8. [DOI: 10.1016/j.pharmthera.2011.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 10/13/2011] [Indexed: 01/14/2023]
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Leung YM, Huang CF, Chao CC, Lu DY, Kuo CS, Cheng TH, Chang LY, Chou CH. Voltage-gated K+ channels play a role in cAMP-stimulated neuritogenesis in mouse neuroblastoma N2A cells. J Cell Physiol 2011; 226:1090-8. [PMID: 20857407 DOI: 10.1002/jcp.22430] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Neuritogenesis is essential in establishing the neuronal circuitry. An important intracellular signal causing neuritogenesis is cAMP. In this report, we showed that an increase in intracellular cAMP stimulated neuritogenesis in neuroblastoma N2A cells via a PKA-dependent pathway. Two voltage-gated K(+) (Kv) channel blockers, 4-aminopyridine (4-AP) and tetraethylammonium (TEA), inhibited cAMP-stimulated neuritogenesis in N2A cells in a concentration-dependent manner that remarkably matched their ability to inhibit Kv currents in these cells. Consistently, siRNA knock down of Kv1.1, Kv1.4, and Kv2.1 expression reduced Kv currents and inhibited cAMP-stimulated neuritogenesis. Kv1.1, Kv1.4, and Kv2.1 channels were expressed in the cell bodies and neurites as shown by immunohistochemistry. Microfluorimetric imaging of intracellular [K(+)] demonstrated that [K(+)] in neurites was lower than that in the cell body. We also showed that cAMP-stimulated neuritogenesis may not involve voltage-gated Ca(2+) or Na(+) channels. Taken together, the results suggest a role of Kv channels and enhanced K(+) efflux in cAMP/PKA-stimulated neuritogenesis in N2A cells.
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Affiliation(s)
- Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan.
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11
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Leung YM, Tsou YH, Kuo CS, Lin SY, Wu PY, Hour MJ, Kuo YH. Arylnaphthalene lignans from Taiwania cryptomerioides as novel blockers of voltage-gated K+ channels. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2010; 18:46-51. [PMID: 20684875 DOI: 10.1016/j.phymed.2010.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/19/2010] [Accepted: 04/01/2010] [Indexed: 05/29/2023]
Abstract
Lignans are natural phytochemicals which exhibit multiple pharmacological effects such as anti-inflammation, antivirus and anti-tumor activities. Whether they have effects on neural tissues and ion channels is still unknown. The effects of several arylnaphathalene lignans purified from Taiwania cryptomerioides on voltage-gated K(+) (Kv) channels in mouse neuroblastoma N2A cells were examined. These lignans included Taiwanin E, helioxanthin (HXT) and diphyllin. All lignans showed inhibitory effects on Kv channels and HXT was the most potent compound (IC(50)=1.7 μM). The mechanism of HXT block was further investigated. Its action was found to be extracellular but not intracellular. HXT accelerated current decay, caused a left-shift in steady-state inactivation curve but had no effect on voltage-dependence of activation. HXT block was unaffected by intracellular K(+) concentrations. Further, it did not affect ATP-sensitive K(+) channels. Our data therefore suggest that HXT is a potent and specific blocker of Kv channels, possibly with an inhibitory mechanism involving acceleration of slow inactivation.
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Affiliation(s)
- Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan.
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12
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Leung YM. Voltage-gated K+ channel modulators as neuroprotective agents. Life Sci 2010; 86:775-80. [PMID: 20385147 DOI: 10.1016/j.lfs.2010.04.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 03/18/2010] [Accepted: 04/01/2010] [Indexed: 01/11/2023]
Abstract
A manifestation in neurodegeneration is apoptosis of neurons. Neurons undergoing apoptosis may lose a substantial amount of cytosolic K+ through a number of pathways including K+ efflux via voltage-gated K+ (Kv) channels. The consequent drop in cytosolic [K+] relieves inhibition of an array of pro-apoptotic enzymes such as caspases and nucleases. Blocking Kv channels has been known to prevent neuronal apoptosis by preventing K+ efflux. Some neural diseases such as epilepsy are caused by neuronal hyperexcitability, which eventually may lead to neuronal apoptosis. Reduction in activities of A-type Kv channels and Kv7 subfamily members is amongst the etiological causes of neuronal hyperexcitation; enhancing the opening of these channels may offer opportunities of remedy. This review discusses the potential uses of Kv channel modulators as neuroprotective drugs.
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Affiliation(s)
- Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan, ROC.
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13
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Leung YM, Wong KL, Lin CH, Chao CC, Chou CH, Chang LY, Chen SW, Cheng TH, Kuo YH. Dependence of 6beta-acetoxy-7alpha-hydroxyroyleanone block of Kv1.2 channels on C-type inactivation. Cell Mol Life Sci 2010; 67:147-56. [PMID: 19865797 PMCID: PMC11115866 DOI: 10.1007/s00018-009-0178-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/27/2009] [Accepted: 10/06/2009] [Indexed: 11/30/2022]
Abstract
Voltage-gated K(+) (Kv) channels exhibit slow or C-type inactivation during continuous depolarization. A selective pharmacological agent targeting C-type inactivation is hitherto lacking. Here, we report that 6beta-acetoxy-7alpha-hydroxyroyleanone (AHR), a diterpenoid compound isolated from Taiwania cryptomerioides, can selectively modify C-type inactivation of Kv1.2 channels. Extracellular, but not intracellular, AHR (50 muM) dramatically accelerated the slow decay of Kv currents and left-shifted the steady-state inactivation curve. AHR blocked Kv currents with an IC(50) of 17.7 muM. AHR did not affect the kinetics and voltage-dependence of Kv1.2 channel activation. Channel block by AHR was independent of intracellular K(+) concentration. In addition, effect of AHR was much attenuated in a Kv1.2 V370G mutant defective in C-type inactivation. Therefore, block of Kv1.2 channels by AHR did not appear to involve direct occlusion of the outer pore but depended on C-type inactivation. AHR could thus be a probe targeting Kv channel C-type inactivation gate.
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Affiliation(s)
- Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, 40402 Taiwan
| | - Kar-Lok Wong
- Department of Anesthesia, China Medical University and Hospital, Taichung, 40402 Taiwan
| | - Chia-Huei Lin
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, 40402 Taiwan
| | - Chia-Chia Chao
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, 40402 Taiwan
| | - Chun-Hsiao Chou
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, 40402 Taiwan
| | - Li-Yun Chang
- Graduate Institute of Molecular Systems Biomedicine, China Medical University, Taichung, 40402 Taiwan
| | - Siao-Wei Chen
- Department of Biological Science and Technology, China Medical University, Taichung, 40402 Taiwan
| | - Tzu-Hurng Cheng
- Department of Biological Science and Technology, China Medical University, Taichung, 40402 Taiwan
| | - Yueh-Hsiung Kuo
- Tsuzuki Institute for Traditional Medicine, China Medical University, Taichung, 40402 Taiwan
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14
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Chou CH, Gong CL, Chao CC, Lin CH, Kwan CY, Hsieh CL, Leung YM. Rhynchophylline from Uncaria rhynchophylla functionally turns delayed rectifiers into A-Type K+ channels. JOURNAL OF NATURAL PRODUCTS 2009; 72:830-834. [PMID: 19331340 DOI: 10.1021/np800729q] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Rhynchophylline (1), a neuroprotective agent isolated from the traditional Chinese medicinal herb Uncaria rhynchophylla, was shown to affect voltage-gated K(+) (Kv) channel slow inactivation in mouse neuroblastoma N2A cells. Extracellular 1 (30 microM) accelerated the slow decay of Kv currents and shifted the steady-state inactivation curve to the left. Intracellular dialysis of 1 did not accelerate the slow current decay, suggesting that this compound acts extracellularly. In addition, the percent blockage of Kv currents by this substance was independent of the degree of depolarization and the intracellular K(+) concentration. Therefore, 1 did not appear to directly block the outer channel pore, with the results obtained suggesting that it drastically accelerated Kv channel slow inactivation. Interestingly, 1 also shifted the activation curve to the left. This alkaloid also strongly accelerated slow inactivation and caused a left shift of the activation curve of Kv1.2 channels heterologously expressed in HEK293 cells. Thus, this compound functionally turned delayed rectifiers into A-type K(+) channels.
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Affiliation(s)
- Chun-Hsiao Chou
- Department of Physiology, Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung 40402, Taiwan, Republic of China
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