The Novel KV7.2/KV7.3 Channel Opener ICA-069673 reveals subtype-specific functional roles in Guinea pig Detrusor smooth muscle excitability and contractility

Aaron Provence, John Malysz, Georgi Petkov

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4 Citations (Scopus)

Abstract

The physiologic roles of voltage-gated KV7 channel subtypes (KV7.1-KV7.5) in detrusor smooth muscle (DSM) are poorly understood. Here, we sought to elucidate the functional roles of KV7.2/KV7.3 channels in Guinea pig DSM excitability and contractility using the novel KV7.2/KV7.3 channel activator ICA-069673 [N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide]. We employed a multilevel experimental approach using Western blot analysis, immunocytochemistry, isometric DSM tension recordings, fluorescence Ca21 imaging, and perforated whole-cell patch-clamp electrophysiology. Western blot experiments revealed the protein expression of KV7.2 and KV7.3 channel subunits in DSM tissue. In isolated DSM cells, immunocytochemistry with confocal microscopy further confirmed protein expression for KV7.2 and KV7.3 channel subunits, where they localize within the vicinity of the cell membrane. ICA-069673 inhibited spontaneous phasic, pharmacologically induced, and nerve-evoked contractions in DSM isolated strips in a concentration-dependent manner. The inhibitory effects of ICA-069673 on DSM spontaneous phasic and tonic contractions were abolished in the presence of the KV7 channel inhibitor XE991 [10,10-bis(4-pyridinylmethyl)-9 (10H)-Anthracenone dihydrochloride]. Under conditions of elevated extracellular K1 (60 mM), the effects of ICA-069673 on DSM tonic contractions were significantly attenuated. ICA-069673 decreased the global intracellular Ca21 concentration in DSM cells, an effect blocked by the L-Type Ca21 channel inhibitor nifedipine. ICA-069673 hyperpolarized the membrane potential and inhibited spontaneous action potentials of isolated DSM cells, effects that were blocked in the presence of XE991. In conclusion, using the novel KV7.2/ KV7.3 channel activator ICA-069673, this study provides strong evidence for a critical role for the KV7.2-and KV7.3-containing channels in DSM function at both cellular and tissue levels.

Original languageEnglish (US)
Pages (from-to)290-301
Number of pages12
JournalJournal of Pharmacology and Experimental Therapeutics
Volume354
Issue number3
DOIs
StatePublished - Sep 1 2015

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Smooth Muscle
Guinea Pigs
Smooth Muscle Myocytes
Western Blotting
Immunohistochemistry
Muscle Tonus
Electrophysiology
Optical Imaging
Nifedipine
Muscle Contraction
Confocal Microscopy
Membrane Potentials
Action Potentials
Proteins
Cell Membrane
Muscles

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Molecular Medicine
  • Medicine(all)

Cite this

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title = "The Novel KV7.2/KV7.3 Channel Opener ICA-069673 reveals subtype-specific functional roles in Guinea pig Detrusor smooth muscle excitability and contractility",
abstract = "The physiologic roles of voltage-gated KV7 channel subtypes (KV7.1-KV7.5) in detrusor smooth muscle (DSM) are poorly understood. Here, we sought to elucidate the functional roles of KV7.2/KV7.3 channels in Guinea pig DSM excitability and contractility using the novel KV7.2/KV7.3 channel activator ICA-069673 [N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide]. We employed a multilevel experimental approach using Western blot analysis, immunocytochemistry, isometric DSM tension recordings, fluorescence Ca21 imaging, and perforated whole-cell patch-clamp electrophysiology. Western blot experiments revealed the protein expression of KV7.2 and KV7.3 channel subunits in DSM tissue. In isolated DSM cells, immunocytochemistry with confocal microscopy further confirmed protein expression for KV7.2 and KV7.3 channel subunits, where they localize within the vicinity of the cell membrane. ICA-069673 inhibited spontaneous phasic, pharmacologically induced, and nerve-evoked contractions in DSM isolated strips in a concentration-dependent manner. The inhibitory effects of ICA-069673 on DSM spontaneous phasic and tonic contractions were abolished in the presence of the KV7 channel inhibitor XE991 [10,10-bis(4-pyridinylmethyl)-9 (10H)-Anthracenone dihydrochloride]. Under conditions of elevated extracellular K1 (60 mM), the effects of ICA-069673 on DSM tonic contractions were significantly attenuated. ICA-069673 decreased the global intracellular Ca21 concentration in DSM cells, an effect blocked by the L-Type Ca21 channel inhibitor nifedipine. ICA-069673 hyperpolarized the membrane potential and inhibited spontaneous action potentials of isolated DSM cells, effects that were blocked in the presence of XE991. In conclusion, using the novel KV7.2/ KV7.3 channel activator ICA-069673, this study provides strong evidence for a critical role for the KV7.2-and KV7.3-containing channels in DSM function at both cellular and tissue levels.",
author = "Aaron Provence and John Malysz and Georgi Petkov",
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T1 - The Novel KV7.2/KV7.3 Channel Opener ICA-069673 reveals subtype-specific functional roles in Guinea pig Detrusor smooth muscle excitability and contractility

AU - Provence, Aaron

AU - Malysz, John

AU - Petkov, Georgi

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N2 - The physiologic roles of voltage-gated KV7 channel subtypes (KV7.1-KV7.5) in detrusor smooth muscle (DSM) are poorly understood. Here, we sought to elucidate the functional roles of KV7.2/KV7.3 channels in Guinea pig DSM excitability and contractility using the novel KV7.2/KV7.3 channel activator ICA-069673 [N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide]. We employed a multilevel experimental approach using Western blot analysis, immunocytochemistry, isometric DSM tension recordings, fluorescence Ca21 imaging, and perforated whole-cell patch-clamp electrophysiology. Western blot experiments revealed the protein expression of KV7.2 and KV7.3 channel subunits in DSM tissue. In isolated DSM cells, immunocytochemistry with confocal microscopy further confirmed protein expression for KV7.2 and KV7.3 channel subunits, where they localize within the vicinity of the cell membrane. ICA-069673 inhibited spontaneous phasic, pharmacologically induced, and nerve-evoked contractions in DSM isolated strips in a concentration-dependent manner. The inhibitory effects of ICA-069673 on DSM spontaneous phasic and tonic contractions were abolished in the presence of the KV7 channel inhibitor XE991 [10,10-bis(4-pyridinylmethyl)-9 (10H)-Anthracenone dihydrochloride]. Under conditions of elevated extracellular K1 (60 mM), the effects of ICA-069673 on DSM tonic contractions were significantly attenuated. ICA-069673 decreased the global intracellular Ca21 concentration in DSM cells, an effect blocked by the L-Type Ca21 channel inhibitor nifedipine. ICA-069673 hyperpolarized the membrane potential and inhibited spontaneous action potentials of isolated DSM cells, effects that were blocked in the presence of XE991. In conclusion, using the novel KV7.2/ KV7.3 channel activator ICA-069673, this study provides strong evidence for a critical role for the KV7.2-and KV7.3-containing channels in DSM function at both cellular and tissue levels.

AB - The physiologic roles of voltage-gated KV7 channel subtypes (KV7.1-KV7.5) in detrusor smooth muscle (DSM) are poorly understood. Here, we sought to elucidate the functional roles of KV7.2/KV7.3 channels in Guinea pig DSM excitability and contractility using the novel KV7.2/KV7.3 channel activator ICA-069673 [N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide]. We employed a multilevel experimental approach using Western blot analysis, immunocytochemistry, isometric DSM tension recordings, fluorescence Ca21 imaging, and perforated whole-cell patch-clamp electrophysiology. Western blot experiments revealed the protein expression of KV7.2 and KV7.3 channel subunits in DSM tissue. In isolated DSM cells, immunocytochemistry with confocal microscopy further confirmed protein expression for KV7.2 and KV7.3 channel subunits, where they localize within the vicinity of the cell membrane. ICA-069673 inhibited spontaneous phasic, pharmacologically induced, and nerve-evoked contractions in DSM isolated strips in a concentration-dependent manner. The inhibitory effects of ICA-069673 on DSM spontaneous phasic and tonic contractions were abolished in the presence of the KV7 channel inhibitor XE991 [10,10-bis(4-pyridinylmethyl)-9 (10H)-Anthracenone dihydrochloride]. Under conditions of elevated extracellular K1 (60 mM), the effects of ICA-069673 on DSM tonic contractions were significantly attenuated. ICA-069673 decreased the global intracellular Ca21 concentration in DSM cells, an effect blocked by the L-Type Ca21 channel inhibitor nifedipine. ICA-069673 hyperpolarized the membrane potential and inhibited spontaneous action potentials of isolated DSM cells, effects that were blocked in the presence of XE991. In conclusion, using the novel KV7.2/ KV7.3 channel activator ICA-069673, this study provides strong evidence for a critical role for the KV7.2-and KV7.3-containing channels in DSM function at both cellular and tissue levels.

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