Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye
Voltage-gated sodium channels (Navs) are critical for membrane potential depolarisation in cells, with especially important roles in neuronal and cardiomyocyte membranes. Their malfunction results in a range of disorders, and they are the target of many widely used drugs. A rapid yet accurate functi...
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MDPI AG
2025-03-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/15/3/80 |
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| author | Sarah C. R. Lummis Samantha C. Salvage Christopher L.-H. Huang Antony P. Jackson |
| author_facet | Sarah C. R. Lummis Samantha C. Salvage Christopher L.-H. Huang Antony P. Jackson |
| author_sort | Sarah C. R. Lummis |
| collection | DOAJ |
| description | Voltage-gated sodium channels (Navs) are critical for membrane potential depolarisation in cells, with especially important roles in neuronal and cardiomyocyte membranes. Their malfunction results in a range of disorders, and they are the target of many widely used drugs. A rapid yet accurate functional assay is therefore desirable both to probe for novel active compounds and to better understand the many different Nav isoforms. Here, we use fluorescence to monitor Nav function: cells expressing either the cardiac Nav 1.5 or pain-associated Nav 1.7 were loaded with fluorescent membrane potential sensitive dye and then stimulated with veratridine. Cells expressing Nav 1.5 show a concentration-dependent slow rise and then a plateau in fluorescence. In contrast, cells expressing Nav 1.7 show a more rapid rise and then unexpected oscillatory behavior. Inhibition by flecainide and mexiletine demonstrates that these oscillations are Nav-dependent. Thus, we show that this fluorescent membrane potential dye can provide useful functional data and that we can readily distinguish between these two Nav isoforms because of the behavior of cells expressing them when activated by veratridine. We consider these distinct behaviors may be due to different interactions of veratridine with the different Nav isoforms, although more studies are needed to understand the mechanism underlying the oscillations. |
| format | Article |
| id | doaj-art-2cb02deff7094eeba79081024716d694 |
| institution | OA Journals |
| issn | 2077-0375 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj-art-2cb02deff7094eeba79081024716d6942025-08-20T01:48:48ZengMDPI AGMembranes2077-03752025-03-011538010.3390/membranes15030080Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive DyeSarah C. R. Lummis0Samantha C. Salvage1Christopher L.-H. Huang2Antony P. Jackson3Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UKDepartment of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UKDepartment of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UKDepartment of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UKVoltage-gated sodium channels (Navs) are critical for membrane potential depolarisation in cells, with especially important roles in neuronal and cardiomyocyte membranes. Their malfunction results in a range of disorders, and they are the target of many widely used drugs. A rapid yet accurate functional assay is therefore desirable both to probe for novel active compounds and to better understand the many different Nav isoforms. Here, we use fluorescence to monitor Nav function: cells expressing either the cardiac Nav 1.5 or pain-associated Nav 1.7 were loaded with fluorescent membrane potential sensitive dye and then stimulated with veratridine. Cells expressing Nav 1.5 show a concentration-dependent slow rise and then a plateau in fluorescence. In contrast, cells expressing Nav 1.7 show a more rapid rise and then unexpected oscillatory behavior. Inhibition by flecainide and mexiletine demonstrates that these oscillations are Nav-dependent. Thus, we show that this fluorescent membrane potential dye can provide useful functional data and that we can readily distinguish between these two Nav isoforms because of the behavior of cells expressing them when activated by veratridine. We consider these distinct behaviors may be due to different interactions of veratridine with the different Nav isoforms, although more studies are needed to understand the mechanism underlying the oscillations.https://www.mdpi.com/2077-0375/15/3/80oscillationsdepolarizationFlexstationvoltage-gated sodium channelvoltage-sensitive dye |
| spellingShingle | Sarah C. R. Lummis Samantha C. Salvage Christopher L.-H. Huang Antony P. Jackson Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye Membranes oscillations depolarization Flexstation voltage-gated sodium channel voltage-sensitive dye |
| title | Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye |
| title_full | Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye |
| title_fullStr | Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye |
| title_full_unstemmed | Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye |
| title_short | Veratridine-Induced Oscillations in Nav 1.7 but Not Nav 1.5 Sodium Channels Are Revealed by Membrane Potential Sensitive Dye |
| title_sort | veratridine induced oscillations in nav 1 7 but not nav 1 5 sodium channels are revealed by membrane potential sensitive dye |
| topic | oscillations depolarization Flexstation voltage-gated sodium channel voltage-sensitive dye |
| url | https://www.mdpi.com/2077-0375/15/3/80 |
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