title: High-precision recording of the action potential in isolated cardiomyocytes using the near-infrared fluorescent dye di-4-ANBDQBS.
abstract: The use of voltage-sensitive fluorescent dyes (VSD) for noninvasive measurement of the action potential (AP) in isolated cells has been hindered by low-photon yield of the preparation, dye toxicity, and photodynamic damage. Here we used a new red-shifted VSD, di-4-ANBDQBS, and a fast electron-multiplied charge-coupled device camera for optical AP (OAP) recording in guinea pig cardiac myocytes. Loading di-4-ANBDQBS did not alter APs recorded with micropipette. With short laser exposures (just enough to record one OAP every 1-5 min), di-4-ANBDQBS yielded fluorescent signals with very high signal-to-background ratios (change in fluorescence on depolarization/fluorescence at resting potential: 19.2 ± 4.1%) and signal-to-noise ratios (40 ± 13.2). Quantum chemical calculations comparing the ANBDQ chromophore to the conventional ANEP chromophore showed that the higher wavelength and the greater voltage sensitivity of the former have the same electro-optical origin: a longer path for electron redistribution in the excited state. OAP closely tracked simultaneously recorded electrical APs, permitting measurement of AP duration within 1% error. Prolonged laser exposure caused progressive AP duration prolongation and instability. However, these effects were alleviated or abolished by reducing the dye concentration and by perfusion with antioxidants. Thus the presented technique provides a unique opportunity for noninvasive AP recording in single cardiomyocytes.
authors.affiliation: Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112-5000, USA. warren@cvrti.utah.edu
authors.forename: Mark
authors.initials: M
authors.lastname: Warren
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Spitzer
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Steadman
authors.forename: Tyler D
authors.initials: TD
authors.lastname: Rees
authors.forename: Paul
authors.initials: P
authors.lastname: Venable
authors.forename: Tyson
authors.initials: T
authors.lastname: Taylor
authors.forename: Junko
authors.initials: J
authors.lastname: Shibayama
authors.forename: Ping
authors.initials: P
authors.lastname: Yan
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Wuskell
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Loew
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Zaitsev
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives*; D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods*; D011806:Quinolinium Compounds
chemical_list: C553754:1-(4-sulfanatobutyl)-4-(beta-(2-(di-n-butylamino)-6-naphthyl)butadienyl)quinolinium betaine; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; D015081:2-Naphthylamine