biostudies-literatureWarren MNIBIB NIH HHSNHLBI NIH HHSH1271-81https://www.ebi.ac.uk/biostudies/studies/S-EPMC2957348biostudies-literatureUnknown299(4)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 ANBDAmerican journal of physiology. Heart and circulatory physiologyHigh-precision recording of the action potential in isolated cardiomyocytes using the near-infrared fluorescent dye di-4-ANBDQBS.PMC29573482R01EB0019635R37HL042873R01 EB0019635R01HL088444R01 HL088444R01 EB001963-27Warren MRees TDZaitsev AVSteadman BWYan PLoew LMVenable PTaylor TShibayama JSpitzer KWWuskell JPfalseHigh-precision recording of the action potential in isolated cardiomyocytes using the near-infrared fluorescent dye di-4-ANBDQBS.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 ANBD2010-01-01T00:00:00Z2010 Oct2025-04-18T15:50:47.04Z2019-03-27T00:34:58ZS-EPMC29573482060145810.1152/ajpheart.00248.2010