Abstract 14882: Optical Control of Cardiomyocyte Depolarization and Inhibition Utilizing Channelrhodopsin-2 (ChR2) and a Third Generation Halorhodopsin (eNpHR3.0)
Introduction: Precise control of cardiomyocyte activity without tissue contact could be an important technique with research and clinical applications. Optical control of neurons has previously been achieved using genetically targeted light-gated ion channels. Our objective was to utilize this technique, called optogenetics, for optical control of cardiomyocytes.
Methods: We infected neonatal rat ventricular cardiomyocytes with lentivirus containing the cation channel ChR2 or an enhanced halorhodopsin chloride pump eNpHR3.0, and used a cardiac troponin T promoter to drive cardiac-specific expression. Electrophysiological data was obtained at 5-days post-infection using whole-cell patch clamp. Optical pacing and inhibition were recorded with video microscopy and sharp electrodes.
Results: We measured strong peak and steady-state currents with ChR2 (1415 ± 243 pA and 401 ± 82 pA; 470nm light; n=17) and eNpHR3.0 (252 ± 66 pA and 208 ± 52 pA; 590nm light; n=8), and observed rapid recovery of peak ChR2 photocurrents (recovery = 6.2 ± 1.3 s; n=4). ChR2 activation reliably elicited action potentials at varying frequencies (Figure 1, left; n=9), while eNpHR3.0 activation successfully inhibited current-induced cell firing (Figure 1, right; n=4). We then demonstrated successful ChR2-mediated optical pacing at 1 Hz, 1.25 Hz, 1.5 Hz, and 2 Hz (470nm light), and eNpHR3.0-mediated inhibition of spontaneous beating with 560nm, 590nm, and 610nm light (baseline beat rate 60bpm).
Conclusions: We have shown that optically-induced depolarization and inhibition of rat cardiomyocytes is possible with ChR2 and eNpHR3.0. This technique may have important future research and therapeutic applications.
- © 2010 by American Heart Association, Inc.