Voltage Sensitive Protein 2.3: A Novel Tool to Study Sarcolemmal Structure and Electrical Activity in Mouse Hearts

Optical imaging of cardiac electrical activity is of considerable interest, especially in cardiac pathophysiology and pharmacology studies. Voltage sensitive fluorescent dyes are widely used in this context, but have a limited applicability in long-term studies. We hypothesized that novel genetically encoded voltage sensitive fluorescent proteins (VSFPs) can be stably expressed in mouse hearts to (1) specifically label sarcolemmal membranes and (2) monitor membrane voltage transients. Methods: cDNA encoding for the VSFP2.3 voltage probe (see W.