Imaging cellular signals in the heart in vivo: Cardiac expression of the high-signal Ca2+ indicator GCaMP2

摘要: Genetically encoded sensor proteins provide unique opportunities to advance the understanding of complex cellular interactions in physiologically relevant contexts; however, previously described sensors have proved be limited use report cell signaling vivo mammals. Here, we describe an improved Ca2+ sensor, GCaMP2, its inducible expression mouse heart, and examine heart cells vivo. The high brightness stability GCaMP2 enable measurement myocyte transients all regions beating prolonged pacing mapping studies isolated, perfused hearts. Transgene is efficiently temporally regulated cardiomyocyte mice, allowing recording signals 4 weeks after transgene induction. High-resolution imaging waves GCaMP2-expressing embryos revealed key aspects electrical conduction preseptated heart. At embryonic day (e.d.) 10.5, atrial ventricular occur rapidly, consistent with early formation specialized pathways. However, markedly slowed through atrioventricular canal e.d. 10.5 forming basis for effective delay before development AV node, as rapid activation occurs distal tissue. Consistent elimination inner muscle layer at 13.5, was abolished this stage. These demonstrate that will broad utility dissection numerous mammals,