Dynamic Changes in Sarcoplasmic Reticulum Structure in Ventricular Myocytes

Figure 2

Imaging of network, junctional, and corbular SR boutons in living and fixed ventricular myocytes. (a) A cartoon of the tRFP-SR construct. (b) Confocal image of representative living neonatal ventricular myocyte expressing tRFP-SR. (c) Confocal images of representative living adult ventricular myocyte. Insets show zooms of a corbular SR bouton (red box) and SR network (green box) in these cells. Graphs show fluorescence intensity profile in the region in the image marked by arrows. (d) Electron microscopy image of non-permeabilized neonatal ventricular myocytes infected with tRFP-SR (scale bar = 1 μm; N = nucleus). Insets depict invaginations of the endoplasmic/sarcoplasmic reticulum (scale bar = 100 nm). Panel Dii shows an example of how the dimensions of SR boutons were made. (e) Immunogold labeling of tRFP-SR (arrows of insets) from a permeabilized neonatal ventricular myocyte infected with tRFP-SR depicting invaginations of the endoplasmic/sarcoplasmic reticulum (scale bar = 500 nm and 100 nm (insets); N = nucleus).