Module 6: Figure smooth muscle caveolae
Caveolae in coronary smooth muscle cells of the mouse.
The tangential section at the top reveals the large number of concentric caveolae (yellow arrows), many of which are surrounded by an extensive interconnected network of the sarcoplasmic reticulum (SR). In the longitudinal section at the bottom, the caveolae are shown opening to the surface. The SR makes close contact with both the caveolae (green arrows) and the plasma membrane, where it forms a typical junctional zone (red arrows). Such junctions may play a role in store-operated Ca2+ entry (Module 3: Figure capacitative Ca2+ entry). Reproduced from J. Ultrastruct. Res., Vol. 67, Forbes, M.S., Rennels, M.L. and Nelson, E., Caveolar systems and sarcoplasmic reticulum in coronary smooth muscle cells of the mouse, pp. 325–339. Copyright (1979), with permission from Elsevier; see Forbes et al. 1979.