A unique aspect of smooth muscle cells is their retention of mitotic capability throughout life. Neither skeletal nor cardiac muscle possesses this ability. Indeed, cardiac muscle cells are completely incapable of regeneration, while those of skeletal muscles can only regenerate due to the occurrence of satellite cells. Located in shallow depressions on the surface of skeletal muscle cells, satellite cells may undergo mitosis and help increase muscle mass under certain conditions such as weight training or injury. These regenerative cells are not necessary to smooth muscles, however, which are capable of creating new cells whenever necessary. In addition to mitosis, new smooth muscle cells may be generated by the differentiation of the pericytes associated with some blood vessels.

An adherent culture of A-10 cells (illustrated above) was fluorescently labeled with MitoTracker Red CMXRos, Alexa Fluor 350 conjugated to phalloidin, and SYTOX Green, targeting the mitochondria, filamentous actin network, and nuclei, respectively. Similar to the other images presented with this staining regimen, the cellular nuclei appear bright green, while the mitochondria are red and the actin stress fibers are deep blue. Images were recorded in grayscale with a QImaging Retiga Fast-EXi camera system coupled to an Olympus BX-51 microscope equipped with bandpass emission fluorescence filter optical blocks provided by Omega Optical. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.