[Ultrastructural similarities of secretory processes in arterial smooth muscle cells and elastic cartilage chondrocytes. vacuolar apparatus and microtubules (author's transl)].

A highly developed vacuolar apparatus is found in aorta and pulmonary trunk smooth muscle cells and elastic cartilage chondrocytes, and its relationship with cytoplasmic microtubules is described. The Golgi complex as well as the rough endoplasmic reticulum (RER) may be the intracellular sources of the components of the vacuolar apparatus. Some vacuoles, Golgi-related only, showed an association with microtubules. Smooth muscle cells which contained vacuoles derived from RER did not possess Golgi vacuoles and microtubules. In chondrocytes, both Golgi-related and RER vacuoles coexisted in a single cell. 2 main secretory pathways are suggested to operate in smooth muscle cells and chondrocytes: Golgi and RER pathway. The former requires an intact cell tubulin system (cytoplasmic microtubules and membrane-bound tubulin), while the latter is probably microtubule-independent.