Association of actin and 10 nm filaments with the dense body in smooth muscle cells of the chicken gizzard.

Association of actin filaments and intermediate, 10 nm filaments with the dense bodies in smooth muscle cells of the chicken gizzard was studied by thin-section and freeze-etch-replica electron microscopy. For thin-section electron microscopy we used the isolated dense bodies with attached filaments. Actin filaments appeared to be inserted into both ends (poles) of individual oblong dense bodies in such a way that arrowheads with HMM S-1 pointed away from the dense body. 10 nm filaments were attached laterally to the dense body in a side-to-side fashion. This site-specific association of actin and 10 nm filaments with the dense body was confirmed by the freeze-etch replica observations on Triton-treated smooth muscles.