A STUDY OF INTERCELLULAR RELATIONSHIPS IN DEVELOPING AND MATURE VISCERAL SMOOTH MUSCLE

A study has been made of the intercellular relationships in developing and mature smooth muscle of the chick gizzard. Prior to about stage 44 (18th day of incubation), it was possible to demonstrate focal tight junctions between adjacent myoblasts, but only by using potassium permanganate as a fixative. After this stage adult-type nexuses, often associated with protrusions of one cell into another, were present and were demonstrable with permanganate, aldehyde or osmium tetroxide fixation. In tissue impregnated with lanthanum the central lamella of the nexus was stained by the lanthanum, which suggests that the use of this material as an indicator of extracellular space is not valid. The ultrastructure of cell junctions in smooth muscle is discussed. © 1969 Springer-Verlag.