GAP JUNCTIONAL INTERCELLULAR COMMUNICATION OF CULTURED RAT-LIVER PARENCHYMAL-CELLS IS STABILIZED BY EPITHELIAL-CELLS AND THEIR ISOLATED PLASMA-MEMBRANES

The gap junctional intercellular communication (GJIC) determined by me asuring dye coupling with Lucifer yellow, decreased within 3 d from 66 % to 28% in monocultures of rat liver parenchymal cells. Coculturing o f the parenchymal cells with a nonparenchymal epithelial cell line fro m rat liver resulted in increased and stabilized intercellular communi cation (83% after 3 d). The presence of isolated plasma membrane vesic les of the nonparenchymal epithelial cells also stabilized the interce llular communication between the liver parenchymal cells (70% after 3 d). When liver parenchymal cells were cocultured with a rat liver fibr oblast cell line the gap junctional communication between the parenchy mal cells was not stabilized (43% after 3 d), and isolated plasma memb rane vesicles of the fibroblast were also unable to support the GJIC i n parenchymal cells (35% after 3 d). It is concluded that plasma membr ane constituents of the nonparenchymal epithelial cells were responsib le for the stabilization of the GJIC between parenchymal cells. A hete rotypic gap junctional communication between parenchymal and nonparenc hymal cells was not observed.