it was thought previously that cardiac muscle gap junctions provide low-resistance connections between cells and permit the local-circuit current to flow. some evidences show that myocardial cells may not require low-resistance connections for successful propagation of the action potential (ap). it seems that some other types of mechanisms must be involved in ap propagation. in this article, we...

It is widely accepted that there is a family of gap junction connexon proteins, their distribution appearing to vary with tissue type and species. In cardiac tissues the major junctional channel component identified is a 43K (K = 10(3) Mr) polypeptide. Using a gap junction isolation protocol in which low temperatures are maintained, and which is detergent-free, we have identified a second gap j...

Changes in the total amount of the gap junction protein (M(r) 26,000) after partial hepatectomy or bile duct ligation and recanalization were investigated in rat liver membranes by quantitative immunoblot with rabbit antiserum to the M(r) 26,000 protein. The loss and reappearance of the M(r) 26,000 protein roughly paralleled loss and reappearance of gap junction plaques analyzed previously unde...

During blood vessel assembly, endothelial cells recruit mesenchymal progenitors and induce their differentiation into mural cells via contact-dependent transforming growth factor-beta (TGF-beta) activation. We investigated whether gap junction channels are formed between endothelial cells and recruited mesenchymal progenitors and whether intercellular communication is necessary for endothelial-...

The topological organization of the major rat liver gap junction protein has been examined in intact gap junctions and gap junction-derived single membrane structures. Two methods, low pH and urea at alkaline pH, were used to "transform" or "split" double membrane gap junctions into single membrane structures. Low pH treatment "transforms" rat liver gap junctions into small single membrane vesi...

The gap junction is a specialized contact between adjacent cells in a wide variety of tissues (1, 2) which is thought to mediate electrotonic coupling (3) . This junction is characterized by a hexagonal lattice of subunits which may be seen in lanthanum-impregnated, negative-stained, and freezefractured preparations (1) . A method for isolation of morphologically intact gap junctions from mouse...

Despite their significance in wound healing, little is known about the molecular determinants of cell-to-cell adhesion and gap junctional communication in fibroblasts. We characterized intercellular adherens junctions and gap junctions in human gingival fibroblasts (HGFs) using a novel model. Calcein-labeled donor cells in suspension were added onto an established, Texas red dextran (10 kDa)-la...