UNIDIRECTIONAL COUPLING OF GAP-JUNCTIONS BETWEEN NEUROGLIA

Gap junctions permit the passage of ions and small molecules between c ells, thereby providing a basis for direct intercellular communication . In the rabbit retina, the low molecular weight dyes Lucifer yellow a nd biocytin passed readily from astrocytes into adjacent astrocytes, o ligodendrocytes, and Muller cells. However, the dyes rarely passed fro m either oligodendrocytes or Muller cells into astrocytes. Unidirectio nal passage of dye suggests the presence of an asymmetric barrier to t he movement of molecules through heterologous gap junctions and indica tes the potential for a hierarchy of command between interconnected ce lls.