Communication compartments in the post-trochal ectoderm of the mollusc Lymnaea stagnalis.

Cell-to-cell communication via gap junctions provides a pathway for the transfer of small molecules and ions which may be significant for control of metabolic cooperation, cell proliferation, and differentiation. We have assessed the patterns of gap junctional communication in embryos of the mollusc Lymnaea stagnalis during the subdivision of the post-trochal ectoderm into developmental domains. We have microinjected the tracer Lucifer Yellow CH and subsequently analyzed its transfer to other cells. The post-trochal ectoderm of mollucs develops the shell field, the foot, and the stomodeum anlagen. We have found that the cells within the separate anlagen are well dye-coupled but poorly coupled to cells of adjacent anlagen. These results indicate that in Lymnaea embryos the specification of the different developmental domains is associated with the development of corresponding dye-coupling compartments.