Selective gap junctional communication within the V79-4 Chinese hamster cell line

The probability of cell-to-cell coupling between directly adjacent cells (communication capability) in the V79-4 Chinese hamster cell line was evaluated under standard conditions or after 18-h treatment with EG. The cell monolayer did not form a continuous network of cells interconnected via gap junctions, but an average cell was coupled to only one half of its directly adjacent neighbours under standard conditions, or to one third of its directly neighbouring cells after 18-h exposure to EG. The rest of the directly adjacent neighbours did not establish functional gap junctions with an injected cell, although they were competent to couple to other cells with a probability similar to that of the coupling between the injected cell and its direct neighbours. Moreover, all the cells possessed the identical connexin--cx43, present on all cell membranes. The results indicated that the choice of a cell to which neighbour be coupled was rather random in the standard cell population as a whole, although the population contained some clones whose capability to couple was more or less different from that of the original cell population. Ethylene glycol reduced the gap junctional communication by increasing the frequency of cells not coupled to any of their direct neighbours from 1% for untreated cells to 23.3% for cells exposed to EG, and consequently by reducing the number of directly adjacent cells coupled to communicating injected cells. The communication capability of the cell population appeared to be unstable. It varied slightly in time and so did the response of the cells to EG. The results indicate that a cell can control its coupling to different directly adjacent neighbours independently, being able to control the gap junctional communication not only in time but in space as well. All control mechanisms of GJIC, known so far, affect a cell as a whole, while our results indicate that another regulatory mechanism may exist, controlling the gap junctional communication to different adjacent neighbouring cells independently.