Gap junctions and development

The hypothesis that gap junctions provide a pathway mediating the cellular interactions of embryonic development gained in attractiveness as gap junctions, electrotonic coupling and dye coupling were found in successively more embryos. Recent examples of the formation and disappearance of junctions show that this coupling can exhibit striking temporal and cellular specificity. As knowledge of factors controlling junctional conductance increases, it is becoming possible to suggest physiological mechanisms which could alter the degree of communication between embryonic cells. Yet without knowing the message, there is still only circumstantial evidence that gap junctions mediate intercellular communication required for embryogenesis.