Re: Ý ve got questions about gap junctions

The closing of gap junctions are controlled by various gating mechanisms 
depending on the type of gap junction and its environment (eg type of 
tissue). Gap junctions can respnd to a variety of physiological conditions 
including cAMP-dependent protein phosphorylation, rises in intracellular 
calcium, decreased pH, and differences in cytoplasmic potentials btween 
two connected cells as well as changes in membrane potential.

Hille, B. Ion Channels of Excitable membranes, 3rd edition, Sinaer 
Associates, Inc., 2001, pages 300-304.