Abstract
Neighbouring cells in gland tissues communicate with each other through special channels (gas junctions). These junctions allow electrical communication and the transfer of molecules with mol. wt. up to about 1000 from cell to cell. In the exocrine pancreas, electrical communication is restricted to units consisting of a small number of neighbouring cells. Cell to cell communication is generally thought to be controlled by the cytosolic ionized calcium ([Ca]i) in such a way that an increased [Ca]i tends to decrease the conductance of the junctional channels. Junctional conductance can be reduced markedly by neurotransmitters and hormons in exocrine pancreas and this is due to a neurotransmitter or hormon-induced increased in cytosolic [Ca]i. It has, however, recently been shown that a very large decrease in intracellular pH can also evoke electrical uncoupling of neighbouring cells. The physiological significance of the control of the junctional conductance is still obscure.
