摘要：

Gap junctional communication is a universal property of metazoan animals. Biochemical, immunological, molecular biological, ultrastructural, biophysical and physiological studies of gap junctions have permitted increasingly detailed modelling of gap junctional structure and function. In spite of this progress the questions to be addressed are whether the channel is a mixed oligomer and the stoichiometry for each tissue is fixed. Also the extent of homology among gap junction proteins in different tissues and their possible regulatory function have to be clarified. As long as the different channels are not cloned and expressed, the ultrastructural correlates of the physiological concepts such as channel gating, selectivity and regulation, as well as assembly and disassembly cannot be determined. The genetic approach is in full progress. The observed differences between gap junction proteins from different tissues and the multiplicity of subunits in even one channel implies a functional specialization for gap junctions. Correlative studies on the molecular and cellular level should help to clarify the physiological meaning of intercellular communication by gap junctions.

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