Gap junction distribution

What is the role of the gap junctions By coupling the myocardial cells in both directions (longitudinal and transverse) they are responsible for the biophysical properties of the tissue. A reduction in gap junction distribution or a closure of the gap junction channels causes nonuniformities and discontinuities which alter the biophysical properties of the tissue and make it more prone to nonuniform anisotropic reentry. According to the model proposed by Krinsky [1966], a reduction in gap junctions or a closure of gap junction channels will lead to local slowing of conduction, thereby allowing smaller perimeters of reentrant arrhythmia. In addition, slowing of conduction is generally believed to be a risk factor for initiation of reentry. Since in many... 

Conduction disturbances are frequently found in acute and chronic Chagas disease. In cultures of neonatal rat hearts, changes in the gap junction distribution were studied to discover whether they were associated with the infection. In cultured cardiomyocytes infected with the unicellular parasite Trypanosoma cruzi responsible for Chagas disease, which is the most common cause of heart disease in South America, reduced gap junctional conductance... 

However, it is well known that with increasing age microfibrosis is observed which in turn will seperate the fibers from each other and thereby enhance the degree of nonuniformity as discussed in the first chapter of this book. This is accompanied by a reduction in side-to-side connections [Spach and Dolber, 1986]. Thus, with increasing age the intercellular communication can be expected to be reduced probably due to structural changes in the tissue with deposition of collagenous fibers. Concomitant changes in the gap junction distribution are probably secondary to cardiac diseases, although at present an effect of age per se cannot be excluded. 

Campos de Carvalho AC, Tanowitz HB, Wittner M, Dermietzel R, Roy C, Hertzberg EL, Spray DC Gap junction distribution is altered between cardiac myocytes infected with Trypanosoma cruzi Circ Res 1992 70 733-742. 

Smith JH, Green CR, Peters NS, Rothery S, Severs NJ Altered patterns of gap junction distribution in ischemic heart disease. An immunohistochemical study of human myocardium using laser scanning confocal microsopy. Am J Pathol 1991 139 801-821. 

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