Chronic volume overload leads to cardiac hypertrophy and later to heart failure (HF), which are both associated with increased risk of cardiac arrhythmias. The goal of this study was to describe changes in myocardial morphology and to characterize arrhythmogenic substrate in rat model of developing HF due to volume overload. An arteriovenous fistula (AVF) was created in male Wistar rats between...

Given the essential role played by gap junctions in the coordination of cardiac muscle contraction, it is plausible that down-regulation of gap junctional conduction is in part responsible for the contractile dysfunction observed in hypertrophied and failing hearts. In the present study, we analyzed the expression and function of the gap junction protein, connexin43, in the ventricular myocardi...

Decreased connexin gene expression and loss of the capacity for either homologous or heterologous intercellular communication has been associated with neoplastic transformation. We tested the hypothesis that loss of gap junctional intercellular communication (GJIC) correlates with tumorigenic potential in the HeLa x skin fibroblast human hybrid cell system. Connexin gene expression, gap junctio...

Insulin-mediated increases in cytosolic calcium are synchronized among the cells in a pancreatic islet, and result in pulsatile secretion of insulin. Pancreatic beta cells express the gap junction protein connexin43 and are functionally coupled, making gap junctional communication a likely mechanism for the synchronization of calcium transients among islet cells. To define the mechanism by whic...

Vascular endothelial cells are linked by gap junctions, which facilitate the propagation of electrical and chemical signals along the vessel wall. The aim of this study was to determine the distribution and identity of the gap junction structural proteins (connexins) expressed by endothelial cells in situ. Connexin expression in different regions of the rat aortic endothelium was analyzed with ...

The action of Ca(2+)-dependent cell-cell adhesion molecules (cadherins) on cell-to-cell channel-mediated intercellular communication was investigated in mouse L and rat Morris hepatoma cells. These cells fail to adhere to one another in aggregation assays and thus seem to lack cell adhesion molecules. Expression of exogenous cadherin induced strong cell-cell adhesion in both cell types, but had...

The smooth muscle cells of the uterus contract in unison during delivery. These cells achieve coordinated activity via electrical connections called gap junctions which consist of aggregated connexin proteins such as connexin43 and connexin45. The density of gap junctions governs the excitability of the myometrium (among other factors). An increase in gap junction density occurs immediately pri...

Astrocytes form functional networks that participate in active signaling in which external stimuli are generated and amplified in many of the same ways as in neurons. Gap junctions between astrocytes offer the structural avenue by which the electrical and metabolic signals are propagated from one cell to another. Little is known about the trafficking, assembly, and degradation mechanisms of the...

The gap-junctional proteins connexin43 and connexin42 have been shown to be expressed in the developing and mature avian heart, but their respective spatiotemporal distributions are unknown. In the present study, we have immunolocalized connexin42 in the conduction tissues of the adult avian heart (nonbranching bundle, bundle branches, and Purkinje fibers) and vascular endothelial cells. Connex...