Intercellular communication in the kidney – University of Copenhagen

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Intercellular communication in the kidney

The myogenic response and the tubuloglomerular feedback (TGF) autoregulate renal blood flow and glomerular filtration rate. These two mechanisms cooperate to maintain an efficient afferent arteriolar tone. This depends on a functional communication between the vascular cells. Gap junctions between smooth muscle cells and endothelial cells allow signalling between cells. Gap junctions are built from different connexin (Cx) isoforms. In the renal vasculature Cx37, Cx40, Cx43 and Cx45 are expressed. The function and expression of Cx is changed during hypertension.

Cx40 in the renal vasculature
Mice lacking expression of Cx40 (Cx40 knockouts) have increased blood pressure and renin secretion. Furthermore, the conduction of vascular dilatations is significantly reduced. We have shown that this affects the function of TGF. In Cx40 knockout mice we further investigate the effect of changes in renal perfusion pressure on the afferent and efferent diameter. Experiments are performed in absence or presence of drugs known to affect renal autoregulation. Also, we investigate the significance of Cx40 on conduction of vascular responses in afferent arterioles.

Cx45 in the renal vasculature
Mice lacking expression of Cx45 in the vasculature also have increased blood pressure and renin secretion. The conduction of Ca2+ waves between vascular smooth muscle cells in these mice is impaired and this could greatly affect the conduction of vasoconstriction in the afferent arteriole. In mice lacking expression of Cx45 we investigate the effect of changes in renal perfusion pressure on the afferent and efferent diameter. We also investigate the effect of Cx45 on conduction of vascular responses in afferent arterioles.