In the juxtaglomerular apparatus (JGA) the regulation of renin synthesis and secretion in renin producing cells depends on a tight coupling of the various cell types composing the JGA. To ensure the intercellular communication between the preglomerular renal vasculature endothelial cells and renin-producing cells in this area, the predominantly expressed connexins (Cx) Cx40, Cx37 and Cx43 appear to be of strong importance. Findings in Cx40 knockout and Cx43 knockin Cx32 mice showed striking changes in the renin expression and failures in the modulation of blood pressure. For that reason mainly these two connexins are supposed to be required for the control of the renin system. To study the function of Cx43 for the regulation of the renin system in a cell specific manner we investigated mice with a floxed Cx43 gene (Cx43 flfl) combined with a renin cell specific Cre recombinase expression (Cx43flfl RenCre) as well as mice with an endothelial specific Cx43 deletion (Cx43flfl Tie-2Cre). 3D reconstructions showed no structural changes in the renal arterial trees of endothelial as well as renin cell specific Cx43 knockout models. Moreover it could be demonstrated that the renin expression pattern did not differ in control conditions or under chronic stimulation of the renin system, with no measurably changes in renal mRNA expression or plasma renin activity.

The data suggest that the depletion of Cx43 in renin producing cells as well as in endothelial cells doesn't remarkably affect renin synthesis and secretion.