Renin producing cells in the adult kidney are normally located in the media of afferent arterioles nearby the vascular poles of the glomeruli. The underlying mechanisms for this characteristic position are yet unknown. We now demonstrate that the architecture of the juxtaglomerular apparatus is disturbed in mice lacking connexin 40 (Cx40), which is the predominant connexin protein in renin producing cells. Thus renin producing cells are no longer integrated into the wall of the afferent arterioles at the transition into the capillary network, but they spread out into the juxta- /periglomerular interstitium. Moreover, after stimulation of renin secretion by low salt diet combined with ACE inhibition renin producing cells do not appear and recruit in the wall of afferent arterioles as normally but remain outside the vessel walls in the periglomerular region in Cx40 deficient mice. In spite of the aberrant position of renin producing cells in the kidneys of adult Cx40 deficient mice, renin expression in the vessels of developing kidneys is normal, but it spread out into the interstitium when renin expression starts in the juxtaglomerular region. We conclude from our data that cellular coupling via Cx40 composed gap junctions is a determining factor for the correct juxtaglomerular position and recruitment of renin producing cells.