Methods for Imaging Renin-Synthesizing, -Storing, and -Secreting Cells
Figure 1
Microscopic views of paraffin kidney sections from a rat chronically treated with the converting enzyme inhibitor captopril (30 mg per day for 7 weeks per os; Sigma, St Louis, MO). Sections were double-stained against -smooth muscle actin (red label, monoclonal anti--SM actin, clone # 1A4, dilution, Sigma), and against renin (brown label, polyclonal anti-rat renin antibody, ref. # 936, dilution, gift from T. Inagami, Vanderbuilt University, Nashville, TN), using Dako En Vision Doublestain System (Ref. K1395, Dako A/S, Glostrup, Denmark). (a) A juxtamedullary glomerulus (GL) with its afferent (AA) and efferent arterioles (EA), close to an interlobular artery (ILA), and proximal tubules (PT). Renin cells accumulate near the glomerular vascular pole (single arrow) and other renin cells were recruited upstream along the afferent arteriole (dashed arrows). (b) Enlarged view of two transversally cut afferent arterioles (AA) near a glomerulus (GL). Arrows point to individual granulated renin cells (brown label) that exhibit a variety of topologies with respect to smooth muscle cells (red label). The renin cell in the lower arteriole is included within the arteriolar wall between smooth muscle cell processes. In the upper arteriole, one renin cell (lower arrow) is part of the arteriolar wall, whereas the upper two renin cells are located on top of the smooth muscle cell layer. Regarding the latter two observations, it is interesting to note that recent studies in connexin 40-deficient mice [82] unveiled a “topological escape” of renin-cells away from afferent arterioles towards the extraglomerular mesangium. Bars: 50 m.
