Fig 6. Apela, apelin and aplnr expression in the adult rat heart ventricle and kidney by branched-chain ISHH.

The tissues were hybridized with RNAscope probes and processed in one day. Positive apela, apelin and aplnr and negative control staining of the heart is shown in (A, B) and (C), respectively. In (A) aplnr-expressing cells (green dots; labelled 1–6 with green arrows) are widely distributed in the heart myocardium. The rare cells express only apela (red dots; labelled 7 with a red arrow). Some cells are labelled with both aplnr + apelin (white dots) probes (labelled 8–10 with yellow arrows). A few cells express aplnr + apela + apelin (labelled 11 with a white arrow) or aplnr + apela (labelled 12 with a purple arrow). (B) is an enlargement of the dotted area outlined in (A). There was no labelling with negative control probes in all three channels in the heart ventricles (C) where * denotes vessel. In the kidney inner medulla (D) the vast majority of cell expressing apela (red dots; labelled 1–8 with red arrows) do not express aplnr (green dots) or apelin (yellow dots). Some cells express both aplnr + apela transcripts (labelled 9 with a purple arrow) while aplnr + apelin cells are more common (labelled 10–13 with yellow arrows). The rare cell exhibits apela + apelin + aplnr labelling (14; white arrow). Removing the DAPI channel in (E) (corresponding image of (D)) highlights the distinction between apela (red) and aplnr/apelin expression (green and yellow, respectively) in the kidney. (F) is an enlargement of the dotted area outlined in (D). In (G) the red channel diffuse background is enhanced to clearly show the renal tubular apela (red) labelling. (H) shows aplnr expression (white dots; e.g., arrowed) in a glomerulus (partial boundaries shown by dotted line). The images are representative of results obtained from the hearts and kidneys of 3 and 4 rats, respectively. DAPI counterstaining is shown in blue. Scale bar = 50μm.