Expression and distribution of brain natriuretic peptide in human right atria
Kiyoshi Doyama, MD*,
Manabu Fukumoto, MD*,
Genzou Takemura, MD ,
Masaru Tanaka, MD*,
Teiji Oda, MD ,
Koji Hasegawa, MD*,
Tsukasa Inada, MD*,
Seiji Ohtani, MD*,
Takako Fujiwara, MD ,
Hiroshi Itoh, MD*,
Kazuwa Nakao, MD*,
Shigetake Sasayama, MD* and
Hisayoshi Fujiwara, MD
* Third and Second Department of Internal Medicine and Second Department of Pathology, Kyoto University School of Medicine, Kyoto, Japan
Second Department of Internal Medicine, Gifu University School of Medicine, Gifu, Japan
Department of Cardiovascular Surgery, Rakuwakai-Otowa Hospital, Kyoto, Japan
Kyoto Womens University, Kyoto, Japan

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Figure 1 Photomicrographs showing immunohistochemistry of ANP and BNP in human right atrial appendage (panels A through H). Note that panels A and C, panels B and D are serial sections from patient 14 in Table 1, panels E, F, G and H are serial sections from patient 1 in Table 1. Panels A and B show epicardial and endocardial side, respectively, in a section stained with anti-ANP antibody. Panels C and D, and panels E and F also show epicardial side and endocardial side, respectively, in each section stained with anti-BNP antibody. ANP-positive myocytes (brown staining) were seen from subendocardium (panel B) to subepicardium (panel A). The BNP-positive myocytes were seen in the subendocardial side of the atrial wall (panel D), and were not seen in subepicardial side (panel C) in patient 14. However, in patient 1, BNP-positive myocytes were seen in the subepicardial side as well as in the subendocardial side (panels E and F). Panel G (a serial section of panel E) shows ANP immunostaining. A control section (a serial section of panels E and G) incubated with anti-BNP antibody preabsorbed with BNP (panel H) showed no immunoreactivity. Asterisks and arrowheads indicates epicardial side and endocardial side, respectively. Original magnification was x200 (panels A through H).
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Figure 2 Plots showing the relationship between the mean right atrial pressure (mRAP) and immunostaining of brain natriuretic peptide (BNP). The BNP-scores of the atria were well correlated with mRAP (p < 0.01). See text regarding the BNP score.
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Figure 3 Representative Northern blot showing mRNA levels of ANP, BNP and beta-2-microglobulin (BMG). Two µg and 5 µg of total RNA per lane were hybridized with 32P-labeled ANP and BNP cDNA probes, respectively, and they were rehybridized with 32P-labeled BMG cDNA probes. Mean right atrial pressure (mRAP) of each patient was indicated above the lane number (lane 1 through 5). Lane 1, patient 15 in Table 1; lane 2, patient 13; lane 3, patient 8; lane 4, patient 3; lane 5, patient 1, respectively.
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Figure 4 Panel A: Plots showing a positive correlation between the right atrial mRNA levels of ANP (ANP mRNA) and mean right atrial pressure (mRAP). Panel B: Plots showing a positive correlation between the right atrial mRNA levels of BNP (BNP mRNA) and the mRAP. Panel C: Plots showing a positive correlation between the levels of ANP mRNA and BNP mRNA.
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Figure 5 Photomicrographs showing in situ hybridization of ANP mRNA and BNP mRNA. Hybridization signals were dark precipitates in the cytoplasm. Panels A and B: serial sections. No hybridization signal was found in any connective tissue or vasculature. The BNP mRNA signals were found only in the subendocardial myocytes of the atria with mRAP less than 5 mm Hg (panel A), whereas they were found diffusely and transmurally in the atria with mRAP of 5 mm Hg or more (panels C and E). The ANP mRNA signals were also found in a similar distribution; they were found either in the subendocardial myocytes of the atria with lower mRAP (panel B) or diffusely and transmurally in those with higher mRAP (panel D). A control section (a serial section of panel E) incubated with digoxigenin-labeled sense riboprobes of BNP showed no signals (panel F). Asterisks and arrowheads indicate epicardial and endocardial side, respectively. Original magnification was x200 (panels A through E).
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