Phosphorylation of CaMK and CREB-Mediated Cardiac Aldosterone Synthesis Induced by Arginine Vasopressin in Rats with Myocardial Infarction

Figures

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  Figure 1. Type I collagen expression in left ventricular non-infarcted region of rats. MI, myocardial infarction; sham, rats having undergone a sham operation; 16w sham, 16-week post-sham-operation group; 6w MI, 6-week post-infarction group; 11w MI, 11-week post-infarction group; 16w-MI, 16-week post-infarction group. (A) Representative images of immunohistochemical staining for type I collagen (collagen I) (magnification: ×200). Blue indicates nucleus, and brown indicates collagen I. (B) Graphical representation of collagens I protein expression in the sections. AOD, average optical density; the results are presented as mean ± SD. # p < 0.05 vs. sham-operated rats of the same age; * p < 0.05 vs. 6w MI; + p < 0.05 vs. 11w MI.

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  Figure 2. Concentrations of aldosterone and AVP in left ventricular non-infarcted region of rats. (A) Representative graph of aldosterone concentration. (B) Representative graph of AVP concentration. AVP, arginine vasopressin. (C) Correlation analysis between aldosterone and AVP. # p < 0.05 vs. sham-operated rats of the same age; * p < 0.05 vs. 6w MI; + p < 0.05 vs. 11w MI.

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  Figure 3. Effects of AVP on aldosterone secretion in CMECs. CMECs, cardiac microvascular endothelial cells; SR49059, AVP V1R antagonist; KN93, CaMK antagonist. (A) Effects of different concentrations of AVP on aldosterone secretion. * p < 0.05 vs. vehicle; # p < 0.05 vs. 10−8 mol/L AVP; + p < 0.05 vs. 10−7 mol/L AVP; ** p < 0.05 vs. 10−6 mol/L AVP. (B) AVP (10−7 mol/L) time-independently induced secretion of aldosterone. (C) Effects of different antagonists on AVP-induced secretion of aldosterone. AVP, 10−7 mol/L; SR49059, 10−6 mol/L; KN93, 10−7 mol/L. * p < 0.05 vs. vehicle; # p < 0.05 vs. AVP; + p < 0.05 vs. (AVP + SR49059).

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  Figure 4. Effects of AVP on CYP11B2 mRNA expression in CMECs. (A) Effects of different concentrations of AVP on CYP11B2 mRNA expression. * p < 0.05 vs. vehicle; # p < 0.05 vs. 10−8 mol/L AVP; + p < 0.05 vs. 10−7 mol/L AVP; ** p < 0.05 vs. 10−6 mol/L AVP. (B) AVP (10−7 mol/L) time-independently upregulated CYP11B2 mRNA expression. (C) Effects of different antagonists on AVP-upregulated CYP11B2 mRNA expression. AVP, 10−7 mol/L; SR49059, 10−6 mol/L; KN93, 10−6 mol/L. * p < 0.05 vs. vehicle; # p < 0.05 vs. AVP; + p < 0.05 vs. (AVP + SR49059).

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  Figure 5. Effects of AVP on p-CREB expression in CMECs. p-CREB, phosphorylated CREB; AVP, 10−7 mol/L; SR49059, 10−6 mol/L; KN93, 10−6 mol/L. (A) Representative images of Western blots. (B) Graphical representation of protein expression of p-CREB. * p < 0.05 vs. vehicle; # p < 0.05 vs. AVP; + p < 0.05 vs. (AVP + SR49059).