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. Author manuscript; available in PMC: 2013 Jan 17.
Published in final edited form as: Circulation. 2011 Dec 9;125(2):298–307. doi: 10.1161/CIRCULATIONAHA.111.059097

Figure 4.

Figure 4

PKA dependence of the catecholamine-releasing effect of BNP and cGMP. A. intracellular cAMP levels in NGF-differentiated PC12 cells treated with BNP (100 nM), 8-Br-cGMP (1 μM), 8-pCPT-cGMP (3 μM) or forskolin (10 μM). Bars are means of absolute values (± SEM; n=7–11). ***, P<0.001 from control by unpaired t-test. B. PKA activity in NGF-differentiated PC12 cells treated with BNP (100 nM), 8-Br-cGMP (1 μM), 8-pCPT-cGMP (3 μM) or forskolin (10 μM). Upper strips, representative immunoblot of PC12 cell lysate probed with anti-phosphorylated PKA antibody. Lower strips, same immunoblot probed with β-actin antibody. Bars represent mean quantitative values (± SEM; n=6–8). **, P<0.01 from control by unpaired t-test. C. Concentration-response curves for the NE- and DA-releasing effect of the cell-permeable analog of cGMP, 8-Br-cGMP (0.1–100 μM) in synaptosomes isolated from guinea pig hearts (panel a) and NGF-differentiated PC12 cells (panel b) in the absence (control) or presence of the PKA inhibitor PKI14–22 (20 nM). Points are means (± SEM; a, n=12; b, n=4–15). *, ** and ***, P<0.05, P<0.01 and P<0.0001 respectively, from corresponding control point by unpaired t-test. Basal NE and DA levels were 1.4 ± 0.08 and 6.94 ± 0.92 pmol/mg protein, n=12 and 20, respectively.