Figure 5. Effect of angiotensin II treatment on PDE1 activity in left cardiac ventricle.

cGMP-PDE1 specific activity (A), cAMP-PDE1 specific activity (B), and PDE1 activated over basal activity ratio (C). Basal PDE1 activity was assessed in presence of EGTA and CaM-activated PDE1 was assessed in presence of Ca²⁺ and CaM. Effects on treated rats (T, ▪; n = 4) were compared with control rats (C, □□; n = 6). Specific activities were determined on total homogenate and expressed as pmol.min⁻¹.mg⁻¹ of protein. Effects of angiotensin II treatment on protein expression of PDE1A (D) and PDE1C (E). Results were normalized with GAPDH signal and expressed in percentage of untreated rat. n.s.: not significant; *: P<0.05; **: P<0.01; ***: P<0.001.