Fig. 6

a, b Inhibitory effects of DP, Hy-DP, 5-uRCK and mixtures of Hy-DP and 5-uRCK on ACE activity in vitro. Different concentrations and mixture ratios of Hy-DP and 5-uRCK were added to the reaction mixtures, and ACE inhibition was recorded. ^*P < 0.05 and ^**P < 0.01 vs the 1:0 group 10 μg/mL); ^#P < 0.05 and ^##P < 0.01 vs the 1:0 group 30 μg/mL). d, e Inhibitory effects of DP, Hy-DP, 5-uRCK and mixtures of Hy-DP and 5-uRCK on cGMP-dependent PDE activity in vitro. Different concentrations and mixture ratios of Hy-DP and 5-uRCK were added to the reaction mixtures, and cGMP-dependent PDE inhibition was recorded. g, h Inhibitory effects of DP, Hy-DP, 5-uRCK and mixtures of Hy-DP and 5-uRCK on cAMP-dependent PDE activity in vitro. Different concentrations and mixture ratios of Hy-DP and 5-uRCK were added to the reaction mixtures, and cAMP-dependent PDE inhibition was recorded. ^**P < 0.01 vs the 1:0 group 1 μg/mL); ^#P < 0.05 vs the 1:0 group 3 μg/mL). c, f, i Inhibitory effects of GABA and _L-arginine (Arg) on ACE- and cGMP−/cAMP-dependent PDE activity in vitro