Comparison of forskolin (FSK)-induced relaxations in the cGKI+/+ and cGKI−/− aorta and IAS. Sample traces showing relaxations elicited with FSK in the cGKI+/+ aorta (Aa) and IAS (Ba) and in the cGKI−/− aorta (Ab) and IAS (Bb). The concentration-dependent responses to FSK were not significantly different between cGKI+/+ and cGKI−/− mice in either aorta (C) or IAS (D). IC50 values were 3.7 × 10−7 M and 8.7 × 10−8 M in aorta and IAS of cGKI+/+ mice, respectively, and 6.7 × 10−7 M and 1.4 × 10−7 M in aorta and IAS of cGKI−/− mice, respectively; n = 4 cGKI+/+, n = 4 cGKI−/− aorta; n = 4 cGKI+/+, n = 4 cGKI−/− IAS.