Fig. 4.

Sildenafil-induced relaxation of PE-precontracted CCSM strips is reduced in Slo^−/−. A and B: sample recordings from a PE-precontracted Slo^+/+ (left) and a Slo^−/− (right) CCSM strip in the absence (A) and presence (B) of IBTX that represent the SIL-induced relaxation. C and D: average oscillation amplitudes and frequency, respectively, of Slo^+/+ and a Slo^−/− CCSM strip in the absence and presence of IBTX, before and after adding SIL. E, average %SIL-induced relaxation of PE-precontracted strips shown in A and B. F: dose-response curves of Slo^+/+ and Slo^−/− CCSM strips to SIL from 1 nM to 10 μM in the absence and presence of ODQ; n, no. of CCSM strips; N, no. of mice. P < 0.05, Slo^+/+ vs. all others (*), untreated vs. sildenafil treated (#), Slo^−/− vs. Slo^−/− + ODQ (£), and Slo^+/+ + ODQ vs. Slo^−/− + ODQ ($).