Figure 5.

(a) Concentration-related effect of NaHS (a; 10–1600 μM) on PE-precontracted aortic rings, which were partially relaxed by addition of histamine (100 μM). Results show % contraction (reversal of histamine-mediated relaxation) and are mean±s.e.m., n=7. (b) Upper trace: representative trace showing the effect of NaHS (50–1600 μM) on PE-precontracted aortic rings, which were partially relaxed by addition of isoprenaline (400 nM). Vertical bar indicates tension scale (g). Horizontal bar shows time (min). Drugs were injected at the arrows as indicated. Lower graph: effect of NaHS (a; 50–1600 μM) on rat aortic rings, which had been precontracted with PE (200 nM) and then partially relaxed by addition of isoprenaline (400 nM). Deionized water was used a vehicle control. Results show % contraction (reversal of isoprenaline-mediated relaxation) and are mean±s.e.m., n=12.