Figure 2.

Effects of Dalbergia isolates on KCl-induced contraction of rat aorta rings. (A,B) Traces of vascular smooth muscle tension (representative of 4–6 similar experiments) showing the relaxation developed in response to cumulative concentrations of biochanin A (μM), added at the plateau of (A) 60 mM (K60) or (B) 25 mM KCl (K25) used to contract the preparations. The effect of 10 μM nifedipine (nife) and 100 μM sodium nitroprusside (SNP) is also shown. Horizontal bars indicate time (in min) and vertical bars muscle tension (expressed as mg). (C,D) Concentration–response curves for Dalbergia isolates in endothelium-denuded rings precontracted with either (C) 60 or (D) 25 mM KCl. In the ordinate scale, the response is reported as a percentage of the initial tension induced by KCl. Data points represent the mean ± SEM (n = 1–8).