Figure 1.

Investigation of the autoregulation hypothesis in cultured SMCs derived from the rabbit aorta. (A) Effect of 3 h drug treatments followed by 1 h drug washout incubation period on the specific binding of [³H]Lys-des-Arg⁹-BK (4 nM) to rabbit aortic SMCs maintained in serum-free medium for 24 h. Cells were treated with saline vehicle (2 μl per well), human recombinant IL-1β (5 ng ml⁻¹), the B₁R agonist Sar-[D-Phe⁸]des-Arg⁹-BK (100 nM), captopril (1 μM) alone or combined with the B₂R agonist BK (100 nM). Results are the means±s.e.mean of four determinations based on cell lines derived from different animals. (B) Effect of 3 h drug treatments on B₁R mRNA concentration in rabbit aortic SMCs maintained in serum-free medium for 24 h. Values (B₁R GAPDH⁻¹ ratio, derived from RT–PCR) are arbitrary scanning units normalized to saline group=1 and are the mean±s.e.mean of six determinations. The treatments were the same as in A. In both A and B, one-way analysis of variance showed that the experimental groups were different between them (P<0.05). Dunnett's test was applied to compare the effect of each treatment with the control values (*P<0.05).