Figure 3.

Effect of elevated cAMP levels on collagen gel contraction. Cells grown embedded in collagen gels were treated with the indicated drug combinations for 48 hours. The area of the gels before the addition of drugs was approximately 140 mm². (A, B) Treatment with ET-1 (100 nM) led to a 20% decrease in area compared with untreated cells. Addition of Y-27632 (5 μΜ) or Fsk (10 μΜ) + rolipram (50 μΜ) significantly opposed (ET-1)–induced gel contraction (Y-27632, 25%; Fsk, 70%; P < 0.0001). Blebbistatin (10 μΜ) also opposed (ET-1)–induced gel contraction by 75%, which is comparable to Fsk. These drugs opposed the basal level of gel contraction (B). The results of three independent experiments are expressed as mean ± SEM. E, endothelin-1; Bstat, blebbistatin, Fsk, forskolin.