Figure 3. Role of Src tyrosine kinase in contractions induced by Ang II, the TXA₂ analogue, U46619, and PE in rat aorta.

Endothelium-denuded aortic rings were pretreated with 10 μm PP2 or with its inactive analogue, PP3 (10 μm), for 20 min before stimulation with Ang II (20 nm), U46619 (2.5 nm) or PE (18 nm) at their EC₇₅. A, C and E show contractile traces of Ang II (A), U46619 (C) and PE stimulation (E). After washing out the drugs (arrows), all of the rings were contracted with 80 mm KCl. B, D and F show mean contraction expressed as a percentage of the response to 80 mm KCl, showing PP2 inhibitory effectiveness Ang II > U46619 (B and D) and lack thereof for PE-induced contraction (F). Pretreatment with PP3 had no significant effect in all cases. n = 5 (Ang II), n = 3–11 (U46619) and n = 4 (PE); *P < 0.05 and **P < 0.01 versus respective agonists. Statistical analysis was performed using ANOVA followed by the multiple comparison Newman–Keuls test.