FIGURE 7.

The UTP-mediated vasoconstrictions are dependent on EGFR signaling. A representative tracing of a vascular reactivity assay of a HCA ring shows that the contractile response of 1 μm UTP was halved by 0.1 or 3 μm AG1478 (A and B). As a control, AG1478 did not modify the KCl-induced vasoconstrictions (C). As an additional control, we also evaluated whether the vasomotor responses evoked by 300 nm 5-HT were modified by AG1478. Quantification of the polygraphic recordings showed that 0.1 μm AG1478 increased by 40% the 5-HT-induced contractions, whereas at 3 μm, these were halved (D). Columns, mean average contraction (n = number of independent experiments); bars, S.E.; *, p < 0.05.