Figure 8.

Effects of La³⁺ and NPPB on thrombin- and trypsin-activated inward currents in smooth muscle cells (SMCs)

A and B, representative traces using Cs⁺-rich pipette solutions showed that inward currents activated by thrombin (A) and trypsin (B) were blocked by La³⁺ (10 μm; HP = −50 mV). C, summarized data showing that La³⁺ decreased the average current density activated by thrombin (n = 4) and trypsin (n = 4). *P < 0.05 compared with control; ^#P < 0.05 compared with thrombin or trypsin. D and E show effects of NPPB (10 μm) inward currents activated by thrombin (D) and trypsin (E); HP = −50 mV in tests of both PAR agonists. F, summarized data showing increase in average current density after exposure to thrombin (n = 4) and trypsin (n = 4). NPPB had no significant effect on currents activated by either PAR agonist (data were compared with current densities 2 min after addition of thrombin or trypsin in the absence of NPPB; see Fig. 7F). *P < 0.05 compared with control. G and H show thrombin (G) and trypsin (H) effects after pretreatment with NPPB. I, summarized data showing thrombin (n = 4) and trypsin (n = 4) activated inward currents in the presence of NPPB (HP = −50 mV). *P < 0.05 compared with NPPB alone.