Protease-activated receptor activity in mouse trophoblast cells. Panel A shows real-time changes in intracellular calcium levels in response to thrombin (10 nM), peptide agonists for PAR1 (TRAP1, 100 μM), PAR2 (TRAP2, 100 μM), and PAR4 (TRAP4; 100 uM) in DT cells. Arrows indicate time of addition of the agonist. Bar represents 100 seconds. No change in intracellular calcium level was observed with scrambled peptides. Panel B shows Egr1, Fos, Cyr61, and Ctgf mRNA induction in mouse trophoblast cells determined by real-time PCR analysis of DT cells stimulated with TRAP1, TRAP2, or TRAP4 for 45 minutes. Transcript abundance was normalized to GAPDH and expressed as fold change over average abundance in unstimulated cells. *Statistically significant (P < .05) fold changes.