Fig. 6.

S1P-induced vasoconstriction requires the S1P₂ cell surface receptor. A: representative filtered P_PA tracings from S1P₂^+/+ C57/SvJ129 mouse lungs exposed to 10 μM S1P, S1P₂^−/− mouse lungs exposed to 10 μM S1P, or S1P₂^−/− mouse lungs exposed to 10 μM S1P in the presence of 100 μM nitro-l-arginine methyl ester (l-NAME). B: the increase in PVR in response to 10 μM S1P in S1P₂^+/+ mouse lungs (n = 5), 10 μM S1P in S1P₂^−/− mouse lungs (n = 5), or 10 μM S1P in the presence of 100 μM l-NAME in S1P₂^−/− mouse lungs (n = 4). *P = 0.004 compared with S1P₂^+/+ control (by 1-way ANOVA). PVR increases depicted represent the magnitude of the exponential component of the response.