Fig. 8

PEA stimulates DAGL-α and -β. a Concentration-response curve for the stimulation of DAGL-α activity by PEA. The curve shows the % of stimulation compared to the activity of the enzyme with no PEA, observed with increasing concentrations of PEA in membranes obtained from COS-7 cells over-expressing human recombinant DAGL-α. Data are the means ± SEM. b Effect of PEA (25 μM) and CaCl₂ (10 mM) on DAGL-β activity in RBL-2H3 cell membranes. Data are the means ± SEM. *p < 0.05 and **p < 0.01 compared with Control. c The levels of 2-AG by LC-MS were measured after that membrane preparations (70 μg of protein) from COS-7 cells over-expressing DAGL-α were incubated with 1-oleoyl-2-arachidonoylglycerol (25 μM) in the presence or absence of PEA (25 μM) for 20 min at 37 °C, i.e., using the same conditions for enzyme activity assay as in a. Each bar shows the mean ± SEM. **p < 0.01 and ***p < 0.001 compared with DAGL-α. °p < 0.05 compared with DAGL-α + substrate. d The endogenous levels of 2-AG were measured after that RBL-2H3 cells were treated with PEA (10 μM) in the presence or absence of the DAGL inhibitor, OMDM188 (10 μM), or stimulated with SP (10 μM) and treated with PEA (10 μM) in the presence or absence of OMDM188 (10 μM), for 15 min at 37 °C in a 5% CO₂ atmosphere. Each bar shows the mean ± SEM. ***p < 0.001 compared with vehicle. °°°p < 0.001 compared with SP + PEA 10 μM. ^≠≠≠p < 0.001 compared with PEA 10 μM. Vehicle, SP + PEA 10 μM and PEA 10 μM data are the same as in Fig. 5b