Figure 3. Effects of N^G-methyl-L-arginine (L-NMA) and indomethacin on antiaggregation of the supernatant from endothelial cells (EC). (A) Changes in light transmission of platelet-rich plasma (PRP). Control = PRP stimulated with collagen (4 micro gram/ml); Bk = same conditions as in control except that the supernatant of bradykinin (1.0 micro Meter)-stimulated EC was added; L-NMA = same conditions as in Bk except that the endothelial cells were preincubated with L-NMA (300 micro Meter) for 30 min before the stimulation of cells with bradykinin; indomethacin = same conditions as in L-NMA except that cells were preincubated with indomethacin (10 micro Meter) instead of L-NMA; L-NMA + indo = same conditions as in L-NMA except that cells were preincubated with L-NMA and indomethacin simultaneously. c = collagen; s = supernatant from EC. (B) Percentage inhibition of antiaggregation derived from EC. A single application of L-NMA or indomethacin significantly inhibited the antiaggregation derived from EC (both, n = 6). A simultaneous application of both compounds completely abolished the antiaggregatory effect of EC (n = 6). *Significantly different from control; #significantly different from Bk.