Figure 1.

(A) S1P inhibits acute L_p response to PAF. Representative data from one experiment show that treatment with S1P (1 µM) inhibits the first test with PAF (10 nM), whereas a second test in the absence of S1P after recovery to baseline shows a typical PAF response. (B) Dose–response relation for inhibition of PAF by S1P. The ratio of the peak L_p response to PAF (10 nM) in the presence of S1P to the peak value in the absence of S1P is shown. Both 1 and 5 µM S1P inhibit about 65% of the acute L_p peak response. Control value shows that repeated treatment with PAF yields comparable peaks (*different from control, P < 0.05, Wilcoxon's signed-rank test, n for each group shown in parentheses).