(a) CBD inhibition of cell migration is not prevented by pretreatment with selective antagonists for CB1 and CB2, respectively, SR141716 (diagonal bars) and SR144528 (cross-hatched bars). Cells were preincubated for 30 min with the antagonists, then 30 min with CBD (black bar, CBD alone) and loaded in the upper compartment of the Boyden chamber. (b) CBD inhibition of cell migration is not prevented by the combination of the two cannabinoid receptor antagonists (SR1+SR2) and capsazepine (CPZ). Results are expressed as percentages of control migration (U87 cell migration in presence of vehicle, open column). Values are mean±s.e.m. of at least three independent experiments. *P<0.05, **P<0.01 vs vehicle Tukey's t-test.