The role of calcium in interleukin- (IL) 8-, IL-1 alpha- and IL-1 beta-induced lymphocyte migration has been investigated by using the calcium channel antagonists, verapamil, nifedipine, diltiazem (IL-8) and the optical isomers of the dihydropyridine analogue SDZ 202-791 (IL-8, IL-1 alpha and IL-1 beta). Potent inhibition of IL-8-induced migration was observed in response to nifedipine (IC50 = 10 nM), verapamil (IC50 = 60 nM) and diltiazem (IC50 = 10 nM). The (+)-isomer of SDZ 202-791 was without effect on any of the agonists tested, however, the (-)-isomer induced dose-related inhibition of stimulated migration, IC50 values being 0.1 nM, 10 pM and 1.0 nM, for IL-8-, IL-1 alpha- and IL-1 beta-induced migration, respectively. Reversal of the inhibitory effects of the (-)-isomer was obtained in the presence of increasing concentrations of (+)-isomer. The induction of lymphocyte migration by IL-8, IL-1 alpha and IL-1 beta therefore appears to be a process dependent on calcium channel activation.