Abstract
We have previously reported that calcium channel blockers interfere with the chemotaxis of guinea-pig PMNs. The concentrations required for inhibition of PMN chemotaxis are usually one or two orders of magnitude higher than those necessary for inhibition of calcium ion translocation across smooth muscle cell membranes. These compounds possess a calmodulin inhibitory property at relatively high concentration. In the studies reported herein, we examined the possible role of calmodulin in the chemotaxis of guinea-pig PMNs using calmodulin inhibitors. Calmodulin inhibitors, N- (6-aminohexyl) -5-chloro-1-naphthalene sulfonamide (W-7), trifluoperazine (TFP) and chlorpromazine (CPZ), suppressed the PMN chemotaxis in a dose-dependent manner. N- (6-aminohexyl) -1-naphthalene sulfonamide (W-5) TFP-sulfoxide and CPZ-sulfoxide, which have very low affinity for calmodulin, had practically no inhibiting effect on the PMN chemotaxis. Calmodulin inhibitors also inhibited the PMN chemotaxis in the absence of extracellular calcium ions. These results suggest that calmodulin plays some role in the chemotaxis of neutrophils.
