Abstract
Indomethacin (0.15-5 mu g/ml), diclofenac (0.1-1.0 mu g/ml) and tenoxicam (1.25-50 mu g/ml) or the calcium channel blockers, verapamil (25-400 mu g/ml) and diltiazem (25-300 mu g/ml), when added separately, inhibited the chemiluminescence (CL) response of isolated human polymorphonuclear leukocytes (PMNs) stimulated with either the soluble agent, phorbol myristate acetate (PMA) or by particulate opsonized zymosan (OPZ) in a concentration-dependent manner. When diltiazem was combined with either indomethacin or diclofenac, in vitro, the inhibitory effect on PMA or OPZ-induced CL response was synergistic. Similarly, verapamil produced such a synergistic effect on CL when added together with indomethacin or diclofenac. In contrast, tenoxicam failed to show any synergistic effect on the CL response when it was combined with either diltiazem or verapamil. The NSAIDs and the calcium channel blockers did not significantly affect the viability of PMNs and their inhibitory effects on CL were readily reversible when PMNs were washed with phosphate buffered saline (PBS). II is concluded that extracellular calcium may be essential for indomethacin and diclofenac but not tenoxicam to increase the inhibitory effects of NSAIDs on the CL response.