The effect of NPC-14686, a potential anti-inflammatory drug, on cytosolic free Ca 2 + levels ([Ca 2 + ] i ) in HA22/VGH human hepatoma cells was explored by using fura-2 as a fluorescent Ca 2 + indicator. NPC-14686 at concentrations above 10 μM increased [Ca 2 + ] i in a concentration-dependent manner with an EC 5 0 value of 100 μM. The Ca 2 + signal was reduced by removing extracellular Ca 2 + or by 10 μM nifedipine and was not changed by verapamil or diltiazem. Pretreatment with 1 μM thapsigargin (an endoplasmic reticulum Ca 2 + pump inhibitor) to deplete the endoplasmic reticulum Ca 2 + abolished 200 μM NPC-14686-induced Ca 2 + release; and conversely pretreatment with NPC-14686 abolished thapsigargin-induced Ca 2 + release. The Ca 2 + release induced by 200 μM NPC-14686 was not changed by inhibiting phospholipase C with 2 μM U73122. Together, the results suggest that in human hepatoma cells, NPC-14686 induced a [Ca 2 + ] i increase by causing store Ca 2 + release from the endoplasmic reticulum in an phospholipase C-independent manner, and by inducing nifedipine-sensitive Ca 2 + influx.