Calmodulin antagonists inhibit the phagocytic activity of cultured Kupffer cells.

The mechanism of phagocytosis by Kupffer cells is still unknown. In this study we found that trifluoperazine, chlorpromazine, and W-7, drugs which bind to Ca2+-calmodulin and inhibit its interaction with other proteins, inhibit phagocytosis by cultured Kupffer cells using polystyrene beads, time-lapse VTR systems, and fluorescent staining techniques. Inhibitory effects of these drugs on phagocytosis suggests that the Ca2+-calmodulin system may be involved in this complex cellular function and the integrity of the cytoskeletal system of Kupffer cells is essential to this phenomenon.