In vitro effects of calmodulin antagonists on macrophage function in the posterior necrotic zone of the chick wing

Excised tissues from the prospective posterior necrotic zone (pPNZ) of the stage 21 chick wing were cultured in the presence of the calmodulin antagonists/protein kinase C inhibitors trifluoperazine (TFP) or chlorpromazine (CPZ). The appearance of cell death in vitro was not affected by the drugs. Macrophages differentiated normally and were competent to engulf debris. Lysosomal fusion with phagosomes and the digestion of most debris also occurred in the presence of the drugs. However, the macrophages were unable to process internalized cell membranes properly and continued accumulating membrane until they were grossly distended. The effect was reversible upon removal of the drugs. The results suggest a role for calmodulin and/or protein kinase C in the proper recycling of internalized membrane in embryonic macrophages.