Effects of phenothiazines on cultured retinal pigment epithelial cells

Phenothiazines (chlorpromazine, trifluoperazine, prochlorperazine, and fluphenazine) showed dose-dependent inhibition of phagocytosis of latex particles by cultured chick retinal pigment epithelial cells at concentrations of 10(-5)-10(-14) mol/l. Calmodulin antagonists (W-5, W-7, W-12, and W-13) showed similar effects as phenothiazines at concentrations of 10(-5)-10(-14) mol/l. These reactions were partially reversible at a concentration of 10(-9) mol/l. Cells cultured for 3 days in the presence of 10(-5) mol/l chlorpromazine or 10(-5) mol/l W-7 demonstrated morphologic alterations in their microvilli which were similar to those seen after cytochalasin B treatment, i.e., thinning and elongation of the microvilli with honeycomb-like changes.