Chlorpromazine inhibits neutrophil chemotaxis beyond the chemotactic receptor-ligand interaction.

K M Lohr, J B Feix, C Kurth

The Journal of infectious diseases 1984 Nov

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Phenothiazines depress Ca++-dependent neutrophil functions, perhaps by binding to calmodulin or perturbing membrane structure through hydrophobic interactions. We examined effects of chlorpromazine (CPZ) on the human polymorphonuclear neutrophil (PMN) chemotactic-oligopeptide receptor and PMN membrane fluidity. CPZ had a reversible, biphasic effect on PMN motility in the Boyden chamber (slight depression at 5 microM, enhancement at 10 microM, and dose-dependent inhibition at higher concentrations). Order of potency for inhibition of motility (trifluoperazine greater than CPZ greater than promethazine) was identical to that for both inhibition of superoxide (O-2) release and binding to calmodulin. CPZ nonspecifically altered the binding affinity of chemotactic fMet-Leu-[3H]Phe. As assessed with two spin-probes, PMN membrane fluidity was unaltered at CPZ concentrations that depressed PMN receptor-mediated chemotaxis and O-2 release. The data suggest that CPZ nonspecifically alters receptor affinity and depresses chemotaxis and O-2 release independently, without altering bulk membrane fluidity. We speculate that unidentified "post-receptor changes" at a common translocation step for functions tested account for the observed inhibition.

Citation

K M Lohr, J B Feix, C Kurth. Chlorpromazine inhibits neutrophil chemotaxis beyond the chemotactic receptor-ligand interaction. The Journal of infectious diseases. 1984 Nov;150(5):643-52