Chlorpromazine inhibits the calcium-mediated effects of S-100 protein(s) on assembled brain microtubule proteins, but not those on microtubule protein assembly.
We have examined the S-100-chlorpromazine interplay at the level of brain microtubule proteins in vitro. The results indicate that in the presence of 0.12 M KCl and 10 microM free Ca2+ the inhibitory effect of S-100 on microtubule assembly is additive to that of chlorpromazine, but S-100 fails to potentiate the disassembling effect of 0.1 mM Ca2+ if added to assembled microtubule proteins after chlorpromazine and Ca2+, probably because of inhibition of S-100 by the phenothiazine. Chlorpromazine does not compete with S-100 for binding to purified tubulin.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D002746:Chlorpromazine / Q000494:pharmacology*; D007700:Kinetics; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D009418:S100 Proteins / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism
D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; D009418:S100 Proteins; D014404:Tubulin; D002118:Calcium; D002746:Chlorpromazine