In vivo effects of local anesthetics on the production of major outer membrane proteins by Escherichia coli.

Synthesis of a major outer membrane pore protein (the OmpF protein) by Escherichia coli K-12 was specifically and reversibly inhibited by low doses of procaine and other local anesthetics. The treated cells maintained the same total number of pores in their outer membrane by increased synthesis of the OmpC pore protein. Procaine also inhibited synthesis of the OmpF protein by Salmonella typhimurium and by E. coli B, although in the latter case, some OmpF protein was still detected in the outer membrane of treated cells. Experiments in which transcription was blocked by pretreatment with rifampicin indicated that procaine did not inhibit translation of the stable OmpF mRNA and that there was no pool of preformed OmpF and mRNA in cells grown in the presence of procaine. Procaine did not affect biosynthesis of the lipopolysaccharide core and did not inhibit the association of OmpF protein with the peptidoglycan. These results are discussed in terms of the known effects of procaine on membrane molecular packaging.