[Nonenzymatic models of histochemical tetrazolium reduction (author's transl)]

4 nonenzymatic biochemical systems (NADH-mediator-tetrazolium; NADH-riboflavin-tetrazolium; methionine-riboflavin-tetrazolium; potassium superoxide (KO2)-tetrazolium) were tested as models for histochemical tetrazolium reduction. A NADH-PMS-tetrazolium system was proved to be most suitable. The reaction rates of some histochemically used tetrazolium salts, the stimulation of the reaction rates by the detergents Tween, Triton X-100, and N-Cetylpyridinium chloride and the effectiveness of some histologic dyes (oxazines, phenazines, thiazines) as mediators were determined as examples of application. The reported results are discussed in relation to the role of detergents and oxygen in the mechanism of tetrazolium reduction.