Fluorometric Assay of Tissue Histamine Kazuyoshi Kurahashi and Motohatsu Fujiwara

There have been numerous studies on the distribution of endogenous histamine (1-5). Many mammalian tissues contain large to small amounts of histamine preformed. Amongst them skin, stomach and lung contain extremely high concentration of histamine. These organs are exposed to the outside directly or indirectly and prone to traumatic injury. The tissue level of histamine has been estimated with the bioassay procedure using isolated guinea-pig intestine or uterus. The fluorometric analysis of tissue histamine was devised by Shore et al. (6). The method involves extraction of histamine to n-butanol from alkali nized perchloric acid tissue extracts, return of the histamine to an aqueous solution and condensation with o-phthalaldehyde (OPT) to yield a product with strong and stable fluorescence. This fluorometric determination of tissue histamine is simple, precise and sensitive, but inadequate for the analysis of brain histamine because of the presence of inter fering substance. Kremzner and Pfeiffer (7) have shown that the major interfering sub stance, spermidine, is separable from histamine by the use of a phosphorylated cellulose column. After that, Medina and Shore (8) modified the Kremzner and Pfeiffer procedure so as to increase the sensitivity. In the present experiments the Medina and Shore's modi fication for the fluorometric analysis of tissue histamine was carefully re-examined for the application to pharmacological studies.