A Quantitative Histochemical Method for estimating Phospholipids

Abstract

THE affinity of the ‘Luxol’ solvent dyes for phospholipids has been investigated. One of these dyes, ‘Luxol’ fast blue MBS, was introduced by Kluver and Barrera¹ as a myelin stain. It is a diarylguanidine salt of a sulphonated copper phthalocyanine dye. The dyes used in this investigation are diarylguanidine salts of sulphonated azo dyes. ‘Luxol’ fast blue G, ‘Luxol’ fast blue ARN, and ‘Luxol’ fast black L, have been found to form complexes with phosphotidyl, choline, phosphotidyl ethanolamine, and phosphotidyl serine. Pearse² has already noted that ‘Luxol’ fast blue MBS forms precipitates with certain phospholipids in in vitro tests. He believed it was possibly an acid base reaction and that the base of the phospholipid replaced the base of the dye. He found his precipitates confined to the choline containing phospholipids. I have found that the dyes ‘Luxol’ fast blue G and ARN, and the phospholipids, phosphotidyl choline and phosphotidyl serine, form complexes stoichiometrically. Furthermore, there is a reversal of their common solubility in absolute ethanol (Table 1).