On the convulsive action of castrix

Castrix, a vitamin B6 antagonist, shifted the visible absorption spectrum of methylene blue towards the longer wavelength with increase of absorbaney. This spectral alteration was similar to that observed by dilution of the dye. Several castrix derivatives also had some ability to alter the spectrum of methylene blue, and an approximate correlation was found between their ability to alter the spectrum and their convulsant activity. This correlation was observed also with other metachromatic dyes; toluidine blue and thionine. A similar shift of spectrum of methylene blue was observed also after the addition of substances known to have good electron donor or good electron acceptor properties, pyridoxal Schiff bases or some vitamin B6 antagonists. The electron donor property of castrix was shown by studying its complex with iodine monochloride and it was suggested that the convulsive action of castrix may be due to the electron donor property.