Subject disclosure relates to a stable free-radical product, its use to produce brain excitation in non-human mammals when intravenously administered, and a method of preparing the free-radical product. The free-radical product is prepared from purified plasma proteins, pituitary peptides and other structures containing tyrosine or tryptophan by oxidation with a free-radical nitrosyl disulfonate product in alkaline solution under controlled conditions. Intravenous administration of the free-radical product into non-human mammals causes a sudden electroencephalographic arousal accompanied by behavioral changes indicative of brain excitation. Illumination of the free-radical product by visible light prior to administration substantially enhances the arousal and brain excitation effects.
Stable free-radical structures