Detection Of Tyramine Research Articles

Development of immunoassays for tyramine and tryptamine toxins of Phalaris aquatica L.

The leaves of the perennial pasture grass Phalaris aquatica L. (phalaris) contain two groups of known toxins, indole alkaloids, primarily dimethyltryptamines and N-methyltyramines, which cause illnesses in grazing animals, especially sheep. Using amino-reactive and phenolic hydroxyl-reactive homobifunctional reagents, simple methods were devised for coupling toxins representative of those in phalaris to carrier proteins and enzymes for ELISA development. ELISAs were produced for both groups of toxins. Dimethyltryptamines were most sensitively detected [lower limit of detection (LLD) of 1 microg/L for bufotenine] using rabbit anti-bufotenine antibodies, coupled to ovalbumin using divinyl sulfone, with detection using a peroxidase conjugate prepared using the same hapten coupled with 1, 4-butanediol diglycidyl ether. The assay cross-reacted with other toxins of the same class (N,N-dimethyltryptamine and N, N-dimethyl-5-methoxytryptamine) but not with the structurally related amino acids histidine and tryptophan. The most sensitive N-methyltyramine assay (LLD of 1 microg/mL for N-methyltyramine) utilized antisera to tyramine with N-methyltyramine coupled to peroxidase. Significant cross-reaction was seen with the low-grade toxin hordenine, but detection of tyramine was poorer, whereas the amino acid tyrosine was not detected. These assays could be applied to the analysis of simple extracts of Phalaris leaves with minimal interference. A good correspondence was observed between toxin levels by ELISA and estimates from a more tedious thin-layer chromatography method. The method has now been incorporated in a Phalaris breeding program.

Candicine from Stapelia gigantea

Hordenine (N, N-dimethyltyramine) was found previously in the title plant. The detection of tyramine, N-methyltyramine, and choline and the crystallization of candicine (N, N, N-trimethyltyramine chloride) is now reported for this species.

Detection of urinary primary amines through negative chemical ionization mass spectrometry of fluorescamine derivatives.

We report the successful detection of urinary biogenic amines by a procedure which involves isolation of the amines on CG-50 cation exchange resin, derivatization of the amines with fluorescamine while on the resin, followed by direct probe negative chemical ionization mass spectrometry screening of the resin extract. This isolation procedure allowed the detection of tyramine, octopamine, normetanephrine, 3-methoxytyramine and a variety of aliphatic amines. Norepinephrine, dopamine and serotonin were chemically reactive under these conditions and were not detectable at physiological concentrations.