Background: Tryptamine, a biogenic monoamine that is present in trace levels in the mammalian
central nervous system, has probable roles as a neurotransmitter and/or a neuromodulator and
may be associated with various neuropsychiatric disorders. One of the ways tryptamine may affect the
body is by the competitive inhibition of the attachment of tryptophan to tryptophanyl tRNA synthetases.
Methods: This study has explored the effects of tryptamine on growth of six yeast species (Saccharomyces
cerevisiae, Candida glabrata, C. krusei, C. dubliniensis, C. tropicalis and C. lusitaniae) in media
with glucose or ethanol as the carbon source, as well as recovery of growth inhibition by the addition of
Results: Tryptamine was found to have an inhibitory effect on respiratory growth of all yeast species
when grown with ethanol as the carbon source. Tryptamine also inhibited fermentative growth of Saccharomyces
cerevisiae, C. krusei and C. tropicalis with glucose as the carbon source. In most cases the
inhibitory effects were reduced by added tryptophan.
Conclusion: The results obtained in this study are consistent with tryptamine competing with tryptophan
to bind mitochondrial and cytoplasmic tryptophanyl tRNA synthetases in yeast: effects on mitochondrial
and cytoplasmic protein synthesis can be studied as a function of growth with glucose or ethanol
as a carbon source. Of the yeast species tested, there is variation in the sensitivity to tryptamine and
the rescue by tryptophan. The current study suggests appropriate yeast strains and approaches for further