Cell doi: 10.1016/j.cell.2018.04.014 (2018)

Did you ever feel better, sharper after a little time outside? Well, you are not alone. Moderate doses of sunshine have been linked to improved emotional and learning states, but the ‘how’ for these effects has remained largely unexplained. UV-irradiation does lead to changes in levels of small and large molecules in the skin. In a new study, investigators linked one such metabolite, urocanic acid (UCA), to these beneficial effects.

Using new single neuron metabolomics and isotopic labeling, authors reported that UCA was metabolized to glutamic acid (GLU), the most common excitatory neurotransmitter in mammals, in several regions of the brain. Moreover, increases in UCA-derived GLU improved memory and learning. This metabolic pathway was not previously known to exist in neural tissues.