RT Journal Article
SR Electronic
T1 Minute Impurities Contribute Significantly to Olfactory Receptor Ligand Studies: Tales from Testing the Vibration Theory
JF eneuro
JO eNeuro
FD Society for Neuroscience
SP ENEURO.0070-17.2017
DO 10.1523/ENEURO.0070-17.2017
VO 4
IS 3
A1 M. Paoli
A1 D. Münch
A1 A. Haase
A1 E. Skoulakis
A1 L. Turin
A1 C. G. Galizia
YR 2017
UL http://www.eneuro.org/content/4/3/ENEURO.0070-17.2017.abstract
AB Several studies have attempted to test the vibrational hypothesis of odorant receptor activation in behavioral and physiological studies using deuterated compounds as odorants. The results have been mixed. Here, we attempted to test how deuterated compounds activate odorant receptors using calcium imaging of the fruit fly antennal lobe. We found specific activation of one area of the antennal lobe corresponding to inputs from a specific receptor. However, upon more detailed analysis, we discovered that an impurity of 0.0006% ethyl acetate in a chemical sample of benzaldehyde-d5 was entirely responsible for a sizable odorant-evoked response in Drosophila melanogaster olfactory receptor cells expressing dOr42b. Without gas chromatographic purification within the experimental setup, this impurity would have created a difference in the responses of deuterated and nondeuterated benzaldehyde, suggesting that dOr42b be a vibration sensitive receptor, which we show here not to be the case. Our results point to a broad problem in the literature on use of non-GC-pure compounds to test receptor selectivity, and we suggest how the limitations can be overcome in future studies.