Aa. Nikonov et al., A photoaffinity-labeled green leaf volatile compound 'tricks' highly selective and sensitive insect olfactory receptor neurons, CHEM SENSE, 26(1), 2001, pp. 49-54
The sex pheromone of the scarab beetle, Phyllopertha diversa, is emitted by
females and specifically detected by olfactory receptor neurons in the mal
e and female antennae. Single sensillum recordings showed that, in contrast
to the less sensitive pheromone sensilla in females, olfactory receptor ne
urons in the male antennae had a low threshold (1 ng), which rivals those o
f moths. The male and female antennae also possessed olfactory receptor neu
rons specific for the detection of floral and green leaf volatile compounds
. Detectors for the green leaf volatile (Z)-3-hexenyl acetate had a thresho
ld (10 pg) far below the sensitivity of the pheromone-detecting machinery.
In addition, these neurons showed a remarkable selectivity even when challe
nged with related compounds at 10 000-fold higher concentrations. Surprisin
gly, a diazo analog, (Z)-3-hexenyl diazoacetate, elicited slightly higher n
ervous activity than the natural ligand in the neurons specific and selecti
ve for (Z)-3-hexenyl acetate. The inability of the green leaf volatile-dete
cting machinery to discriminate the photoaffinity-labeled compound from the
natural product indicates that the synthetic ligand interacts with odorant
-binding protein, odorant receptor and odorant-degrading enzyme as does the
cognate ligand.