Enhancement of cellular olfactory signal by electrical stimulation.

The binding of olfactory receptors with odorant molecules initiates olfactory signal transduction, which leads to a cationic influx. In the present study, human embryonic kidney-293 cells were recombinantly engineered to co-express olfactory receptors I7 and gustatory cyclic nucleotide gated channels, which increased the cationic influx. The odorant-induced change in the membrane potential was measured in the extracellular region using microelectrode arrays. A biphasic electrical current stimulation was applied to the cells in order to increase the intrinsic cellular activity. Upon odorants recognition, the electrical cellular activity was enhanced following each electrical stimulation pulse. Compared with odorant-only stimulation, the electrical stimulation induced up to a fivefold increase in the amplitude of the electrical signal, which was produced in response to the odorants. These results demonstrate that electrical stimulation can enhance cellular activity and increase the response signal for detecting ligand binding. This paradigm of electrical stimulation can be used as a novel method in the field of versatile cell-based biosensors for detection of specific odorants.