FBS Colloquia No.348Physiological Laboratory

Investigation of olfactory masking mechanisms localized in the olfactory cilia by electrophysiological techniques

Sensory cells express their functions in accordance with their respective characteristics. For example, photoreceptor cells, which are the first stage of vision, have light and dark adaptation and respond to changes in the external environment surrounding us by shifting the dynamic range. Olfactory receptor cells (ORCs) are similarly characterized by olfactory adaptation, which quantitatively controls the relationship between odor intensity and response. In the past, it was believed that their olfactory adaptation was caused by modification of olfactory emotion signals only in the brain. However, the first stage of olfactory reception, at the level of the olfactory neuron, is already triggered by negative feedback from the intracellular Ca-CAM complex of information transduction channels. These have already been described in basic physiology textbooks. The specific functions of ORCs are localized in the cilia, the site of signal transduction, but due to the nanoscale structure of such cilia, many of these functions have not been elucidated by previous experimental techniques. Among them, "olfactory masking," which modifies the perception of odors from outside the cell, is a recently discovered finding based on precise experimental techniques, mainly in electrophysiology, and is not yet described in older textbooks. In this talk, I will introduce the mechanism of "olfactory masking" in the olfactory cilia and examples of research on olfactory masking in our ordinary days.