Sensory Modulatory Effects of Different Odorants on Chemesthesis

To investigate the sensory modulatory effects of different types of odorants on chemesthesis and their relationship with odor preference, first, nicotine was used as a representative substance to induce pungent stimulation in mice, and by detecting respiratory system indices in mice, the modulatory effects of 15 typical food-derived odorants on the mouse respiratory system after pungent-stimulation exposure were evaluated. Then, a bilateral olfactory preference test was performed to determine the olfactory preference of mice for 15 different odorants. Finally, a multidimensional evaluation coordinate system of odorants was constructed to elaborate the olfactory preference, physiological irritancy, and the ability to alleviate respiratory suppression induced by the representative irritant substance of different odorants in mice. Whole-body plethysmography was used to establish an exposure model of nicotine aerosol at different mass concentrations, and it was found that with increasing nicotine mass concentration, the respiratory frequency of mice changed significantly and exhibited a dose-dependent characteristic. Subsequently, on the basis of determining 20 mg/mL nicotine as a representative strongly irritant dose, it was co-exposed with 15 typical food-derived odorants, respectively, to evaluate the modulatory capacity of different odorants on respiratory suppression induced by pungent irritant substances. The results showed that most odorants alleviated the nicotine-induced decrease in respiratory frequency to varying degrees. For example, ethyl maltol, menthol, carvacrol and thymol significantly increased respiratory frequency from 281.45 breaths/min under nicotine alone to approximately 460 breaths/min under combined exposure, corresponding to a relief rate of more than 60%, and the modulation percentage exceeded 170% for some odorants, indicating that they not only counteracted the suppressive effect but even induced a certain degree of respiratory excitation. In contrast, individual odorants such as furaneol further aggravated respiratory suppression, demonstrating directional differences and chemical specificity in odor-dependent modulation. On this basis, a bilateral olfactory preference test was used to determine the innate olfactory preference levels of mice for different odorants. Combined with whole-body plethysmography measurements of the bronchoconstriction index (Penh) under odorant-only exposure to evaluate the intrinsic irritancy of each odorant, the percentage relief of respiratory frequency under combined exposure of odorants with nicotine was further calculated. The results showed that most highly preferred odorants effectively alleviated nicotine-induced respiratory suppression, whereas some odorants with relatively low preference still exhibited strong alleviating effects, suggesting that odor-mediated modulation might involve sensory pathways beyond emotional valence. A multidimensional evaluation coordinate system for odorants was constructed based on three indices—preference, modulatory effect, and irritancy—to achieve a systematic classification of odorant modulatory capacity and to establish an analytical framework. It was expected that this study could reveal, at the level of animal model, the differential modulatory characteristics of food-derived odorants on pungent stimulation, and provide a theoretical basis for the application of odorants in the design of multisensory food experiences and the optimization of comfort.