[P3-3-09] Reduced Intraoral Menthol Sensitivity in A Prodromal Parkinson's Disease Model Mice with Intranasal Rotenone
キーワード：パーキンソン病、ロテノン、メントール
Parkinson’s disease (PD), the second most common neurodegenerative disease characterized primarily by motor symptoms, causes prodromal non-motor symptoms including sensory dysfunction (e.g., impaired senses of smell, taste and/or touch). We previously report that bitter taste impairments may occur simultaneously, but independently, of olfactory impairments in a presumed animal model in the early-stage of PD. Other sensation such as cold/cool may at least partly affect taste sensation, but it remains unclear whether our model exhibits other sensory impairments. In this study, we examined the disturbances of the intraoral/intranasal menthol sensation, such as coolness/irritation at low and high concentrations of menthol, in 1-week intranasal rotenone administrated-mice using brief-access exposure test. One solution from the 7-concentration series of (–)-menthol (0-2.3 mM) or the bitter taste quinine-HCl (0.3 mM) were randomly selected, respectively, to be presented once a day for 10-s to the water-deprived mice at before and 1-week after rotenone treatment. Correlated to increasing in the menthol concentration, the latency of the first lick was gradually increased before rotenone treatment, but not 1-week after. The mean standardized cumulative lick curve for menthol was observed as a dose-dependent slope, and not altered by the rotenone treatment. In addition, the total number of licks during 20 trials was significantly increased in rotenone-treated animals at high concentration of menthol and 0.3 mM quinine-HCl, compared to the data obtained before rotenone treatment. These results indicated that mice administrated with rotenone intranasally for 1-week exhibited a reduction in the intraoral/intranasal menthol sensitivity in addition to bitter taste impairments.