Stress Repression in Restrained Rats by (R)-(−)-Linalool Inhalation and Gene Expression Profiling of Their Whole Blood Cells

As an attempt to quantitatively analyze the physiopsychological effects elicited by odorants, white blood cells and gene expression were profiled in the whole blood of the rats exposed to (R)-(-)-linalool during restraint stress for 2 h. In neutrophils and lymphocytes, significant changes caused by the restraint were repressed by their exposure to the odorant. This indicates that inhalation attenuates stress-induced changes. Significant changes on the stress-induced variations were induced by inhalation in 115 gene expression levels. Of those, 109 genes were down-regulated, whereas the remaining 6 were up-regulated. These findings show that (R)-(-)-linalool inhalation represses stress-induced effects on the profiles of both blood cells and gene expression. Furthermore, these results suggest the possibility that the odorant-induced effects can be quantitatively evaluated by analyzing the profiles of blood cells and gene expression.