β-eudesmol, an oxygenized sesquiterpene, affects efferent adrenal sympathetic nerve activity via transient receptor potential ankyrin 1 in rats

The autonomic nervous system innervates various peripheral tissue functions. Various external stimuli affect autonomic nerve activity, however, there is little information about the involvement of sensory receptors in the responses. The TRPA1 is a calcium-permeable non-selective cation channel which plays a crucial role in the susceptibility to various stimuli. β-Eudesmol, an oxygenated sesquiterpene found in hop essential oil and beer, activates the TRPA1. Intragastric administration of β-eudesmol decreased efferent adrenal sympathetic nerve activity (ASNA) in rats, whereas subcutaneous administration did not. ASNA suppression by β-eudesmol was not observed in TRPA1 knockout rats. The β-eudesmol derived ASNA suppression was partially, but significantly, eliminated by subdiaphragmatic vagotomy in rats, suggesting the afferent vagal nerve from the gastrointestinal tract to the brain is involved in the effect of β-eudesmol on ASNA. Our results indicate that β-eudesmol suppresses ASNA, partly through TRPA1 and the afferent vagus nerve. These findings introduce the physiological significance of the TRPA1 in the control of ASNA.