Valeric acid attracts C. elegans by activating the AWC neurons through a tax-4 -dependent signaling pathway.

Abstract

Medicinal plants of the Valeriana genus have been traditionally used around the world to treat several nervous system disorders, yet our understanding of how they do so remains poorly understood. To deepen the understanding of their ability to influence nervous system pathways, we explored the ability of the model organism Caenorhabditis elegans to chemotax to crude extracts of Valeriana officinalis and found that C. elegans are weakly attracted to it. Upon investigating which chemical entities give rise to this behavior, we identified valeric acid (VA) as a primary candidate. Through chemotaxis assays, we show that wild-type C. elegans are strongly attracted to VA in a dose-dependent manner. Chemotaxis assays with mutant strains of C. elegans deficient in chemosensation indicate that the tax-4 -dependent nervous pathways are most heavily responsible for detecting VA. However, osm-9 -dependent pathways may also play a small role in regulating the worm's response to VA. Additionally, animals lacking AWC neurons are indifferent to this compound, and therefore, future research should focus on what molecular entities grant the AWC neurons the ability to detect VA.