Terpenes as modulators of nociceptive signaling: behavioral and molecular insights from Caenorhabditis elegans

Terpenes such as Limonene (LIMO) and β-Caryophyllene (BC) have demonstrated pain-modulating properties, potentially through interactions with the Transient receptor potential vanilloid 1 (TRPV1) receptor. This study examines the antinociceptive effects of four terpenes derived from Cannabis sativa: Limonene, β-Caryophyllene, α-Humulene (HUM), and α-Myrcene (MYR) using Caenorhabditis elegans (C. elegans). The primary objective was to characterize terpene-induced modulation of nocifensive responses to noxious heat, and to elucidate their influence on molecular pathways via specific receptor targets. Thermotaxis assays quantified the antinociceptive activity of increasing terpene concentrations in wild-type nematodes. To assess receptor-specific mechanisms, assays were performed in mutant strains lacking functional OCR-2 and OSM-9 (TRPV-like nociceptors) and NPR-19 and NPR-32 (encoding cannabinoid-like receptors). Proteomic profiling coupled with bioinformatics analysis identified terpene-induced alterations in signaling pathways and biological processes. All four terpenes exhibited significant antinociceptive activity in wild-type C. elegans, with impaired effects observed in vanilloid receptor mutants, implicating TRPV-like channels in their mechanism of action. Proteomic and pathway analyses revealed terpene-specific molecular signatures, highlighting differential modulation of neuronal and stress-responsive signaling cascades. By elucidating the molecular mechanisms underlying terpene-induced nociceptive modulation, this work strengthens the growing body of evidence supporting the therapeutic promise of terpenes in pain management outside the effect referred to as the "entourage effect".