TRPV1, endocannabinoid, and opioid systems in analgesia: molecular mechanisms and drug development strategies

Pain modulation relies on complex molecular interactions among ion channels, G protein-coupled receptors, and intracellular signaling cascades. The Transient Receptor Potential Vanilloid 1 (TRPV1) channel serves as a polymodal detector and integrator of noxious stimuli, linking sensory transduction with broader neuromodulatory systems. This review delineates the mechanistic crosstalk between TRPV1, endocannabinoid, and opioid pathways in nociceptive regulation. TRPV1 activation by heat, protons, or endogenous lipids induces calcium influx and engages protein kinase C (PKC), protein kinase A (PKA), and mitogen-activated protein kinase (MAPK) pathways that modulate channel phosphorylation and neuronal excitability. Endocannabinoids such as anandamide act as dual CB₁ and TRPV1 agonists, establishing feedback loops that adjust nociceptive thresholds, while μ-opioid receptor activation inhibits adenylate cyclase and TRPV1 sensitization through Gi/o-mediated signaling. Given the recent progress in cryo-electron microscopy and molecular modeling, simulation studies have been possible, revealing key structural determinants underlying key receptor interactions. Integrating pharmacophore modeling, molecular docking, and artificial intelligence-based screening enables rational design of multi-target ligands that exploit TRPV1-endocannabinoid-opioid synergy. This mechanistic framework supports the development of next-generation analgesics that achieve potent, sustained, and safe modulation of nociceptive signaling.