TRP channels represent a large and diverse family of non-selective cation channels that respond to a wide range of chemical and physical stimuli. TRPV1 (transient receptor potential vanilloid) is a non-selective cation channel, highly permeable to Ca²⁺.

TRPV1 is comprised of four subunits arranged around a central ion permeation pore. Each subunit consists of six transmembrane α-helices (S1–S6) that span the lipid bilayer and a re-entrant loop with a pore helix located between S5 and S6. The outer pore region of TRPV1 is wide open compared to K_V channels, with a broad funnel-like structure that probably enhances accessibility to both small and large pharmacophores.

TRPV1 is the receptor for capsaicin, the pungent agent from chili peppers. TRPV1 is activated by noxious heat, elicits burning pain and is modulated by inflammatory agents, such as extracellular protons and bioactive lipids, which contribute to pain hypersensitivity¹. TRPV1 activation by capsaicin is followed by nociceptor desensitization, is markedly depending on Ca²⁺ and involves various intracellular signaling pathways. Subsequently, dephosphorylation by the phosphatase calcineurin of TRPV1 previously phosphorylated by protein kinase A (PKA) or Ca²⁺-calmodulin-dependent kinase II leads to TRPV1 desensitization².

Recently, the GABA(B) R1 receptor subunit has been identified as an inhibitor of TRPV1 sensitization in the context of diverse inflammatory settings. The endogenous GABA(B) agonist, GABA, is released from nociceptive nerve terminals, suggesting an autocrine feedback mechanism limiting TRPV1 sensitization. The effect of GABA(B) on TRPV1 is independent of canonical G protein signaling and rather relies on close juxtaposition of the GABA(B) R1 receptor subunit and TRPV1³.