Effect of a non-membrane permeable inhibitor of calmodulin on TRPV1-mediated Ca²⁺-transport.

Camstatin, a recently identified, selective, 25-mer polypeptide blocker of calmodulin, was employed, which inhibited capsaicin-induced Ca²⁺-uptake with comparable activity (IC₅₀ = 20 µM) determined previously to other, more conventional antagonists, of calmodulin in TRPV1-NIH3T3 cells. Results with camstatin suggests calmodulin-like structure at the extracellular domains of TRPV1. Experiments were repeated two additional times in triplicate with similar results.