Acetylsalicylic acid enhances tachyphylaxis of repetitive capsaicin responses in TRPV1-GFP expressing HEK293 cells

Since many years acetylsalicylic acid (ASA) is known for its antithrombotic, antiphlogistic and analgesic effects caused by irreversible acetylation of cyclooxygenase. ASA also inhibits capsaicin- and heat-induced responses in cultured dorsal root ganglia (DRG) neurons, suggesting TRPV1 (transient receptor potential channel of the vanilloid receptor family, subtype 1) to be an additional target of ASA. We now studied the effect of ASA on heterologously expressed rat TRPV1 using calcium microfluorimetry. Capsaicin dose-dependently increased intracellular calcium with an EC50 of 0.29 μM in rTRPV1 expressing HEK293 cells. During repetitive stimulation the second response to capsaicin was reduced (53.4 ± 8.3% compared to vehicle control; p