Fig. 3. Lidocaine enhances human adenosine 1 receptor–coupled signaling. (A ) Lidocaine (10−5–10−1M) reduced cAMP in a concentration-dependent manner in the absence (ctrl) and in the presence of the adenosine 1 receptor antagonist 8-cyclopentylxanthine (CPX) at similar EC50s. (B ) This inhibitory effect was independent of the presence of an agonist: 1 mm lidocaine reduced cAMP by 47.6 ± 8.42% (lidocaine vs. control, **P < 0.001) at a concentration of N6-cyclopentyladenosine (CPA) of 10−10M and by 52.1 ± 5.96% (lidocaine vs. control, **P < 0.001) in the absence of the agonist CPA.
