A3 adenosine receptors are required for the inhibition of ConA-induced ALT and TNFα by inosine. C57BL/6 (A-B), A2aR^-/- (C-D), A3R^-/- (E-F), and A2aA3R^-/- (G-H) mice were injected with ConA, inosine (100 mg/kg), or both, and the level of TNFα and ALT in the serum at 1 hour and 24 hours, respectively, after challenge was determined. Because excessive inflammation is observed in the absence of the A2aR,³  A2aR^-/- and A2aA3R^-/- mice were injected with 15 mg/kg, whereas the C57BL/6 and A3R^-/- mice were injected with 20 mg/kg ConA. This figure shows that inosine inhibited ConA-induced hepatitis only in mice expressing the A3R. Representative results from one of 3 separate experiments.