ADORA2A and peritonitis: In a mouse model of peritonitis, MTX increased adenosine concentration in peritoneal exudates of all mice studied, and reduced the leukocyte accumulation and TNF-α levels in the wild-type mice and ADORA3 knockout mice but not in ADORA2A knockout mice suggesting that ADORA2A is the principal anti-inflammatory adenosine receptor in this model [72].