FIG. 5.

Effect of blast TBI on purine metabolites in prefrontal cortex at 2 or 24 h after injury. LC-MS/MS assessment of (A) 3′,5′-cAMP, (B) ATP, (C) ADP, (D) 5′-AMP, (E) 2′-AMP, (F) adenosine, and (G) inosine using LC-MS/MS. There was no difference between sham and blast injury groups at either 2 or 24 h after injury for any of these metabolites, suggesting that energy failure and ATP depletion were not occurring. Levels of the endogenous neuroprotectant, adenosine, were not correlated with 5′-AMP (H), but were highly correlated with 2′-AMP (I), suggesting the possibility that mRNA breakdown after blast TBI was leading to the generation of adenosine from 2′-AMP through the 2′,3′-cAMP pathway. See text for details. LC-MS/MS, liquid chromatography tandem mass spectrometry; cAMP, cyclic adenosine monophosphate; ATP, adenosine triphosphate; ADP, adenosine diphosphate; mRNA, messenger RNA.