Fig. 6.

Demonstration of the efficacy of purine salvage pathways in restoration of adenosine release from brain slices. Top: Metabolism of ATP and purine salvage pathway for adenine and d-ribose utilization: APRT adenine phosphoribosyltransferase, HGPRT hypoxanthine phosphoribosyltransferase. Solid lines indicate direct routes, and dashed lines indicate indirect routes. The reactions of the purine salvage pathway are catalyzed by HGPRT and APRT. bLower: Preincubation of hippocampal slices for 2 h with d-ribose (1 mM) and adenine (50 μM; RibAde) results in greater adenosine (Ado) release in response to three periods of theta burst stimulation (arrows). Concentration of adenosine in nanomolar’ indicates that the signal recorded reflects adenosine and metabolites such as inosine. Reproduced with permission from [70]