Purine levels in the intact rat brain. Studies with an implanted perfused hollow fibre.
A thin dialysis tube was implanted stereotaxically under halothane anesthesia in the caudate nucleus of Sprague-Dawley rats and perfused with Ringer solution at a rate of 2 microliters/min. Initially there was a high rate of purine outflow but after 1-2 h of perfusion the rate was essentially constant (anesthetized - adenosine 0.4 +/- 0.04 microM, inosine 0.8 +/- 0.2 microM; non-anesthetized - adenosine 0.33 +/- 0.03 microM, inosine 0.21 +/- 0.07 microM). Hypoxia (9% O2) increased the levels more than 3-fold. The adenosine deaminase inhibitor erythro-2-(2-hydroxy-3-nonyl)adenine (EHNA) increased the adenosine level and decreased the inosine level. In vitro recovery of adenosine was about 30%. Therefore, we conclude that the free exchangable concentration of adenosine in the rat brain is likely to be 102 micro M. This level is high enough to potentially affect central nervous function.
D000225:Adenine / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006151:Guanosine / Q000378:metabolism; D007042:Hypoxanthines / Q000378:metabolism; D007288:Inosine / Q000378:metabolism; D008297:Male; D011687:Purines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007042:Hypoxanthines; D011687:Purines; D006151:Guanosine; D007288:Inosine; D000225:Adenine; D000241:Adenosine