PROTECTIVE EFFECT OF PRECONDITIONING ON THE INJURY ASSOCIATED TO HEPATIC ISCHEMIA-REPERFUSION IN THE RAT - ROLE OF NITRIC-OXIDE AND ADENOSINE

The effects of ischemic preconditioning on rat liver integrity, as wel l as the implication of nitric oxide (NO) and adenosine in this proces s, has been evaluated. Preconditioning before ischemia-reperfusion pre vented the increases in alanine transaminase (ALT), aspartate transami nase (AST), and lactate dehydrogenase (LDH) levels, but did not modify blood flow. Adenosine or NO administration previous to hepatic ischem ia-reperfusion simulated the effect of preconditioning, whereas inhibi tion of adenosine or NO synthesis abolished the protective effect of h epatic preconditioning. Nevertheless, inhibition of adenosine and simu ltaneous administration of NO in preconditioned animals offered simila r results to those found in the preconditioned group, indicating that, in the absence of adenosine, NO is able to maintain the preconditioni ng benefits. It is suggested that, in preconditioning, adenosine stimu lates NO production to protect against the injury associated with isch emia-reperfusion.