Retinal ischemic preconditioning in the rat: requirement for adenosine and repetitive induction.

摘要: PURPOSE. A brief period of ischemia can induce a remarkably complete state ischemic tolerance in the retina, phenomenon known as preconditioning (IPC). The mechanisms IPC were studied rat retina by examining role adenosine possible mediator and determining whether protection could be induced more than once same rat. METHODS. Retinal was produced for 60 minutes ketamine-xylazine-anesthetized Sprague-Dawley rats, recovery measured using electroretinography. Twenty-four hours earlier, stimulus 5 applied. To test IPC, selective Al receptor antagonist 8-cyclopentyl-1,3-dipropylxanthin (DPCPX; 0.45 mg/kg, 2.25 or 4.5 mg/kg), A2a 8-(3-chlorostyryl)caffeine (CSC; 0.1 mg/kg 1.0 their cyclodextrin vehicle administered 15 before IPC. examine exogenous administration mimic animals received intravitreal injections stimulant amine congener (ADAC) CGS21680, followed 24 later. hypothesis that repeatedly without loss protection, rats divided to receive sham 10 days later procedure, ischemia. RESULTS. Adenosine blockade with DPCPX intraperitoneally (IP) immediately after completely blocked whereas lower doses resulted partial blockade. CSC at lowest dose (0.1 mg/kg) had no significant effect on IPC's protective effect, found CSC. stimulation but mimicking effects antagonized Ischemic applied twice, separated days, second stimulus, nearly identical function compared performed one time. CONCLUSIONS. Adenosine, acting through receptors, is critical component induction retina. neuroprotective are lost over time may reinduced subsequent application stimulus.