Preconditioning is induced by exposing tissue to sublethal insults resulting in a tolerant state within the tissue protecting against further damage. To investigate the role of adenosine in excitotoxic preconditioning, we evoked responses from rat hippocampal slices exposed to glutamate and ouabain. A significant depression was observed in epsp slope, orthodromic population spike and antidromic population spike amplitudes in response to 10mM glutamate and 100µM ouabain. Antidromic population spikes showed a significantly greater recovery following ouabain exposure (82.6 ± 1.6%) (n = 6) compared with the orthodromic responses (epsps 58.6 ± 7.1%, n = 7; population spikes 56.6 ± 8.3%, n = 8) (p<0.05). The reduction in antidromic spike amplitude was unaffected by 1mM kynurenic acid, a broad-spectrum glutamate antagonist. We applied an LTP stimulus (100Hz/1sec) to orthodromic population spikes one hour following either chemical stimulus; a significant potentiation was induced in slices exposed to ouabain but not those exposed to glutamate. 100µM adenosine was applied to orthodromic population spikes to see if preconditioning protection could be induced. A greater recovery was observed following ouabain exposure in preconditioned slices (79.8 ± 6.8%) (p<0.05) compared with controls (56.6 ± 8.3%) but no protection was induced against glutamate. Ouabain and glutamate therefore exert different effects on evoked responses from CA1 neurons and adenosine preconditions against ouabain toxicity but not glutamate.