Does fucose or piracetam modify the effect of hypoxia preconditioning against pentylenetetrazol-induced seizures?

To clarify the question whether the duration of hypoxia exposure has an inf luence on the point in time or the strength of hypoxic preconditioning, hyp oxia exposure of rats lasting 1 and 8 h was tested regarding the modificati on of susceptibility to acute pentylenetetrazol-induced seizures. Following the short-lasting (1 h) hypoxia, the maximum level of preconditioning acti on was observed 7 days after hypoxia, whereas the longer-lasting hypoxia (8 h) produced the maximum level of protection 14 days after hypoxia. We inve stigated the influence of fucose and piracetam on the effect of hypoxia pre conditioning by the application of the substances 20 min before the beginni ng of hypoxia exposure. Fucose did not modify the result of hypoxia precond itioning. But after the treatment with piracetam, the preconditioning effec t was prevented following hypoxia lasting 1 and 8 h. We suggest that the ra dical scavenger properties of piracetam are responsible for the absence of protection against pentylenetetrazol-evoked seizures. (C) 2000 Elsevier Sci ence B.V. All rights reserved.