Incorporation of [35S]methionine into proteins and two-dimensional gel autoradiograms was used to characterize early post-anoxia–aglycaemia protein synthesis in the CA1 area of rat hippocampal slices maintained in vitro. We have compared the effects of 3–4 min and 5–10 min insults, since the former but not the latter produces a reversible block of synaptic transmission (see companion paper). An insult of between 3 min 30 s and 4 min induces a transient increase in the labelled proteins during the first hour of reoxygenation, as compared to control. The increase in protein synthesis is conspicuous for several proteins, including actin, α-tubulin and heat-shock proteins (hsp70c and hsp90), as determined by immunoblotting. In the case of α-tubulin, we show with in situ hybridization and polymerase chain reaction procedures that the increase in protein synthesis is associated with a marked increase in the expression of the corresponding messenger RNAs. The results demonstrate that, in addition to regulatory proteins such as hsps, the synthesis of several polypeptides, including those associated with the cytoskeleton, is altered in anoxic damage.