[Effect of long-term space flight on polyamine levels in the rat brain].

The concentration of polyamines, i.e. putrescine, spermidine and spermine, was measured in different brain compartments of rats flown for 18.5 days on Cosmos-1129. Exposure to space flight led to changes in the polyamine content that were most distinct in medulla oblongata. It is suggested that the changes develop as a result of a chronic stress associated with the effects of weightlessness.