PUTRESCINE, POLYAMINES, AND N-1-ACETYLPOLYAMINE LEVELS IN RETINA, VISUAL-CORTEX AND CEREBELLUM OF FREE-RUNNING MICE KEPT UNDER CONTINUOUS LIGHT OR DARKNESS

Putrescine, spermidine and spermine levels were detected in the retina , visual cortex, cerebellum and parietal cortex of CD1 mice exposed to 36h continuous light or darkness. Retinal putrescine and polyamine co ncentrations were found to be highest in dark-adapted mice, and the st imulation of dark-adapted retina with flicker illumination was also ac companied by a significant decrease in putrescine, spermidine and sper mine levels. In visual cortex as well as in cerebellum spermidine and spermine contents were higher in dark-adapted mice in comparison to li ght-exposed animals, while in parietal cortex no significant change wa s found neither in spermidine nor spermine levels. In the brain areas studied flicker illumination produced no significant decreases in putr escine and polyamine contents. The total polyamines expressed as putre scine equivalents were noticeably decreased in retina, visual cortex a nd cerebellum of light-adapted mice. In the retina spermine/spermidine molar ratio was significantly higher than in dark-adapted mice. The a dministration of N1, N2-bis-(2,3-butadienyl)-1,4-butanediamine (MDL 72 527) produced a strong decrease of retinal putrescine and spermidine c oncentrations in both dark-adapted and light-exposed mice, and in the retina of mice exposed to continuous light a significant decrease in t he spermine level was also observed. According to the influence on pol yamine reutilization, after the irreversible inhibition of polyamine o xidase by MDL 72527, in the retina N1-acetylspermidine and N1-acetylsp ermine accumulation was highest in light-adapted mice. On the contrary in visual cortex, cerebellum and parietal cortex the MDL 72527 admini stration produced a more marked decrease of putrescine and spermidine contents in mice kept in continuous darkness.