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Evidence that oxidative stress is involved in the inhibitory effect of proline on Na + ,K + ‐ATPase activity in synaptic plasma membrane of rat hippocampus
Author(s) -
Franzon Renata,
Lamers Marcelo L.,
Stefanello Francieli M.,
Wannmacher Clóvis M.D.,
Wajner Moacir,
Wyse Angela T.S.
Publication year - 2003
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/s0736-5748(03)00076-5
Subject(s) - trolox , chemistry , glutathione , atpase , vitamin c , medicine , endocrinology , antioxidant , arginine , hippocampus , oxidative stress , biochemistry , enzyme , biology , amino acid , antioxidant capacity
In the present study, we investigated the effect of Vitamins E and C on the inhibition of Na + ,K + ‐ATPase activity provoked by proline (Pro) administration in rat hippocampus. Five‐day‐old rats were pretreated for 1 week with daily i.p. administration of saline (control) or Vitamin E (40 mg/kg) and Vitamin C (100 mg/kg). Twelve hours after the last injection, animals received one single injection of Pro (12.8 μmol/g of body weight) or saline and were killed 1 h later. Results showed that Na + ,K + ‐ATPase activity was decreased in the Pro‐treated rats and that the pretreatment with Vitamins E and C prevented this effect. In another set of experiments, we investigated the in vitro effect of 1.0 mM Pro on Na + ,K + ‐ATPase activity from synaptic membranes of hippocampus of rats. Pro significantly inhibited (30%) Na + ,K + ‐ATPase activity. We also evaluated the effect of preincubating glutathione, trolox and N ϖ ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME) alone or combined with Pro on Na + ,K + ‐ATPase activity. Tested drugs did not alter Na + ,K + ‐ATPase activity, but glutathione prevented the inhibitory effect of Pro on this enzyme activity. These results suggest that the in vivo and in vitro inhibitory effect of Pro on Na + ,K + ‐ATPase activity is probably mediated by free radicals that may be involved in the neurological dysfunction found in hyperprolinemic patients.