Nitric oxide synthase inhibition by L-NAME prevents the decrease of Na+,K+-ATPase activity in midbrain of rats subjected to arginine administration.
In the present study we investigated the effect of acute administration of L-arginine on Na(+),K(+)-ATPase and Mg(2+)-ATPase activities and on some parameters of oxidative stress (chemiluminescence and total radical-trapping antioxidant parameter-TRAP) in midbrain of adult rats. We also tested the effect of L-NAME on the effects produced by arginine. Sixty-day-old rats were treated with an acute intraperitoneal injection of saline (group I, control), arginine (0.8 g/kg) (group II), L-NAME (2 mg/kg) (group III) or arginine (0.8 g/kg) plus L-NAME (2 mg/kg) (group IV). Na(+),K(+)-ATPase activity was significantly reduced in the arginine-treated rats, but was not affected by other treatments. In contrast, Mg(2+)-ATPase activity was not altered by any treatment. Furthermore, chemiluminescence was significantly increased and TRAP was significantly decreased in arginine-treated rats, whereas the simultaneous injection of L-NAME prevented these effects. These results demonstrate that in vivo arginine administration reduces Na(+),K(+)-ATPase activity possibly through free radical generation induced by NO formation.
Wyse
A T
AT
Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. wyse@ufrgs.br
Bavaresco
C S
CS
Bandinelli
C
C
Streck
E L
EL
Franzon
R
R
Dutra-Filho
C S
CS
Wajner
M
M
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008636:Mesencephalon / Q000187:drug effects* / Q000201:enzymology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D004791:Enzyme Inhibitors; D001120:Arginine; D019001:Nitric Oxide Synthase; D000254:Sodium-Potassium-Exchanging ATPase; D019331:NG-Nitroarginine Methyl Ester