Biologia, Bratislava 54/Suppl. 6: 197-202, 1999.
ISSN 0006-3088 (Biologia). ISSN 1335-6399 (Biologia. Section Cellular and Molecular Biology).
Effects of nitro-L-agrinine methyl ester (L-NAME) and 7-nitroindazole (7-NI) on NADPH-diaphorase activity after cerebral ischemia.
Institute of Neurobiology, Slovak Academy of Sciences, Soltesovej 6, SK-04001 Kosice, Slovakia; tel.:++421 95 765064, fax:++421 95 765074, e-mail: email@example.com
Received: February 18, 1998 / Accepted: October 5, 1999
Nitro-L-arginine methyl ester (L-NAME) is a nonspecific inhibitor of the nitric oxide synthase (NOS), and 7-nitroindazole (7-NI) is the selective neuronal NOS inhibitor on the NADPH-diaphorase activity. The effects of systemic administration of L-LAME and 7-NI were studied in the neocortex, hippocampus, striatum and cerebellum during 7 days reperfusion after transient (30 min) forebrain ischemia in the rat and the changes were compared with the same ischemia without pretreatment and with the sham-operated control group. After ischemia without pre-treatment, a significant two-fold increase in NADPH-diaphorase activity was found in all the areas that were investigated. A systemic administration of L-NAME (20 mg/kg b.w. i.p.) for 30 min before ischemia preserved NADPH-diaphorase activity at the control level in the neocortex and cerebellum and depressed this activity below the control level in the hippocampus and striatum during the 7 days reperfusion after ischemia. In rats that were pretreated with 7-NI (25 mg/kg b.w. i.p.), NADPH-diaphorase activity was significantly reduced by 50% compared to the same ischemia without pre-treatment. The results indicated that the inhibition effect of L-NAME was more pronounced and longer-range than that of 7-NI and that NADPH-diaphorase is probably identical with NOS.
Key words: cerebral ischemia, NADPH-diaphorase, NOS, L-NAME, 7-NI.