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NMDA receptor‐dependent nitric oxide and cGMP synthesis in brain hemispheres and cerebellum during reperfusion after transient forebrain ischemia in gerbils: Effect of 7‐nitroindazole
Author(s) -
Chalimoniuk Małgorzata,
Strosznajder Joanna
Publication year - 1998
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19981201)54:5<681::aid-jnr13>3.0.co;2-l
Subject(s) - nmda receptor , gerbil , chemistry , nitric oxide , cerebellum , lipid peroxidation , glutamate receptor , nitric oxide synthase , medicine , endocrinology , dizocilpine , hippocampus , ischemia , pharmacology , biochemistry , receptor , biology , oxidative stress
In this study, the N‐Methyl‐D‐Aspartate (NMDA) receptor‐dependent nitric oxide and cyclic GMP (cGMP) synthesis in the course of reperfusion after 5 min of ischemia in gerbil brain hemispheres and cerebellum were investigated. Moreover, the role of the neuronal isoform of nitric oxide (NO) synthase (nNOS) in liberation of NO in postischemic brain and the involvement of NO in membrane lipoperoxidations activated during reperfusion were evaluated. Enhancement of Ca 2+ /calmodulin‐regulated NOS activity and cGMP level in brain hemispheres and in cerebellum during reperfusion was found to be coupled to the activation of the NMDA receptor. cGMP concentration 40% above the control level was observed to persist up to 7 days after ischemia. The amount of conjugated double bounds in membrane lipids and the level of thiobarbituric acid reactive substances were increased exclusively in brain hemispheres, indicating activation of lipid peroxidation. The NMDA receptor antagonist, MK‐801, eliminated, and a rather selective nNOS inhibitor, 7‐Nitroindazole (7‐NI) attenuated, NMDA receptor‐evoked enhancement of NOS activity and cGMP level in brain hemispheres and in cerebellum during reperfusion. Moreover, 7‐NI decreased significantly membrane lipid peroxidation during the early time of reperfusion. Histological examination demonstrated that 7‐NI protects against death a selected population of neuronal cells in CA 1 layer of hippocampus. It is suggested that NMDA receptor dependence of NO release during reperfusion is responsible for the degeneration of some populations of neurons and that the effect is mediated by activation of free radical formation and lipid peroxidation. Moreover, in cerebellum, ischemia‐evoked activation of glutamatergic system stimulates NO‐dependent signal transmission. Our results indicated that 7‐NI has a significant ameliorating effect on biochemical alterations evoked by ischemia, suggesting nNOS inhibitors as a potential therapeutic agents in reperfusion injury. J. Neurosci. Res. 54:681–690, 1998. © 1998 Wiley‐Liss, Inc.