[Role of nitric oxide in excitotoxicity and memory impairment induced by kainic acid].
OBJECTIVE
The role of nitric oxide (NO) in excitotoxicity of kainic acid (KA) in the brain was investigated.


METHODS
Adult female rats were bilaterally intra-caudate nucleus injected with KA. The nitric oxide synthase (NOS) was determined by measuring NO2- concentration produced from homogenized brain tissue in the enzyme response system at three time point after surgery. Another groups of rats were daily administrated (i.p.) L-NAME(10 mg/kg) or 7-NI(25 mg/kg) at 2nd to 6th day after intra-caudate KA injection. Behavioral tests for learning and memory were started at 10th day after surgery.


RESULTS
NOS activity in caudate nucleus remained unchanged in 6-8 hours after surgery. It increased significantly in 3 days and slightly increased in 5 days after surgery. Both L-NAME and 7-NI ameliorated memory impairment induced by KA injection in passive avoidance response task. Only L-NAME improved KA-induced deficit in active avoidance response behavior.


CONCLUSIONS
This study gives further evidence that NOS activation and excessive NO may mediate KA-induced excitotoxicity. Early and repetitive use of NOS inhibitors shows some protective effect on memory deficit induced by KA excitotoxicity.
Li
C
C
Department of Physiology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China.
Zhang
S
S
Chen
J
J
D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D007191:Indazoles / Q000494:pharmacology; D007608:Kainic Acid / Q000633:toxicity; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D007191:Indazoles; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D007608:Kainic Acid; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester