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AIM To observe the expression of inducible nitric ox ide synthase (iNOS) in the rats' hippocampus of kainic acid (KA) induced-seizur es and the effect of L-arginine(L-Arg) or L-nitroarginine(L- NNA) chronic intervention before KA. METHODS The expression of iN OS mRNA by RT-PCR and behaviour were observed after administration of convulsan t dose of KA (10 mg?kg -1 ) and pretreatment with NO predecessor (L-Ar g, 40 mg?kg -1 ) or a inhibitor of NOS(L-NNA, 50 mg?kg -1 ) befo re KA. RESULTS The time-dependent seizures were induced on rats after giving KA, and were improved and serious in the animals with L-NNA pr etreatment, but they were alleviated by L-Arg pretreatment before KA. Compa red with control, iNOS mRNA expression was feebly at KA 3 h, continuative improv ement accompanying KA time prolonged, and it was markedly enhanced at KA 24 h. I t couldn't be examined at KA 2 d or 3 d, and was obviously improved at KA 7 d a gain. iNOS mRNA appeared weak in the rats hippocampus with L-Arg pretreatme nt after KA 1 h, whereas it wasn't found in L-NNA pretreatment animals. CONCLUSION iNOS mRNA expression appeared in the hippocampus of seizu re rats at a few time after KA, and L-Arg chronic intervention before KA ha s a little effect on it.
ABSTRACT
Objective :To study the effects of NO precursor, L-arginine(L-Arg) and constitutive nitric oxide synthase(cNOS) inhibitor, L-nitroarginine(L-NNA)) on the expression of cNOS in facial nerve and surrounding tissues in traumatic facial paralysis rats. Methods:Facial paralysis was surgicaly created by impact in 57 SD rats. The rats were divided into 3 groups with 18 in each group, another 3 rats were used for morphological study. L-Arg at 40 mg/kg or L-NNA at 50 mg/kg were intraperitoneally injected into rats 2 times a day, from 4 days before untill 14 days after surgery(group L-Arg and group L-NNA). In control group(NS) same volume of normal saline was given to the rats after creation of facial paralysis. The facial nerve and surrounding tissue samples were obtained at different time. Immunohistochemical ABC method was used to examine cNOS and inducible NOS (iNOS) expression in facial nerve and surrounding tissues. Results:cNOS immunoreactivity was observed in traumatic facial nerve in L-Arg group 7 days after trauma and in the adjacent muscle in the 3 groups from 6 h to 3 d after trauma. iNOS was found in the paralyzed nerves from 1 d to 7 d after trauma in the 3 groups, and in the adjacent tissues from 6 h to 3 d after trauma in the 3 groups. Conclusions:L-Arg may stimulate constitutive NOS expression in facial nerve and probably promote the nerve regeneration.
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AIM To explore the role of nitric oxide (NO) mediators in seizure behavior and the related expression of interlukin 6(IL 6). METHODS The IL 6 immunoreactivity (IL 6 ir) and behaviour were observed in kainic acid (KA) induced seizure following pretreatment with L nitroarginine( L NNA), a inhibitor of nitric oxide synthase(NOS), or the same number of moles of L arginine( L Arg). RESULTS The results showed that time dependent seizures were induced on animals after administration of KA (10 mg?kg -1 ), accompanied by the immediate enhancement of IL 6 ir in hippocampal structure, piriform area and cortex. The behaviors of rats were not markedly altered by chronic pretreatment with L NNA (50 mg?kg -1 ) or L Arg (40 mg?kg -1 ). However, after the administration of KA, the seizure behaviors were obviously different in the group of L NNA and L Arg respectively. Seizure was agrevated in the animals with L NNA pretreatment and many rats died at KA 3 hours, whereas seizure was alleviated after KA in the group of L Arg. IL 6 expression was apparently up regulated in some brain areas such as hippocampus in the group of KA pretreated with L NNA, but opposite effects appeared in the group pretreated with L Arg before KA injection. CONCLUSION These results indicate that endogenous NO mediators may alleviate the seizure behaviors and may down regulated the early expression of IL 6 in KA challenged seizure, but it the mechanism of the early expression of IL 6 with the homeostasis of endogenous NO mediator merits further study.nismoftheearlyexpressionofIL 6withthehome