Effects of intracerebroventricular injection of 7-nitroindazole on depression-like behaviors and nNOS expression in hippocampal of rats / 中华行为医学与脑科学杂志

Objective To evaluate the effect of intracerebroventricular injection of 7-nitroindazole (7-NI) on the depression-like behaviors in normal rats.Methods According to body weights,48 SD rats were randomly divided into normal group,model group,sham-operation group and 7-NI groups at different concentrations (n=8).The model group was treated with chronic and unpredictable mild stress.The 7-NI groups received intracerebroventricular injection with 7-NI solutions at different concentrations,once every 3 days for 3 times in total.The sham-operation group was injected with DMSO of the same volume.The rat behaviors were then subjected to the open field test (OFT).The hippocampal nNOS protein levels were detected by Western blot.Results Compared with the normal group((132.47±31.72) m),the total movement distances of model group ((15.04±8.61) m) and 200 nmol/0.5 μl surgery group((18.18± 11.82) m) decreased significantly (P＜ 0.05).Compared with the model group,such distances of sham-operation group ((107.33±20.35)m) and 7-NI groups(50 nmol/0.5 μl:(138.40±56.85)m,(86.97±36.20)m);100 nmol/0.5 μl:(86.97±36.20)m) increased significantly (P＜ 0.05).The normal group entered the central area significantly more times(2.25±2.05) than model group (0.25±0.46)and 200nmol/0.5μl 7-NI group (0.25± 0.46) did (P＜0.05),and the number of times entering the central area of the model group (0.25±0.46)was significantly lower than that of the sham-operation group (1.00 ± 1.07,P＜ 0.05) and 50 nmol/0.5 μl group (0.75 ± 1.16).Compared with the normal group ((46.53 ±41.16) s),the durations of stay in the central area of model group ((1.27 ± 1.92) s) and 200 nmol/0.5 μl 7-NI group ((1.53 ± 2.90) s) were shortened significantly (P＜0.05).Compared with the model group,the durations of stay in the central area of 100 nmol/0.5μl group ((36.54±67.80) s) was lengthened significantly (P＜ 0.05).Western blotting showed that the hippocampal nNOS protein levels of model group (0.43±0.11) and 200 nmol/0.5μl 7-NI group(0.56±0.08) significantly exceeded that of the normal group (0.04±0.02,P＜0.05).The levels of nNOS in sham-operation group (0.04 ±0.02) and 50 nmol/0.5 μl 7-NI group (0.22± 0.08),which were significantly lower than that of the model group (0.43 ± 0.11,P＜ 0.05),were similar to that of the normal group (0.04 ± 0.02,P＞ 0.05).Conclusion Intracerebroventricular injection 200 nmol/0.5 μl 7-NI solution results in depression-like behaviors and increased the expression of nNOS protein reflexively in rats.

Nitric oxide synthase inhibitors protect against brain and liver damage caused by acute malathion intoxication

Objective To investigate the effect of N

Nitric oxide synthase inhibitors protect against brain and liver damage caused by acute malathion intoxication

OBJECTIVE@#To investigate the effect of N-nitro-l-arginine methyl ester (l-NAME), a non-selective nitric oxide synthase (NOS) inhibitor, and 7-nitroindazole (7-NI), a selective neuronal NOS inhibitor, on oxidative stress and tissue damage in brain and liver and on DNA damage of peripheral blood lymphocytes in malathion intoxicated rats.@*METHODS@#Malathion (150 mg/kg) was given intraperitoneally (i.p.) along with l-NAME or 7-NI (10 or 20 mg/kg, i.p.) and rats were euthanized 4 h later. The lipid peroxidation product malondialdehyde (MDA), nitric oxide (nitrite), reduced glutathione (GSH) concentrations and paraoxonase-1 (PON-1) activity were measured in both brain and liver. Moreover, the activities of glutathione peroxidase (GPx) acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), total antioxidant capacity (TAC), glucose concentrations were determined in brain. Liver enzyme determination, Comet assay, histopathological examination of brain and liver sections and inducible nitric oxide synthase (iNOS) immunohistochemistry were also performed.@*RESULTS@#(i) Rats treated with only malathion exhibited increased nitric oxide and lipid peroxidation (malondialdehyde) accompanied with a decrease in GSH content, and PON-1 activity in brain and liver. Glutathione peroxidase activity, TAC, glucose concentrations, AChE and BChE activities were decreased in brain. There were also raised liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and increased DNA damage of peripheral blood lymphocytes (Comet assay). Malathion caused marked histopathological changes and increased the expression of iNOS in brain and liver tissues. (ii) In brain of malathion-intoxicated rats, l-NAME or 7-NI resulted in decreased nitrite and MDA contents while increasing TAC and PON1 activity. Reduced GSH and GPx activity showed an increase by l-NAME. AChE activity increased by 20 mg/kg l-NAME and 10 mg/kg 7-NI. AChE activity decreased by the higher dose of 7-NI while either dose of 7-NI resulted in decreased BChE activity. (iii) In liver of malathion-intoxicated rats, decreased MDA content was observed after l-NAME or 7-NI. Nitrite level was unchanged by l-NAME but increased after 7-NI which also resulted in decreased GSH concentration and PON1 activity. Either inhibitor resulted in decreased liver ALT activity. (iv) DNA damage of peripheral blood lymphocytes was markedly inhibited by l-NAME or 7-NI treatment. (v) iNOS expression in brain and liver decreased by l-NAME or 7-NI. (vi) More marked improvement of the histopathological alterations induced by malathion in brain and liver was observed after 7-NI compared with l-NAME.@*CONCLUSIONS@#In malathion intoxicated rats, the neuronal NOS inhibitor 7-NI and to much less extent l-NAME were able to protect the brain and liver tissue integrity along with improvement in oxidative stress parameters. The decrease in DNA damage of peripheral blood lymphocytes by NOS inhibitors also suggests the involvement of nitric oxide in this process.

Neurotoxicity induced by methamphetamine and the protective role of nNOS inhibitor in rats / 中国药理学通报

Aim Tostudytheprotectiveeffectsofin-hibition of neuronal nitric oxide synthase ( nNOS ) in methamphetamine ( METH ) induced neurotoxicity via oxidativestressinjuryinrats.Methods Ratmodelsof acute METH poisoning with/without 7 nitroindazole (7-NI) pretreatment were built to evaluate the protec-tive effects on the changes of ethology, nNOS, nitro-proteins, dopamine ( DA ) and apoptosis in rat stria-tum.Results ThenNOSexpression,nitroproteinex-pression and apoptosis increased significantly in the METH group( P0. 05 ) . Stereotyped behavior increased significantly in the METH group and the 7-NI combined group compared with the 7-NI group and the control group(P<0. 01). Conclusions 7-NIshowssignificantprotectiveeffects against the alterations of DA level, nNOS expression, nitroprotein expression and apoptosis in rat striatum caused by acute METH poisoning. However, there is no obvious protective effect on METH-induced stereo-typed behavior.

Neurobiological effect of 7-nitroindazole, a neuronal nitric oxide synthase inhibitor, in experimental paradigm of Alzheimer’s disease.

Nitric oxide plays a role in a series of neurobiological functions, underlying behaviour and memory. The functional role of nNOS derived nitric oxide in cognitive functions is elusive. The present study was designed to investigate the effect of specific neuronal nitric oxide synthase inhibitor, 7-nitroindazole, against intracerebroventricular streptozotocin-induced cognitive impairment in rats. Learning and memory behaviour was assessed using Morris water maze and elevated plus maze. 7-nitroindazole (25 mg/kg, ip) was administered as prophylactically (30 min before intracerebroventricular streptozotocin injection on day 1) and therapeutically (30 min before the assessment of memory by Morris water maze on day 15). Intracerebroventricular streptozotocin produced significant cognitive deficits coupled with alterations in biochemical indices.These behavioural and biochemical changes were significantly prevented by prophylactic treatment of 7-nitroindazole. However, therapeutic intervention of 7-nitroindazole did not show any significant reversal. The results suggests that 7-nitroindazole can be effective in the protection of dementiainduced by intracerebroventricular streptozotocin only when given prophylactically but not therapeutically.

Lack of tolerance for the anti-dyskinetic effects of 7-nitroindazole, a neuronal nitric oxide synthase inhibitor, in rats

7-Nitroindazole (7-NI) inhibits neuronal nitric oxide synthase in vivo and reduces l-DOPA-induced dyskinesias in a rat model of parkinsonism. The aim of the present study was to determine if the anti-dyskinetic effect of 7-NI was subject to tolerance after repeated treatment and if this drug could interfere with the priming effect of l-DOPA. Adult male Wistar rats (200-250 g) with unilateral depletion of dopamine in the substantia nigra compacta were treated with l-DOPA (30 mg/kg) for 34 days. On the 1st day, 6 rats received ip saline and 6 received ip 7-NI (30 mg/kg) before l-DOPA. From the 2nd to the 26th day, all rats received l-DOPA daily and, from the 27th to the 34th day, they also received 7-NI before l-DOPA. Animals were evaluated before the drug and 1 h after l-DOPA using an abnormal involuntary movement scale and a stepping test. All rats had a similar initial motor deficit. 7-NI decreased abnormal involuntary movement induced by l-DOPA and the effect was maintained during the experiment before 7-NI, median (interquartile interval), day 26: 16.75 (15.88-17.00); day 28: 0.00 (0.00-9.63); day 29: 13.75 (2.25-15.50); day 30: 0.5 (0.00-6.25); day 31: 4.00 (0.00-7.13), and day 34: 0.5 (0.00-14.63), Friedman followed by Wilcoxon test,vs day 26, P < 0.05;. The response to l-DOPA alone was not modified by the use of 7-NI before the first administration of the drug (l-DOPA vs time interaction, F1,10 = 1.5, NS). The data suggest that tolerance to the anti-dyskinetic effects of a neuronal nitric oxide synthase inhibitor does not develop over a short-term period of repeated administration. These observations open a possible new therapeutic approach to motor complications of chronic l-DOPA therapy in patients with Parkinson’s disease.

Effects of 7-Nitroindazole on Brain Cell Membrane Function and Energy Metabolism during Transient Global Cerebral Hypoxia-Ischemia and Reoxygenation-Reperfusion in Newborn Piglets / 소아과

PURPOSE: Our study was undertaken to discover whether a selective neuronal nitric oxide synthase inhibitor, 7-nitroindazole, influences brain cell membrane function and energy metabolism during and after transient global hypoxia-ischemia(HI) in newborn piglets. METHODS: Cerebral HI was induced by temporary complete occlusion of bilateral common carotid arteries and simultaneous breathing with 8% oxygen for 30 minutes, followed by release of carotid occlusion and normoxic ventilation for one hour(reoxygenation-reperfusion, RR). 7-Nitroindazole(50 mg/kg) or vehicle was administered intraperitoneally just before the induction of HI or RR. Brain cortex was harvested for the biochemical analysis at the end of HI or RR. RESULTS: The level of conjugated dienes significantly increased and the activity of Na+, K+-ATPase significantly decreased during HI, and they did not recover during RR. The levels of ATP and phosphocreatine(PCr) significantly decreased during HI, and recovered during RR. 7-Nitroindazole did not influence significantly the level of conjugated dienes, the activity of Na+, K+-ATPase, and the levels of ATP and PCr during HI and RR. CONCLUSION: 7-nitroindazole did not demonstrate a neuroprotective effect in our piglet model of transient global cerebral HI and one hour of RR.

Effects of L-Arginine and 7-Nitroindazole in the Gerbil Model of Global Cerebral Ischemia

PURPOSE: This study was performed to determine whether L-Arginine would improve or worsen the neurologic out-come after ischemic brain injury and whether 7- Nitroindazole (7-NI, inhibitors of neuronal nitric oxide (NO) synthase inhibitor) would improve or worsen. METHODS: Five (5) groups (N =11 to 14) of anesthetized gerbils were subjected to 10 min of global cerebral ischemia by means of a bilateral carotid artery occlusion. One group (N =11) was the control group. In a second group (N =12), the animals were pretreated with intraperitoneal L-Arginine (300 mg/kg) one hour before ischemic insult. In a third group (N =12), pretreatment with L-Arginine was performed in the same manner and intraperitoneal 7-NI were given at the time of reperfusion and 2 hours after reperfusion. The animals of a fourth group (N =12) were treated with 7-NI in the same manner without any pretreatment with L-Arginine. The animals in the last group (N =14) underwent sham operations. RESULTS: Compared with control group, concomittent treatment with L-Arginine and 7-NI showed no significant improvement in the neurological cell survival rate. Also, group pretreated with L-Arginine only showed a similar out-come. The group treated with 7-NI at the time of reperfusion and 2 hours after reperfusion showed a significant improvement in the neurological cell survival rate compared with the control group and the other two experimental groups (p<0.05). CONCLUSION: In the ischemia-reperfusion injury of global ischemia in gerbils, NO from endothelial NO synthase has no important role in the neurological outcome.