Improvement of impaired endothelial progenitor cell functions by in vitro drug interference in DOCA-salt hypertensive mice / 药学实践杂志

Objective To investigate the effect of tetrahydrobiopterin (BH4), superoxide dismutase-polyethylene glycol (PEG-SOD) and N(G)-nitro-L-arginine (L-NNA) on impaired endothelial progenitor cell (EPC) functions in DOCA-salt hypertensive mice. Methods DOCA-salt hypertension was created and systolic blood pressure was measured by tail-cuff methods. EPC was isolated from bone marrow of mice and characterized by flow cytometry and fluorescence microscopy. EPC of DOCA-salt mice was incubated with BH4, PEG-SOD, and L-NNA for 24 h, then in vitro EPC function assays were performed. Results Compared with control group, systolic blood pressure was significantly increased in DOCA-salt mice. Both EPC adhesion and angiogenesis functions were impaired in DOCA-salt mice compared to control animals, which were reversed by incubation with BH4, PEG-SOD and L-NNA. Conclusion BH4, PEG-SOD and L-NNA rescued the impairments from EPC functions in DOCA-salt hypertensive mice.

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.

Effects of Nitric Oxide Synthesis Inhibition on Indomethacin-Induced Downregulation of Renal Aquaporins in Rats / 대한신장학회잡지

BACKGROUND:The present study aimed to determine whether there is a regulatory mechanism exerted by endogenous nitric oxide (NO) in the regulation of aquaporin (AQP) water channels in the kidney. METHODS:Male Sprague-Dawley rats were used. They were divided into 4 groups: 1) L-NAME group was treated with N(G)-nitro-L-arginine methyl ester (L-NAME, 100 mg/L drinking water) for 1 week, 2) indomethacin group was treated with indomethacin (5 mg/kg, twice a day, i.p.) for 2 days, 3) L-NAME/ indomethacin group was treated with L-NAME for 1 week in which indomethacin was cotreated for the last two days, and 4) control group was kept untreated. The abundance of AQP2 and AQP3 proteins was determined in the inner medulla of the kidney. RESULTS:The expression of AQP2 and AQP3 proteins was significantly decreased by indomethacin. L-NAME abolished the indomethacin-induced decreases of AQP channels, although it did not significantly affect the expression of AQP channels by itself. CONCLUSION:These results suggest that endogenous NO system, when stimulated, may downregulate the expression of AQP2 and AQP3 channels in the kidney.

Elevated Contractile Responses to Acetylcholine in Organ Cultured Rabbit Carotid Artery

The aim of the present study was to examine the functional changes that occur when a rabbit carotid artery is cultured in serum-free medium. In endothelium (EC)-intact arteries cultured under serum-free conditions, acetylcholine (ACh)-induced relaxation responses were partially, yet significantly, reduced when compared with freshly isolated arteries. After pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, application of ACh resulted in a significant contraction in organ cultured arteries. The amplitude of the ACh-induced contractions increased with the duration of culture. In EC-denuded arteries cultured under serum-free conditions, ACh induced responses similar to those in EC-intact arteries pretreated with L-NAME. Furthermore, ACh caused a significant increase in intracellular Ca2+ concentration ([Ca2+]i) in EC-denuded arteries cultured under serum-free condition for 7 days. There was little change in either [Ca2+]i or tension in freshly isolated carotid rings. There was no difference in sodium nitroprusside-induced relaxation responses between fresh and cultured arteries. These results suggest that prolonged culture of carotid arteries under serum-free conditions changes the functional properties of vascular reactivity in rabbit carotid arteries.

Vascular Response of Isolated Rat Thoracic Aorta after Chemical Hypoxia/Reoxygenation / 대한마취과학회지

BACKGROUND: Hypoxia/reoxygenation (H/R) results in formation of toxic reactive oxygen species (ROS), which can impair the vascular pathophysiology. Nitric oxide (NO) is an important free radical in many physiological or pathological processes including H/R injury. The loss of NO after H/R might be one of the major causes of an impaired vascular response. METHODS: Isolated rat aortic rings were prepared and NaCN was used to induce chemical hypoxia. The NaCN concentration and the hypoxia/reoxygenation time were determined by the responsiveness of phenylephrine (Phe), sodium nitroprusside (SNP) and acetylcholine (Ach). A cumulative doses of Phe and SNP (10(-9)-10(-5.5) M) were added to construct the vascular contraction and relaxation curves. The cumulative doses of Ach (10(-9)-10(-5) M) were added to construct the relaxation after precontraction with Phe (10(-6) M). The effects of the N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) and the superoxide dismutase (SOD, 50 unit) pretreatment during chemical H/R were evaluated. RESULTS: The NaCN concentration and H/R time were 1 mM, 30 minutes/5 minutes, respectively. Chemical hypoxia reduced the Phe-induced vascular contraction significantly. However chemical H/R increased the Phe-induced contraction significantly, and impaired the relaxation by SNP and Ach. A pretreatment with L-NAME increased the Phe-induced contraction and impaired the relaxation by SNP as well as Ach. The SOD pretreatment reduced the Phe-induced increased vascular contraction after NaCN-induced chemical H/R. CONCLUSIONS: NO plays a key role in endothelial-dependent relaxation and the recovery of the augmented contractility by vasoconstrictors after chemically-induced H/R.

Inhibitory Effect of N~G-Nitro-L-Arginine Methyl Ester on Growth of Colorectal Cancer Xenografts in Nude Mice / 中国普外基础与临床杂志

Objective To investigate the effect of N~G-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase, on the growth of colorectal cancer xenografts in vivo and on tumor-associated neovascularization. Methods Twenty BALB/c nude mice were randomly divided into control group and study group equally. Human colorectal cancer cell line SL174T was inoculated subcutaneously into nude mice to form transplantation tumors. Saline 0.2 ml was intragastric-administrated to mice in control group and L-NAME (4 mg toties guoties) was administrated orally to mice in study group three times per week for four weeks. The changes of tumors in both groups were recorded and the microvessel density (MVD) was also measured by immunohistochemistry assay. Results L-NAME significantly inhibited the growth of colorectal cancer xenografts in nude mice. The weight of transplantation tumor reduced with the inhibitory rate of 41.36%, and the inhibitory rate of tumor volume was 43.48 % in study group. MVD in the study group and control group were 14.83?2.10 and 21.04?3.11, respectively, which showed that the former was significantly lower than that of the control group (P

Influence of Nitric Oxide Synthesis Inhibition on Endothelin-1 and Its Receptor Expression in Rat Kidney / 대한신장학회잡지

BACKGROUND: The present study was aimed to evaluate the influence of nitric oxide(NO) synthesis inhibition on endothelin(ET) expression in rat kidney. METHODS: Male Sprague-Dawley rats were treated with N(G)-nitro-L-arginine methyl ester(L-NAME, 100 mg/L drinking water) for 4 weeks to inhibit the endogenous synthesis of NO. The tissue expression of ET-1, ET(A) receptor, and ET(B) receptor mRNA in the kidney was determined by reverse transcription-polymerase chain reaction. RESULTS: Tissue levels of NO metabolites were significantly decreased in the plasma and the kidney, along with the increased blood pressure. The expression of ET-1 mRNA was increased in the cortex, but not in the medulla. The expression of ET(A) and ET(B) receptor mRNA was not significantly altered either in the cortex or in the medulla. The plasma level of ET-1 peptide was significantly increased, along with the increased blood pressure, when L-NAME(200 microgram/kg per min, iv) was administered in an acute preparation of animals. Accordingly, the expression of ET-1 mRNA was increased in the cortex, whereas that of ET(A) and ET(B) receptor mRNA was not altered. CONCLUSION: These results suggest that enhanced activity of ET system induced by NO synthesis inhibition may be associated with hypertension although direct association between two factors is not confirmed.

Effects of nitric oxide synthase inhibitors on focal cerebral ischemic injury in rats / 中国病理生理杂志

AIM:To observe the effects of nitric oxide and different isoforms of nitric oxide synthase inhibitors on the focal cerebral ischemic injury in rats. METHODS: After the rat model of focal cerebral ischemia were established with middle cerebral artery occlusion (MCAO), aminoguanidine(AG)and N G-nitro-L-arginine(L-NA )were administrated and the cerebral infarct size, NO production,MDA content, nitric oxide synthase(NOS) and SOD activities in the focal ischemic brain tissues were examined. RESULTS: AG could significantly attenuate the focal cerebral ischemic injury, and L-NA had a protective effect when it was administrated at 1 h,6 h but not at 3 h after surgery. CONCLUSION: Cerebral ischemic injury could be attenuated by both selective and nonselective inhibition of NOS.

Mechanism underlying endothelin-induced responses in canine isolated pulmonary veins / 中国药理学通报

AIM To study mechanism of endothelin (ET) on canine pulmonary veins. METHODS The isometric tension of pulmonary venous strips was recorded. RESULTS ET 3 and IRL1640 produced contraction in pulmonary venous strips. ET 3 induced contraction was markedly suppressed by BQ123 (P

The effects of nitric oxide synthase inhibitors on the early stage of focal cerebral ischemic injury in rats / 中国药理学通报

AIM To study the role of nitric oxide (NO) and nitric oxide synthase (NOS) inhibitors during the early stage of focal cerebral ischemic injury in rats. METHODS The rat models of middle cerebral artery occlusion were established with the intraluminal suture method. The nonselective NOS inhibitor and selective inducible NOS inhibitor were used for investigating the effects of NO and NOS changes in the focal ischemic brain tissue and their respective roles during the early stage of focal cerebral ischemic injury. RESULTS This study showed that nonselective NOS inhibitors(N G nitro L arginine) aggravated brain damage in the early stage of focal cerebral ischemia and selective iNOS inhibitors (Aminoguanidine )did not significantly improve the brain damage , but could decrease markedly the deterioration of brain damage. CONCLUSION It may be concluded that the NO from defferent cells and types of NOS play unlike roles in the early stage of focal cerebral ischemic injury.