• The Korean Journal of Physiology and Pharmacology
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• v.9 no.6
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• pp.347-352
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• 2005

The effects of nitric oxide (NO) on inhibitory neurotransmitter receptors and some types of inhibitory receptors in dissociated rod bipolar cell (RBC) were investigated. In the whole cell voltage-clamping mode, the gamma-aminobutyric acid (GABA) activated current showed both sustained and transient components. GABA activated transient current was fully blocked by bicuculine, a $GABA_A$ receptor antagonist. The cis-4-aminocrotonic acid (CACA), a $GABA_C$ receptor agonist, evoked the sustained current that was not blocked by bicuculline (BIC). Glycine activated the transient current. These results indicate that the RBCs possess $GABA_A$, $GABA_C$, and glycine inhibitory receptors. Sodium nitroprusside (SNP), a NO analogue, reduced the currents activated by $GABA_A$ receptor only, however, did not reduce the currents activated by either $GABA_C$ or glycine receptors. This study signifies further that only NO depresses the fast inhibitory response activated by $GABA_A$ receptor in RBC. We, therefore, postulate that NO might depress the light-on/off transient inhibitory responses in RBCs in the rat retina.

• Toxicological Research
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• v.11 no.2
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• pp.303-308
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• 1995

Nitric oxide, a physiological transmitter, is reported to mediate cellular injury in various tissues. Its reactivity to free radical is believed to be one of the reasons for its involvement in cytotoxicity. Menadione, a representative quinone, is cytotoxic to several cell systems including isolated hepatocyte, endothelial cell and red blood cells. Its toxic mechanism is related to oxidative stress, mediated by toxic free radicals. Our previous studies demonstrated that menadione induced cell lysis and increase of oxygen consumption in platelets. It has been reported that platelets have nitric oxide producing enzyme, nitric oxide synthase. Thus, we have investigated to manifest the role of nitric oxide.in menadione-induced cytotoxicity in rat platelets. Menadione induced cytotoxicity in platelets was unaffected by $N^G$-nitro-arginine methyl ester (L-NAME), selective and competitive inhibitor of nitric oxide synthase. We also invesitgated the role of extracellular nitric oxide in menadione-induced cytotoxicity of platelets by addition with sodium nitroprusside (SNP). SNP did not affect platelet cytotoxicity by menadione. These results suggested that nitric oxide which was generated endogeneously or exogeneously might have a negligible role in menadione-induced cytotoxicity in rat platelets.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.243-251
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• 2010

Nitric oxide (NO) has been shown to be involved in diverse physiological processes in microbes, animals and plants. In this study, the involvement of NO in the development and possible roles in oxidative stress protection of Chinese cabbage (Brassica rapa subsp. pekinensis cv. Samrack-ulgari) seedlings were investigated. Exogenous application of sodium nitroprusside (SNP) retarded root elongation, while increasing lateral root formation of Chinese cabbage. Plants showed no signs of external stress due to SNP application in true leaves. Cotyledons of 3-week-old Chinese cabbage plants were found to be highly sensitive to SNP application. Treated cotyledons displayed rapid tissue collapse and associated cell death. Although SNP application reduced root growth under normal growth conditions, it also enhanced methyl viologen (MV)-mediated oxidative stress tolerance. Analysis of SNP application to Chinese cabbage leaf disks, revealed SNP-induced tolerance against oxidative stresses by MV and $H_2O_2$, and evidence includes prevention of chlorophyll loss, superoxide anion (${O_2}^-$) accumulation and lipid peroxidation. This report supports a role for nitric oxide in modulating early seedling development, programmed cell death and stress tolerance in Chinese cabbage.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.511-519
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• 1998

This study investigated the role of nitric oxide on the oxidative damage in gastric mucosa of rats which received ischemia/reperfusion and its relation to mucus. Nitric oxide synthesis modulators such as L-arginine and $N^G-nitro-L-arginine$ methyl ester, and sodium nitroprusside, a nitric oxide donor, were injected intraperitoneally to the rats 30 min prior to ischemia/reperfusion which was induced by clamping the celiac artery and the superior mesenteric artery for 30 min and reperfusion for 1 h. Lipid peroxide production, the contents of glutathione and mucus, and glutathione peroxidase activities of gastric mucosa were determined. Histological observation of gastric mucosa was performed by using hematoxylin-eosin staining and scanning electron microscopy. The result showed that ischemia/reperfusion increased lipid peroxide production and decreased the contents of glutathione and mucus as well as glutathione peroxidase activities of gastric mucosa. Ischemia/reperfusion induced gastric erosion and gross epithelial disruption of gastric mucosa. Pretreatment of L-arginine, a substrate for nitric oxide synthase, and sodium nitroprusside prevented ischemia/reperfusion-induced alterations of gastric mucosa. However, $N^G-nitro-$ L- arginine methyl ester, a nitric oxide synthase inhibitor, deteriorated oxidative damage induced by ischemia/reperfusion. In conclusion, nitric oxide has an antioxidant defensive role on gastric mucosa by maintaining mucus, glutathione, and glutathione peroxidase of gastric mucosa.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.43-52
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• 2024

Cadmium (Cd) is non-essential heavy metal that negatively affects plant metabolism. Nitric oxide (NO) is an increasingly important molecule for plant metabolism that makes signaling. In this study, it was aimed to investigate the alleviating effect of sodium nitroprusside (SNP) application as NO donor in white poplar (Populus alba) under Cd stress conditions. SNP and without SNP treatments increased the Cd accumulation in root tissue. While photosynthetic pigments (Chl a, Chl b, Chl a+b, and carotenoid) content decreased by only Cd application, SNP+Cd application decreased the rate of photosynthetic pigments reduction. When the results of Cd and Cd+SNP applications were evaluated for mineral (Fe, Zn, Mn and Cu) uptake, it was found that the positive effect of SNP was heterogeneously affected. Depending on SNP application, it was found that malondialdehyde (MDA) amount decreased in leaf in 100 µM Cd applications while hydrogen peroxide (H₂O₂) amount decreased in 100 and 500 µM Cd applications. When antioxidant enzyme activities were examined, it was found that catalase (CAT) and ascorbate peroxidase (APX) enzyme activities increased with 100 µM SNP applications under all Cd applications. As a result, it was found that SNP application under Cd stress generally supports physiological processes positively in white poplar, suggesting that NO molecule plays important alleviating roles in plant metabolism.

• Archives of Pharmacal Research
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• v.16 no.1
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• pp.1-5
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• 1993

The reaction of sulfhydryl groups in human serum ablumin with bacteriostatic and hypotensive notrosating agents such as sodium nitorprusside and sodium nitrite has been examined. The low reactivity of sodium nitroprusside to sulfhydral groups in albumin has been observed and the sterical inaccessilibility of the agent site which sulfhydryl group resides was implicated. The reaction of sodium nitrite with albumin was highly influenced by pH and little reactivity was observed at physiological pH. On the other hand, the reaction between albumin and S-nitrosoglutatione, an intermediate induced from the reaction of glutathione and nitrosating agents, resulted in the rapid decrease of free sulfhydryl groups in albumin. S-Nitrosylation of the sulfhydryl group by S-nitrosoglutathione and the subsequent production of mixed disulfide is the probable route of modification. In the physiological system, S-nitroso-glutathione may act as an active intermediate in expressing reacivity of nitrosating agents to sulfhydryl groups in albumin.

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1055-1065
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• 1996

This experiment was undertaken to assess the effect of nitric oxide, isosorbide dinitrate, and sodium nitroprusside, which are known to increase coronary flow by vasodilation and to improve the cardiac function of an ischemic heart The experiment was carried out to investigate the effect of nitric oxide on the coronary artery of an ischemic rat myocardium using isolated constant pressure Langendorfr system. The experimental parameters were lactate and CK-MB for the frozen myocardium and coronary flow. the quantity of coyonary flow, left ventricular developed pressure (LVDP), and dp/dt. The experimental groups were decided as control group (Group I), nitric oxide group (Group II), Iso orbide dinitrate group (Group III) and sodium nitroprusside group (Group IV). Statistical analysis was performed using repeated measured analysis of variance and 2tudent t-test The results were as follows: 1 . The lactic acid contents of group II and IV were less than other groups for the frozen myocardium at preischemic state (p< 0.0025), whereas the determined coronary flows were higher. 2. In the ratio of produced lactic acid between the preischemia and reperfusion for the coronary flow, group II and IV exhibitrod less value than others (p< 0.005). 3. Group II and III were less than others in the coronary flow for the quantity of CK-MB, but or the frozen myocardium, group II and IV were less. 4. Group II and IV showed higher coronary flow compared to others throughout entire experimental period (p< 0.005). 5. Group II was highest at the preischemic state for the left ventricular developed pressure. 6. The +maximal dp/dt of group II was highest compared to others. 7. Group I exhibi ed the highest recovery rate of coronary flow between prelschemla and reperfusion. 8. The(-dp/dt)1(+dp/dt) ratio was 116%, 100%, 100%, and 55% for the 4 groups, respectively And the recovery rate of total dp/dt was 34%, 67%, 51%, and 76% for the four groups, respectively.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.279-289
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• 1995

This study was designed 1) to develop a hypertensive animal model in which the blood pressures (BPs) of symmetric regions (right and left upper extremities) are significantly different and 2) to test the effect of BP per se on the contractility and endothelium-dependent relaxation of vascular smooth muscle. Rabbits were anesthetized with sodium pentobarbital and ventilated with room air via animal respirator. The transverse aorta was exposed through the left second intercostal space and the lumen of the aorta was narrowed partially by ligation using 3-0 silk and a probe at a point between the origins of the brachiocephalic trunk and the left subclavian artery. Four to eight weeks postoperatively, BPs were measured in the carotid artery as the high BP area (proximal to coactation site) and in the femoral artery as the low BP area (distal to coarctation site). In the animal model, pressure-overload hypertension was developed and the BP of the right subclavian artery was higher than that of the left subclavian artery. The concentrations of circulating epinephrine, norepinephrine, angiotensin I, and angiotensin II were measured. The right and left subclavian arteries and their branches were used for isometric tension recording in organ baths and their responsiveness to phenylephrine, serotonin, acetylcholine, and sodium nitroprusside were examined. The BPs of carotid and femoral artery in control animals were $116{\pm} 12/75{\pm}9\;mmHg (mean ${\pm}SEM$) and $130{\pm}16/68{\pm}9\;mmHg$ respectively, while those of carotid and femoral artery in the hypetensive animals were $172{\pm}6/111{\pm}10\;mmHg$ and 136{\pm} 4/100 {\pm}9\;mmHg$ respectively. There were no significant differences in the concentrations of circulating epinephrine, norepinephrine, angiotensin I, and angiotensin II between controls and the animal models. No significant differences were found in the vascular sensitivities to phenylephrine and serotonin between the high pressure-exposed vessels and the low pressure-exposed vessels. However, the endothelium-dependent relaxation to acetylcholine and nitroprusside-induced relaxation showed significant differences between the high pressure-exposed and the low pressure-exposed subclavian arteries. From the above results, we suggest that the contractility of vascular smooth muscle is unchanged by the elevated pressure per se. However, the endothelium-dependent relaxation to acetylcholine and the nitroprusside-induced relaxation are attenuated by pressure.

• Journal of Plant Biotechnology
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• v.41 no.2
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• pp.73-80
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• 2014

Pretreatment of chinese cabbage leaves with $100{\mu}M$ sodium nitroprusside (SNP), a nitric oxide (NO) donor, effectively improved their tolerance to subsequent $2{\mu}M$ paraquat (PQ)-induced oxidative damage. The fresh weight, and chlorophyll and protein contents in primary leaves treated with PQ alone were noticeably reduced over 24 h light incubation. However, these leaf injury symptoms were significantly alleviated with $100{\mu}M$ SNP pretreatment for 3 h prior to PQ exposure. In additions, the increase of the contents of malondialdehyde (MDA) and $H_2O_2$ due to PQ exposure were significantly inhibited by SNP pretreatment. Together with the protective effects of SNP against PQ toxicity in leaves, the changes of ascorbate-glutathione cycle enzymes activities were examined. In the PQ alone treatment, the activities of APX, DHAR, and GR after 6 h incubation were rapidly reduced and showed 19%, 50% and 39% respectively, compared with those of the control. However, the decreases in these enzyme activities were significantly inhibited by SNP pretreatment. As a result, their activities were higher than those of PQ alone treatment by 5 times, 2 times, and 1.5 times, respectively, at 6 h incubation. Thereafter, these enzymes decrease their activities gradually showing high levels than those of PQ alone. Based on the above results, it can be assumed that the activation of ascorbate-glutathione cycle by SNP pretreatment in chinese cabbage leaves exposed to PQ can prevent $H_2O_2$ accumulation, thereby leading to protection against PQ-induced oxidative stress. Also, these results indicate that NO acts as an protectant against PQ stress in the leaves of chinese cabbage.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.293-300
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• 2005

The possible role of nitric oxide (NO)-induced cell division was investigated to explain the physiologycal effects of a NO donor, sodium nitroprusside (SNP) on the growth of primary leaves in chinese cabbage seedling plants. Exogenous treatment of SNP to chinese cabbage plants for 8 days at different concentrations (0, 200, 500 and 1000 ${\mu}M$) affected the leaf growth in a concentration-dependent manner, showing a maximum growth at $200\;{\mu}M$. In accordance with leaf growth responses, the chlorophyll and soluble protein contents increased strongly to 142% and 134% of control at $200\;{\mu}M$ SNP, respectively. However, a very little decrease in chlorophyll and a 13%> decrease in protein were observed at $1000\;{\mu}M$ SNP. In addition, the content of DNA and RNA also increased maximumly to 142% and 139% of the control at $200\;{\mu}M$ SNP, respectively, whereas they decreased to 80% and 84% of the control at $1000\;{\mu}M$ SNP. With respect to the development of enzymes related to cell wall synthesis, $200\;{\mu}M$ SNP led to the maximum activities in both phenylalanine ammonia-lyase (212% of the control) and guaiacol peroxidase (134% of the control). However, the activities of both enzymes were not modified significantly at $1000\;{\mu}M$ SNP. In conclusion, these results suggest that the enhancement of leaf growth in chinese cabbage plants by SNP at the effective concentration was probably due to the NO ability in the induction of cell division.