Effects of Nitric Oxide Synthase Inhibitor on Hindlimb Muscles in Rats with Neuropathic Pain Induced by Unilateral Peripheral Nerve Injury

PURPOSE: The purpose of this study was to examine effects of nitric oxide synthase (NOS) inhibitor on muscle weight and myofibrillar protein content of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. METHODS: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The NOSI group (n=19) had NOS inhibitor (L-NAME) injections daily for 14 days, and the Vehicle group (n=20) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from hindlimbs. Muscle weight and myofibrillar protein content of the dissected muscles were determined. RESULTS: The NOSI group showed significant increases as compared to the Vehicle group for body weight at 15 days, muscle weight and myofibrillar protein content of the unaffected soleus and gastrocnemius. The NOSI group demonstrated a higher pain threshold than the vehicle group. CONCLUSION: NOSI for 14 days attenuates unaffected soleus and gastrocnemius muscle atrophy in neuropathic pain model.

Atelectasis Induced by Thoracotomy Causes Lung Injury during Mechanical Ventilation in Endotoxemic Rats

Atelectasis can impair arterial oxygenation and decrease lung compliance. However, the effects of atelectasis on endotoxemic lungs during ventilation have not been well studied. We hypothesized that ventilation at low volumes below functional residual capacity (FRC) would accentuate lung injury in lipopolysaccharide (LPS)-pretreated rats. LPS-pretreated rats were ventilated with room air at 85 breaths/min for 2 hr at a tidal volume of 10 mL/kg with or without thoracotomy. Positive end-expiratory pressure (PEEP) was applied to restore FRC in the thoracotomy group. While LPS or thoracotomy alone did not cause significant injury, the combination of endotoxemia and thoracotomy caused significant hypoxemia and hypercapnia. The injury was observed along with a marked accumulation of inflammatory cells in the interstitium of the lungs, predominantly comprising neutrophils and mononuclear cells. Immunohistochemistry showed increased inducible nitric oxide synthase (iNOS) expression in mononuclear cells accumulated in the interstitium in the injury group. Pretreatment with PEEP or an iNOS inhibitor (1400 W) attenuated hypoxemia, hypercapnia, and the accumulation of inflammatory cells in the lung. In conclusion, the data suggest that atelectasis induced by thoracotomy causes lung injury during mechanical ventilation in endotoxemic rats through iNOS expression.

Effects of Prenatal Exposure to Nitric Oxide Synthase Inhibitor on MK-801-Elicited Behavioral Sensitivity in Postnatal Rats / 신경정신의학

OBJECTIVES: The aim of the present study was to investigate the role of prenatal exposure to NOS (nitric oxide synthase) inhibitor during the 3rd trimester of pregnancy on MK-801-elicited behavioral sensitivity in postnatal juvenile rats and the effect of an antipsychotic drug on the change in MK-801-elicited behavioral sensitivity in an attempt to elucidate the participation of NO (nitric oxide) in the pathophysiology of schizophrenia. METHODS: L-NA (N-nitro-L-arginine, 25 mg/kg, 40 mg/kg) was injected intraperitoneally in pregnant Sprague-Dawley rats during the 3rd trimester of pregrancy. On postnatal day 35, MK-801-elicited behavioral sensitivity was measured using Neurovision Analysis (automatic motor analysis program). Animals were pretreated with haloperidol or clozapine as a antipsychotic drug before administration of MK-801. Statistical tests of drug effects were performed using ANOVA. A value producing p<0.05 was considered to be significant. RESULTS: MK-801-elicited locomotor activity was significantly increased with prenatal exposure to L-NA in postnatal rats. The change in MK-801-elicited behavioral sensitivity was significantly diminished by pretreatment with haloperidol and clozapine. CONCLUSION: These findings suggest that NO may in part play an important role in neurodevelopment in that prenatal exposure to NOS inhibitor can influence MK-801-elicited behavioral sensitivity in postnatal rats. These results also indicate that the neurodevelopmental abnormality may predispose schizophrenia.

The effect of differential modulation of N-methyl-D-aspartate receptor on the proliferation of primary cultured normal human oral keratinocytes: DNA synthesis rate analysis

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOSI), alone or in combination, on the proliferation of cultured primary normal human oral keratinocytes (NHOK). The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. The DNA synthesis was measured by the BrdU assay. Addition of low concentration of AA (1 micro M) and high concentration of AA with NMDA group (NMDA+AA 10 micro M) made DNA synthesis rate increase significantly at the early stage. Adding NNA (10 micro M) affected DNA synthesis rate to increase significantly in 4 hours. At the early stage, DNA synthesis was significantly active in the NOS-I with NMDA groups than in the control and the NMDA-only group, while it didn't become statistically meaningful in 24 hours. AA 1 micro M and NNA 10 micro M may induce the proliferation of the NHOK independently and NOS-I may induce the proliferation of the NHOK with NMDA. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

Effects of Prenatal Exposure to Nitric Oxide Synthase Inhibitor on Behavioral Changes in Forced Swimming Test in Postnatal Rats / 신경정신의학

OBJECTIVES: It has been demonstrated that nitric oxide (NO) serves as an inter- and intra-cellular messenger in the brain. NO has been implicated in the regulation of monoaminergic neurotransmission and the neuronal growth and synaptogenesis. Recently, NO has been suggested to be involved in the pathogenesis of depression. The aim of this study was to investigate the involvement of NO in the underlying mechanisms of biological vulnerability to depression. METHODS: The author measured locomotor activities and postnatal behavioral changes in the forced swimming test (FST) in rats that were exposed prenatally to N omega-nitro-L-arginine, a NO synthase (NOS) inhibitor. It was also investigated that paroxetine, a selective serotonin reuptake inhibitor, may affect the behavioral changes in the FST. RESULTS: Locomotor activities were significantly diminished, and the immobility times in the FST were significantly prolonged in the rats that were exposed prenatally to NOS inhibitor compared with controls. Pretreatment with paroxetine blocked the prolongation of the immobility times in the FST. CONCLUSION: The results indicate that postnatal behavioral changes due to prenatal exposure to NOS inhibitor in rats may suggest an animal model of endogenous depression, and that the glutamate-NMDA-NO pathway may be involved in the pathophysiology of depression. It is also indicated that the action of NO may, in part, be affected by serotonergic mechanism. This implicates that the glutamate-NMDA-NO pathway may lead to a novel approach to the treatment of depression.

The effect of differential modulation of n-methyl-d-aspart ate receptor on the viability of primary cultured normal human oral keratinocytes

INHIBITION OF HYPOXIC PULMONARY VASOCONSTRICTION BY HYPOXIC EXERCISE TRAINING IN RATS / 体力科学

This study reviewed the influence of hypoxic training on hypoxic pulmonary vasoconstriction (HPV) sensitivity in the isolated perfused lungs preparation of rats. In addition, the study examined the kind of mechanism involved. Therefore, we inhibited nitric oxide (NO) release of endothelial cells, using on NO synthase inhibitor, and reviewed the impact on HPV.As a result, the following became clear. 1)Hypoxic training inhibited HPV. 2) HPV was increased by the administration of NO synthase inhibitor L-NMMA, in particular, conspicuously inhibited HPV in the hypoxic training group was increased. 3) The negative correlation between the onset of blood lactate accumulation and HPV was significant.From the above, it can be concluded that hypoxic training inhibited HPV and NO release for a pulmonary vascular endothelial cell. In addition, we understood that HPV was decreased by hypoxic training as the ability for endurance exercise was increased.

The Antinociceptive Effect of Intraperitoneally Administered Nonselective Nitric Oxide Synthase Inhibitor on the Rat Formalin Test / 대한통증학회지

BACKGROUND: Nitric oxide (NO) is involved in the transmission and modulation of nociceptive information at the peripheral, spinal cord and supraspinal levels. We conducted this experiment to assess the antinociceptive effects of a nonselective nitric oxide synthase (NOS) inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on the modulation of pain in rats subjected to the formalin test. METHODS: Formalin 5% was injected in the right hind paw after intraperitoneal (IP) injection of various doses of L-NAME (0.5 mg/kg, 1.5 mg/kg with and without L-arginine 100 mg/kg, 5.0 mg/kg). The number of flinches was measured. RESULTS: Formalin injected into the rat hind paw induced a biphasic nociceptive behavior. IP injected L-NAME diminished the nociceptive behaviors in a dose-dependent manner during phases 1 and 2. The concomitant injection of L-arginine reversed the antinocipetive effect of L-NAME. CONCLUSIONS: The data demonstrates that a nonselective NOS inhibitor, L-NAME, possesses antinociceptive properties in rats subjected to the formalin test, and the antinociceptive effect of L-NAME is reversed by the concomitant administration of L-arginine.

Changes of Nitric Oxide and Cell Proliferation after Bacillus Calmette-Guerin and Nitric Oxide Synthase Inhibitor Treatment on Murine Bladder Tumor-2 Cell Line / 대한비뇨기과학회지

PURPOSE: We hypothesize that the cytolytic activity of Bacillus Calmette-Guerin (BCG) may act through nitric oxide (NO) production, and that cell death is correlated with apoptosis, changes of NO and cell proliferation following BCG and/or nitric oxide synthase (NOS) inhibition treatment of a murine bladder tumor-2 (MBT-2) cell line. If these cell lines show cell death due to apoptosis was also determined. MATERIALS AND METHODS: NO production and proliferation activity of the MBT-2 cell line were measured after stimulation, with BCG and/or L-NAME, using an enzyme- linked immunosorbent assay (ELISA). After incubation of the MBT-2 cells with BCG and/or L-NAME, the cell cycle was analysis was performed by immunocytometry. RESULTS: The production of NO in the MBT-2 cells was significantly increased by the BCG. The BCG had direct dose-dependent cytotoxic effects on the MBT-2 cell line. After the L-NAME treatment, both the NO production and cytotoxicity were decreased (p<0.05). When the MBT-2 cells were cultured with BCG, the apoptotic cell ratio increased compared to that of the MBT-2 cells treated with L-NAME (p<0.05). CONCLUSIONS: The up-regulation of the production of NO following BCG treatment of the MBT-2 cell line may be due, in part, to the cytolytic action of the BCG. The cell death, when BCG was instilled, correlated with apoptosis.

Effects of Non-selective NO Inhibition on Hypoxia-, Acetylcholine- and Bradykinin-induced Vasoconstriction in Septic Isolated Rat Lungs / 대한마취과학회지

BACKGROUND: Endotoxin stimulates nitric oxide synthase (NOS) and the free radical nitric oxide (NO) is produced by NOS, which vasodilates the smooth muscle of pulmonary vessels. Otherwise, endotoxemia stimulates the release of cyclooxygenase (COX) products, which may modify hypoxic pulmonary vasoconstriction (HPV). We also observed the effect of nonselective NOS inhibition by NG-nitro-L-arginine methyl ester (L-NAME) on receptor-mediated acetylcholine (Ach)/bradykinin (BK) induced vasoconstriction and receptor independent HPV in E.coli lipopolysaccharide (LPS) induced septic isolated rat lungs. METHODS: Four hours before surgical instrumentation for lung isolation, we administered saline (1 ml) to the control group (n = 15), E.coli LPS (20 mg/kg) to the LPS group (n = 14) and LPS (30 mg/kg) the nitric oxide synthase inhibitor, L-NAME (15 mg/kg) to the LPS + L-NAME group (n = 14), intraperitoneally. In 43 isolated rat lungs perfused with physiologic salt-albumin- blood mixture, angiotensin II 0.2 microgram was injected into the perfusion circuit, to confirm pulmonary vascular reactivity in each isolated lung. HPV responses were induced by three hypoxic challenges for 5 minutes separated by 5 minutes of ventilation with a normoxic gas mixture. We observed the pulmonary arterial pressure at each challenge, ten minutes after the last HPV, 0.01, 0.1, 1.0 microgram of Ach and 1, 3, 10 microgram of BK were injected. PAP and static lung compliance were measured. RESULTS: The baseline pulmonary artery pressure in the LPS group higher than in the controls and HPV in the LPS group was changed compared to the controls but in the LPS + L-NAME it was higher than in the controls. The administration of Ach 0.1, 1.0 microgram and BK 3, 10 microgram causedpulmonary vasoconstriction and the vasoconstrictions of BK were dosage-dependent. Lung stiffness in the LPS and LPS + L-NAME groups were higher than those of the controls. CONCLUSIONS: Vascular constriction of pulmonary vessels and increased lung stiffness by Ach and BK might be the result of the endothelial injury. But pulmonary vasoconstriction and stiffness by Ach and BK were similar in the LPS and LPS + L-NAME groups, showing that factors other rather than excessive NO production might be involved in endothelial injury.

Effects of Nitric Oxide Synthase (NOS) Inhibitor on MIL801-elicited Behaviors in Rats / 대한정신약물학회지

OBJECTIVE: The aim of the present study was to investigate the effects of nitric oxide synthase (NOS) inhibitor on MK-801-elicited behaviors in rats in an attempt to elucidate the participation of NO in the pathophysiology of schizophrenia and to identify the possibility of NOS inhibitor's antipsychotic property. METHODS: Male Sprague-Dawley rats, weighing 250-300g, were given MK-801 in order to know behavioral changes induced by MK-801. Next time, animals were pretreated with Nomega-nitro-L-arginine (L-NA) as a NOS inhibitor and haloperidol before administration of MK-801, respectively. Separate behavioral rating scales were introduced for quantifying MK-801-induced locomotor activity, stereotyped behaviors and ataxia in order that these behaviors might be assessed independently. Animals were observed for 30 seconds and scored once every 10 min. during a period of 1 hour. RESULTS: 1) Locomotor activity and stereotyped behavior were significantly increased by MK-801 in rats. 2) Locomotor activity and stereotyped behavior were significantly diminished by pretreatment with haloperidol. 3) Locomotor activity and stereotyped behavior were also significantly diminished by pretreatment with L-NA. CONCLUSIONS: These findings suggest that NO may, in part, mediate behavioral changes induced by MK-801, and that inhibitors of NOS may have antipsychotic action.

Effects of Nitric Oxide Synthase Inhibitior on Energy Metabolism in Acute Ischemic-Reperfused Cat Brain: Investigated by 31P and 1H Magnetic Resonance Spectroscopy / 대한마취과학회지

BACKGROUND: The effects of the inhibitor of nitric oxide synthase (NOS) in cerebral ischemia have been debated. Recently, it has been suggested that it depends on the amount of the inhibitor used. Therefore, this study was carried out to evaluate the effects of the NOS in the acute ischemia-reperfusion of the cat model using variable amounts of the inhibitor. METHODS: Nineteen cats were divided into 3 groups: group 1 (n = 6), 10 mg/kg of N-nitro-L-arginine methyl ester (L-NAME); group 2 (n = 7), 0.5 mg/kg; group 3 (n = 6), control group. Incomplete global cerebral ischemia was induced by ligation of both carotid arteries with arterial hypotension (-40 mmHg) for 30 minutes followed by 3 hours of reperfusion. The NOS inhibitor (L-NAME), was injected intraperitoneally 5 minutes before reperfusion. 31P and 1H MR spectroscopy were performed. A series of spectra was acquired in the time intervals before ligation, during ischemia, and after reperfusion. RESULTS: Phosphocreatine/inorganic phosphate (PCr/Pi) ratios for group 1 were significantly lower than for groups 2 and 3 (P < 0.05), and there was no significant difference between groups 2 and 3. Lactate/N-acetyl aspartate (Lac/NAA) and lactate/creatine (Lac/Cr) ratios at 180 minutes after reperfusion were higher for group 1 than for groups 2 and 3 (P < 0.05). There were no significant differences in pH and lactate/choline (Lac/Cho) ratios among the 3 groups. CONCLUSIONS: It is demonstrated that the effect of the NOS inhibitor is dosage dependent. A high dose (10 mg/kg) of L-NAME seems to have an adverse effect on recovery of the ischemia, but a low dose (0.5 mg/kg) seems to have no effect.

Effects of Nitric Oxide Synthase Inhibition on Hydroxyl Radical Production during Global Cerebral Ischemia/Reperfusion in Rats / 대한마취과학회지

BACKGROUND: Free radical-mediated oxidative damage has been implicated in ischemic brain injury. There are also increasing evidences that nitric oxide is involved in the mechanisms of cerebral ischemia. To elucidate the effect of nitric oxide synthesis inhibition on the hydroxyl radical formation, we used a method based on the chemical trapping of hydroxyl radical in the form of the stable adducts 2,3-DHBA following salicylate adminstration. METHODS: Sprague-Dawley rats were subjected to 15 min of global cerebral ischemia by both carotid artery occlusion plus systemic hemorrhagic hypotension (35 mmHg). Artificial CSF including salicylate (5 mM) was continuously infused through a microdiaysis probe implanted in the left hippocampus CA1. Hippocampal extracellular fluid was sampled at regular intervals before, during, and after ischemia. The levels of 2,3-DHBA were assayed by HPLC with electrochemical detection during 15 minutes of ischemia and reperfusion period. RESULTS: Cerebral blood flow was reduced to 5% level of control in ischemic period, but increased 3 or 4 times in early phase of reperfusion period, and returned to normal 50 to 60 minutes after the cessation of ischemia. Inhibition of NOS by L-NAME did not prevent ischemia-induced 2,3-DHBA elevation, but increased its level during reperfusion. This increase in 2,3-DHBA could be reversed by L-arginine. The elevated 2,3-DHBA after IR in L-NAME treated rats was not due to either changes in CBF or local blood brain barrier permeability. CONCLUSIONS: The above results indicate NO protects brain from damages by hydroxyl radical, at least less than one hour after initiation of reperfusion.

The Effect of Nitric Oxide on Edema Formation in Cryogenic Brain Injury Model of the Rat / 대한마취과학회지

BACKGROUND: Nitric oxide (NO) is a simple molecule with a complex involvement in a wide variety of biologic functions. However, whether NO protects or aggravates brain injury is still controversial. This study was conducted to determine the effect of nitric oxide on the formation of brain edema resulting from a focal cryogenic injury in rats. METHODS: Thirty nine Sprague-Dawley rats (200~250 gm) were allowed food and water ad libitum. Anesthesia was induced in a specially designed plastic box with 5% halothane in oxygen. In experiment I (24 rats), animals were divided randomly into eight group (3 rats in each group) according to the decapitation time in control, 15, 30, 45, 60, 90, 120, and 180 min. Cryogenic injury was made by pouring liquid nitrogen to exposed temporo-parietal area through metal funnel for 60 seconds. After cryogenic injury, brain was quickly removed and cerebral hemispheres were seperated. Separated cerebral hemispheres were dried in a drying oven for 7 days at 60 degrees C. Cerebral water content was assessed by dry-weight method. In experiment II (15 rats), one subgroup (n=8) was control group, normal saline 0.5 ml was injected intraperitoneally 30 minutes before injury. the other (n=7) was experimental group, and a competitive nitiric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME), was given intraperitoneally 30 minutes before injury in a dose of 20 mg/kg. Body temperature was monitored during whole experiment. Ninety minutes after injury, brain was quickly removed and cerebral hemispheres were seperated. The cerebral water content of separated cerebral hemisphere was assessed by dry-weight method. RESULTS: In time courses of cryogenic brain edema of experiment I, the amount of brain edema was increased till 90 minutes after cryogenic brain injury and then decreased. In L-NAME group of ex-periment II, the amount of cerebral edema was not changed significantly (p<0.05). But, there was a tendency of decrease in brain edema formation in L-NAME group than control group. CONCLUSION: It was not proved that nitric oxide had a major role in the edema formation aftercryogenic brain injury, but it still seems that nitric oxide has at least partly involved in the pathogenesis of cerebral edema resulting from traumatic brain injury.

Mechanism of the Hypotension Produced Protamine Sulfate in Dogs / 대한마취과학회지

INTRODUCTION: Protamine reversal of heparin anticoagulation often produces profound hypotension. However, the precise mechanisms of its hypotensive effect have not been fully elucidated. Using a canine model, we explored the effects of cyclo-oxygenase inhibitor, indomethacin (INDO), and nitric oxide synthetase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) either alone or both on the cardiopulmonary responses to protamine. METHODS: Fifty-four mongrel dogs in five groups were studied during 1.5% halothane anesthesia. GroupI (n=17) received heparin (300 IU/kg iv) followed by protamine (3 mg/kg iv over 30 s) 5 min after the heparin. The same protocol were used in groups II (n=11), III (n=12), and IV (n=7), except that L-NAME (20 mg/kg), INDO (10 mg/kg), and INDO (10 mg/kg) plus L-NAME (10 mg/kg) were infused over 10 min beginning 30 min before the protamine injection, respectively. Animals in group V (n=7) were given protamine (3 mg/kg) alone. Mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), left ventricular end-diastolic pressure (LVEDP), LVdP/dt and cardiac output and left circumflex coronary flow (LCX flow) via Doppler flowmeter and heart rate were continuously recorded in baseline conditions and up to 15 min. Plasma NOx (NO2-, NO3-) levels were also measured before (baseline) and 3, 5, 10, and 15 min after protamine injection. RESULTS: In group I, protamine caused immediate but transient decreases of MAP (41%), cardiac index (CI, 58%), dP/dt (28%), and LVEDP (62%) and increases of MPAP (38%) and systemic and pulmonary vascular resistance indices (SVRI, 30%; PVRI, 316%). INDO significantly attenuated the hemodynamic responses to protamine, whereas L-NAME did not affect them at all. INDO plus L-NAME prevented protamine-induced hypotension, but CI (-24%) and LVEDP (-30%) showed similar changes as those in group II. Protamine increased MPAP but inconsistently, meanwhile no correlation was found between the magnitude of increase of MPAP and decrease of MAP at peak responses in groups I-IV. LCX flow increased significantly (124~188%) immediately after protamine infusion without any changes in plasma NOx levels in groups I-IV. Neither significant hemodynamic effects nor NOx release was found in animals given protamine alone. CONCLUSION: Protamine in the presence of heparin induces profound hypotension which may be mediated by a prostanoid and other potent vasodilators. In addition, increase of PAP and NO release may not play a significant role in the protamine-induced hypotension.

Study on the effect of nitric oxide synthase inhibitor on the learning and memory abilities in rats and the effect of nimodipine / 临床神经病学杂志

Objective To investigate the effect of nitric oxide synthase inhibitor on learning and memory abilities and to observe the change of nitric oxide (NO) contents in the hippocampi and the effect of nimodipine in rats.Methods With the administration of L ? nitro L arginine(L NA) into bilateral hippocami,the rat model with disorders of learning and memory abilities was established.Then the intraperitoneal injections of nimodipine were given, Y maze tests were performed, and the NO contents in the hippocampi were measured in turn.Results The experiment showed that the learning and memory abilities of model and intervention rats were worse than those of the control rats ( P