We investigated the antihypertensive effect of lutein on NG-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Daily oral administration of L-NAME (40 mg/kg)-induced a rapid progressive increase in mean arterial pressure (MAP). L-NAME significantly increased MAP from the first week compared to that in the control and reached 193.3+/-9.6 mmHg at the end of treatment. MAP in the lutein groups was dose-dependently lower than that in the L-NAME group. Similar results were observed for systolic and diastolic blood pressure of L-NAME-induced hypertensive rats. The control group showed little change in heart rate for 3 weeks, whereas L-NAME significantly reduced heart rate from 434+/-26 to 376+/-33 beats/min. Lutein (2 mg/kg) significantly prevented the reduced heart rate induced by L-NAME. L-NAME caused hypertrophy of heart and kidney, and increased plasma lipid peroxidation four-fold but significantly reduced plasma nitrite and glutathione concentrations, which were significantly prevented by lutein in a dose-dependent manner. These findings suggest that lutein affords significant antihypertensive and antioxidant effects against L-NAME-induced hypertension in rats.
Administration, Oral ; Animals ; Antioxidants ; Arterial Pressure ; Blood Pressure ; Glutathione ; Heart ; Heart Rate ; Hypertension ; Hypertrophy ; Kidney ; Lipid Peroxidation ; Lutein ; NG-Nitroarginine Methyl Ester ; Plasma ; Rats

BACKGROUND: Production of nitric oxide (NO) radicals may contribute to neuronal injury. We examined that the inhibition of NO synthase (NOS) could improve postischemic neurologic outcome after spinal cord ischemia in rabbits. Also, we measured cGMP as a marker of NOS activation in control and experimental groups. METHODS: Spinal cord ischemia in rabbits was induced by aortic occlusion with aneurysm clip at the level just below branching of left renal artery. Five minutes before aortic occlusion, saline (control group, n=10) or a NOS inhibitor NG-nitro-L-arginine methyl ester (10 mg/kg, L-NAME group, n=10) was injected intravenously. After 15 min ischemia and 1 hour reperfusion, animals were sacrified and the spinal cords were extruded for the measurement of cGMP by enzymeimmunoassay. For neurologic examination, the same procedures of ischemia/reperfusion and drug injection were done, except that rabbits were perfused for 4 hours (control-4 and L-NAME-4, n=8 at each group) or 48 hours (control-48 and L-NAME-48, n=8 at each group) after aortic occlusion. RESULTS: L-NAME (10 mg/kg) increased mean systemic arterial pressure accompanied by bradycardia, and reduced cGMP significantly. Control-4 animals showed better neurologic function than L-NAME-4 animals (p<0.05), however, there was no significant difference of neurologic outcome between control-48 and L-NAME-48 groups. CONCLUSION: Intravenous administration of L-NAME prior to spinal cord ischemia/reperfusion diminishes the extent of postischemic neuronal spinal cord damage at the early postreperfusion period.
Administration, Intravenous ; Aneurysm ; Animals ; Arterial Pressure ; Bradycardia ; Ischemia ; Neurologic Examination ; Neurons ; NG-Nitroarginine Methyl Ester* ; Nitric Oxide ; Nitric Oxide Synthase ; Nitroarginine* ; Rabbits* ; Renal Artery ; Reperfusion ; Spinal Cord Ischemia ; Spinal Cord*

BACKGROUND: Production of nitric oxide (NO) radicals may contribute to neuronal injury. We examined that the inhibition of NO synthase (NOS) could improve postischemic neurologic outcome after spinal cord ischemia in rabbits. Also, we measured cGMP as a marker of NOS activation in control and experimental groups. METHODS: Spinal cord ischemia in rabbits was induced by aortic occlusion with aneurysm clip at the level just below branching of left renal artery. Five minutes before aortic occlusion, saline (control group, n=10) or a NOS inhibitor NG-nitro-L-arginine methyl ester (10 mg/kg, L-NAME group, n=10) was injected intravenously. After 15 min ischemia and 1 hour reperfusion, animals were sacrified and the spinal cords were extruded for the measurement of cGMP by enzymeimmunoassay. For neurologic examination, the same procedures of ischemia/reperfusion and drug injection were done, except that rabbits were perfused for 4 hours (control-4 and L-NAME-4, n=8 at each group) or 48 hours (control-48 and L-NAME-48, n=8 at each group) after aortic occlusion. RESULTS: L-NAME (10 mg/kg) increased mean systemic arterial pressure accompanied by bradycardia, and reduced cGMP significantly. Control-4 animals showed better neurologic function than L-NAME-4 animals (p<0.05), however, there was no significant difference of neurologic outcome between control-48 and L-NAME-48 groups. CONCLUSION: Intravenous administration of L-NAME prior to spinal cord ischemia/reperfusion diminishes the extent of postischemic neuronal spinal cord damage at the early postreperfusion period.
Administration, Intravenous ; Aneurysm ; Animals ; Arterial Pressure ; Bradycardia ; Ischemia ; Neurologic Examination ; Neurons ; NG-Nitroarginine Methyl Ester* ; Nitric Oxide ; Nitric Oxide Synthase ; Nitroarginine* ; Rabbits* ; Renal Artery ; Reperfusion ; Spinal Cord Ischemia ; Spinal Cord*

BACKGROUND AND OBJECTIVES: It has been suggested that nitric oxide (NO) and atrial natriuretic peptide (ANP) share a final common pathway for vascular smooth muscle relaxation. The aim of the present study was to determine the role of NO on the hypotensive and vasorelaxant effects of ANP. MATERIALS AND METHODS: Sprague-Dawley rats weighing 250-300 g each were anesthetized with thiopental (50 mg/kg IP). The femoral artery was cannulated and the arterial blood pressure and heart rate were continuously monitored in the anesthetized rats (n=19). ANP was administered into the jugular vein after L-NAME treatment. In vitro experiments were performed on intact and endothelium-denuded isolated thoracic aortic rings (n=51) in the presence of either L-NAME or methylene blue. RESULTS: Intravenous administration of ANP (5 ug/kg bolus and 0.2 ug/kg/min infusion) caused a decrease in the mean arterial pressure. L-NAME-pretreatment (1 mg/kg) suppressed the depressor response of ANP. In vitro, the ANP caused a dose-dependent relaxation, and the relaxation response to ANP was attenuated by L-NAME (10-4 M). Endothelium removal or methylene blue (10-5 M) also inhibited the ANP-induced vascular relaxation. CONCLUSION: These results suggest that the hypotensive and the vasorelaxant effect of ANP are, at least in part, NO-dependent.
Administration, Intravenous ; Animals ; Arterial Pressure ; Atrial Natriuretic Factor ; Endothelium ; Femoral Artery ; Heart Rate ; Jugular Veins ; Methylene Blue ; Muscle, Smooth, Vascular ; NG-Nitroarginine Methyl Ester ; Nitric Oxide* ; Rats* ; Rats, Sprague-Dawley ; Relaxation ; Thiopental

OBJECTIVETo evaluate the effects of different doses of N(G)-nitro-L-arginine methyl ester (L-NAME) on hemodynamics, cyclic guanosine monophosphate (cGMP) production and the level of beta-adrenergic receptors (beta-ARs) mRNA in a heart failure rat model after BRL-37344 (beta(3)-ARs agonist) injection. Meanwhile, to investigate the influence of beta(3)-ARs and L-NAME on signal transduction in failing heart.

METHODSThe rats were randomly divided into six groups, control group (group I), Iso (isoproterenol) group (group II), Iso + BRL group (group III), Iso + BRL + low dose of L-NAME group (5 mg/kg, group IV), Iso + BRL + moderate dose of L-NAME group (50 mg/kg, group V), Iso + BRL + high dose of L-NAME group (100 mg/kg, group VI). The hemodynamics [left ventricular end systolic pressure (LVESP), +/- dp/dt, left ventricular end diastolic pressure (LVEDP)], cardiac cGMP and the levels of beta(1)-, beta(2)-, and beta(3)-ARs mRNA were measured.

RESULTS(1) LVESP, +/- dp/dt values in group II were significantly lower, and LVEDP was significantly higher than that in group I (except -dp/dt P < 0.05, the rest were P < 0.01). Comparing with group II, group III had lower -dp/dt value and LVESP, higher LVEDP (P < 0.05). The level of +dp/dt had a trend to be lower but lacked statistical significance between two groups. The value of +/- dp/dt got higher and LVEDP got lower along with higher dose of L-NAME, but a large dose of L-NAME had more deteriorated cardiac functions. (2) The cardiac cGMP in group I, II and III had a higher tendency (P < 0.01). The tendency of cardiac cGMP in group IV, V and VI was inversed with the dose of L-NAME. After a large dose of L-NAME was applied, cGMP returned to the same level as Group I. (3) Among groups I, II and III, the level of beta(1)-AR mRNA was the highest in group I and the lowest in group III (P < 0.01). The levels of beta(2)-AR mRNA were also tended to be lower among three groups but with no significance. While the level of beta(3)-AR mRNA was the highest in group III. The levels of beta-AR mRNA were all the same in group VI, V and VI.

CONCLUSIONSThe negative inotropic effect of beta(3)-ARs stimulation was mediated by activation of the NOS pathway. L-NAME blocked beta(3)-ARs agonist negative chronotropic effect on failing heart partly and improved hemodynamics, but a large dose of L-NAME had more deteriorated cardiac functions.

Adrenergic Agonists ; therapeutic use ; Animals ; Cyclic GMP ; metabolism ; Heart Failure ; drug therapy ; metabolism ; physiopathology ; Male ; NG-Nitroarginine Methyl Ester ; administration & dosage ; pharmacology ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Receptors, Adrenergic, beta-3 ; metabolism

We evaluated the effects of a combined therapy of pre-blockade endogenous nitric oxide synthase (NOS) with N-nitro-L-arginine methyl ester (L-NAME) and continuous inhaled NO (iNO) on the gas exchange and hemodynamics of Escherichia coli pneumonia and sepsis in newborn piglets. Seven to ten day old ventilated newborn piglets were randomized into 5 groups: control, E. coli pneumonia control, pneumonia with iNO 10 ppm, pneumonia pre-treated with L-NAME 10 mg/kg, and pneumonia with the combined therapy of L-NAME pretreatment and iNO. E. coli pneumonia was induced via intratracheal instillation of Escherichia coli, which resulted in progressively decreased cardiac index and oxygen tension; increased pulmonary vascular resistance index (PVRI), intrapulmonary shunting, and developed septicemia at the end of 6 hr experiment. iNO ameliorated the progressive hypoxemia and intrapulmonary shunting without affecting the PVRI. Only two of 8 animals with L-NAMEpretreated pneumonia survived. Whereas when iNO was added to infected animals with L-NAME pretreatment, the progressive hypoxemia was abolished as a result of a decrease in intrapulmonary shunting without reverse of the high PVRI and systemic vascular resistance index induced by the L-NAME injection. This result suggests that a NOS blockade may be a possible supportive option for oxygenation by iNO treatment in neonatal Gram-negative bacterial pneumonia and sepsis.
Treatment Outcome ; Swine ; Survival Rate ; Sepsis/diagnosis/drug therapy/physiopathology ; Pulmonary Gas Exchange/*drug effects ; Premedication/*methods ; Pneumonia, Bacterial/diagnosis/*drug therapy/physiopathology ; Oxygen Consumption/*drug effects ; Nitric Oxide Synthase/antagonists & inhibitors ; Nitric Oxide/*administration & dosage ; NG-Nitroarginine Methyl Ester/*administration & dosage ; Injections, Intravenous ; Escherichia coli Infections/diagnosis/*drug therapy/physiopathology ; Drug Therapy, Combination ; Animals, Newborn ; Animals ; Administration, Inhalation

We evaluated the effects of a combined therapy of pre-blockade endogenous nitric oxide synthase (NOS) with N-nitro-L-arginine methyl ester (L-NAME) and continuous inhaled NO (iNO) on the gas exchange and hemodynamics of Escherichia coli pneumonia and sepsis in newborn piglets. Seven to ten day old ventilated newborn piglets were randomized into 5 groups: control, E. coli pneumonia control, pneumonia with iNO 10 ppm, pneumonia pre-treated with L-NAME 10 mg/kg, and pneumonia with the combined therapy of L-NAME pretreatment and iNO. E. coli pneumonia was induced via intratracheal instillation of Escherichia coli, which resulted in progressively decreased cardiac index and oxygen tension; increased pulmonary vascular resistance index (PVRI), intrapulmonary shunting, and developed septicemia at the end of 6 hr experiment. iNO ameliorated the progressive hypoxemia and intrapulmonary shunting without affecting the PVRI. Only two of 8 animals with L-NAMEpretreated pneumonia survived. Whereas when iNO was added to infected animals with L-NAME pretreatment, the progressive hypoxemia was abolished as a result of a decrease in intrapulmonary shunting without reverse of the high PVRI and systemic vascular resistance index induced by the L-NAME injection. This result suggests that a NOS blockade may be a possible supportive option for oxygenation by iNO treatment in neonatal Gram-negative bacterial pneumonia and sepsis.
Treatment Outcome ; Swine ; Survival Rate ; Sepsis/diagnosis/drug therapy/physiopathology ; Pulmonary Gas Exchange/*drug effects ; Premedication/*methods ; Pneumonia, Bacterial/diagnosis/*drug therapy/physiopathology ; Oxygen Consumption/*drug effects ; Nitric Oxide Synthase/antagonists & inhibitors ; Nitric Oxide/*administration & dosage ; NG-Nitroarginine Methyl Ester/*administration & dosage ; Injections, Intravenous ; Escherichia coli Infections/diagnosis/*drug therapy/physiopathology ; Drug Therapy, Combination ; Animals, Newborn ; Animals ; Administration, Inhalation

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.
Animals ; Body Weight/drug effects ; Disease Models, Animal ; Eating/drug effects ; Enzyme Inhibitors/*administration & dosage/pharmacology ; *Hindlimb ; Male ; Muscle Fibers, Skeletal/*drug effects/metabolism ; Muscle Proteins/metabolism ; Muscular Atrophy/drug therapy ; NG-Nitroarginine Methyl Ester/*administration & dosage/pharmacology ; Neuralgia/*etiology ; Nitric Oxide Synthase/*antagonists & inhibitors/metabolism ; *Peripheral Nerve Injuries ; Rats ; Rats, Sprague-Dawley

AIMTo assess heme oxygenase-1 (HO-1) activity in the cavernous tissue of sildenafil citrate-treated rats.

METHODSOne hundred and ninety-two Sprague-Dawley male rats, divided into four equal groups, were investigated. Group 1, the control group, received regular animal chow; group 2 received sildenafil citrate by intragastric tube; group 3 received sildenafil and HO inhibitor (zinc protoporphyrin, ZnPP); and group 4 received sildenafil and nitric oxide synthase (NOS) inhibitor L-nitroarginine methyl ester (L-NAME). Twelve rats from each group were killed after 0.5 h, 1 h, 2 h and 3 h of drug administration. Then HO-1 activity, cGMP levels and NOS enzymatic activity in the cavernous tissues were estimated.

RESULTSIn cavernous tissue, HO-1 activity, NOS enzymatic activity and cGMP concentration increased significantly in sildenafil-treated rats compared to other groups throughout the experiment. Rats receiving either HO or NOS inhibitors showed a significant decrease in these parameters. HO-1 cavernous tissue activity and NOS enzymatic activity demonstrated a positive significant correlation with cGMP levels (r = 0.646, r = 0.612 respectively; P < 0.001).

CONCLUSIONThe actions of PDE5 inhibitor sildenafil citrate in the cavernous tissue are partly mediated through the interdependent relationship between both HO-1 and NOS activities.

Administration, Oral ; Animals ; Cyclic GMP ; metabolism ; Drug Interactions ; Drug Therapy, Combination ; Enzyme Inhibitors ; pharmacology ; Heme Oxygenase-1 ; antagonists & inhibitors ; metabolism ; Male ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide Synthase ; metabolism ; Penis ; drug effects ; enzymology ; Piperazines ; pharmacology ; Protoporphyrins ; pharmacology ; Purines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Sildenafil Citrate ; Sulfones ; pharmacology ; Vasodilator Agents ; pharmacology

OBJECTIVES: Septic shock is characterized by the circulatory failure including vasodilation, hyporeactivity to vasoconstrictor agents and organ ischemia in association with multiple organ failure and increased platelet aggregation and blood coagulation. In the present study, we investigated the preventive effects of N-nitro-L-arginine methyl ester (L-NAME, 30mg/kg, i.p.), a non-selective nitric oxide synthase (NOS) inhibitor, S-methylisothiourea sulfate (SMT, 5mg/kg, i.p.) and pentoxifylline (PTX,10mg/kg, i.p.) on the multiple organ dysfunction in a rat model of circulatory shock induced by bacterial endotoxin (E. coli lipopolysaccharide: LPS) and discussed the mechanism underlying the development of multiple organ failure. METHODS: The effect of each other N-nitro-L-arginine methyl ester(L-NAME, 30 mg/kg, i.p.), a non-selective nitric oxide synthase(NOS) inhibitor, S-methyli-sothiourea sulfate(SMT, 5mg/kg, i.p.) and pentoxifylline (PTX, 10mg/kg, i.p.) were comparatively evaluated following inducing circulatory shock by means of infusion of bacterial endotoxin to the rat model. RESULTS: 1) The systemic mean arterial blood pressure decreased by 48.7mmHg and vascular hyporeactivity to noradrenaline injection(1 g/kg, i.v.) upon intravenous administration of LPS. 2) Endotoxemia for 6hours resulted in little change in the numbers of white blood cells and neutrophils but a significant reduction in the numbers of platelets. The variables were not affected by the inhibitors. 3) Endotoxemia for 6hours caused a significant increase in serum nitric oxide level (P<0.01) which was inhibited by SMT, but not by L-NAME and PTX. 4) Upon injection of LPS, serum creatinine(0.65+/-0.08mg/dl) and urea(28.7+/-5.9mg/dl) were significantly elevated to 0.92+/-0.12 (P<0.05) and 54.3+/-2.1mg/dl (P< 0.01). These elevated levels were significantly attenuated by PTX but not by L-NAME and SMT. 5) Endotoxemia for 6 hours resulted in a significant increases in serum ALT(988.8+/-28.2 IU/L, P<0.01) and AST levels(1470.5+/-396.5 IU/L, P<0.01) from basal levels of ALT(67.8+/- 11.7IU/L) and AST(170.3+/-14.8IU/L). These increased activities were significantly attenuated by PTX, but not by L-NAME and SMT. The level of LDH(1279.8+/-156.2IU/L) was significantly increased by LPS treatment to 2932.0+/-519.9IU/L (P<0.05), which was inhibited by PTX. 6) Upon LPS treatment, the myeloperoxidase activity in the lung homogenate was significantly increased by LPS treatment (P<0.05), whereas that in the liver showed less change. The increased activity was reduced by PTX (P<0.05), but not by L-NAME and SMT. 7) The level of serum malondialdehyde, an index of lipid peroxidation by oxygen free radicals, was little influenced by LPS. CONCLUSION: Based on these results, it is summarized that PTX characteristically inhibited the development of multiple ogran dysfunction in a murine model of endotoxemia. Thus, it is concluded that the formation of TNF and increased activity of neutrophils may importantly contribute to the development of LPS-induced endotoxemia.
Administration, Intravenous ; Animals ; Arterial Pressure ; Blood Coagulation ; Endotoxemia ; Free Radicals ; Ischemia ; Leukocytes ; Lipid Peroxidation ; Liver ; Lung ; Malondialdehyde ; Models, Animal ; Multiple Organ Failure ; Neutrophils ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Nitric Oxide Synthase ; Norepinephrine ; Oxygen ; Pentoxifylline* ; Peroxidase ; Platelet Aggregation ; Rats* ; Shock ; Shock, Septic ; Vasoconstrictor Agents ; Vasodilation