BACKGROUND: According to target cells, apoptosis-inducing agents, and NO concentration, NO concentration, NO shows both pro- and antiapoptotic effects. OBJECTS: Our study was perfermed to verify the role of NO in UVB-induced apoptosis in HaCaT cells. METHODS: After UVB irradiation, FACS using propidium iodide, LDH cytotoxicity assay, and nitrite assay based on Griess reaction were done in HaCaT cells. These procedures were repeated after UVB irradiation and NG-monomethyl-arginine (L-NMMA), a NO synthase (NOS) inhibitor, addition. RESULTS: 1) UVB irradiation (5-80mJ/cm2) induced apoptosis in HaCaT cells dose-dependently. 2) UVB irradiation (80mJ/cm2) stimulated NO production 30-50% more over baseline level, and this was inhibited by 500 micrometer L-NMMA. 3) 500 micrometer L-NMMA did not inhibit UVB-induced apoptosis. CONCLUSION: UVB irradiation evokes apoptosis in HaCaT keratinocytes through NO-independent mechanism.
Apoptosis* ; Keratinocytes* ; Nitric Oxide Synthase ; Nitric Oxide* ; omega-N-Methylarginine ; Propidium

PURPOSE: We investigate the effects of intravesical BCG therapy on the occurance of superficial bladder cancer induced by N-butyl-N-(4-hydroxybutyl) nitrosamine(BBN) in Fisher 344 rats in vivo. We also examine whether NO mediated the antitumor activity of BCG against superficial bladder cancer in Fisher 344 rats. MATERIALS AND METHODS: BBN(0.1%) is orally administered for 20 weeks and it is combined with BCG(0.27mg) or NG-monomethyl-L-arginine (NG MMA, 10mg). once every week from 8th week to 19th week. The rats are sacrified at 20th week. NO secretion in urine for 24 ours is significantly increased in the BCG treated rats compared to the animals treated with saline or NGMMA. RESULTS: Pathologic findings demonstrate that the incidence of carcinoma is not statistically different in saline, BCG, NGMMA(p>0.05). However the size and number of tumor is decreased in the BCG treated rats compared with saline or NGMMA treated rats bearing bladder cancer induced by BBN(p<0.05). Inducible NO synthase(iNOS) is strongly induced in bladder tissue of rats treated with BCG and NGMMA but not in saline. CONCLUSIONS: Intravesical instillation of BCG on bladder cancer induced by BBN does not decrease the cancer occurrence but reduces the number and size of bladder cancer. Our results suggest that nitric oxide induced by intravesical instillation of BCG may mediate antitumor activity against the occupance of superficial bladder cancer.
Administration, Intravesical ; Animals ; Incidence ; Mycobacterium bovis* ; Nitric Oxide ; omega-N-Methylarginine ; Rats ; Urinary Bladder Neoplasms* ; Urinary Bladder*

Local contributing factors in penile erection are trabecular smooth muscle, endothelium, trabecular fibroelastic components, tunica albuginea and local neuro-control. There are three neuroeffector systems in local neuro-control for penile erection. One is adrenergic system causing contraction and the others are cholinergic and noncholinergic nonadrenergic system causing relaxation of corpus cavernosum under normoxia. The effect of these systems under hypoxic condition however is not fully understood. The aims of this study were to detect the pharmacophysiological changes of corporal smooth muscle about 3 local neuroeffector systems under hypoxia in the rabbit and to apply the results of study to the management of the priapism. The strips of rabbit corporal tissues were studied for isometric tension measurement under normoxia, hypoxia and cooling condition in the organ chambers. Influence of NL- monomethyl-L-arginine (L-NMMA) and L-arginine to acetylcholine under normoxia and effects of phenylephrine, norepinephrine, acetylcholine, VIP, endothelin 1, papaverine and KCI on the rabbit corpus cavernosal tissue were monitored under normoxia and hypoxia and changes under cooling condition were observed. Relaxing effect of acetylcholine under normoxia was suppressed with L-NMMA and this suppression was reversed with L-arginine. Relaxation with acetylcholine and contraction with endothelin 1 were suppressed under hypoxic condition. Contracting effect of norepinephrine and phenylephrine was stronger under hypoxia or cooling condition than normoxia or 37 degrees C condition respectively. Relaxing effect of VIP and papaverine on corpus cavernosa was similar under normoxia or hypoxia. These results suggest that endothelium-dependent relaxation by cholinergic and noncholinergic nonadrenergic system and endothelium-dependent contraction by endothelin 1 are suppressed under hypoxic condition. VIP related noncholinergic nonadrenergic relaxation and direct relaxation effect of papaverine to corporal smooth muscle are preserved under hypoxia. Application of adrenergics and local irrigation with cold saline would be effective in the management of priapism.
Acetylcholine ; Adrenergic Agents ; Anoxia* ; Arginine ; Endothelin-1 ; Endothelium ; Male ; Muscle, Smooth ; Norepinephrine ; omega-N-Methylarginine ; Papaverine ; Penile Erection ; Phenylephrine ; Priapism ; Relaxation

BACKGROUND: Since the demonstration of the fact that vascular relaxation by acetylcholine(Ach) results from the release of relaxing factor from the endothelium, the identity and physiology of this endothelium-derived relaxing factor(EDRF) has been the target for many researches. EDRF has been identified as nitric oxide(NO). With the recent evidences that EDRF is an important mediator of vascular tone, there have been increasing interests in defining the role of the EDRF as a potential mediator of hypoxic pulmonary vasoconstriction. But the role of EDRF in modulating the pulmonary circulation is not compeletely clarified. To investigate the endotbelium-dependent pulmonary vasodilation and the role of EDRF during hypoxic pulmonary vasoconstriction, we studied the effects of N(G)-monornethyl-L-arginine(L-NMMA) and L-arginine on the precontracted pulmonary arterial rings of the rat in normoxia and hypoxia. METHODS: The pulmonary arteries of male Sprague Dawley(300~350g) were dissected free of surrounding tissue, and cut into rings. Rings were mounted over fine rigid wires, in organ chambers filled with 20ml of Krebs solution bubbled with 95 percent oxygen and 5 percent carbon dioxide and maintained at 37℃. Changes in isometric tension were recorded with a force transducer(FT. 03 Grass, Quincy, USA). RESULTS: 1) Precontraction of rat pulmonry artery with intact endothelium by phenylephrine(PE, 10(-6)M) was relaxed completely by acetylcholine(Ach, 10(-9) -10(-5)M) and sodium nitroprusside (SN, 10(-9) -10(-5)M), but relaxing response by Ach in rat pulmonary artery with denuded endothelium was significantly decreased. 2) L-NMMA(10-4M) pretreatment inhibited Ach(10(-9) -10(-5)M)-induced relaxation, but L-NMMA(10-4M) had no effect on relaxation induced by SN(10(-9) -10(-5)M). 3) Pretreatment of the L-arginine(10(-4)M) significantly reversed the inhibition of the Ach(10(-9) -10(-5)M)-induced relaxation caused by L-NMMA(10(-4)M). 4) Pulmonary arterial contraction by PE(10(-6)M) was stronger in hypoxia than normoxia but relaxing response by Ach(10(-9) -10(-5)M) was decreased. 5) With pretreatment of L-arginine(10(-4)M), pulmonary arterial relaxation by Ach(10(-9) -10(-5)M) in hypoxia was reversed to the level of relaxation in normoxia. CONCLUSION: It is concluded that rat pulmonary arterial relaxation by Ach is dependent on the intact endothelium and is largely mediated by NO. Acute hypoxic pulmonary vasoconstriction is related to the suppression on NO formation in the vascular endothelium.
Animals ; Anoxia ; Arginine ; Arteries ; Carbon Dioxide ; Endothelium ; Endothelium, Vascular ; Humans ; Male ; Nitric Oxide* ; Nitroprusside ; omega-N-Methylarginine ; Oxygen ; Physiology ; Poaceae ; Pulmonary Artery ; Pulmonary Circulation ; Rats* ; Relaxation* ; Vasoconstriction* ; Vasodilation

BACKGROUND AND OBJECTIVES: The endothelium plays an important role in maintaining vascular tone and function. Essential hypertension may be associated with alterations in endothelial function. The effects of antihypertensive agents on endothelial function have not been fully evaluated in human hypertension and data on the forearm circulation of humans are controversial. The aim of this study was 1) to evaluate the endothelial function in hypertensive patients 2) to investigate whether vitamin C administration has benefit on the endothelial function and 3) to determine whether treatment with ACE inhibitor improve endothelial dysfunction in hypertensive patients. MATERIALS AND METHODS: The endothelial function was estimated using venous occlusion plethysmography(VOP) in 8 hypertensive patients and 8 healthy volunteers. The patients in the hypertension group were treated with enalapril, then examined again. The change of the forearm blood flow(FBF) was measured with the acetylcholine infusion through brachial artery and also with intra-arterial vitamin C. The measurement of forearm volume change was repeated for 7 times each stage. RESULTS: Forearm blood flow response to acetylcholine was significantly enhanced with inra-arterial infusion of vitamin C in hypertensive group before antihypertensive treatment(302+/-58 % --< 446+/-43 %). Co-infusion of L-NMMA, an inhibitor of nitric oxide synthase, blunted forearm blood flow response to acetylcholine(Vit C(+; 446+/-43 % --< Vit C +L-NMMA; 229+/-23 %). After antihypertensive treatment with enalapril for 2 months in hypertensive group, endothelium-dependent vasorelaxation (vasodilatory response to acetylcholine) was significantly improved in treated group compared to before enalapril treatment(302+/-58 % --< 643+/-78 %). CONCLUSIONS: Even though the mechanisms leading to depressed endothelial function in essential hypertension remains to be elucidated, our study shows that vitamin C and ACE inhibitor result in demonstrable improvement by a mechanism that is probably related to antioxidant activity.
Acetylcholine ; Antihypertensive Agents ; Ascorbic Acid* ; Brachial Artery ; Enalapril ; Endothelium ; Forearm ; Healthy Volunteers ; Humans ; Hypertension* ; Nitric Oxide Synthase ; omega-N-Methylarginine ; Vasodilation ; Vitamins*

OBJECTIVETo investigate the effects of repeated injections of L-NMMA on a goat model with osteoarthrotic temporomandibular joint (TMJ) disease.

METHODSEight goats were selected in this study. Bilateral TMJ osteoarthrosis (OA) was induced by injecting 0.5% collagenase. L-NMMA was injected into one side of TMJs at 4 weeks after collagenase injection (one time every three days). Another joint as control was simultaneously injected using 0.9% saline solution. All goats were killed at 12 weeks after collagenase injection. The TMJ specimens were harvested and processed for histological examination. Modified Mankin's grading score system was used for evaluating changes in the TMJ.

RESULTSThe control side of TMJs showed severe osteoarhrotic changes in the condyle whereas the L-NMMA-treated TMJs showed less degenerative alterations. The histologic score was 3.83 in the L-NMMA treated side, and 6.33 in the control. There was a significant difference in osteoarthrotic changes between the L-NMMA-treated and control TMJs (P < 0.01).

CONCLUSIONSRepeated intra-articular injection of L-NMMA into TMJ may play a role in inhibiting TMJOA progression.

Animals ; Enzyme Inhibitors ; administration & dosage ; therapeutic use ; Female ; Goats ; Injections, Intra-Articular ; Male ; Osteoarthritis ; drug therapy ; Temporomandibular Joint Disorders ; drug therapy ; omega-N-Methylarginine ; administration & dosage ; therapeutic use

To examine the role of nitric oxide in the beta-adrenergic vasodilation of epicardial coronary arteries in dogs, 12 dogs were instrumented for measurement of left anterior descending coronary artery diameter by transthoracic echocardiography before and after dobutamine (5 microg/kg/min IV) with and without intracoronary infusion of NG-monomethyl-L-arginine (L-NMMA) (1 mg/kg). In all 12 dogs, the diameter of left anterior descending coronary artery increased significantly from 2.35 +/- 0.25 mm to 2.59 +/- 0.24 mm (P<0.001) after dobutamine administration. In 6 of the 12 dogs, the percent change in left anterior descending coronary artery diameter induced by dobutamine decreased significantly from 12.5% +/- 8.6% to -1.5% +/- 5.4% (P<0.05) after the administration of intracoronary L-NMMA (1 mg/kg for 5 min) to block nitric oxide synthesis from L-arginine. The study demonstrated that nitric oxide formation contributes to the beta-adrenergic dilatory response of epicardial coronary arteries to dobutamine in dogs.
Adrenergic beta-Agonists ; pharmacology ; Animals ; Coronary Vessels ; physiology ; Dobutamine ; pharmacology ; Dogs ; Echocardiography ; Female ; Male ; Nitric Oxide ; physiology ; Receptors, Adrenergic, beta ; physiology ; Vasodilation ; physiology ; omega-N-Methylarginine ; pharmacology

Recently oxygen free radicals and nitric oxide (NO) are known to play an important role in neuronal reperfusion injury. This study was aimed to investigate the role of oxygen f ree radicals and NO during cerebral ischemia/reperfusion, using dimethylthiourea (DMTU) and NG-monomethyl-L-arginine (NMMA), an oxygen f ree radical scavenger and a competitive NOS inhibitor respectively. In the in vivo experiment, the ischemia/reperfusion-induced changes of cerebral biogenic amines were examined in Mongolian gerbil (Meriones unguiculatus) pre-treated with NMMA and/or DMTU. To induce cerebral ischemia/reperfusion, bilateral common carotid arteries were clamped for 10 minutes and then released for 15 minutes. The biogenic amines were measured by using HPLC-ECD(High Performance Liquid Chromatography-Electrochemical detection). To confirm the results from the in vivo experiments, the effect of NMMA and/or DMTU on [3H]dopamine release from striatal slices exposed to hypoxia was investigated. The results are as follows; 1) Ischemia/reperfusion increased the ratio of DOPAC/dopamine and HVA/dopamine as well as the concentrations of DOPAC and HVA, which were evident only in corpus striatum. 2) NMMA attenuated the ischemia/reperfusion-induced increase in the ratio of DOPAC/dopamine in corpus striatum. However, the change of DOPAC or HVA was minimal. 3) DMTU attenuated the ischemia/reperfusion-induced increase of DOPAC and HVA, and the ratio ofDOPAC / dopa- mine and HVA/dopamine in corpus striatum. 4) Simultaneous pre-treatment with NMMA and DMTU attenuated the ischemia/reperfusion-induced increase of DOPAC and HVA, and the ratio Of DOPAC/dopamine and HVA/dopamine in corpus striatum. The extent of attenuation was greater than the single treatment group with NMMA or DMTU. 5) Exposure to hypoxia markedly increased the release of [3H]dopamine in the striatal slices. 6) The administration of either NMMA or DMTU attenuated the increase of [3H]dopamine release induced by hypoxia in the striatal slices. 7) The administration of both NMMA or DMTU markedly attenuated the increase of [3H]dopamine release induced by hypoxia to the extent of the control in the striatal slices. These results suggest that oxygen free radicals play an important role in cerebral ischemia/reperfusion injury, for which NO seems to be responsible.
3,4-Dihydroxyphenylacetic Acid ; Anoxia ; Biogenic Amines* ; Carotid Artery, Common ; Corpus Striatum ; Dopamine ; Free Radicals* ; Gerbillinae ; Ischemia ; Neurons ; Nitric Oxide* ; omega-N-Methylarginine ; Oxygen* ; Reperfusion ; Reperfusion Injury

One of the pathophysiologic change of priapism is known as hypoxic condition of corpus cavernosum. In vitro study of corpus cavernosum under hypoxia showed suppressed endothelium- dependent relaxation caused by cholinergic and nonadrenergic noncholinergic neuroeffector system, but in vivo study it is not fully evaluated yet. So this study aimed to identify the changes of corpus cavernosum related to cholinergic neuroeffector system and endothelium derived relaxation factor (EDRF) under hypoxia in animal study and to understand the Physiologic change of priapism. Under the general anesthesia with tracheostomy, adult male cats were conditioned at normoxia and hypoxia with ventilation. Acetylcholine, Nc-monomethyl-L- arginine (L-NMMA) and L-arginine was infused via internal pudendal artery. The change of intracavernosal pressure in response to drugs were monitored with physiograph (Gilson, IC-MP) in both normoxic and hypoxic state. The relaxation effect of acetylcholine under hypoxia was weaker than under normoxia (n=5, p suppressed by L-NMMA under normoxia but not under hypoxia. L-arginine showed the relaxation effect under normoxia but, no relaxation under hypoxia. These result suggest that acetylcholine induced relaxation was influenced in a some by hypoxic condition but not suppressed completely. EDRF pathway via nitric oxide synthesis does not play a role in relaxation of cat corpus cavernosum under hypoxia.
Acetylcholine ; Adult ; Anesthesia, General ; Animals ; Anoxia* ; Arginine ; Arteries ; Cats* ; Endothelium ; Humans ; Male ; Nitric Oxide* ; omega-N-Methylarginine ; Priapism ; Relaxation* ; Tracheostomy ; Ventilation

Externally applied acetylcholine(Ach) in corpus cavernosum has been shown to cause endothelium dependent smooth muscle relaxation. ATP is accepted as a relaxant of smooth muscle by both a direct action and more powerful indirect action via the endothelial cells. Endothelium-derived relaxing factor(EDRF) is released with stimulation of acetylcholine or other endothelium dependent substances raise cGMP level within the smooth muscle cell and cause relaxation of smooth muscle. EDRF is known as nitric oxide(NO) and its actions are abolished by specific inhibitor of nitric oxide synthesis, such as L-n-monomethyl arginine(L-NMMA) or inhibitors of cyclic GMP synthesis, such as methylene blue(MB). In this study, we evaluated the action of ATP related with NO and compared effect of ATP with acetylcholine and bethanechol chloride in rabbit corpus cavernosal smooth muscle under organ bath. Changes in isometric tension of corporal strips were monitored. With pretreatment L-NMMA or MB, relaxing effects of acetylcholine or bethanechol chloride in corporal strips were completely inhibited, but relaxing effects of ATP were not altered. These data suggested that nitric oxide plays a crucial role in cholinergically induced cavernosal smooth muscle relaxation. ATP mediated rabbit corporal smooth muscle relaxation was not affected by inhibitors of nitric oxide synthesis and independent of cyclic GMP accumulation.
Acetylcholine ; Adenosine Triphosphate* ; Adenosine* ; Baths ; Bethanechol ; Cyclic GMP ; Endothelial Cells ; Endothelium ; Muscle, Smooth* ; Myocytes, Smooth Muscle ; Nitric Oxide ; omega-N-Methylarginine ; Relaxation*