• BMB Reports
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• v.49 no.3
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• pp.185-190
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• 2016

Crotamine is a peptide toxin found in the venom of the rattlesnake Crotalus durissus terrificus and has antiproliferative, antimicrobial, and antifungal activities. Herein, we show that crotamine dose-dependently induced macrophage phagocytic and cytostatic activity by the induction of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α). Moreover, the crotamineinduced expression of iNOS and TNF-α is mediated through the phosphorylation of p38 and the NF-κB signaling cascade in macrophages. Notably, pretreatment with SB203580 (a p38-specific inhibitor) or BAY 11-7082 (an NF-κB inhibitor) inhibited crotamine-induced NO production and macrophage phagocytic and cytotoxic activity. Our results show for the first time that crotamine stimulates macrophage phagocytic and cytostatic activity by induction of NO and TNF-α via the p38 and NF-κB signaling pathways and suggest that crotamine may be a useful therapeutic agent for the treatment of inflammatory disease.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.4
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• pp.265-271
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• 2009

Nitric oxide (NO) has both neuroprotective and neurotoxic effects depending on its concentration and the experimental model. We tested the effects of NG-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a selective inducible NOS (iNOS) inhibitor, on kainic acid (KA)-induced seizures and hippocampal CA3 neuronal death. L-NAME (50 mg/kg, i.p.) and/or aminoguanidine (200 mg/kg, i.p.) were administered 1 h prior to the intracerebroventricular (i.c.v.) injection of KA. Pretreatment with L-NAME significantly increased KA-induced CA3 neuronal death, iNOS expression, and activation of microglia. However, pretreatment with aminoguanidine significantly suppressed both the KA-induced and L-NAME-aggravated hippocampal CA3 neuronal death with concomitant decreases in iNOS expression and microglial activation. The protective effect of aminoguanidine was maintained for up to 2 weeks. Furthermore, iNOS knockout mice ($iNOS^{-1-}$) were resistant to KA-induced neuronal death. The present study demonstrates that aminoguanidine attenuates KA-induced neuronal death, whereas L-NAME aggravates neuronal death, in the CA3 region of the hippocampus, suggesting that NOS isoforms play different roles in KA-induced excitotoxicity.

• The Korean Journal of Pain
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• v.25 no.4
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• pp.221-227
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• 2012

Background: It has been reported that curcumin, the main active compound of Curcuma longa, also known as turmeric, exhibits antinociceptive properties. The aim of this study was to examine the participation of ATP-sensitive potassium channels ($K_{ATP}$ channels) and, in particular, that of the L-arginine-nitric oxide-cyclic GMP-$K_{ATP}$ channel pathway, in the antinociceptive effect of curcumin. Methods: Pain was induced by the intraplantar injection of 1% formalin in the right hind paw of Wistar rats. Formalin-induced flinching behavior was interpreted as an expression of nociception. The antinociceptive effect of oral curcumin was explored in the presence and absence of local pretreatment with L-NAME, an inhibitor of nitric oxide synthase, ODQ, an inhibitor of soluble guanylyl cyclase, and glibenclamide, a blocker of $K_{ATP}$ channels. Results: Oral curcumin produced a dose-dependent antinociceptive effect in the 1% formalin test. Curcumin-induced antinociception was not altered by local L-NAME or ODQ, but was significantly impaired by glibenclamide. Conclusions: Our results confirm that curcumin is an effective antinociceptive agent. Curcumin-induced antinociception appears to involve the participation of $K_{ATP}$ channels at the peripheral level, as local injection of glibenclamide prevented its effect. Activation of $K_{ATP}$ channels, however, does not occur by activation of the L-arginine-nitric oxide-cGMP-$K_{ATP}$ channel pathway.

• Advances in Traditional Medicine
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• v.7 no.4
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• pp.341-347
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• 2007

Red seaweed (Callophyllis japonica) has long formed part of the diet of Asians, but the pharmacological properties of this plant have not been evaluated. In this study, we examined the effect of an ethanol extract of C. japonica on the generation of nitric oxide (NO) in RAW 264.7 cells. The C. japonica extract increased the generation of NO and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), which were detected by the Griess method and an enzyme-linked immunosorbent assay, respectively. The increased production of NO by C. japonica extract was inhibited by $N^G$-monomethyl-L-arginine ($100{\mu}M$), a specific inhibitor of NO production in the L-arginine-dependent pathway, and by the nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) inhibitor, pyrrolidine dithiocarbamate ($10-100{\mu}M$) in a dose-dependent manner. These findings demonstrate that C. japonica extract stimulates the production of NO and $TNF-{\alpha}$ in RAW 264.7 cells through the activation of $NF-{\kappa}B$ and that this extract might also inhibit the growth of the human leukemic cells.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.1
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• pp.163-171
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• 2004

The flowers of Lonicera japonica Thunb. (Caprifoliaceae) has been used as anti-inflammatory drug in the folk medicine recipe and been proved its anti-inflammatory effect in the oriental medicine. However, the action mechanism of Lonicera japonica that exhibits anti-inflammatory effects has not been determined. Since nitric oxide (NO) is one of the major inflammatory parameter, we studied the effect of aqueous extracts of Lonicera japonica (AELJ) on NO production in lipopolysaccharide (LPS)-stimulated mouse peritoneal macrophages. NO and inducible NO synthase (iNOS) level were significantly reduced in LPS-stimulated macrophages by AELJ compared to those without Electrophoretic mobility shift assay (EMSA) indicated that AELJ blocked the activation of nuclear factor kappa B (NF-kB), which was considered to be a potential transcription factor for the iNOS expression. AELJ also blocked the phosphorylation and degradation of inhibitor of kappa B-alpha (IkB-${\alpha}$). Furthermore, IkB kinase alpha (IKK${\alpha}$), which is known to phosphorylate serine residues of IkB directly, is inhibited by AELJ in vivo and in vitro. These results suggest that AELJ could exert its anti-inflammatory actions by suppressing the synthesis of NO through inhibition of NF-kB activity.

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.105-111
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• 1999

Nitric oxide (NO), a cellular messenger synthesized from L-arginine by NO synthase (NOS, EC.1.14.13.39), is considered to be a regulator of gastric secretion. In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat gastric chief cells. Treatment of chief cells with carba-chol resulted in an increase in the arginine conversion to citrulline, the amount of $NO_{x}$, the release of pepsine-gen, and the level of cGMP Especially, carbachol-stimulated increase of arginine to citrulline transformation, the amount of $NO_{x}$, cGMP level and the release of pepsinogen were partially reduced by the natural NOS inhibitor, $N^{G}$-monomethyl-L-arginine (MMA) and $N^{G}$, $N^{G}$-dimethyl-L-arginine (DMA). Furthermore, MMA- and DMA-induced decrease of pepsinogen secretion showed dose-dependent patters. Activation of NOS is one of the early events in receptor-mediated cascade of reactions in gastric chief cells and NO, not completely, but partially mediates gastric secretion. Agonist-stimulated pepsinogen secretion in chief cells has been considered to be mediated in adenosine 3',5'-cyclic monophosphate pathway and/or guanosine 3', 5'-cyclic monophosphate (cGMP) pathway. Taken together, the above results suggest that partial decrease of exocrine secretion following treatment of NOS inhibitor may result from the inactivation of NOS and subsequent guano- late cyclase, and NO/cGMP pathway may play a pivotal role in exocrine secretion.

• Molecules and Cells
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• v.21 no.3
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• pp.337-342
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• 2006

Interstitial cells of Cajal (ICCs) are pacemaker cells that activate the periodic spontaneous depolarization (pacemaker potentials) responsible for the production of slow waves in gastrointestinal smooth muscle. The effects of vasoactive intestinal polypeptide (VIP) on the pacemaker potentials in cultured ICCs from murine small intestine were investigated by whole-cell patch-clamp techniques. Addition of VIP (50 nM-$1{\mu}M$) decreased the amplitude of pacemaker potentials and depolarized resting membrane potentials. To examine the type of receptors involved in ICC, we examined the effects of the $VIP_1$ agonist and found that it had no effect on pacemaker potentials. Pretreatment with $VIP_1$ antagonist ($1{\mu}M$) for 10 min also did not block the VIP (50 nM)-induced effects. On the other hand exposure to 1H-(1,2,4)oxadiazolo(4,3-A)quinoxalin-1-one (ODQ, $100{\mu}M$), an inhibitor of guanylate cyclase, prevented VIP inhibition of pacemaker potentials. Similarly KT-5823 ($1{\mu}M$) or RP-8-CPT-cGMPS ($10{\mu}M$), inhibitors of protein kinase G (PKG) blocked the effect of VIP (50 nM) on pacemaker potentials as did N-nitro-L-arginine (L-NA, $100{\mu}M$), a non-selective nitric oxide synthase (NOS) inhibitor. These results imply that the inhibition of pacemaker activity by VIP depends on the NO-cGMP-PKG pathway.

• Nutrition Research and Practice
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• v.11 no.2
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• pp.90-96
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• 2017

BACKGROUND/OBJECTIVES: Although the antioxidative effects of lycopene are generally known, the molecular mechanisms underlying the anti-inflammatory properties of lycopene are not fully elucidated. This study aimed to examine the role and mechanism of lycopene as an inhibitor of inflammation. METHODS/MATERIALS: Lipopolysaccharide (LPS)-stimulated SW 480 human colorectal cancer cells were treated with 0, 10, 20, and $30{\mu}M$ lycopene. The MTT assay was performed to determine the effects of lycopene on cell proliferation. Western blotting was performed to observe the expression of inflammation-related proteins, including nuclear factor-kappa B ($NF-{\kappa}B$), inhibitor kappa B ($I{\kappa}B$), mitogen-activated protein kinase (MAPK), extracellular signal-related kinase (ERK), c-jun NH2-terminal kinase (JNK), and p38 (p38 MAP kinase). Real-time polymerase chain reaction was performed to investigate the mRNA expression of tumor necrosis factor ${\alpha}$ ($TNF-{\alpha}$), interleukin-1 beta ($IL-1{\beta}$), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Concentrations of nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) were determined via enzyme-linked immunosorbent assays. RESULTS: In cells treated with lycopene and LPS, the mRNA expression of $TNF-{\alpha}$, $IL-1{\beta}$, IL-6, iNOS, and COX-2 were decreased significantly in a dose-dependent manner (P < 0.05). The concentrations of $PGE_2$ and NO decreased according to the lycopene concentration (P < 0.05). The protein expressions of $NF-{\kappa}B$ and JNK were decreased significantly according to lycopene concertation (P < 0.05). CONCLUSIONS: Lycopene restrains $NF-{\kappa}B$ and JNK activation, which causes inflammation, and suppresses the expression of $TNF-{\alpha}$, $IL-1{\beta}$, IL-6, COX-2, and iNOS in SW480 human colorectal cancer cells.

• The Korean Journal of Zoology
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• v.36 no.3
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• pp.433-438
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• 1993

In the previous paper (Choi et al., 1992), we found that a large but transient elevation in intracellular cGMP levels occur concomitant with the myoblast fusion. To establish the physiological significance of the elevation of cGMP levels, the change in guanylate cyclase activity dudng myoblast fusion and the correlation hetween various chemicals that may affect guanylate cyclase adivity and myoblast fusion were examined. Sodium nitroprusside, a nitric oxide-forming compound, induced a precocious fusion and increased guanylate cyclase activity compared to the control. Furthermore, L-NG-monomethyl arginine, specific inhibitor of L-arginine: nitric oxide synthase, inhibited the cell fusion in a dose-dependent manner, without affecting biochemical differentiation. On the basis of our present findings, we propose that the onset of myoblast fusion is somehow correlated with the rise in cellular cGMP levels that is regulated by the activation or inhibItIon of soluble guanylate cyclase, via as yet undefined mechanism but possibly through L-arginine: nitric oxide pathway.

• Biomedical Science Letters
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• v.29 no.2
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• pp.66-74
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• 2023

Triglyceride (TG) accumulation can cause monocytic death and suppress innate immunity. However, the signaling pathways involved in this phenomenon are not fully understood. This study aimed to examine whether inducible nitric oxide synthase (iNOS) is involved in the TG-induced death of THP-1 monocytes. Results showed that iNOS was upregulated in TG-treated THP-1 monocytes, and iNOS inhibition blocked TG-induced monocytic death. In addition, TG-induced poly (ADP-ribose) polymerase (PARP) cleavage and caspase-3 and -7 activation were suppressed by iNOS inhibition. Furthermore, the expression of X-linked inhibitor of apoptosis protein (XIAP) and survivin, which inhibit caspase-3 and -7, was reduced in TG-treated THP-1 monocytes, but iNOS inhibition recovered the TG-induced downregulation of XIAP and survivin expression. Considering that TG-induced monocytic death is triggered by caspase2 and -8, we investigated whether caspase-2 and -8 are linked to the TG-induced expression of iNOS in THP-1 monocytes. When the activities of caspase-2 and -8 were inhibited by specific inhibitors, the TG-induced upregulation of iNOS and downregulation of XIAP and survivin were restored in THP-1 monocytes. These results suggest that TG-induced monocytic death is mediated by the caspase-2/caspase-8/iNOS/XIAP and survivin/executioner caspase/PARP pathways.