• The Korean Journal of Physiology and Pharmacology
• /
• v.13 no.5
• /
• pp.379-383
• /
• 2009

Nitric oxide (NO), a diffusible gas, is produced in the central nervous system, including the spinal cord dorsal horn and the trigeminal nucleus, the first central areas processing nociceptive information from periphery. In the spinal cord, it has been demonstrated that NO acts as pronociceptive or antinociceptive mediators, apparently in a concentration-dependent manner. However, the central role of NO in the trigeminal nucleus remains uncertain in support of processing the orofacial nociception. Thus, we here investigated the central role of NO in formalin (3%)-induced orofacial pain in rats by administering membrane-permeable or -impermeable inhibitors, relating to the NO signaling pathways, into intracisternal space. The intracisternal pretreatments with the NO synthase inhibitor L-NAME, the NO-sensitive guanylate cyclase inhibitor ODQ, and the protein kinase C inhibitor GF109203X, all of which are permeable to the cell membrane, significantly reduced the formalin-induced pain, whereas the membrane-impermeable NO scavenger PTIO significantly enhanced it, compared to vehicle controls. These data suggest that an overall effect of NO production in the trigeminal nucleus is pronociceptive, but NO extracellularly diffused out of its producing neurons would have an antinociceptive action.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.11
• /
• pp.1836-1844
• /
• 2016

Adipogenesis is one of the cellular processes and a highly controlled program. Nowadays, inhibition of adipogenesis has received attention as an effective way to regulate obesity. In the current study, we investigated the inhibition effect of a chloroform extract of Pleurotus eryngii var. ferulae 'Beesan No. 2' (CEBT) on adipogenesis in 3T3-L1 murine preadipocytes. Pleurotus eryngii var. ferulae is one of many varieties of King oyster mushroom and has been reported to have various biological activities, including antitumor and anti-inflammation effects. Biological activities of 'Beesan No. 2', a new cultivar of Pleurotus eryngii var. ferulae, have not yet been reported. In this study, we found that CEBT suppressed adipogenesis in 3T3-L1 cells through inhibition of key adipogenic transcription factors, such as peroxisome proliferatoractivated receptor ${\gamma}$ and CCAAT/enhancer binding protein ${\alpha}$. Additionally, CEBT reduced the expression of the IRS/PI3K/Akt signaling pathway and its downstream factors, including mammalian target of rapamycin and p70S6 kinase, which stimulate adipogenesis. Furthermore, ${\beta}-catenin$, a suppressor of adipogenesis, was increased in CEBT-treated cells. These results indicate that Pleurotus eryngii var. ferulae 'Beesan No. 2' effectively inhibited adipogenesis, so this mushroom has potential as an anti-obesity food and drug.

• Journal of Ginseng Research
• /
• v.44 no.5
• /
• pp.717-724
• /
• 2020

Background: Malignant arrhythmias require drug therapy. However, most of the currently available antiarrhythmic drugs have significant side effects. Ginsenoside Rg2 exhibits excellent cardioprotective effects and appears to be a promising candidate for cardiovascular drug development. So far, the oral toxicity and antiarrhythmic effects of Rg2 have not been evaluated. Methods: Acute oral toxicity of Rg2 was assessed by the Limit Test method in mice. Subchronic oral toxicity was determined by repeated dose 28-day toxicity study in rats. Antiarrhythmic activities of Rg2 were evaluated in calcium chloride-induced arrhythmic rats. Antiarrhythmic mechanism of Rg2 was investigated in arrhythmic rats and H9c2 cardiomyocytes. Results: The results of toxicity studies indicated that Rg2 exhibited no single-dose (10 g/kg) acute oral toxicity. And 28-day repeated dose treatment with Rg2 (1.75, 3.5 and 5 g/kg/d) demonstrated minimal, if any, subchronic toxicity. Serum biochemical examination showed that total cholesterol in the high-dose cohort was dramatically decreased, whereas prothrombin time was increased at Day 28, suggesting that Rg2 might regulate lipid metabolism and have a potential anticoagulant effect. Moreover, pretreatment with Rg2 showed antiarrhythmic effects on the rat model of calcium chloride induced arrhythmia, in terms of the reduced duration time, mortality, and incidence of malignant arrhythmias. The antiarrhythmic mechanism of Rg2 might be the inhibition of calcium influx through L-type calcium channels by suppressing the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II. Conclusion: Our findings support the development of Rg2 as a promising antiarrhythmic drug with fewer side effects for clinical use.

• Molecules and Cells
• /
• v.39 no.4
• /
• pp.322-329
• /
• 2016

Voltage-gated $Ca^{2+}$ ($Ca_V$) channels are dynamically modulated by Gprotein-coupled receptors (GPCR). The $M_1$ muscarinic receptor stimulation is known to enhance $Ca_V2.3$ channel gating through the activation of protein kinase C (PKC). Here, we found that $M_1$ receptors also inhibit $Ca_V2.3$ currents when the channels are fully activated by PKC. In whole-cell configuration, the application of phorbol 12-myristate 13-acetate (PMA), a PKC activator, potentiated $Ca_V2.3$ currents by ~two-fold. After the PMA-induced potentiation, stimulation of $M_1$ receptors decreased the $Ca_V2.3$ currents by $52{\pm}8%$. We examined whether the depletion of phosphatidylinositol 4,5-bisphosphate ($PI(4,5)P_2$) is responsible for the muscarinic suppression of $Ca_V2.3$ currents by using two methods: the Danio rerio voltage-sensing phosphatase (Dr-VSP) system and the rapamycin-induced translocatable pseudojanin (PJ) system. First, dephosphorylation of $PI(4,5)P_2$ to phosphatidylinositol 4-phosphate (PI(4)P) by Dr-VSP significantly suppressed $Ca_V2.3$ currents, by $53{\pm}3%$. Next, dephosphorylation of both PI(4)P and $PI(4,5)P_2$ to PI by PJ translocation further decreased the current by up to $66{\pm}3%$. The results suggest that $Ca_V2.3$ currents are modulated by the $M_1$ receptor in a dual mode-that is, potentiation through the activation of PKC and suppression by the depletion of membrane $PI(4,5)P_2$. Our results also suggest that there is rapid turnover between PI(4)P and $PI(4,5)P_2$ in the plasma membrane.

• Molecules and Cells
• /
• v.41 no.5
• /
• pp.401-412
• /
• 2018

Oxymatrine (OMT) often used in treatment for chronic hepatitis B virus infection in clinic. However, OMT-induced liver injury has been reported. In this study, we aim to investigate the possible mechanism of OMT-induced hepatotoxicity in human normal liver cells (L02). Exposed cells to OMT, the cell viability was decreased and apoptosis rate increased, the intracellular markers of oxidative stress were changed. Simultaneously, OMT altered apoptotic related proteins levels, including Bcl-2, Bax and pro-caspase-8/-9/-3. In addition, OMT enhanced the protein levels of endoplasmic reticulum (ER) stress makers (GRP78/Bip, CHOP, and cleaved-Caspase-4) and phosphorylation of c-Jun N-terminal kinase (p-JNK), as well as the mRNA levels of GRP78/Bip, CHOP, caspase-4, and ER stress sensors (IREI, ATF6, and PERK). Pre-treatment with Z-VAD-fmk, JNK inhibitor SP600125 and N-acetyl-l-cysteine (NAC), a ROS scavenger, partly improved the survival rates and restored OMT-induced cellular damage, and reduced caspase-3 cleavage. SP600125 or NAC reduced OMT-induced p-JNK and NAC significantly lowered caspase-4. Furthermore, 4-PBA, the ER stress inhibitor, weakened inhibitory effect of OMT on cells, on the contrary, TM worsen. 4-PBA also reduced the levels of p-JNK and cleaved-caspase-3 proteins. Therefore, OMT-induced injury in L02 cells was related to ROS mediated p-JNK and ER stress induction. Antioxidant, by inhibition of p-JNK or ER stress, may be a feasible method to alleviate OMT-induced liver injury.

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.5
• /
• pp.255-261
• /
• 2006

Melittin-induced nociceptive responses are mediated by selective activation of capsaicin-sensitive primary afferent fibers and are modulated by excitatory amino acid receptor, cyclooxygenase, protein kinase C and serotonin receptor. The present study was undertaken to investigate the peripheral and spinal actions of voltage-gated calcium channel antagonists on melittin-induced nociceptive responses. Changes in mechanical threshold and number of flinchings were measured after intraplantar (i.pl.) injection of melittin $(30\;{\mu}g/paw)$ into mid-plantar area of hindpaw. L-type calcium channel antagonists, verapamil [intrathecal (i.t.), 6 or $12\;{\mu}g$; i.pl.,100 & $200\;{\mu}g$; i.p., 10 or 30 mg], N-type calcium channel blocker, ${\omega}-conotoxin$ GVIA (i.t., 0.1 or $0.5\;{\mu}g$; i.pl., $5\;{\mu}g$) and P-type calcium channel antagonist, ${\omega}-agatoxin$ IVA (i.t., $0.5\;{\mu}g$; i.pl., $5\;{\mu}g$) were administered 20 min before or 60 min after i.pl. injection of melittin. Intraplantar pre-treatment and i.t. pre- or post-treatment of verapamil and ${\omega}-conotoxin$ GVIA dose-dependently attenuated the reduction of mechanical threshold, and melittin-induced flinchings were inhibited by i.pl. or i.t. pre-treatment of both antagonists. P-type calcium channel blocker, ${\omega}-agatoxin$ IVA, had significant inhibitory action on flinching behaviors, but had a limited effect on melittin-induced decrease in mechanical threshold. These experimental findings suggest that verapamil and ${\omega}-conotoxin$ GVIA can inhibit the development and maintenance of melittin-induced nociceptive responses.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.6
• /
• pp.431-436
• /
• 2012

Dioscorea species continue to be used in traditional Chinese medicine, and represent a major source of steroid precursors for conventional medicine. In the previous study, We isolated glycoprotein (GDB) from Dioscorea batatas, characterized, and demonstrated immunostimulating activity in C57BL/6 mice. The aim of this study was to investigate the mechanism whereby GDB activates macrophages. Macrophages activation by GDB was investigated by analyzing the effects of GDB on nitric oxide (NO) production, iNOS expression, mitogen activated protein kinase (MAPK) phosphorylation, and transcription factor activation. In the presence of IFN-${\gamma}$, GDB strongly stimulated macrophages to express iNOS and produce NO. Furthermore, the activation of p38 was synergistically induced by GDB plus IFN-${\gamma}$, but SB203580 (a p38 inhibitor) inhibited GDB plus IFN-${\gamma}$-induced p38 activation. This study indicates that GDB is an important activator of macrophages. Furthermore, due to the critical role that macrophage activation plays in innate immune response, the activation effects of GDB on macrophages suggest that GDB may be a useful immunopotentiating agent.

• Journal of Applied Biological Chemistry
• /
• v.57 no.2
• /
• pp.113-122
• /
• 2014

A5E is complex of several medicinal herb ethanol extracts. The aim of this study is investigating the anticancer effect for non-small cell lung cancer. The antitumor effects of A5E on NCI-H460 were examined by regulation of cell proliferation, apoptosis, cell cycle arrest, mitochondrial membrane potential (${\Delta}{\Psi}_m$), and apoptosis-related protein. Cell proliferation was measured by MTS assay. Apoptosis induced by A5E was confirmed by Annexin V-fluorescein isothiocyanate (FITC)/Propidium Iodide (PI) staining, and cell cycle arrest was measured by PI staining. NF-${\kappa}B$ translocation was detected by immunofluorescence and MMP (${\Delta}{\Psi}_m$) was measured by JC-1 staining. The expression of extrinsic pathway molecules such as FasL and FADD were elevated, and procaspase-8 was processed by A5E. In addition, intrinsic pathway related molecules were altered. The Bcl-2 and Bcl-xl levels decreased, Bax increased, and cytochrome C was released. In addition, the mitochondrial membrane potential collapsed, and caspase-3 and poly-(ADP-ribose) polymerase were processed by A5E. Moreover, A5E affected the cellular survival pathway involving phosphatidylinositol 3-kinase (PI3K)/Akt and NF-${\kappa}B$. PI3K and Akt were downregulated, also NF-${\kappa}B$ expression was decreased, and nuclear translocalization was inhibited by A5E. These results suggested that A5E delays proliferation, inhibit cell cycle progression and induce apoptosis in human lung cancer cell. We conclude that A5E is a potential anticancer agent for human lung carcinoma.

• Korean Journal of Veterinary Research
• /
• v.44 no.4
• /
• pp.497-505
• /
• 2004

The proliferation of mesangial cells has been associated with the development of diabetic nephropathy. The cell proliferation has been regulated by diverse growth factors. Among them, insulin like growth factors(IGFs) are also involved in the pathogenesis of diabetic nephropathy. However, it is not yet known about the effect of high glucose on IGF-I and IGF-II secretion and the relationship between high glucose-induced secretion of IGFs and PKC or oxidative stress in the mesangial cells. Thus, we examined the mechanisms by which high glucose regulates secretion of IGFs in mesangial cells. High glucose(25 mM) increased IGF-I and IGF-II secretion. High glucose-induced increase of IGF-I and IGF-II secretion were blocked by taurine($2{\times}10^{-3}$ M), N-acetyl cystein(NAC, $10^{-5}M$), or GSH($10^{-5}M$) (antioxidants), suggesting the role of oxidative stress. High glucose-induced secretion of IGF-I and IGF-II were blocked by H-7, staurosporine, and bisindolylmaleimide I(protein kinase C inhibitors). On the other hand, high glucose also increased lipid peroxide (LPO) formation in a dose dependent manner. In addition, high glucoseinduced stimulation of LPO formation was blocked by PKC inhibitors. These results suggest that PKC is responsible for the increase of oxidative stress in the action of high glucose-induced secretion of IGF-I and IGF-II in mesangial cells. In conclusion, high glucose stimulates IGF-I and IGF-II secretion via PKCoxidative stress signal pathways in mesangial cells.

• Mass Spectrometry Letters
• /
• v.9 no.1
• /
• pp.24-29
• /
• 2018

DC23, a triazolothione resorcinol analogue, is known to inhibit heat shock protein 90 and pyruvate dehydrogenase kinase which are up-regulated in cancer and diabetes, respectively. This study was performed to elucidate the metabolism of DC23 in human liver microsomes (HLMs). HLMs incubated with DC23 in the presence of uridine 5'-diphosphoglucuronic acid (UDPGA) and/or ${\beta}$-nicotinamide adenine dinucleotide phosphate (NADPH) resulted in the formation of four metabolites, M1-M4. M1 was identified as DC23-N-Oxide, on the basis of LC-MS/MS analysis. DC23 was further metabolized to its glucuronide conjugates (M2, M3, and M4). In vitro metabolic stability studies conducted with DC23 in HLMs revealed significant glucuronide conjugation with a $t_{1/2}$ value of 1.3 min. The inhibitory potency of DC23 on five human cytochrome P450s was also investigated in HLMs. In these experiments, DC23 inhibited CYP2C9-mediated tolbutamide hydroxylase activity with an $IC_{50}$ value of $8.7{\mu}M$, which could have implications for drug interactions.