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Fumonisin B1 (FB1) structurally resembles sphingolipids and interferes with their metabolism leading to sphingolipid dysregulation. We questioned if FB1 could exacerbate liver or kidney toxicities in glutathione peroxidase 1 (Gpx1) and catalase (Cat) knockout mice. While higher serum levels of thiobarbituric acid reactive substances (TBARS) and sphinganine (Sa) were measured in Gpx1/Cat knockout mice (Gpx1/Cat KO) than wild type mice after 5 days of FB1 treatment, serum levels of alanine aminotransferase (ALT), sphingosine-1 phosphate (So-1-P), and sphinganine-1 phosphate (Sa-1-P) were found to be relatively low. Although Sa was highly elevated in Gpx1/Cat KO mice and wild mice, lower levels of So and Sa were found in both the kidney and liver tissues of Gpx/Cat KO mice than wild type mice after FB1 treatment. Paradoxically, FB1-induced cellular apoptosis and necrosis were hastened under oxidative stress in Gpx1/Cat KO mice.

Fangchinoline (FAN) is a bisbenzylisoquinoline alkaloid that is widely known for its anti-tumor properties. The goal of this study is to examine the effects of FAN on arthritis and the possible pathways it acts on. Human fibroblast-like synovial cells (FLS), carrageenan/ kaolin arthritis rat model (C/K), and collagen-induced arthritis (CIA) mice model were used to establish the efficiency of FAN in arthritis. Human FLS cells were treated with FAN (1, 2.5, 5, 10 μM) 1 h before IL-1β (10 ng/mL) stimulation. Cell viability, reactive oxygen species measurement, and western blot analysis of inflammatory mediators and the MAPK and NF-κB pathways were performed. In the animal models, after induction of arthritis, the rodents were given 10 and 30 mg/kg of FAN orally 1 h before conducting behavioral experiments such as weight distribution ratio, knee thickness measurement, squeaking score, body weight measurement, paw volume measurement, and arthritis index measurement. Rodent knee joints were also analyzed histologically through H&E staining and safranin staining. FAN decreased the production of inflammatory cytokines and ROS in human FLS cells as well as the phosphorylation of the MAPK pathway and NF-κB pathway in human FLS cells. The behavioral parameters in the C/K rat model and CIA mouse model and inflammatory signs in the histological analysis were found to be ameliorated in FAN-treated groups. Cartilage degradation in CIA mice knee joints were shown to have been suppressed by FAN. These findings suggest that fangchinoline has the potential to be a therapeutic source for the treatment of rheumatoid arthritis.

The effect of 3, 4, 5-trimethoxy cinnamic acid (TMCA) against morphine-induced dependence in mice and rats was investigated. Mice were pretreated with TMCA and then morphine was injected intraperitoneally; whereas rats were treated with TMCA (i.p.) and infused with morphine into the lateral ventricle of brain. Naloxone-induced morphine withdrawal syndrome and conditioned place preference test were performed. Moreover, western blotting and immunohistochemistry were used to measure protein expressions. Number of naloxone-precipitated jumps and conditioned place preference score in mice were attenuated by TMCA. Likewise, TMCA attenuated morphine dependent behavioral patterns such as diarrhea, grooming, penis licking, rearing, teeth chattering, and vocalization in rats. Moreover, the expression levels of pNR1and pERK in the frontal cortex of mice and cultured cortical neurons were diminished by TMCA. In the striatum, pERK expression was attenuated despite unaltered expression of pNR1 and NR1. Interestingly, morphine-induced elevations of FosB/ΔFosB+ cells were suppressed by TMCA (50, 100 mg/kg) in the nucleus accumbens sub-shell region of mice. In conclusion, TMCA could be considered as potential therapeutic agent against morphine-induced dependence.

Cocaine- and amphetamine-regulated transcript (CART) peptide is a widely distributed neurotransmitter expressed in the central nervous systems. Previously, several reports demonstrated that nucleus accumbal-injected CART peptide positively modulated behavioral sensitization induced by psychostimulants and regulated the mesocorticolimbic dopaminergic pathway. It is confirmed that CART peptide exerted inhibitory effect on psychostimulant-enhanced dopamine receptors signaling, Ca2+/calmodulin-dependent kinase signaling and crucial transcription factors expression. Besides modulation of dopamine receptors-related pathways, CART peptide also exhibited elaborated interactions with other neurotransmitter receptors, such as glutamate receptors and γ-aminobutyric acid receptors, which further account for attribution of CART peptide to inhibition of psychostimulant-potentiated locomotor activity. Recently, CART peptide has been shown to have anxiolytic functions on the aversive mood and uncontrolled drug-seeking behaviors following drug withdrawal. Moreover, microinjection of CART peptide has been shown to have an anti-depressant effect, which suggests its potential utility in the mood regulation and avoidance of depression-like behaviors. In this review, we discuss CART pathways in neural circuits and their interactions with neurotransmitters associated with psychostimulant-induced depression.

Although drugs such as barbiturates and benzodiazepines are often used for the treatment of insomnia, they are associated with various side effects such as habituations, tolerance and addiction. Alternatively, natural products with minimal unwanted effects have been preferred for the treatment of acute and/or mild insomnia, with additional benefits of overall health-promotion. Basic and clinical researches on the mechanisms of action of natural products have been carried out so far in insomnia treatments. Recent studies have been focusing on diverse chemical components available in natural products, with an interest of developing drugs that can improve sleep duration and quality. In the last 15 years, our co-workers have been actively looking for candidate substances from natural products that can relieve insomnia. This review is, therefore, intended to bring pharmacological data regarding to the effects of natural products on sleep duration and quality, mainly through the activation of GABAA receptors. It is imperative that phytochemicals will provide useful information during electroencephalography (EEG) analysis and serve as an alternative medications for insomnia patients who are reluctant to use conventional drugs.

Sleep is the most basic and essential physiological requirement for mental health, and sleep disorders pose potential risks of metabolic and neurodegenerative diseases. Tryptic hydrolysate of αS1-casein (αS1-CH) has been shown to possess stress relieving and sleep promoting effects. However, the differential effects of αS1-CH on electroencephalographic wave patterns and its effects on the protein levels of γ-aminobutyric acid A (GABAA) receptor subtypes in hypothalamic neurons are not well understood. We found αS1-CH (120, 240 mg/kg) increased sleep duration in mice and reduced sleep-wake cycle numbers in rats. While αS1-CH (300 mg/kg) increased total sleeping time in rats, it significantly decreased wakefulness. In addition, electroencephalographic theta (θ) power densities were increased whereas alpha (α) power densities were decreased by αS1-CH (300 mg/kg) during sleep-wake cycles. Furthermore, protein expressions of GABAA receptor β1 subtypes were elevated in rat hypothalamus by αS1-CH. These results suggest αS1-CH, through GABAA receptor modulation, might be useful for treating sleep disorders.

Altered redox state modulates the expression levels of endothelial KCa2.3 and KCa3.1 (KCas) in normal pregnancy (NP) and preeclampsia (PE), thereby regulating vascular contractility. The mechanisms underlying KCas endocytosis and transportation remain unknown. We investigated the regulation of KCas expression in plasma membrane (PM) during NP and PE. Cultured human uterine artery endothelial cells were incubated in serum from normal nonpregnant women and women with NP or PE, or in oxidized LDL-, or lysophosphatidylcholine- (LPC-) containing a medium for 24 hours. NP serum elevated PM levels of KCas and reduced caveolin-1 and clathrin levels. PE serum, oxidized LDL, or LPC reduced PM levels of KCas and elevated caveolin-1, clathrin, Rab5c, and early endosome antigen-1 (EEA1) levels. Reduced KCas levels by PE serum or LPC were reversed by inhibition of caveolin-1, clathrin, or EEA1. Catalase and glutathione peroxidase 1 (GPX1) knockdown elevated PM-localized KCas levels and reduced caveolin-1 and clathrin levels. Elevated KCa2.3 levels upon catalase and GPX1 knockdown were reversed by PEG-catalase treatment. An H2O2 donor reduced clathrin and Rab5c. In contrast, elevated clathrin, caveolin-1, or colocalization of caveolin-1 with KCa3.1 by PE serum or LPC was reversed by NADPH oxidase inhibitors or antioxidants. A superoxide donor xanthine+xanthine oxidase elevated caveolin-1 or Rab5c levels. We concluded that KCas are endocytosed in a caveola- or a clathrin-dependent manner and transported in a Rab5c- and EEA1-dependent manner during pregnancy. The endocytosis and transportation processes may slow down via H2O2-mediated pathways in NP and may be accelerated via superoxide-mediated pathways in PE.

This study provides the scientific basis for the anti-inflammatory effects of licorice extract in a t-BHP (tert-butyl hydrogen peroxide)-induced liver damage model and the effects of its ingredients, glycyrrhizic acid (GA), liquiritin (LQ) and liquiritigenin (LG), in a lipopolysaccharide (LPS)-stimulated microglial cell model. The GA, LQ and LG inhibited the LPS-stimulated elevation of pro-inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and interleukin (IL)-6 in BV2 (mouse brain microglia) cells. Furthermore, licorice extract inhibited the expression levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in the livers of t-BHP-treated mice models. This result suggested that mechanistic-based evidence substantiating the traditional claims of licorice extract and its three bioactive components can be applied for the treatment of inflammation-related disorders, such as oxidative liver damage and inflammation diseases.

Chronic stress is a precipitating factor for disorders including depression. The basolateral amygdala (BLA) is a critical substrate that interconnects with stress-modulated neural networks to generate emotion- and mood-related behaviors. The current study shows that 3 h per day of restraint stress for 14 days caused mice to exhibit long-term depressive behaviors, manifested by disrupted sociality and despair levels, which were rescued by fluoxetine. These behavioral changes corresponded with morphological and molecular changes in BLA neurons, including chronic stress-elicited increases in arborization, dendritic length, and spine density of BLA principal neurons. At the molecular level, calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (CP-AMPARs) within the synaptosome exhibited an increased GluR1:GluR2 subunit ratio. We also observed increased GluR1 phosphorylation at Ser 845 and enhanced cyclic AMP-dependent protein kinase (PKA) activity in the BLA. These molecular changes reverted to the basal state post-treatment with fluoxetine. The expression of synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95) at BLA neuronal synapses was also enhanced by chronic stress, which was reversed post-treatment. Finally, chronic stress-provoked depressive behavior was overcome by local blockage of CP-AMPARs in the BLA via stereotaxic injection (IEM-1460). Chronic stress-elicited depressive behavior may be due to hypertrophy of BLA neuronal dendrites and increased of PKA-dependent CP-AMPAR levels in BLA neurons. Furthermore, fluoxetine can reverse chronic stress-triggered cytoarchitectural and functional changes of BLA neurons. These findings provide insights into depression-linked structural and functional changes in BLA neurons.

A simple synthesis and biologic evaluation of trans-3,4,5-trimethoxycinnamamides 10a–e and 11 as novel antinarcotic agents is described. The synthetic key strategies involve condensation reaction and coupling reaction to generate trans-3,4,5-trimethoxycinnamamides 10a–e and 11. They were evaluated for free radical scavenging, inhibitory action for neurotoxicity in cultured neurons, and antinarcotic activity in mice. It was found that compounds 10a, 10d, and 10e displayed significant inhibitory action of the glutamate-induced neurotoxicity and 10a–e and 11 showed high antinarcotic activity in mice.

A series of 3,4,5-trimethoxycinnamic acid derivatives was prepared and evaluated for antinarcotic effects on morphine dependence in mice and binding affinities on serotonergic receptors. The key synthetic strategies involve generation of ketones 6-7, esters 9-12 through condensation reaction, and amides 13-19 via coupling reaction using 1-hydroxybenzotriazole/ethyl(dimethylaminopropryl)carbodiimide system in high yield. We found that the naloxone-induced morphine withdrawal syndrome was significantly suppressed by new synthetic 3,4,5-trimethoxycinnamic acid derivatives (20 mg/kg/day). Most of 3,4,5-trimethoxycinnamic acid derivatives were found to have high affinity to 5-HT(1A) receptor. The naloxone-induced morphine withdrawal syndrome was attenuated by (+)8-OH-DPAT (0.1 mg/kg/day, i.p.), a 5-HT(1A) receptor agonist. In cortical neuronal cells, (+)8-OH-DPAT (1 μM) produced an elevation of the pERK 1/2 expression, and the elevated pERK levels were inhibited by WAY 100635, a 5-HT(1A) receptor-specific antagonist. Interestingly, the pERK levels were increased by the 3,4,5-trimethoxycinnamic acid derivatives and the derivatives-mediated changes in pERK levels were blocked by the WAY 100635. These results suggested that new synthetic 3,4,5-trimethoxycinnamic acid derivatives have a potential antinarcotic effect through acting as a 5-HT(1A) receptor agonist in mice.

Background Our previous study suggested that licorice has anti-inflammatory activity in lipopolysaccharide-stimulated microglial cells and anti-oxidative activity in tert-butyl hydroperoxide–induced oxidative liver damage. In this study, we evaluated the effect of licorice on chronic alcohol-induced fatty liver injury mediated by inflammation and oxidative stress. Methods Raw licorice was extracted, and quantitative and qualitative analysis of its components was performed by using LC–MS/MS. Mice were fed a liquid alcohol diet with or without licorice for 4 weeks. Results We have standardized 70 % fermented ethanol extracted licorice and confirmed by LC-MS/MS as glycyrrhizic acid (GA), 15.77 ± 0.34 μg/mg; liquiritin (LQ), 14.55 ± 0.42 μg/mg; and liquiritigenin (LG), 1.34 ± 0.02 μg/mg, respectively. Alcohol consumption increased serum alanine aminotransferase and aspartate aminotransferase activities and the levels of triglycerides and tumor necrosis factor (TNF)-α. Lipid accumulation in the liver was also markedly induced, whereas the glutathione level was reduced. All these alcohol-induced changes were effectively inhibited by licorice treatment. In particular, the hepatic glutathione level was restored and alcohol-induced TNF-α production was significantly inhibited by licorice. Conclusion Taken together, our data suggests that protective effect of licorice against alcohol-induced liver injury may be attributed to its anti-inflammatory activity and enhancement of antioxidant defense. Electronic supplementary material The online version of this article (doi:10.1186/s12906-016-0997-0) contains supplementary material, which is available to authorized users.

Endothelial oxidative stress develops with aging and reactive oxygen species impair endothelium-dependent relaxation (EDR) by decreasing nitric oxide (NO) availability. Endothelial KCa 3.1, which contributes to EDR, is upregulated by H2 O2 . We investigated whether KCa 3.1 upregulation compensates for diminished EDR to NO during aging-related oxidative stress. Previous studies identified that the levels of ceramide synthase 5 (CerS5), sphingosine, and sphingosine 1-phosphate were increased in aged wild-type and CerS2 mice. In primary mouse aortic endothelial cells (MAECs) from aged wild-type and CerS2 null mice, superoxide dismutase (SOD) was upregulated, and catalase and glutathione peroxidase 1 (GPX1) were downregulated, when compared to MAECs from young and age-matched wild-type mice. Increased H2 O2 levels induced Fyn and extracellular signal-regulated kinases (ERKs) phosphorylation and KCa 3.1 upregulation. Catalase/GPX1 double knockout (catalase(-/-) /GPX1(-/-) ) upregulated KCa 3.1 in MAECs. NO production was decreased in aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) MAECs. However, KCa 3.1 activation-induced, N(G) -nitro-l-arginine-, and indomethacin-resistant EDR was increased without a change in acetylcholine-induced EDR in aortic rings from aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) mice. CerS5 transfection or exogenous application of sphingosine or sphingosine 1-phosphate induced similar changes in levels of the antioxidant enzymes and upregulated KCa 3.1. Our findings suggest that, during aging-related oxidative stress, SOD upregulation and downregulation of catalase and GPX1, which occur upon altering the sphingolipid composition or acyl chain length, generate H2 O2 and thereby upregulate KCa 3.1 expression and function via a H2 O2 /Fyn-mediated pathway. Altogether, enhanced KCa 3.1 activity may compensate for decreased NO signaling during vascular aging.

Actoprotectors are preparations that enhance body stability against physical loads without increasing oxygen consumption or heat production. Or, in short, actoprotectors are synthetic adaptogens with a significant capacity to improve physical performance. This paper explores the history of actoprotectors'development, their pharmacological properties, mechanism of action, and practical application to the improvement of mental and physical performance. A brief summary of the clinico-pharmacological characteristics of the main representatives of this class (bemitil and bromantane) is provided. Some other synthesized compounds, and even natural ones such as ginseng, also are regarded as potential actoprotectors, and these are treated herein as well. Actoprotectors, owing to their wide-ranging pharmacological activities, high efficiency and safety, can be applied under either normal or extreme conditions.

Repeated stress induces corticosterone release. However, it is not clear that stress results in further elevation of corticosterone levels, and the roles of released corticosterone to aggravate stress-related symptoms are also not clear. This study investigated whether neuronal modulation was induced in the amygdala after two kinds of stress, that is, such as electric shock and corticosterone injection. It was found that stress by electric shock decreased the expression of tyrosine hydoroxylase (TH) in the amygdala while the expression of pERK was increased. However, there is no difference in the expressions of TH and pERK in the frontal cortex compared with those of the control group. The level of corticosterone was significantly increased in the serum after stress. To determine the effect of corticosterone on the induction of anxiety and the expression of TH, the rats received corticosterone (20 mg or 40 mg/kg i.p.) for 1 day, 1 week, 2 weeks and 3 weeks, respectively. The spent time in open arms of the EPM (elevated plus maze) test was significantly decreased after 1 week, 2 weeks and 3 weeks. The time spent in open arms of the EPM test after repeated injections of corticosterone was significantly decreased in a dose-dependent manner. The expression of TH in the amygdala was reduced after following repeated corticosterone treatment for 2 weeks and 3 weeks. Collectively, this study suggests that corticosterone has a major role in the induction of anxiety and the modulation of TH expression, at least, in the amygdala.

Here, we describe the practical synthesis and biological properties of bergenin and its structural analogs. Synthetic bergenin compounds were prepared by acylation of bergenin. These compounds were then evaluated for suppression of lipopolysaccharide-induced nitric oxide (NO) generation in cultured cells and anti-narcotic effects on morphine-dependent mice. We found that bergenin derivatives showed potent anti-inflammatory activity (suppression of NO generation) at concentrations ranging from 20 to 30 μmin vitro, and bergenin derivatives (10-20 mg/kg) exhibited significant anti-narcotic effects on morphine dependence in mice. These results suggest the potential utility of bergenin and its analogs as anti-narcotic agents and the design of more potent anti-inflammatory compounds.

Sphingosine kinase (SPHK) has a central role to control cell death and cell proliferation, which is suggested as a sphingolipid rheostat by regulating the levels between ceramide and sphingosine 1-phosphate (S1P). Therefore, physiological regulators of SPHK will be a good candidate to develop a new targeted drug. For this purpose, a series of synthetic pseudoceramides were tested by SPHK assay either cell-based or cell-free system. K10PC-5 strongly inhibited SPHK, while K6PC-5 activated SPHK in cell-free system. Specifically, K6PC-5 activated SPHK under the co-treatment with 50 uM dimethylsphingosine (DMS), a SPHK inhibitor. Collectively, we developed a simple SPHK assay system to find SPHK regulatory pseudoceramide compounds, K10PC-5 and K6PC-5 which may be useful to cancer treatment or immune regulation like FTY720, a synthetic sphingolipid mimetic compound.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder of the central nervous system resulting in memory loss and dementia. Some of the associated pathogenic changes are amyloid peptide aggregation, excitotoxicity, oxidative stress and inflammation. Oxidative stress plays an indispensable role in the pathophysiology of AD. Therefore, antioxidant therapies appear to be promising approaches in dealing with AD patients. In that line, we evaluated the free radical scavenging capabilities of 13 different chalcones (1,3-diphenyl-2-propen-1-one) derivatives against the free-radical damaging effects of hydrogen peroxide (H₂O₂) on the SK-N-MC neuroblastoma cell line. Pretreatment of the cells for 3 h with 20 µ m of each of these derivatives (compounds 8-20) followed by exposure to 300 µ m H₂O₂ for 24 h indicated that all compounds, except compound 20, were capable of restoring the viabilities of cells relative to the control (H₂O₂ -treated) cells. The destructive effect of H₂O₂ on the adhesive behavior of the cells was almost totally restored by each of the derivatives. In addition, each of the derivatives except compounds 20 and 14 significantly reduced the extent of lipofuscin formation among the cells time-dependently. Despite these activities, some of the derivatives, such as compounds 12 and 19, did not reduce the H₂O₂ -induced intracellular ROS (reactive oxygen species) levels, meaning that these two derivatives act through a different mechanism other than free-radical scavenging activity. On the other hand, for those derivatives acting as anti-oxidants, structure-activity evaluation clearly revealed that the hydroxyl group of vanillin ring is required for their free-radical scavenging activities.

We investigated the neuroprotective effect of glucosamine (GlcN) in a rat middle cerebral artery occlusion model. At the highest dose used, intraperitoneal GlcN reduced infarct volume to 14.3% ± 7.4% that of untreated controls and afforded a reduction in motor impairment and neurological deficits. Neuroprotective effects were not reproduced by other amine sugars or acetylated-GlcN, and GlcN suppressed postischemic microglial activation. Moreover, GlcN suppressed lipopolysaccharide (LPS)-induced upregulation of proinflammatory mediators both in vivo and in culture systems using microglial or macrophage cells. The anti-inflammatory effects of GlcN were mainly attributable to its ability to inhibit nuclear factor kappaB (NF-κB) activation. GlcN inhibited LPS-induced nuclear translocation and DNA binding of p65 to both NF-κB consensus sequence and NF-κB binding sequence of inducible nitric oxide synthase promoter. In addition, we found that GlcN strongly repressed p65 transactivation in BV2 cells using Gal4-p65 chimeras system. P65 displayed increased O-GlcNAcylation in response to LPS; this effect was also reversed by GlcN. The LPS-induced increase in p65 O-GlcNAcylation was paralleled by an increase in interaction with O-GlcNAc transferase, which was reversed by GlcN. Finally, our results suggest that GlcN or its derivatives may serve as novel neuroprotective or anti-inflammatory agents.

－ We have investigated the effect of glucosamine on the retinal cells after continuous infusion into cerebroventricle by using osmotic minipump to avoid peripheral effect. Continuous intracerebroventricular (i.c.v) infusion of glucosamine with the rate of 0.1 μmol/10 μl/hr for 7 days resulted in morphological changes of the optic nerve in electron microscopic level as well as morphological changes of the retina in light microscopic level. Retinal sections were immunostained for the detection of morphological changes of astro-cytes. GFAP immunoreactivity appeared not only in the Muller cells but also many of the radial processes of Muller cells. The optic nerve showed deformed axon and slight lamellar separation of myelin sheath after continuous infusion of glucosamine in observing with electron microscope. Interestingly, vacuoles were observed in deformed axons and retinal layers were folded and detached. These results suggested that glucosamine plays a role in induction of morphological dysfunction in retina and optic nerves.Keywords: Glucosamine, Retinal cell, O-glycosylation, GFAP, Vimentin, Osmotic minipump

A simple synthesis involving a key coupling reaction and biological activity of N-protected cyclopropylethylcarbamates (18-21) are described. The key fragments are amine.HCl salt (13) and acids (16 and 17) which were smoothly coupled by using 2-(7-aza-1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate in high yield. We have found that the in vitro growth inhibitory potency of new compound 19 exhibited good histone deacetylase activity.

In this study, we investigated the neuroprotective effect of a benzylideneacetophenone derivative, JC3, in a mouse model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD). C57BL/6 mice were treated with MPTP (30 mg/kg, i.p.) for 5 consecutive days. JC3 (10 mg/kg, i.p.) treatment was initiated 2 h after the first administration of MPTP and then at 24-h intervals for 3 consecutive days. The mice were sacrificed for analyses 7 days after the last MPTP injection. Immunohistochemistry and Western blot were used to determine the expression levels of tyrosine hydroxylase (TH), dopamine transporter (DAT), OX-42 (a marker of microglial activation), and glial fibrillary acid protein (GFAP, a marker of astrocyte activation) in the substantia nigra (SN) and striatum (ST). The results of these experiments demonstrated that JC3 restored the decreased TH-immunoreactivity (IR) and DAT and JC3 attenuated the increase in OX-42, GFAP, and COX-2 on the SN and ST on day 7 post-MPTP injection. These results suggest that JC3 can be a neuroprotective agent in an MPTP-induced model of PD.

Apoptosis is essential for a variety of pathophysiological progress. Apoptosis induction by various agents changes cellular morphology, DNA content and lipid membrane composition. Recently, sphingosine 1-phosphate (S1P) is avidly released from not only platelets and erythrocytes but vascular endothelium. Here we established S1P releasing cells by deleting S1P lyase (F9-12 cells). We observed apoptosis induction by the treatment of fumonisin B1 (FB1) in F9-12 cells but not in F9 wild-type cells. We measured high amounts of accumulated S1P and dihydroS1P (DHS1P) in FB1-induced apoptotic F9-12 cells. We also showed DHS1P release in an early stage of the apoptosis induction by FB1 but not by phorbol 12-myristate 13-acetate (PMA)-induced apoptosis, suggesting differential apoptotic processes.

The sphingolipid metabolites act as lipid mediator for cell proliferation and apoptosis in mammalian cells. In bacteria, sphingolipid metabolism remains unknown. The purpose of this study was to investigate whether sphingolipid metabolism is potential target for fumonisin B 1 (FB 1 ) and desipramine in Sphingomonas chungbukensis, Gram-negative bacteria, by comparing the intracellular contents of bacterial sphingolipids with ones of HIT-T15 β-cells, hamster pancreatic cells. The concentrations of ceramide and dihydroceramide were 18.0± 12.0 and 0.025± 0.018 nmol/mg protein, respectively, in HIT-T15 cells. However, the concentrations of ceramide and dihydroceramide in the bacterial culture were 2.0± 1.2 and 10.6± 5.5 nmol/mg protein, respec- tively. FB 1 decreased the level of ceramide from 18.0 to 3.8 nmol/mg protein in HIT-T15 β-cells. However, dihy- droceramide content in FB 1 -treated HIT-T15 cells was slightly decreased compared with the control culture. When S. chungbukensis was treated with either FB 1 or desipramine, dihydroceramide level was increased by 5- and 4-fold, respectively, compared with the control bacteria. These results indicate that FB 1 and desipramine may act as an activator in bacterial sphingolipid biosynthetic pathway, and bacterial sphingolipid metabolism pathway appears to be different from the pathway of mammalian cells.

A simple synthesis and biological properties of 1,3-diphenyl-2-propen-1-ones 18-22 and 25-26 are described. The key synthetic strategies involve Grignard reaction of aldehyde 2 and oxidation reaction of 8-12 in high yields. The prepared compounds 18-22 and 25-26 were evaluated for free-radical scavenging, suppression of LPS-induced NO generation, and anti-excitotoxicity in vitro. It was found that a couple of compounds, especially 21 and 26, were potent suppressors of NO generation and demonstrated anti-excitotoxicity with the concentration range 10-20 microM in vitro.

A simple synthesis of sulfonamides 4–22 as novel histone deacetylase (HDAC) inhibitors is described. The key synthetic strategies involve N–sulfonylation of L–proline benzyl ester hydrochloride (2) and coupling reaction of N–sulfonyl chloride 3 with amines in high yields. It was found that several compounds showed good cellular potency with the most potent compound 20 exhibiting an IC50 = 2.8 μM in vitro.

Sphingolipids are present in animals, plants, fungi, yeasts and some bacteria. In mammalian cells sphingolipids act as lipid mediators for cell growth, differentiation, apoptosis and angiogenesis. In contrast, in bacteria the biological significance of sphingolipids has not been fully elucidated and sphingolipid metabolism has not been investigated. The aim of this study was to compare the pattern of sphingolipid metabolites in HIT-T15 beta cells originating from hamster pancreas to that in the bacterial strain Sphingomonas chungbukensis DJ77, under various culture conditions. It was found that the concentration of cellular sphinganine (Sa) in S. chungbukensis was higher than that of sphingosine (So), while the level of cellular So in HIT-T15 cells was higher than that of Sa. Aeration and shaking during culture increased bacterial growth in S. chungbukensis, and the contents of So and Sa were also elevated. These results indicate that a de novo sphingolipid pathway appeared to be active in bacteria and that bacterial growth may be closely related to Sa levels.

The effect of sphingosine-1-phosphate (S1P) on large-conductance Ca2+-activated K+(BKCa) channels was examined in primary cultured human umbilical vein endothelial cells by measuring intracellular Ca2+concentration ([Ca2+]i), whole cell membrane currents, and single-channel activity. In nystatin-perforated current-clamped cells, S1P hyperpolarized the membrane and simultaneously increased [Ca2+]i. [Ca2+]iand membrane potentials were strongly correlated. In whole cell clamped cells, BKCacurrents were activated by increasing [Ca2+]ivia cell dialysis with pipette solution, and the activated BKCacurrents were further enhanced by S1P. When [Ca2+]iwas buffered at 1 μM, the S1P concentration required to evoke half-maximal activation was 403 ± 13 nM. In inside-out patches, when S1P was included in the bath solution, S1P enhanced BKCachannel activity in a reversible manner and shifted the relationship between Ca2+concentration in the bath solution and the mean open probability to the left. In whole cell clamped cells or inside-out patches loaded with guanosine 5′- O-(2-thiodiphosphate) (GDPβS; 1 mM) using a patch pipette, GDPβS application or pretreatment of cells with pertussis toxin (100 ng/ml) for 15 h did not affect S1P-induced BKCacurrent and channel activation. These results suggest that S1P enhances BKCachannel activity by increasing Ca2+sensitivity. This channel activation hyperpolarizes the membrane and thereby increases Ca2+influx through Ca2+entry channels. Inasmuch as S1P activates BKCachannels via a mechanism independent of G protein-coupled receptors, S1P may be a component of the intracellular second messenger that is involved in Ca2+mobilization in human endothelial cells.

These studies addressed the possible involvement between sensitivity to the hypnotic action of ethanol and function of the NMDA receptor. The studies were carried out using high-alcohol sensitive (HAS) and low-alcohol sensitive (LAS) rats, two rats having differential sensitivity to the acute hypnotic action of ethanol. The animal models were developed by a selective breeding experiment. Using a quantitative autoradiograph technique, it was demonstrated that [3H]MK-801 binding to the NMDA receptor was highest in hippocampus in both HAS and LAS rats, but significant [3H]MK-801 binding was also detected in cortex, caudate-putamen, and thalamus of HAS and LAS rats. The density of [3H]MK-801 binding was lower only in cerebellar granule layers of untreated HAS rats as compared to the same brain area in untreated LAS rats. Activation of protein kinase C (PKC) by 100 nM PDBu, increased [3H]MK-801 binding in cortex, caudate-putamen, thalamus, central gray, and cerebellum of HAS rats but activation of PKC did not influence [3H]MK-801 binding in LAS rats. These activation of PKC differentiates between [3H]MK-801 binding of HAS and LAS rats in frontal cortex (layer II-IV and cingulate), caudate-putamen, and ventral lateral thalamic nuclei. The basal level of PKC-gamma mRNA was higher in HAS rats than that of LAS rats. These results suggest that the activation of PKC potentiates NMDA receptor function of the rat line which is more sensitive to alcohol (HAS) but does not affect [3H]MK-801 binding of alcohol resistant (LAS) rats.

A series of 4-hydroxycoumarin derivatives was prepared and evaluated for antitumor activity. The key fragments were 2a-c, 5c, 12b, 13b, 17, and 18 which were prepared via dianion ring cyclization, Friedel-Crafts acylation, and Reformatsky reaction. Compound 20b showed the most potent antitumor activity among the total 12 derivatives and compounds 19a and 19b exhibited efficacy comparable to etoposide in vitro antitumor activity.

Butorphanol was infused continuously into cerebral ventricle at a constant rate of 26 nmol/μl/h for 3 days, and the withdrawal from opioid was rendered 7 h after the cessation of infusion. The G-protein α-subunit has been implicated in opioid tolerance and withdrawal. The effects of continuous infusion of butorphanol on the modulation of G protein α-subunit mRNA were investigated by using in situ hybridization techniques. In situ hybridization showed marked changes in the levels of Gαs during butorphanol tolerance and withdrawal. Specifically, the level of Gαs mRNA was significantly decreased in almost all areas of brain except hippocampus during the butorphanol withdrawal. It was also decreased in the septum and cerebellar granule layer in butorphanol tolerant rats. The level of Gαi mRNA was significantly decreased only in the cerebral cortex of butorphanol tolerant rat. However, no such change was noted during the withdrawal from butorphanol. The level of Gαo mRNA was not changed either in butorphanol tolerant or in the butorphanol withdrawal rats. No alterations were noted in the level of [3H]forskolin binding to adenylyl cyclase in butorphanol tolerant as well as withdrawing rats. The levels of pCREB were significantly elevated in the hippocampus in the butorphanol withdrawal rats. These results suggest that region-specific changes of G protein α-subunit mRNA and pCREB without marked changes in the level of adenylyl cyclase may underlie the tolerance to and withdrawal from butorphanol.

We have investigated the effects of centrally administered ginsenoside Rc and Rg1 on the modulation of G protein expression in the central nervous system in rat brain. The effects of continuous infusion of ginsenosides on the modulation of G protein α-subunit mRNA were investigated by using in situ hybridization study. Rats were infused with ginsenoside Rc or Rg1 (10 μg/10 μl/h, i.c.v.) for 7 days, through preimplanted cannula by osmotic minipumps. The level of Gαs mRNA was not changed by the infusion of ginsenoside Rc or Rg1. The level of Gai mRNA was significantly elevated in frontal cortex and hippocampus following treatment with ginsenoside Rc as well as ginsenoside Rg1. However, the level of Gαo mRNA was significantly decreased in part of the hippocampus and cerebellum after the animals had received ginsenoside Rg1 infusion. These results suggest that prolonged infusion of ginsenosides could differentially modulate the expression of G protein α-subunit mRNA in rat brain in a region-specific manner.

We have investigated the effects of continuous infusion of butorphanol on the modulation of GABAA receptor binding. Butorphanol was infused continuously into intracerebroventricle (ICV) at a constant rate of 26 nmol/μl/h for 3 days, and the withdrawal from opioid was rendered 7 h after the cessation of infusion. The GABAA receptor bindings in rat brain slices were analyzed by quantitative autoradiography using [3H]muscimol and [3H]flunitrazepam. In the rats withdrawn from butorphanol, the levels of [3H]muscimol binding were significantly elevated in cortex, thalamus, and part of the hippocampus. The levels of [3H]flunitrazepam binding were elevated in almost all of brain regions including cortex, caudate putamen, thalamus, hippocampus, brainstem, and cerebellum in the rats withdrawn from butorphanol. The levels of binding of either [3H]muscimol or [3H]flunitrazepam were not changed in the rats tolerant to butorphanol. However, the activity of GABAergic neuron was not found to have been modulated by butorphanol withdrawal, because the level of glutamic acid decarboxylase was not changed markedly either in rats that were tolerant to or withdrawn from butorphanol by Western blot and immunohistochemical data. These results suggest that the withdrawal from butorphanol infusion markedly elevates the binding of [3H]muscimol and [3H]flunitrazepam throughout the brain in a region-specific manner, and that the regulatory mechanisms in butorphanol tolerance and withdrawal may be different.

Pentobarbital was continuously infused intracerebroventricularly (i.c.v.) at the rate of 300 micrograms/10 microliters/h for 7 days, and withdrawal from pentobarbital was rendered 24 h after the stopping of the infusion. To eliminate the induction of hepatic metabolism by systemic administration of pentobarbital, an i.c.v. infusion model of tolerance to and withdrawal from pentobarbital was used. Little is known about the functional modulation of the G protein alpha-subunits at the molecular level. The effects of continuous infusion of pentobarbital on the modulation of G protein alpha-subunits mRNA were investigated by using in situ hybridization study. In situ hybridization showed that the level of G alpha s mRNA was increased in the septum and brainstem, and the level of G alpha o mRNA was elevated in the cortex during the pentobarbital withdrawal. The level of G alpha i mRNA was significantly elevated in almost all area of brain during the pentobarbital withdrawal. These results suggest that region-specific changes of G protein alpha-subunit mRNA were involved in the withdrawal from pentobarbital, whereas alpha-subunit is not so highly involved in the pentobarbital tolerance.

The effects of continuous infusion of NMDA receptor antagonist MK-801 on the modulation of NMDA receptor subunits NR1, NR2A, NR2B, and NR2C were investigated by using in situ hybridization study. Differential assembly of NMDA receptor subunits determines their functional characteristics. Continuous intracerebroventricular (i.c.v.) infusion with MK-801 (1 pmol/10 μl/h) for 7 days resulted in significant modulations in the NR1, NR2A, and NR2B mRNA levels without producing stereotypic motor syndromes. The levels of NR1 mRNA were significantly increased (9-20%) in the cerebral cortex, striatum, septum, and CA1 of hippocampus in MK-801-infused rats. The levels of NR2A mRNA were significantly decreased (11-16%) in the CA3 and dentate gyrus of hippocampus in MK-801-infused rats. In contrast to NR2A, NR2B subunit mRNA levels were increased (10-14%) in the cerebral cortex, caudate putamen, and thalamus. However, no changes of NR2C subunits in cerebellar granule layer were observed. Using quantitative ligand autoradiography, the binding of NMDA receptor ligand [3H]MK-801 was increased (12-25%) significantly in almost all brain regions except in the thalamus and cerebellum after 7 days infusion with MK-801. These results suggest that region-specific changes of NMDA receptor subunit mRNA and [3H]MK-801 binding are involved in the MK-801-infused adult rats.

Ginsenoside compound K (CK) is a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer (Araliaceae), has long been used to treat against the development of cancer, inflammation, allergies, and diabetes. This study examined the anti-angiogenic properties of CK against sphingosine 1-phosphate (S1P)-induced cell migration via regulation of sphingosine kinase 1 (SPHK1) in human umbilical vein endothelial cells (HUVEC). Studies on S1P-induced cell migration, expression of SPHK1 and MMPs and analysis of sphingolipid metabolites by LC-MS/MS were examined after the treatment of CK (2.5, 5, 10 μg/mL) in HUVEC. S1P produced by SPHK1 is also involved in cell growth, migration, and protection of apoptosis; therefore, we sought to investigate whether ginsenosides are able to regulate SPHK1. For this purpose, we developed an inhibitory assay of SPHK1 activity and an analytical method for detection of S1P and other sphingolipid metabolites in HUVEC. Ginsenoside CK inhibited 100 nM S1P-induced cell migrations in a dose-dependent manner. Among tested ginsenosides, CK exclusively inhibited S1P production, SPHK1 activity and SPHK1 expression in HUVEC, whereas expression of the pro-apoptotic sphingolipids, sphingosine and ceramide, was increased in response to CK. The major subspecies of the increased ceramide was C24:0-ceramide. CK also disrupted the sphingolipid rheostat, which ultimately influences cell fate, and dose-dependently inhibited HUVEC migration by reducing expression of metalloproteinases (MMPs). Ginsenoside CK acts as a unique HUVEC migration inhibitor by regulating MMP expression, as well as the activity of SPHK1 and its related sphingolipid metabolites.

The hepatoprotective effects of acetylbergenin were examined against D -galactosamine (GalN)-induced liver damage in rats, compared with that of bergenin reported previously. Acetylbergenin was synthesized from acetylation of bergenin, isolated from Mallotus japonicus, to increase lipophilic and physiological activities. Acetylbergenin was administered orally once daily for 7 days and then GalN (400 mg kg−1, i.p.) was injected at 24 h and 96 h after the final administration of acetylbergenin. Acetylbergenin reduced the elevated serum enzyme activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and γ -glutamyltransferase and the formation of hepatic malondialdehyde induced by GalN. Acetylbergenin also significantly restored towards normalization the decreased levels of glutathione and the decreased activities of glutathione S-transferase and glutathione reductase induced by GalN. Therefore, these results suggest that acetylbergenin has hepatoprotective effects against GalN-induced hepatotoxicity by inhibiting lipid peroxidation and maintaining an adequate level of GSH for the detoxification of xenobiotics as underlying hepatoprotective mechanisms. In addition, lipophilic acetylbergenin showed more activity in the hepatoprotection than that of the much less lipophilic bergenin reported previously.

The hepatoprotective effects of bergenin, a major constituent of Mallotus japonicus , were evaluated against carbon tetrachloride (CCl 4 )-induced liver damage in rats. Bergenin at a dose of 50, 100 or 200 mg/kg was administered orally once daily for successive 7 days and then a mixture of 0.5 ml/kg (ip) of CCl 4 in olive oil (1:1) was injected two times each at 12 and 36 h after the final administration of bergenin. The substantially elevated serum enzymatic activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and γ-glutamyltransferase due to CCl 4 treatment were dose dependently restored towards normalization. Meanwhile, the decreased activities of glutathione S-transferase and glutathione reductase were restored towards normalization. In addition, bergenin also significantly prevented the elevation of hepatic malondialdehyde formation and depletion of reduced glutathione content in the liver of CCl 4 -intoxicated rats in a dose dependent fashion. The results of this study clearly indicate that bergenin has a potent hepatoprotective action against CCl 4 -induced hepatic damage in rats.

The NMDA receptor has been implicated in opioid tolerance and withdrawal. The effects of continuous infusion of butorphanol on the modulation of NMDA receptor subunit NR1, NR2A, NR2B, and NR2C gene expression were investigated by using in situ hybridization technique. Continuous intracerebroventricular (i.c.v.) infusion with butorphanol (26 nmol/microl/h) resulted in significant modulations in the NRI, NR2A, and NR2B mRNA levels. The level of NR1 mRNA was significantly decreased in the cerebral cortex, thalamus, and CA1 area of hippocampus in butorphanol tolerant and withdrawal (7 h after stopping the infusion) rats. The NR2A mRNA was significantly decreased in the CA1 and CA3 of hippocampus in tolerant rats and increased in the cerebral cortex and dentate gyrus in butorphanol withdrawal rats. NR2B subunit mRNA was decreased in the cerebral cortex, caudate putamen, thalamus, CA3 of hippocampus in butorphanol withdrawal rats. No changes of NR1, NR2A, NR2C subunit mRNA in the cerebellar granule cell layer were observed in either butorphanol tolerant or withdrawal rats. Using quantitative ligand autoradiography, the binding of NMDA receptor ligand [3H]MK-801 was increased significantly in all brain regions except in the thalamus and hippocampus, at the 7 hr after stopping the butorphanol infusion. These results suggest that region-specific changes of NMDA receptor subunit mRNA (NR1 and NR2) as well as NMDA receptor binding ([3H]MK-801) are involved in the development of tolerance to and withdrawal from butorphanol.

Effects of continuous pentobarbital administration on binding characteristics of [3H]muscimol were examined by autoradiography, and levels of GABAA receptor β2-subunit mRNA were investigated by in situ hybridization histochemistry in the rat brain. In order to eliminate the induction of hepatic metabolism by systemic administration of pentobarbital, an i.c.v. infusion model of tolerance to and withdrawal from pentobarbital was used. An experimental model of barbiturate tolerance and withdrawal was developed using i.c.v. infusion of pentobarbital (300 μg/10 μl/hr for 7 days) by osmotic minipumps and abrupt withdrawal from pentobarbital. The levels of [3H]muscimol binding were elevated in cingulate of frontal cortex (46%) and granule layer of cerebellum (32%) of rats 24-hr after withdrawal from pentobarbital, while it was only elevated in cingulate (58%) of tolerant rats. The GABAA receptor β2-subunit mRNA was increased in the withdrawal rats only: in the cortex (9–14%), hippocampus (15–21%), inferior colliculus (21%), and granule layer of cerebellum (24%). These results show the involvement of GABAA receptor and its β2-subunit up-regulations in pentobarbital withdrawal rats, and suggest that the levels of [3H]muscimol binding and GABAA receptor β2-subunit mRNA are altered in a region-specific manner during pentobarbital withdrawal.

Little is known about the functional modulation of NMDA receptor subunits at the molecular level. Therefore, a series of experiments were conducted to elucidate more fully the role of NMDA receptor subtypes in pentobarbital tolerance and withdrawal. We investigated the influence of centrally administered pentobarbital on the regulation of mRNA levels of the family of NMDA receptor 2 (NR2) subtypes (NR2A, NR2B, and NR2C) by in situ hybridization histochemistry in rat brain. Animals were rendered tolerant by continuous intracerebroventricular (i.c.v.) infusion with pentobarbital (300 μg/10 μl/hr for 6 days) through pre-implanted cannulae connected to osmotic mini-pumps, and dependent, by abrupt withdrawal from pentobarbital. The NR2A subunit mRNA was increased in cortical areas in pentobarbital tolerant and withdrawal rats. In contrast, the NR2B mRNA was decreased in parietal cortex and hippocampus in both tolerance and withdrawal rats. The level of NR2C mRNA was increased in withdrawal rats, while there was no change in tolerant rats. These results indicate that continuous i.c.v. infusion with pentobarbital alters NR2 subunit mRNA expression in the rat brain, suggesting that NR2 subunits may play an important role in the development of tolerance to and withdrawal from pentobarbital.

These studies were designed to examine the effect of chronic administration of pentobarbital on activity of adenylate cyclase (AC) and protein kinase C (PKC) in the rat brain by autoradiography. Recently, it has been suggested that the phosphorylation of specific proteins may be involved in the development of physical dependence. An experimental model of barbiturate tolerance and dependence was developed using i.c.v. infusion of pentobarbital (300 μg/ 10 μl/hr for 7 days) by osmotic minipumps and abrupt withdrawal from pentobarbital. The levels of [3H]forskolin binding were elevated (28–67%) in cortex, thalamus, dentate gyrus, hippocampal CA3 and cerebellum of the pentobarbital withdrawal animals, while these changes were not observed in tolerant rats. The levels of [3H]phorbol dibutyrate binding were highly elevated (38–65%) in the region of cortex, caudate putamen, septum, thalamus, dentate gyrus, and cerebellum of rats withdrawal from pentobarbital. These results show that the levels of AC and PKC were significantly elevated in pentobarbital withdrawal rats, and suggest that the levels of AC and PKC are altered in a region-specific manner during pentobarbital withdrawal.

Effects of continuous pentobarbital administration on binding characteristics of [3H]MK-801 in the rat brain were examined by autoradiography. Animals were rendered tolerant to pentobarbital using i.c.v. infusion of pentobarbital (300μg/10μl/hr for 7 days) by osmotic minipumps and dependent by abrupt withdrawal from pentobarbital. The levels of [3H]MK-801 binding were elevated in rats 24-hr after withdrawal from pentobarbital while there were no changes except in septum and anterior ventral nuclei in tolerant rats. For assessing the role of NMDA receptor in barbiturate action, an NMDA receptor antagonist (MK-801, 2.7 femto g/10μl/hr) was co-infused with pentobarbital. The pentobarbital-infused group had a shorter duration of pentobarbital-induced loss of righting reflex (sleeping time) than that of the control group, and MK-801 alone did not affect the righting reflex. However, co-infusion of MK-801 blocked hyperthermia, and prolonged the onset of convulsions induced by t-butylbicyclophosphorothionate (TBPS) in pentobarbital withdrawal rats. In addition, elevated [35S]TBPS binding was significantly attenuated by co-infusion with MK-801. These results suggest the involvement of NMDA receptor up-regulation in pentobarbital withdrawal and that the development of dependence can be attenuated by the treatment of subtoxic dose of MK-801.

Exogenously applied oxygen free radical generating agent, pyrogallol, highly elevated extracellular glutamate accumulation and augmented N-methyl-D-aspartate (NMDA)-induced glutamate accumulation in cerebellar granule neuronal cells, but did not in astrocytes. Superoxide dismutase remarkably decreased the pyrogallol-induced glutamate accumulation, but either NMDA or kainate antagonists did not. In addition, pyrogallol did not affect the NMDA-induced intracellular calcium elevation. Pyrogallol partially blocked glutamate uptake into astrocytes. These results suggest that oxygen free radicals elevate extracellular glutamate accumulation by stimulating the release of glutamate as well as blocking the glutamate uptake.

1. 1. Treatment of cultured cerebellar granule cells for 3 min with N-methyl-D-aspartate (NMDA) resulted in a concentration-dependent elevation of cyclic GMP. However, neither kainate (KA) nor NMDA produced a concentration-dependent elevation of this nucleotide after exposing cells to the agonist for 60 min. 2. 2. Unlike the case for cGMP, both KA and NMDA produced concentration-dependent elevations of glutamate for 60 min incubation. 3. 3. The NMDA-induced elevations of cGMP and glutamate were blocked by selective NMDA receptor antagonists. 4. 4. The selective KA/α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor antagonist, 6,7-nitroquinoxaline-2,3-dione (DNQX), blocked the KA-induced elevations of cGMP with 3-min exposures, but it augmented the response with 60-min exposures. However, the KA-induced release of glutamate was prevented by DNQX. 5. 5. The KA/AMPA receptor antagonist, GYKI 52466, blocked all KA-induced responses regardless of the incubation times.

Several lines of evidence indicate that physiological activity of N-methyl-D-aspartate (NMDA) receptor was blocked by physiological concentration of Mg2+ (1.2 mM). However, the activity of NMDA receptor may not be blocked totally with this concentration of Mg2+ under elevated membrane potential by kainate. Here, we described the effect of Mg2+ on NMDA receptor and how much of NMDA receptor functions could be activated by kainate. Effects of NMDA receptor antagonist on kainate-induced elevation of intracellular Ca2+ levels ([Ca2+]i) and extracellular glutamate level were examined in cultured rat cerebellar granule neurons. Kainate-induced elevation of [Ca2+]i was not affected by physiological concentration of Mg2+ though NMDA-induced elevation was blocked by the same concentration of Mg2+. Kainate-induced elevation of [Ca2+]i was decreased by 32% in the presence of NMDA antagonists, MK-801 and CPP (3-[2-carboxypiperazine-4-yl]propyl-1-phosphonic acid), in Mg2+ free buffer. Kainate receptor-activated glutamate release was also decreased (30%) by MK-801 or CPP. These results show that certain extent of elevations of intracellular Ca2+ and extracellular glutamate by kainate is due to coactivation of NMDA receptors.

The levels of extracellular glutamate, intracellular Ca2+ ([Ca2+]i) and cGMP were determined for 1 h with the excitatory amino acids, N-methyl-D-aspartate (NMDA) or kainate in cultured cerebellar granule cells. Both NMDA and kainate produced a time-dependent release of glutamate, and kainate was more potent than NMDA in glutamate elevation. The elevation of extracellular glutamate was not purely governed by intracellular Ca2+ concentration. However, in opposite to the time-dependent elevation of glutamate, the elevation of cGMP by NMDA and kainate were at maximum level in short-time (1 min) incubation then remarkably decreased with longer incubation times. Post-applications (30 min after agonist) of EAA antagonst did not block EAAs-induced glutamate elevation. However, NMDA antagonist, phencyclidine (PCP), blocked NMDA-induced cGMP elevation at pre- or post-application, but kainate antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), paradoxically augmented kainate-induced cGMP elevation for 1 h incubation. These results show that NMDA or kainate induces time-dependent elevations of extracellular glutamate, while the elevations of cGMP by these EAAs are remarkably decreased with longer incubation times. However, NMDA- and kainate-induced glutamate release was blocked by pre-application of each receptor antagonist but not by post-application while EAA-induced [Ca2+]i was blocked by post-application of antagonist. These observations suggest that EAA-induced elevation of [Ca2+]i is not parallel with elevation of glutamate release or cGMP.

The Swedish mutation of amyloid precursor protein (APP-sw) has been reported to dramatically increase beta amyloid production through aberrant cleavage at the beta secretase site, causing early-onset Alzheimer’s disease (AD). DNA methylation has been reported to be associated with AD pathogenesis, but the underlying molecular mechanism of APP-sw-mediated epigenetic alterations in AD pathogenesis remains largely unknown. We analyzed genome-wide interplay between promoter CpG DNA methylation and gene expression in an APP-sw-expressing AD model cell line. To identify genes whose expression was regulated by DNA methylation status, we performed integrated analysis of CpG methylation and mRNA expression profiles, and identified three target genes of the APP-sw mutant; hypomethylated CTIF (CBP80/CBP20-dependent translation initiation factor) and NXT2 (nuclear exporting factor 2), and hypermethylated DDR2 (discoidin domain receptor 2). Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored mRNA expression of these three genes, implying methylation-dependent transcriptional regulation. The profound alteration in the methylation status was detected at the −435, −295, and −271 CpG sites of CTIF, and at the −505 to −341 region in the promoter of DDR2. In the promoter region of NXT2, only one CpG site located at −432 was differentially unmethylated in APP-sw cells. Thus, we demonstrated the effect of the APP-sw mutation on alteration of DNA methylation and subsequent gene expression. This epigenetic regulatory mechanism may contribute to the pathogenesis of AD.

Fumonisins are causative agents of diseases in mice and rats, including liver and renal toxicities, as well as cancer, and are specific inhibitors of ceramide synthase in the metabolism of sphingolipid. The purpose of this study was to determine whether an elevated level of sphingoid base 1-phosphate was related to the expressions of metabolism enzymes in the liver of fumonisin B1 (FB1)-treated mice and acted as a contributing factor to hepatotoxicity. In our previous study, FB1 was confirmed to be toxic to both liver and kidneys, coupled with simultaneous elevation of sphinganine 1-phosphate. ICR mice were treated intraperitoneally with 10 mg/kg/day FB1 for 5 days, with the concentrations of sphingolipid metabolites in the serum and liver measured using HPLC following Bligh-Dyer extraction. The levels of sphingoid bases and their 1-phosphates in the serum and liver were markedly elevated in response to treatment with FB1. In the liver, FB1 increased the expression of sphingosine kinase and inhibited the expression of sphingosine 1-phosphate lyase. The cleaved form of caspase-3 was detected in the liver of FB1-treated mice, indicating the occurrence of apoptosis in the liver following exposure to FB1. The expressions of proapoptotic signaling molecules, such as phosphorylated forms of c-Jun N-terminus kinase (JNK), p38 MAPK and extracellular signal-regulated kinase (ERK), were increased in the liver of FB1-treated mice. In conclusion, these results suggest the elevation of sphingoid base 1-phosphate, as a result of the activation of sphingosine kinase and the inhibition of sphingosine 1-phosphate lyase, may be a major target for FB1-induced hepatotoxicity via the activation of an apoptotic signaling pathway.