European Journal of Pharmacology (v.664, #1-3)
Editorial Board (ii).
Dehydrocostus lactone prevents mitochondrial dysfunction in osteoblastic MC3T3-E1 cells by Eun Mi Choi (1-7).
The dried root of Saussurea lappa Clarke (Compositae) has been used as a traditional medicine. Dehydrocostus lactone is one of the main bioactive constituents of this medicinal plant. In the present study, the protective effect of dehydrocostus lactone against antimycin A (an inhibitor of mitochondrial complex III)-induced cytotoxicity was investigated in osteoblastic MC3T3-E1 cells. Pre-treatment with dehydrocostus lactone prior to antimycin A exposure significantly prevented mitochondrial membrane potential dissipation, complex IV inactivation, ATP loss, cytochrome c release, intracellular calcium elevation and potassium loss, and reactive oxygen species production induced by antimycin A. These results suggest that dehydrocostus lactone protects osteoblastic MC3T3-E1 cells from antimycin A-induced cell damage through the improved mitochondrial function.Display Omitted
Keywords: Dehydrocostus lactone; Mitochondrial dysfunction; Osteoblastic MC3T3-E1 cells;
Proglumide enhances the antinociceptive effect of cyclooxygenase inhibitors in diabetic rats in the formalin test by Deysi Y. Bermúdez-Ocaña; Hidemi Aguilar-Mariscal; Teresa Ramón Frías; Jorge L. Blé-Castillo; Francisco J. Flores-Murrieta; Juan C. Díaz-Zagoya; Vinicio Granados-Soto; Isela Esther Juárez-Rojop (8-13).
The purpose of this study was to assess the effect of the non-selective cholecystokinin receptor antagonist proglumide on the antinociceptive activity of ketorolac and meloxicam in non-diabetic and diabetic rats. Streptozotocin (60 mg/kg) injection caused hyperglycemia which was maintained for 2 weeks. Formalin-evoked flinching was increased in diabetic rats as compared to non-diabetic rats. Local peripheral ipsilateral, but not contralateral, administration of ketorolac and meloxicam produced antinociception in non-diabetic and diabetic rats. However, the antinociceptive effect of both drugs was significantly reduced in diabetic animals. Proglumide was ineffective by itself and it did not affect the antinociception induced by the cyclooxygenase inhibitors in non-diabetic rats. Contrariwise, proglumide reduced formalin-induced nociception and it increased ketorolac- or meloxicam-induced antinociception in diabetic rats. These results suggest that peripheral cholecystokinin plays an important role in diabetes-induced sensitization as well as in the reduction of the antinociceptive effects of ketorolac and meloxicam in diabetic rats. The combination of cholecystokinin receptor antagonists and ketorolac or meloxicam may be a useful strategy to reduce nociception in diabetic patients.
Keywords: Diabetes; Meloxicam; Ketorolac; Cholecystokinin; Proglumide;
Effect of pioglitazone on altered expression of Aβ metabolism-associated molecules in the brain of fructose-drinking rats, a rodent model of insulin resistance by Dingzhen Luo; Xunyao Hou; Liang Hou; Meixia Wang; Song Xu; Chuanfang Dong; Xueping Liu (14-19).
Accumulation of β-amyloid (Aβ) peptide in the brain is a major hallmark of Alzheimer's disease. An optimal brain insulin level promotes Aβ clearance, which may play protective roles against Alzheimer's disease. In this study we examined the role of dietary conditions leading to insulin resistance on amyloidosis in fructose-drinking rats. Further investigations tested pioglitazone, an insulin sensitizer, intervention on the altered amyloidosis in this rodent model of insulin resistance. Six-week-old male Wistar rats were fed a standard commercial diet and water without (control) or with 10% fructose for 16 weeks. The animals were randomly divided into 4 groups (n = 10): non-treated and water-drinking rats (control group); pioglitazone treated and water-drinking (control treatment group); non-treated and fructose-drinking rats (fructose group) and pioglitazone-treated and fructose-drinking rats (fructose treatment group). Pioglitazone was given at the dose of 10 mg/kg d by gavage for the last 12 weeks of the 16-week period. We found that diet-induced insulin resistance induced Aβ overproduction with altered expression of Aβ metabolism-associated molecules, which corresponded with increased β-secretase-1 (BACE1), γ-secretase (PS-1) activities and decreased insulin degrading enzyme (IDE) activities, but not neprilysin in the cortex and hippocampus. Additionally, pioglitazone treatment prevented all these observed abnormalities. This study indicates that insulin resistance induced by fructose-drinking affects the expression of Aβ metabolism-associated molecules that are responsible for Aβ deposition and pioglitazone treatment negatively modulate amyloidogenesis.
Keywords: Pioglitazone; Insulin resistance; β-amyloid;
Cordycepin protects against cerebral ischemia/reperfusion injury in vivo and in vitro by Zhenyong Cheng; Wei He; Xiaoxia Zhou; Qing Lv; Xulin Xu; Shanshan Yang; Chenming Zhao; Lianjun Guo (20-28).
Cordycepin, (3′-deoxyadenosine), a bioactive compound of Cordyceps militaris, has been shown to exhibit many pharmacological actions, such as anti-inflammatory, antioxidative and anticancer activities. Little is known about the neuroprotective action of cordycepin as well as its molecular mechanisms. In this study, cordycepin was investigated for its neuroprotective potential in mice with ischemia following 15 min of the bilateral common carotid artery occlusion and 4 h of reperfusion. The effect of cordycepin was also studied in mice brain slices treated with oxygen–glucose deprivation (OGD) injury. Our results showed that cordycepin was able to prevent postischemic neuronal degeneration and brain slice injury. Excitatory amino acids such as glutamate and aspartate in brain homogenized supernatant, which were increased in ischemia/reperfusion group, were detected by high performance liquid chromatography (HPLC). The results showed that cordycepin was able to decrease the extracellular level of glutamate and aspartate significantly. Moreover, cordycepin was able to increase the activity of superoxide dismutase (SOD) and decrease the level of malondialdehyde (MDA), ameliorating the extent of oxidation. Furthermore, matrix metalloproteinase-3(MMP-3), a key enzyme involved in inflammatory reactions, was markedly increased after ischemia reperfusion, whereas cordycepin was able to inhibit its expression obviously. In conclusion, our in vivo and in vitro study showed that cordycepin was able to exert a potent neuroprotective function after cerebral ischemia/reperfusion.
Keywords: Cordycepin; Cerebral ischemia reperfusion; Matrix metalloproteinase-3; Oxygen–glucose deprivation;
Tyramine reduces glycinergic transmission by inhibiting presynaptic Ca2+ channels in the rat trigeminal subnucleus caudalis by In-Sun Choi; Jin-Hwa Cho; Maan-Gee Lee; Il-Sung Jang (29-35).
We have recently reported that tyramine acts on putative presynaptic trace amine receptors to inhibit glycinergic transmission in substantia gelatinosa (SG) neurons of the rat trigeminal subnucleus caudalis. However, it is still unknown how tyramine elicits presynaptic inhibition of glycine release. In the present study, therefore, we investigated cellular mechanisms underlying the tyramine-induced inhibition of glycinergic transmission in SG neurons using a conventional whole-cell patch clamp technique. Tyramine (100 μM) reversibly and repetitively decreased the amplitude of action potential-dependent glycinergic inhibitory postsynaptic currents (IPSCs), and increased the paired-pulse ratio. Pharmacological data suggest that the tyramine-induced decrease in glycinergic IPSCs was not mediated by the modulation of adenylyl cyclase, protein kinase A and C, or G-protein coupled inwardly rectifying K+ channels. On the other hand, glycinergic IPSCs were mainly mediated by the Ca2+ influx passing through presynaptic N-type and P/Q-type Ca2+ channels. The tyramine-induced decrease in glycinergic IPSCs was completely blocked by ω-conotoxin GVIA, an N-type Ca2+ channel blocker, but not ω-agatoxin IVA, a P/Q-type Ca2+ channel blocker. The results suggest that tyramine acts presynaptically to decrease action potential-dependent glycine release onto SG neurons via the selective inhibition of presynaptic N-type Ca2+ channels. This tyramine-induced inhibition of glycinergic transmission in SG neurons might affect the process of orofacial nociceptive signals.
Keywords: Trigeminal subnucleus caudalis; Tyramine; Trace amine; Glycinergic IPSC; Presynaptic inhibition; Ca2+ channel;
Binding characteristics of brivaracetam, a selective, high affinity SV2A ligand in rat, mouse and human brain: Relationship to anti-convulsant properties by Michel Gillard; Bruno Fuks; Karine Leclercq; Alain Matagne (36-44).
Brivaracetam is a novel synaptic vesicle protein 2A (SV2A) ligand reported to be 10 fold more potent than levetiracetam in animal models of epilepsy. This study reports the binding profile of brivaracetam in the brain of several species in relation to its anticonvulsant properties.The affinity, kinetics and selectivity of brivaracetam and its tritiated form [3H]ucb 34714 have been determined by in vitro binding experiments in rat, human and mouse brain and on recombinant human SV2A. Brivaracetam and levetiracetam ex vivo binding to SV2A and anticonvulsant activities in audiogenic mice were compared in relation to dose and time.Brivaracetam bound selectively with 20 fold higher affinity than levetiracetam to SV2A. [3H]ucb 34714 bound reversibly and with high affinity to an homogenous population of binding sites in rat and human brain and to human SV2A expressed in CHO cells. The binding sites labeled by [3H]ucb 34714 in brain had the pharmacological characteristics of SV2A and no specific binding could be detected in the brain of SV2A−/− knock-out mice. The time- and dose-dependency of brivaracetam and levetiracetam for binding to brain SV2A and for providing seizure protection in audiogenic mice correlated well; brivaracetam being more potent and faster than levetiracetam.Brivaracetam is a potent and selective SV2A ligand. From its affinity and pharmacokinetics, simulations predicted that at therapeutically relevant doses, brivaracetam should occupy more than 80% of SV2A in human brain, in line with levels of occupancy observed in pre-clinical models of epilepsy.
Keywords: Brivaracetam; Levetiracetam; Antiepileptic; Synaptic vesicle; SV2A;
Resveratrol modifies risk factors for coronary artery disease in swine with metabolic syndrome and myocardial ischemia by Michael P. Robich; Robert M. Osipov; Louis M. Chu; Yuchi Han; Jun Feng; Reza Nezafat; Richard T. Clements; Warren J. Manning; Frank W. Sellke (45-53).
Resveratrol has been purported to modify risk factors for obesity and cardiovascular disease. We sought to examine the effects of resveratrol in a porcine model of metabolic syndrome and chronic myocardial ischemia. Yorkshire swine were fed either a normal diet (control), a high cholesterol diet (HCD), or a high cholesterol diet with supplemental resveratrol (HCD-R; 100 mg/kg/day) for 11 weeks. After 4 weeks of diet modification a baseline cardiovascular MRI was performed and an ameroid constrictor was placed on the left circumflex coronary artery of each animal to induce chronic myocardial ischemia. At 7 weeks, a second cardiovascular MRI was performed and swine were sacrificed and myocardial tissue harvested. Resveratrol supplementation resulted in lower body mass indices, serum cholesterol, and C-reactive protein levels, improved glucose tolerance and endothelial function, and favorably augmented signaling pathways associated with myocardial metabolism. Interestingly, serum tumor necrosis factor-α levels were not influenced by resveratrol treatment. Immunoblotting for markers of metabolism demonstrated that insulin receptor substrate-1, glucose transporters 1 and 4, and phospho-AMPK were increased in the HCD-R group. Peroxisome proliferator-activated receptor γ and retinol binding protein 4 were downregulated in the HCD-R group as compared to the HCD group. Myocardial perfusion and function at rest as assessed with magnetic resonance imaging were not different between groups. By favorably influencing risk factors, resveratrol may decrease the burden of chronic metabolic disease and improve cardiovascular health.
Keywords: Resveratrol; Metabolic syndrome; Myocardial ischemia; Glucose metabolism; Myocardial infarction risk factor modification;
Poncirin promotes osteoblast differentiation but inhibits adipocyte differentiation in mesenchymal stem cells by Hyung-Young Yoon; Sun-Il Yun; Bo-Young Kim; Qinglong Jin; Eun-Rhan Woo; Seon-Yong Jeong; Yoon-Sok Chung (54-59).
Poncirin, flavanone glycoside, isolated from the fruit of Poncirus trifoliata, has anti-bacterial and anti-inflammatory activities. In this study, the effects of poncirin on the differentiation of mesenchymal stem cells were investigated. The C3H10T1/2 mesenchymal stem cells and primary bone marrow mesenchymal stem cells were studied. In the C3H10T1/2 cells, poncirin prevented adipocyte differentiation, as demonstrated by inhibition of cytoplasm lipid droplet accumulation and peroxisome proliferator-activating receptor-γ (PPAR-γ) and CCAAT-enhancer-binding protein-β (C/EBP-β) mRNA expression. By contrast, poncirin enhanced the expression of the key osteogenic transcription factors, runt-related transcription factor 2 (Runx2) and transcriptional coactivator with PDZ-binding motif (TAZ). Poncirin also enhanced expression of the osteogenic marker genes including alkaline phosphatase (ALP) and osteocalcin (OC). Poncirin increased mineral nodule formation in primary bone marrow mesenchymal stem cells. These results suggest that poncirin prevents adipogenesis and enhances osteoblast differentiation in mesenchymal stem cells.
Keywords: Poncirin; Mesenchymal stem cell; Differentiation; Osteoblast; Adipocyte;