Inhibition of cardiac late sodium current (late I Na ) is a strategy to suppress arrhythmias and sodium-dependent calcium overload associated with myocardial ischemia and heart failure. Current inhibitors of late I Na are unselective and can be proarrhythmic. This study introduces GS967 (6-[4-(trifluoromethoxy), a potent and selective inhibitor of late I Na , and demonstrates its effectiveness to suppress ventricular arrhythmias. The effects of GS967 on rabbit ventricular myocyte ion channel currents and action potentials were determined. Anti-arrhythmic actions of GS967 were characterized in ex vivo and in vivo rabbit models of reduced repolarization reserve and ischemia. GS967 inhibited Anemonia sulcata toxin II (ATX-II)-induced late I Na in ventricular myocytes and isolated hearts with IC 50 values of 0.13 and 0.21 mM, respectively. Reduction of peak I Na by GS967 was minimal at a holding potential of 2120 mV but increased at 280 mV. GS967 did not prolong action potential duration or the QRS interval. GS967 prevented and reversed proarrhythmic effects (afterdepolarizations and torsades de pointes) of the late I Na enhancer ATX-II and the I Kr inhibitor E-4031 in isolated ventricular myocytes and hearts. GS967 significantly attenuated the proarrhythmic effects of methoxamine1clofilium and suppressed ischemiainduced arrhythmias. GS967 was more potent and effective to reduce late I Na and arrhythmias than either flecainide or ranolazine. Results of all studies and assays of binding and activity of GS967 at numerous receptors, transporters, and enzymes indicated that GS967 selectively inhibited late I Na . In summary, GS967 selectively suppressed late I Na and prevented and/or reduced the incidence of experimentally induced arrhythmias in rabbit myocytes and hearts.
Epidemiological investigations have shown that fetuses with intrauterine growth retardation (IUGR) are susceptible to adult metabolic syndrome. Clinical investigations and experiments have demonstrated that caffeine is a definite inducer of IUGR, as children who ingest caffeine-containing food or drinks are highly susceptible to adult obesity and hypertension. Our goals for this study were to investigate the effect of prenatal caffeine ingestion on the functional development of the fetal hippocampus and the hypothalamic-pituitary-adrenal (HPA) axis and to clarify an intrauterine HPA axis-associated neuroendocrine alteration induced by caffeine. Pregnant Wistar rats were intragastrically administered 20, 60, and 180 mg/kg·d caffeine from gestational days 11–20. The results show that prenatal caffeine ingestion significantly decreased the expression of fetal hypothalamus corticotrophin-releasing hormone. The fetal adrenal cortex changed into slight and the expression of fetal adrenal steroid acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc), as well as the level of fetal adrenal endogenous corticosterone (CORT), were all significantly decreased after caffeine treatment. Moreover, caffeine ingestion significantly increased the levels of maternal and fetal blood CORT and decreased the expression of placental 11β-hydroxysteroid dehydrogenase-2 (11β-HSD-2). Additionally, both in vivo and in vitro studies show that caffeine can downregulate the expression of fetal hippocampal 11β-HSD-2, promote the expression of 11β-hydroxysteroid dehydrogenase 1 and glucocorticoid receptor (GR), and enhance DNA methylation within the hippocampal 11β-HSD-2 promoter. These results suggest that prenatal caffeine ingestion inhibits the development of the fetal HPA axis, which may be associated with the fetal overexposure to maternal glucocorticoid and activated glucocorticoid metabolism in the fetal hippocampus. These results will be beneficial in elucidating the developmental toxicity of caffeine and in exploring the fetal origin of adult HPA axis dysfunction and metabolic syndrome susceptibility for offspring with IUGR induced by caffeine.
Physician assessment as a means for predicting malignancy in pulmonary nodules is more accurate than previously validated nodule prediction calculators. Despite the accuracy of clinical intuition, physicians did not follow guideline-based recommendations when selecting the next diagnostic test. To provide optimal patient care, focus in the areas of guideline refinement, implementation, and dissemination is needed.
IntroductionSodium ferulate (SF) is a natural component of traditional Chinese herbs. Our previous study shows that SF has a protective effect on osteoarthritis (OA). The objective of this study was to investigate the effect of SF on the TNF/TNF receptor (TNFR) signal transduction pathway of rat OA chondrocytes.MethodsPrimary rat articular chondrocytes were co-treated with IL-1β and SF. Chondrocyte apoptosis was assessed by fluorescein isothiocyanate-annexin V/propidium iodide assay. The PCR array was used to screen the expression of 84 key genes involved in apoptosis. The release of TNFα and prostaglandin E2 were analyzed by ELISA. Expressions of proteins were assessed by western blotting. The activity of NF-κB was determined by electrophoretic mobility shift assay (EMSA). Gene expression of inducible nitric oxide synthase (iNOS) was evaluated by real-time quantitative PCR. The nitric oxide content was measured with the Griess method.ResultsAfter treatment with SF, the apoptosis rate of chondrocytes significantly attenuated (P < 0.01). Results of the apoptosis PCR array suggested that mRNA expression of some core proteins in the TNF/TNFR pathway showed valuable regulation. The protein expressions of TNFα, TNFR-1, TNF receptor-associated death domain, caspase-8 and caspase-3 were prevented by SF in a concentration-dependent manner. SF also inhibited activities of caspase-8 and caspase-3 compared with the OA model control (P < 0.01). TNF receptor-associated factor-2 expression, phosphorylations of inhibitor of NF-κB kinase (IKK) subunits alpha and beta, and NF-κB inhibitor, alpha (IκBα) were all concentration-dependently suppressed by SF treatment. The results of EMSA showed that SF inhibited the activity of NF-κB. In addition, the expressions of cycloxygenase-2 and iNOS and the contents of prostaglandin E2 and NO were attenuated with the treatment of SF (P < 0.01).ConclusionSF has anti-apoptosis and anti-inflammatory effects on an OA model induced by IL-1β in vitro, which were due to inhibitory actions on the caspase-dependent apoptosis pathway and the IKK/NF-κB signal transduction pathway of the TNF/TNFR pathway.
Abstract. As a traditional Chinese medicine, dragon's blood (DB) is widely used in treating various pains for thousands of years due to its potent anti-inflammatory and analgesic effects. In the present study, we observed that intragastric administration of DB at dosages of 0.14, 0.56, and 1.12 g/kg potently inhibited paw edema, hyperalgesia, cyclooxygenase-2 (COX-2) protein expression, or preprotachykinin-A mRNA expression in carrageenan-inflamed or sciatic nerve-injured (chronic constriction injury) rats, respectively. A short-term (15 s or 10 min) pre-exposure of cultured rat dorsal root ganglion (DRG) neurons to DB (0.3, 3, and 30 μg/ml) or its component cochinchinenin B (CB; 0.1, 1, and 10 μM) blocked capsaicin-evoked increases in both the intracellular calcium ion concentration and the substance P release. Moreover, a long-term (180 min) exposure of cultured rat DRG neurons to DB or CB significantly attenuated bradykinin-induced substance P release. These findings indicate that DB exerts anti-inflammatory and analgesic effects by blocking the synthesis and release of substance P through inhibition of COX-2 protein induction and intracellular calcium ion concentration. Therefore, DB may serve as a promising potent therapeutic agent for treatment of chronic pain, and its effective component CB might partly contribute to anti-inflammatory and analgesic effects.
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