Long-lasting Inhibitory Effect Research Articles

The role of opicapone in the management of Parkinson's disease: an Italian consensus through a combined Nominal Group Technique and Delphi approach.

Opicapone (OPC) is a third-generation peripheral catechol-O-methyl transferase inhibitor (COMT-i) approved as add-on therapy to levodopa/DOPA decarboxylase inhibitors (DDCI) combinations in Parkinson's disease (PD) patients with end-of-dose motor fluctuations. While the OPC effectiveness on motor symptoms is well known, there is still uncertainty about the timing of introduction, the management of levodopa dose, and the efficacy on non-motor symptoms (NMS). A group of PD experts participated in a consensus activity composed of the Nominal Group Technique (NGT) and the Delphi method to better define the role of OPC. A list of statements was defined with the NGT and voted on through an online Delphi process by a panel of 85 Italian clinicians. 24 statements were selected for the Delphi voting. Most statements (n=15, 62%) reached a consensus. A wide agreement was reached about the efficacy of OPC in treating motor fluctuations, including early morning akinesia and nocturnal akinesia. The panel widely agreed about the effectiveness of OPC in early fluctuating patients. The long-lasting inhibitory effect of OPC was recognized as an advantage over other COMT-i, resulting in a single daily dose and greater ease of introduction into the levodopa therapeutic regimen. The efficacy of OPC observed in the clinical trials for the management of PD patients with motor fluctuations is also experienced in clinical practice. The review of the current positioning of OPC from the late to early stages of the disease may represent an important step in the evolution of the PD therapeutic approach.

Imidazo[1,2-a]pyridine: a Highly Potent Therapeutic Agent Clears Piroplasm Infection In Vitro.

The imidazo[1,2-a] pyridines have huge applications in medicinal chemistry with potent activity against wide spectrum of infectious agents. The efficacy of imidazo[1,2-a]pyridine on the in vitro growth of different piroplasms, including Babesia bovis, B. bigemina, B. divergens, B. caballi, and Theileria equi, was investigated in this study. The anti-piroplasm efficacy of imidazo[1,2-a] pyridines was assessed using a fluorescence-based SYBR Green I assay. Furthermore, efficacy of imidazo[1,2-a]pyridine against piroplasms following discontinuation of treatment was also assessed using a viability assay. In vitro cultures of B. bovis and T. equi were used to assess the imidazo[1,2-a]pyridine and diminazene aceturate (DA) interaction. In vitro, imidazo[1,2-a]pyridine inhibited the growth of B. bovis, B. bigemina, B. caballi, and T. equi in a dose-dependent manner. The highest inhibitoryeffects of imidazo[1,2-a]pyridine were detected on the growth of B. caballi with IC50 value of 0.47 ± 0.07. Interestingly, the efficacy of imidazo[1,2-a]pyridine was higher against B. bigemina (IC50: 1.37 ± 0.15) compared to the positive-control DA (IC50: 2.29 ± 0.06). The viability test findings indicate that imidazo[1,2-a]pyridine had a long-lasting inhibitory effect on bovine Babesia parasites in vitro growth up to 4days after treatment. Notably, when coupled with DA at 0.75 or 0.50 IC50, a high concentration (0.75 IC50) of imidazo[1,2-a]pyridine produced additive suppression of B. bovis growth which suggest that imidazo[1,2-a]pyridine/DA could be a promising combination therapy for the treatment of B. bovis. The obtained encouraging findings pave the way for in vitro and in vivo efficacy trials of imidazo[1,2-a]pyridine derivatives against several piroplasmids.

Lactobacillus cell envelope-coated nanoparticles for antibiotic delivery against cariogenic biofilm and dental caries

BackgroundDue to their prevalence, dental caries ranks first among all diseases endangering human health. Therefore, the prevention of caries is of great significance, as caries have become a serious public health problem worldwide. Currently, using nanoscale drug delivery systems to prevent caries has received increased attention. However, the preventive efficacy of these systems is substantially limited due to the unique physiological structure of cariogenic biofilms. Thus, novel strategies aimed at combating cariogenic biofilms to improve preventive efficiency against caries are meaningful and very necessary. Herein, inspired by cell membrane coating technology and Lactobacillus strains, we coated triclosan (TCS)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TCS@PLGA-NPs) with an envelope of Lactobacillus (LA/TCS@PLGA-NPs) and investigated their potential as a nanoparticle delivery system against cariogenic biofilms and dental caries.ResultsLA/TCS@PLGA-NPs were successfully prepared with favorable properties, including a coated envelope, controllable size, negative charge, sustained drug-release kinetics and so on. The LA/TCS@PLGA-NPs inherited native properties from the source cell surface, thus the LA/TCS@PLGA-NPs adhered to S. mutans, integrated into the S. mutans biofilm, and interfered with the biofilm formation of S. mutans. The nanoparticles significantly inhibited the activity, biomass and virulence gene expression of S. mutans biofilms in vitro. Additionally, LA/TCS@PLGA-NPs exhibited a long-lasting inhibitory effect on the progression of caries in vivo. The safety performance of the nanoparticles is also favorable.ConclusionsOur findings reveal that the antibiofilm effect of LA/TCS@PLGA-NPs relies not only on the inheritance of native properties from the Lactobacillus cell surface but also on the inhibitory effect on the activity, biomass and virulence of S. mutans biofilms. Thus, these nanoparticles could be considered feasible candidates for a new class of effective drug delivery systems for the prevention of caries. Furthermore, this work provides new insights into cell membrane coating technology and presents a novel strategy to combat bacterial biofilms and associated infections.Graphical

Lemongrass-Incorporated Tissue Conditioner with Adjustable Inhibitory Effect Against Candida albicans: An In Vitro Study.

To develop and assess lemongrass-incorporated tissue conditioners (LG-TCs) with a potent and long-lasting inhibitory effect against Candida albicans cultures to control the accumulation of fungi. LG essential oil with concentrations of 7.17%, 3.56%, 1.77%, and 0.89% (w/w) or nystatin were mixed with the liquid part of the TC before being added to the powder part to form 486 TC samples of 6-mm diameter x 2-mm thickness (n = 81 samples for each group of LG-/nystatin-incorporated or unmodified TCs). After being immersed in 37°C water for 1, 2, 3, 5, 7, 9, 12, or 14 days, these TC samples were removed, blotted with sterile filter paper, and then exposed to fungal suspension (1 × 105 CFU/mL). The TC samples were evaluated for their capacity to inhibit fungal growth by 99.9%. The anti-Candida effect of the unmodified TCs was reduced significantly after the samples were immersed in water. Interestingly, a long-lasting anti-Candida effect was observed in the TCs incorporated with LG essential oil. After being immersed in water for at least 14 days, the TCs with 1.77% LG oil were still able to inhibit fungal growth substantially. In contrast, a shorter-lasting (5 days) anti-Candida effect was found in the TCs with 0.89% (w/w) LG oil. Additionally, the TCs incorporated with LG oil at concentrations of 3.56% (w/w) or more inhibited the growth of the fungus by 99.99%, and its anti-Candida effect lasted for 14 days. LG-TCs showed an impressive and long-lasting inhibitory effect against C. albicans.

Inhibition effect and adsorption behavior of two pyrimidine derivatives as corrosion inhibitors for Q235 steel in CO2-saturated chloride solution

• The studied inhibitors exhibit excellent and long-lasting inhibition performance. • 2-MP shows better inhibiting effect due to its tautomers of thiol and thione forms. • The adsorption process of the inhibitors is a mix of physisorption and chemisorption. • The adsorption process is spontaneous, exothermic and follows Langmuir isotherm. The anticorrosion performance of two pyrimidine derivatives 2-mercaptopyrimidine (2-MP) and 4-methyl-2-mercaptopyrimidine (4 M−2MP) on Q235 plain carbon steel in CO 2 -saturated 3 wt% NaCl aqueous solution has been comparatively examined utilizing weight loss methods, electrochemical techniques as well as surface analysis. The results indicate that the two kinds of pyrimidine derivatives serve as mixed-type inhibitors and show excellent and long-lasting inhibitory effect for Q235 steel against general and localized corrosion even at very low concentrations. The inhibition efficiencies increase with a rise in concentration but decrease with temperature rising. Compared with 4 M−2MP inhibitor, the 2-MP exhibits stronger adsorption ability and higher inhibition efficiency due to the existence of two tautomers of thiol and thione forms. The adsorption of both inhibitors over Q235 steel surface can be well fitted by Langmuir adsorption isotherm. The values of standard Gibbs free energy of adsorption ( Δ G a d s 0 ) indicate that both physisorption and chemisorption processes have taken place. Furthermore, thermodynamic parameters are extracted from Langmuir rule to discuss the adsorption mechanism and the XPS analysis is applied to describe the bonding characteristics between inhibitors and steel substrate.

Biofilm Formation in Methicillin-Resistant Staphylococcus aureus Isolated in Cystic Fibrosis Patients Is Strain-Dependent and Differentially Influenced by Antibiotics.

Cystic fibrosis (CF) is a genetic disease with lung abnormalities making patients particularly predisposed to pulmonary infections. Staphylococcus aureus is the most frequently identified pathogen, and multidrug-resistant strains (MRSA, methicillin-resistant S. aureus) have been associated with more severe lung dysfunction leading to eradication recommendations. Diverse bacterial traits and adaptive skills, including biofilm formation, may, however, make antimicrobial therapy challenging. In this context, we compared the ability of a collection of genotyped MRSA isolates from CF patients to form biofilm with and without antibiotics (ceftaroline, ceftobiprole, linezolid, trimethoprim, and rifampicin). Our study used standardized approaches not previously applied to CF MRSA, the BioFilm Ring test® (BRT®), the Antibiofilmogram®, and the BioFlux™ 200 system which were adapted for use with the artificial sputum medium (ASM) mimicking conditions more relevant to the CF lung. We included 63 strains of 10 multilocus sequence types (STs) isolated from 35 CF patients, 16 of whom had chronic colonization. The BRT® showed that 27% of the strains isolated in 37% of the patients were strong biofilm producers. The Antibiofilmogram® performed on these strains showed that broad-spectrum cephalosporins had the lowest minimum biofilm inhibitory concentrations (bMIC) on a majority of strains. A focus on four chronically colonized patients with inclusion of successively isolated strains showed that ceftaroline, ceftobiprole, and/or linezolid bMICs may remain below the resistance thresholds over time. Studying the dynamics of biofilm formation by strains isolated 3years apart in one of these patients using BioFlux™ 200 showed that inhibition of biofilm formation was observed for up to 36h of exposure to bMIC and ceftaroline and ceftobiprole had a significantly greater effect than linezolid. This study has brought new insights into the behavior of CF MRSA which has been little studied for its ability to form biofilm. Biofilm formation is a common characteristic of prevalent MRSA clones in CF. Early biofilm formation was strain-dependent, even within a sample, and not only observed during chronic colonization. Ceftaroline and ceftobiprole showed a remarkable activity with a long-lasting inhibitory effect on biofilm formation and a conserved activity on certain strains adapted to the CF lung environment after years of colonization.

Impact of CYP2C19 Genotype on Voriconazole Exposure and Effect of Voriconazole on the Activity of CYP3A in Patients with Hematological Malignancies

Voriconazole (VRC) is a first-line drug for the treatment of invasive fungal infections (IFIs) and an inhibitor of CYP3A activity.The aims of this study is to investigate the influence of related factors on the plasma concentration of voriconazole and the effect of voriconazole on the activity of CYP3A in patients with hematological malignancies. A total of 89 patients received an initial dose of 6 mg/kg followed by 4 mg/kg every 12 h were included in the study. Blood samples were collected before and 2 h after administration for subsequent testing and for the extraction of DNA samples. Voriconazole and voriconazole N-oxide in the plasma were detected by LC-MS/MS. The effect of voriconazole on CYP3A activity was evaluated by the ratio of the endogenous biomarkers 6β-hydroxycortisol and cortisol. During the study period, the overall incidence of adverse reactions was 33.6% (with no deaths). The metabolite type of CYP2C19 and combined use of CYP2C19 enzyme inhibitors both had a significant impact on voriconazole exposure. Voriconazole has a long-lasting and potent inhibitory effect on CYP3A activity. The exposure of CYP3A substrate in combination with metabolic enzyme inhibitors voriconazole could increase. Therefore, the combination uses with voriconazole need to be considered carefully and assessed adequately.

Microbial Characteristics of the Combined Ozone and Tea Polyphenols or Sodium Hypochlorite Disinfection in the Pipe Network

Microbiological safety of water in the pipe network is an important guarantee for safe drinking water. Simulation tests of stainless steel pipe network were carried out using te4a polyphenols and sodium hypochlorite as auxiliary disinfectants for ozone disinfection to analyze the persistent disinfection effects of different combined disinfection methods by measuring the changes in total bacterial colonies in the water. High-throughput sequencing of microorganisms in the pipe network was performed to analyze the differences in the community structure of microorganisms in the water and pipe wall under different disinfection methods. The results showed that the application of auxiliary disinfectants had a relatively long-lasting inhibitory effect on the bacterial colonies in the water, and the diversity of microorganisms in the pipe network varied significantly. As an auxiliary disinfectant for ozone disinfection, tea polyphenols are more powerful than sodium hypochlorite in killing pathogens and chlorine-resistant bacteria, so they are more beneficial to ensure the microbiological safety of water in stainless steel pipe networks.

Nature-derived bionanomaterials for sustained release of 5-fluorouracil to inhibit subconjunctival fibrosis

Effectively inhibiting subconjunctival fibrosis remains a challenge in pterygium and antiglaucoma surgery. As one of the superior first-line clinical drugs, 5-fluorouracil (5-FU) possesses certain disadvantages, such as fast drug metabolism and poor dose controllability. The emergence of appropriate pharmaceutical formulation and administration routes provides attractive solutions. In this work, we report the development of a multilevel drug release strategy using two types of nature-derived biomaterials (biocompatible chitosan and silk protein) processed into nanofibers of different size ranges, which was shown to achieve sustained release of 5-FU, toward the unique application of inhibiting subconjunctival fibrosis. In vitro data demonstrated that this system achieved fast 5-FU release during the first 25 days, where the release became relatively stable and lengthy (3 months) afterward. More importantly, the in vivo outcomes also suggested a continuous long-lasting inhibitory effect on subconjunctival myofibroblasts. These results indicated that our nature-derived bionanomaterials served as a promising drug-carrying platform for inhibiting subconjunctival fibrosis by providing sustained release of pharmaceutical compounds thus reducing the administration frequency, which may find broad utility in the treatment of ocular diseases and possibly other biomedical applications.

Carbon ion irradiation-induced DNA damage evokes cell cycle arrest and apoptosis via the pRb/E2F1/c-Myc signaling pathway in p53-deficient prostate cancer PC-3 cells

Carbon ion radiotherapy has the advantages of better therapeutic effect and fewer side effects compared with those of X-rays in many kinds of tumors, including prostate cancer, and thus is an attractive treatment approach for prostate cancer. However, the biological effects and underlying mechanisms of carbon ion irradiation in prostate cancer are not yet fully understood. Therefore, this study systematically compared the effects of carbon ion irradiation with those of X-ray irradiation on DNA damage response and found that carbon ion irradiation was more effective than X-ray irradiation. Carbon ion irradiation can induce a high level of DNA double-strand break damage, reflected by the number of γ-H2A histone family member X foci, as well as by the foci lasting time and size. Moreover, carbon ion irradiation exhibited strong and long-lasting inhibitory effect on cell survival capability, induced prolonged cell cycle arrest, and increased apoptosis in PC-3 cells. As an underlying mechanism, we speculated that carbon ion irradiation-induced DNA damage evokes cell cycle arrest and apoptosis via the pRb/E2F1/c-Myc signaling pathway to enhance the radiosensitivity of p53-deficient prostate cancer PC-3 cells. Collectively, the present study suggests that carbon ion irradiation is more efficient than X-ray irradiation and may help to understand the effects of different radiation qualities on the survival potential of p53-deficient prostate cancer cells.

Aptamer-targeting of Aleutian mink disease virus (AMDV) can be an effective strategy to inhibit virus replication

Aleutian mink disease (AMD), which is caused by Aleutian mink disease virus (AMDV), is an important contagious disease for which no effective vaccine is yet available. AMD causes major economic losses for mink farmers globally and threatens some carnivores such as skunks, genets, foxes and raccoons. Aptamers have exciting potential for the diagnosis and/or treatment of infectious viral diseases, including AMD. Using a magnetic beads-based systemic evolution of ligands by exponential enrichment (SELEX) approach, we have developed aptamers with activity against AMDV after 10 rounds of selection. After incubation with the ADVa012 aptamer (4 μM) for 48 h, the concentration of AMDV in the supernatant of infected cells was 47% lower than in the supernatant of untreated cells, whereas a random library of aptamers has no effect. The half-life of ADVa012 was ~ 32 h, which is significantly longer than that of other aptamers. Sequences and three dimensions structural modeling of selected aptamers indicated that they fold into similar stem-loop structures, which may be a preferred structure for binding to the target protein. The ADVa012 aptamer was shown to have an effective and long-lasting inhibitory effect on viral production in vitro.

Activation of the Liver X Receptor Pathway Inhibits HBV Replication in Primary Human Hepatocytes.

Hepatitis B virus (HBV) infection is ranked among the top health priorities worldwide. Accumulating evidence suggests that HBV infection and replication are closely associated with liver metabolism. The liver X receptors (LXRs), which belong to the superfamily of nuclear hormone receptors, are important physiological regulators of lipid and cholesterol metabolism. However, the association between the LXR pathway and HBV infection remains largely unclear. In this study, the antiviral activity of LXR agonists was investigated using multiple HBV cellular models. We observed that in HBV-infected primary human hepatocytes (PHHs), synthetic LXR agonists (T0901317, GW3965, and LXR-623), but not an LXR antagonist (SR9238), potently inhibited HBV replication and gene expression, as demonstrated by substantial reductions in viral RNA, DNA, and antigen production following agonist treatment. However, covalently closed circular DNA (cccDNA) levels were not significantly reduced by the agonists. In addition, no rebound in viral replication was observed after treatment withdrawal, indicating a long-lasting inhibitory effect. These results suggest that LXR agonists decrease the transcriptional activity of cccDNA. In contrast, no significant anti-HBV effect was observed in HepG2-derived cell lines. Interestingly, LXR agonist treatment strongly reduced cholesterol 7α-hydroxylase 1 (CYP7A1) mRNA levels. Knockdown of CYP7A1 gene expression with small interfering RNA inhibited HBV activity in PHHs, suggesting CYP7A1 as a potential factor contributing to the antiviral effects of LXR agonists. We found that activation of the LXR pathway with synthetic LXR agonists could elicit potent anti-HBV activity in PHHs, possibly through sustained suppression of cccDNA transcription. Our work highlights the therapeutic potential of targeting the LXR pathway for the treatment of chronic HBV infection.

Characterization of Apo-Form Selective Inhibition of Indoleamine 2,3-Dioxygenase*.

Indoleamine-2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme that catalyzes the rate-limiting step in the kynurenine pathway of tryptophan (TRP) metabolism. As it is an inflammation-induced immunoregulatory enzyme, pharmacological inhibition of IDO1 activity is currently being pursued as a potential therapeutic tool for the treatment of cancer and other disease states. As such, a detailed understanding of the mechanism of action of IDO1 inhibitors with various mechanisms of inhibition is of great interest. Comparison of an apo-form-binding IDO1 inhibitor (GSK5628) to the heme-coordinating compound, epacadostat (Incyte), allows us to explore the details of the apo-binding inhibition of IDO1. Herein, we demonstrate that GSK5628 inhibits IDO1 by competing with heme for binding to a heme-free conformation of the enzyme (apo-IDO1), whereas epacadostat coordinates its binding with the iron atom of the IDO1 heme cofactor. Comparison of these two compounds in cellular systems reveals a long-lasting inhibitory effect of GSK5628, previously undescribed for other known IDO1 inhibitors. Detailed characterization of this apo-binding mechanism for IDO1 inhibition might help design superior inhibitors or could confer a unique competitive advantage over other IDO1 inhibitors vis-à-vis specificity and pharmacokinetic parameters.

Melanocortin-4 receptor antagonist TCMCB07 ameliorates cancer- and chronic kidney disease-associated cachexia.

Cachexia, a devastating wasting syndrome characterized by severe weight loss with specific losses of muscle and adipose tissue, is driven by reduced food intake, increased energy expenditure, excess catabolism, and inflammation. Cachexia is associated with poor prognosis and high mortality and frequently occurs in patients with cancer, chronic kidney disease, infection, and many other illnesses. There is no effective treatment for this condition. Hypothalamic melanocortins have a potent and long-lasting inhibitory effect on feeding and anabolism, and pathophysiological processes increase melanocortin signaling tone, leading to anorexia, metabolic changes, and eventual cachexia. We used 3 rat models of anorexia and cachexia (LPS, methylcholanthrene sarcoma, and 5/6 subtotal nephrectomy) to evaluate efficacy of TCMCB07, a synthetic antagonist of the melanocortin-4 receptor. Our data show that peripheral treatment using TCMCB07 with intraperitoneal, subcutaneous, and oral administration increased food intake and body weight and preserved fat mass and lean mass during cachexia and LPS-induced anorexia. Furthermore, administration of TCMCB07 diminished hypothalamic inflammatory gene expression in cancer cachexia. These results suggest that peripheral TCMCB07 treatment effectively inhibits central melanocortin signaling and therefore stimulates appetite and enhances anabolism, indicating that TCMCB07 is a promising drug candidate for treating cachexia.

Macrophage-Derived Extracellular Vesicles Induce Long-Lasting Immunity Against Hepatitis C Virus Which Is Blunted by Polyunsaturated Fatty Acids.

Extracellular vesicles (EVs) are increasingly recognized as important mediators of intercellular communication. In this study, we aimed to further characterize the role of macrophage-derived EVs in immune responses against hepatitis C virus (HCV) and the potential of polyunsaturated fatty acids (PUFAs) to modulate this modality of innate immunity. To this end, EVs were isolated from interferon-stimulated macrophage cultures or from serum of patients with acute or chronic hepatitis C. EVs were characterized by electron microscopy, flow cytometry, RNA-sequencing, and Western blot analysis. The effect of EVs on replication of HCV was assessed in coculture models. Functional analyses were performed to assess the impact of PUFAs on EV-mediated antiviral immunity. We found that macrophages secreted various cytokines shortly after stimulation with type I and II IFN, which orchestrated a fast but short-lasting antiviral state. This rapid innate immune answer was followed by the production of macrophage-derived EVs, which induced a late, but long-lasting inhibitory effect on HCV replication. Of note, exposure of macrophages to PUFAs, which are important regulators of immune responses, dampened EV-mediated antiviral immune responses. Finally, EVs from patients with hepatitis C exhibited long-lasting antiviral activities during IFN therapy as well. The antiviral effect of EVs from Caucasian and Japanese patients differed, which may be explained by different nutritional uptake of PUFAs. In conclusion, our data indicate that macrophage-derived EVs mediate long-lasting inhibitory effects on HCV replication, which may bridge the time until efficient adaptive immune responses are established, and which can be blunted by PUFAs.

The Long-Lasting Enhancing Effect of Distigmine on Acetylcholine-Induced Contraction of Guinea Pig Detrusor Smooth Muscle Correlates with Its Anticholinesterase Activity.

Distigmine bromide (distigmine), a reversible, long-lasting cholinesterase (ChE) inhibitor, is used for the treatment of underactive bladder in Japan and has been shown to potentiate urinary bladder (UB) contractility. We studied the duration of distigmine's potentiating effects on acetylcholine (ACh)-induced UB contraction and its inhibitory effects on ChE activity, and compared that with those of other ChE inhibitors (neostigmine, pyridostigmine, and ambenonium). The duration of potentiating/inhibitory effects of ChE inhibitors, including distigmine, on ACh-induced guinea pig UB contraction/ChE activity was evaluated for 12 h following washout. Dissociation rate constants (k) of the inhibitors were also tentatively calculated based on the time courses of their ChE inhibitory effects. The potentiating effect of distigmine (10-6 M) on ACh-induced UB contraction and its inhibitory effect on ChE activity were significantly sustained 12 h after washout. The potentiating effect of other ChE inhibitors on ACh-induced UB contraction, however, was sustained only until 3 h after washout. The ChE inhibitory effects of these inhibitors dissipated in a time-dependent manner after washout, with more than 75% of ChE activity restored by 4 h after washout. The k values of ChE inhibitors approached 0.50 h-1, except for distigmine, where k could not be determined. Compared with that of other ChE inhibitors, the potentiating effect of distigmine on UB contractile function was significantly more sustainable following washout, which was likely associated with its corresponding long-lasting ChE inhibitory effect. Distigmine may associate more strongly with UB ChE than other ChE inhibitors, which would partly explain its sustained effects.

Effect of different directions of attentional shift on inhibition of return in three-dimensional space.

When attention is oriented to a peripheral cue, the processing of nearby stimuli is facilitated. This brief period of facilitation is followed by a long-lasting inhibitory effect, during which there is a delayed response to stimuli presented at a previously cued location. Although the mechanisms underlying the facilitatory effect of attentional orienting/reorienting in three-dimensional (3-D) space have been documented, there is not yet consensus as to how attention orients/reorients in depth during the later inhibitory phase (i.e., inhibition of return [IOR]). In the present study, by incorporating the Posner exogenous cueing paradigm into a virtual 3-D environment, we aimed to investigate whether an IOR effect occurs when attention orients and reorients at the uncued depth in the same hemispace, and whether the IOR effects are the same or different when attention orients/reorients along different trajectories in 3-D space. Our results showed asymmetrical spatial IOR effects when attention was oriented/reoriented at the uncued depth in the same hemispace. Spatial IOR was depth-specific when targets appeared in the near depth plane, whereas it was not depth-specific when targets appeared in the far depth plane. Apart from these results, we also found that attention oriented/reoriented at the same depth but in a different hemispace experienced a reduction in IOR size, thus indicating that the direction-specific spatial IOR mechanisms when attention orients/reorients along different trajectories are different. Taken together, our results suggest that spatial IOR is not entirely "depth-blind," and that the ecological importance of the 3-D world influences the direction of attentional shifts of spatial IOR in 3-D space.

Bulleyaconitine A depresses neuropathic pain and potentiation at C-fiber synapses in spinal dorsal horn induced by paclitaxel in rats

Paclitaxel, a widely used chemotherapeutic agent, often induces painful peripheral neuropathy and at present no effective drug is available for treatment of the serious side effect. Here, we tested if intragastrical application of bulleyaconitine A (BLA), which has been approved for clinical treatment of chronic pain in China since 1985, could relieve the paclitaxel-induced neuropathic pain. A single dose of BLA attenuated the mechanical allodynia, thermal hyperalgesia induced by paclitaxel dose-dependently. Repetitive administration of the drug (0.4 and 0.8mg/kg, t.i.d. for 7 d) during or after paclitaxel treatment produced a long-lasting inhibitory effect on thermal hyperalgesia, but not on mechanical allodynia. In consistency with the behavioral results, in vivo electrophysiological experiments revealed that spinal synaptic transmission mediated by C-fiber but not A fiber was potentiated, and the magnitude of long-term potentiation (LTP) at C-fiber synapses induced by the same high frequency stimulation was ~50% higher in paclitaxel-treated rats, compared to the naïve rats. Spinal or intravenous application of BLA depressed the spinal LTP, dose-dependently. Furthermore, patch clamp recordings in spinal cord slices revealed that the frequency but not amplitude of both spontaneous excitatory postsynaptic current (sEPSCs) and miniature excitatory postsynaptic currents (mEPSCs) in lamina II neurons was increased in paclitaxel-treated rats, and the superfusion of BLA reduced the frequency of sEPSCs and mEPSCs in paclitaxel-treated rats but not in naïve ones. Taken together, we provide novel evidence that BLA attenuates paclitaxel-induced neuropathic pain and that depression of spinal LTP at C-fiber synapses via inhibiting presynaptic transmitter release may contribute to the effect.

Potentiation of temozolomide antitumor effect by purine receptor ligands able to restrain the in vitro growth of human glioblastoma stem cells.

Glioblastoma multiforme (GBM), the most common and aggressive brain tumor in humans, comprises a population of stem-like cells (GSCs) that are currently investigated as potential target for GBM therapy. Here, we used GSCs isolated from three different GBM surgical specimens to examine the antitumor activity of purines. Cultured GSCs expressed either metabotropic adenosine P1 and ATP P2Y receptors or ionotropic P2X7 receptors. GSC exposure for 48 h to 10-150 μM ATP, P2R ligand, or to ADPβS or MRS2365, P2Y1R agonists, enhanced cell expansion. This effect was counteracted by the PY1R antagonist MRS2500. In contrast, 48-h treatment with higher doses of ATP or UTP, which binds to P2Y2/4R, or 2'(3')-O-(4-benzoylbenzoyl)-ATP (Bz-ATP), P2X7R agonist, decreased GSC proliferation. Such a reduction was due to apoptotic or necrotic cell death but mostly to growth arrest. Accordingly, cell regrowth and secondary neurosphere formation were observed 2 weeks after the end of treatment. Suramin, nonselective P2R antagonist, MRS1220 or AZ11645373, selective A3R or P2X7R antagonists, respectively, counteracted ATP antiproliferative effects. AZ11645373 also abolished the inhibitory effect of Bz-ATP low doses on GSC growth. These findings provide important clues on the anticancer potential of ligands for A3R, P2Y1R, and P2X7R, which are involved in the GSC growth control. Interestingly, ATP and BzATP potentiated the cytotoxicity of temozolomide (TMZ), currently used for GBM therapy, enabling it to cause a greater and long-lasting inhibitory effect on GSC duplication when readded to cells previously treated with purine nucleotides plus TMZ. These are the first findings identifying purine nucleotides as able to enhance TMZ antitumor efficacy and might have an immediate translational impact.

Synthesis of H2S in the Gastrointestinal Tract

Hydrogen sulfide (H2S) is the third gaseous signal molecule with interest which is endogenously generated in gastrointestinal tract. H2S play important physiological and pathophysiological roles in regulation of gastrointestinal functions, for example, gastrointestinal motility, secretion and nociception. In the present review we have mainly reviewed the recent findings about the study of H2S in regulation of gastrointestinal motility and its mechanism. The effect of H2S on gastrointestinal smooth muscle shows difference in different concentration of H2S and different regions. In gastric smooth muscle, H2S exhibits dual effects, that is, excitatory (low concentration) and inhibitory (high concentration) effects via suppressing voltage- dependent potassium channels and activating ATP-sensitive potassium channels (KATP), respectively, in guinea-pig and mouse. In intestinal smooth muscle, NaHS induced a biphasic effect, that is, a transient excitatory effect followed a long-lasting inhibitory effect in rat. The excitatory effect is mediated by TRPV1 and NK1 receptors and the inhibitory effect is mediated by KATP. In colonic smooth muscle, H2S induces inhibitory effect mediated by both KATP and SKCa channels in human, rat and mouse. This review gives a synopsis of the H2S function in regulation of gastrointestinal motility and its mechanism.