共查询到20条相似文献,搜索用时 15 毫秒
1.
Aims
To investigate the roles of PPARγ in advanced glycation end product (AGE)-mediated characteristics of neural stem cells (NSCs) and the molecular mechanisms of action.Methods
We prepared pLentiLox3.7 lentiviral vectors expressing short hairpin RNA (shRNA) against PPARγ and transduced NSCs. MTT absorbance and cell counts were used to assay cell growth, and cell differentiation was analysed by confocal laser-scanning and western blots for the expression of MAP2/nestin. The protein and gene expression of the BDNF-CREB pathway components were examined by western blotting and real-time PCR.Results
Immunoblot analysis indicated that shRNA delivered by lentiviral vectors silenced PPARγ expression in NSCs. The proliferation of NSCs and expression of BDNF pathway components dropped in AGE-BSA culture medium (400 mg/L and 200 mg/L) on Day 3 and Day 7, respectively (all P < 0.001). PPARγ-silenced NSCs exhibited a significant increase in cell growth and expression of BDNF pathway components compared with NSCs incubated with AGE-BSA (all P < 0.001). Immunocytochemistry and western blotting analysis showed that AGE-BSA (400 mg/L) induced a significant decrease in the expression of MAP2 both in NSCs and PPARγ-silenced NSCs, as standardised by nestin. There was no significant difference between NSCs and PPARγ-silenced NSCs in the presence of AGE-BSA.Conclusions
PPARγ plays roles in the AGE-mediated regulation of NSC proliferation but not neural differentiation through the BDNF-CREB pathway. 相似文献2.
Mahipal SV Subhashini J Reddy MC Reddy MM Anilkumar K Roy KR Reddy GV Reddanna P 《Biochemical pharmacology》2007,74(2):202-214
Growth inhibitory effects of 15-lipoxygenase-1 [13-(S)-HPODE and 13-(S)-HODE] and 15-lipoxygenase-2 [15-(S)-HPETE and 15-(S)-HETE] (15-LOX-1 and LOX-2) metabolites and the underlying mechanisms were studied on chronic myeloid leukemia cell line (K-562). The hydroperoxy metabolites, 15-(S)-HPETE and 13-(S)-HPODE rapidly inhibited the growth of K-562 cells by 3h with IC(50) values, 10 and 15microM, respectively. In contrast, the hydroxy metabolite of 15-LOX-2, 15-(S)-HETE, showed 50% inhibition only at 40microM by 6h and 13-(S)-HODE, hydroxy metabolite of 15-LOX-1, showed no significant effect up to 160microM. The cells exposed to 10microM of 15-(S)-HPETE and 40microM of 15-(S)-HETE showed typical apoptotic features like release of cytochrome c, caspase-3 activation and PARP-1 (poly(ADP) ribose polymerase-1) cleavage. A flow cytometry based DCFH-DA analysis and inhibitory studies with DPI, a pharmacological inhibitor of NADPH oxidase, NAC (N-acetyl cysteine) and GSH revealed that NADPH oxidase-mediated generation of ROS is responsible for caspase-3 activation and subsequent induction of apoptosis in the K-562 cell line. 相似文献
3.
Context
Hypothyroidism has been observed in the fifties and sixties as an undesirable side-effect of cobalt therapy used for its erythropoietic properties in the treatment of anemia.Objective
This study aims at evaluating the possible impact of both cumulative (long-term) and recent occupational exposure to cobalt on thyroid function and red blood cells.Methods and setting
A cross-sectional survey was conducted from February 2008 to August 2009 in a population of 249 male workers from a cobalt production department in the North of Belgium. The possible effect of cobalt exposure on thyroid and red blood cells was investigated through multiple regression analyses.Results
Blood cobalt ranged from undetectable to 3.20 μg/100 ml (median 0.10); urinary cobalt from 0.30 to 204.30 μg/gcreat (median 3.90) and long-term exposure to cobalt ranged from 0.15 to 6990.46 μg/gcreat·years (median 106.09). No effect of cobalt exposure on thyroid or red blood cell parameters was observed at these levels of exposure.Conclusion
The results support the absence of effects on the thyroid and red blood cells when occupational exposure to cobalt is kept below the recommended biological limit of occupational exposure (15 μg Co/gcreat in urine). 相似文献4.
5.
Cátia C.P. Aires Lodewijk IJlst Carina Prip-Buus Marinus Duran Margarida F.B. Silva 《Biochemical pharmacology》2010,79(5):792-1746
Background/Aims
Carnitine palmitoyl-transferase I (CPT I) catalyses the synthesis of long-chain (LC)-acylcarnitines from LC-acyl-CoA esters. It is the rate-limiting enzyme of mitochondrial fatty acid β-oxidation (FAO) pathway and its activity is regulated by malonyl-CoA. The antiepileptic drug valproic acid (VPA) is a branched chain fatty acid that is activated to the respective CoA ester in the intra- and extra-mitochondrial compartments. This drug has been associated with a clear inhibition of mitochondrial FAO, which motivated our study on its potential effect on hepatic CPT I.Methods
To investigate the effect of valproyl-CoA (VP-CoA) on CPT I, we performed in vitro studies using control human fibroblasts and rat CPT IA expressed in Saccharomyces cerevisiae. In addition to the wild-type enzyme, two mutant rCPT IAs were studied, one of which showing increased sensitivity towards malonyl-CoA (S24A/Q30A), whereas the other one is insensitive to malonyl-CoA (E3A).Results
We demonstrate that VP-CoA inhibits the CPT I activity in control fibroblasts. Similar results were obtained using rCPT IA WT and S24A/Q30A. Importantly, VP-CoA also inhibited the activity of the rCPT IA E3A. We show that VP-CoA inhibits CPT IA competitively with respect to palmitoyl-CoA, and non-competitively to carnitine. Evidence is provided that VP-CoA interferes at the catalytic domain of CPT IA affecting the sensitivity for malonyl-CoA.Conclusions
The interference of VP-CoA with CPT IA, a pivotal enzyme in mitochondrial fatty acid β-oxidation, may be a crucial mechanism in the drug-induced hepatotoxicity and the weight gain frequently observed in patients under VPA therapy. 相似文献6.
Very low density lipoprotein receptor (VLDLR) is a member of the low density receptor family, expressed mostly in adipose tissue, heart, and skeletal muscles. VLDLR binds apolipoprotein-E-triglyceride-rich lipoproteins and plays a key role in lipid metabolism. In adipocytes, VLDLR expression increases with differentiation but it is not known whether it plays a role in the adipogenesis. Here we report that VLDLR expression in 3T3-L1 adipocytes is upregulated by PPARγ agonist 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) in dose- and time-dependant manners. Knockdown of peroxisome proliferator-activated receptor-γ (PPARγ) with siRNA abolished pioglitazone- and 15d-PGJ2-induced VLDLR expression and simultaneously reduced VLDL uptake in adipocytes. In addition, PPARγ-agonist treatment of control mouse adipocytes (vldlr+/+) enhanced adipogenesis and VLDL uptake concurrently with the induction of VLDLR expression. However, vldlr deficiency (vldlr−/−) significantly blunted the proadipogenic effects of PPARγ agonists. Sequence analysis revealed the presence of a putative PPARγ responsive sequence (PPRE) within the vldlr promoter, which is responsive to natural (15d-PGJ2) and synthetic (pioglitazone) PPARγ agonists. Reporter gene assays using serial deletion of the 5′-flanking region showed that this putative PPRE site induced promoter transactivation, while a site-targeted mutation abolished transactivation. Moreover, electrophoresis mobility shift assay (EMSA) and chromatic immunoprecipitation (ChIP) assays showed the specific binding of PPARγ to the PPRE sequence.Together, these results support a crucial function for VLDLR in adipocyte differentiation and mediation of the proadipogenic effect of PPARγ. 相似文献
7.
8.
Schindler EA Dave KD Smolock EM Aloyo VJ Harvey JA 《Pharmacology, biochemistry, and behavior》2012,101(1):69-76
Rationale
After decades of social stigma, hallucinogens have reappeared in the clinical literature demonstrating unique benefits in medicine. The precise behavioral pharmacology of these compounds remains unclear, however.Objectives
Two commonly studied hallucinogens, (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and lysergic acid diethylamide (LSD), were investigated both in vivo and in vitro to determine the pharmacology of their behavioral effects in an animal model.Method
Rabbits were administered DOI or LSD and observed for head bob behavior after chronic drug treatment or after pretreatment with antagonist ligands. The receptor binding characteristics of DOI and LSD were studied in vitro in frontocortical homogenates from naïve rabbits or ex vivo in animals receiving an acute drug injection.Results
Both DOI- and LSD-elicited head bobs required serotonin2A (5-HT2A) and dopamine1 (D1) receptor activation. Serotonin2B/2C receptors were not implicated in these behaviors. In vitro studies demonstrated that LSD and the 5-HT2A/2C receptor antagonist, ritanserin, bound frontocortical 5-HT2A receptors in a pseudo-irreversible manner. In contrast, DOI and the 5-HT2A/2C receptor antagonist, ketanserin, bound reversibly. These binding properties were reflected in ex vivo binding studies. The two hallucinogens also differed in that LSD showed modest D1 receptor binding affinity whereas DOI had negligible binding affinity at this receptor.Conclusion
Although DOI and LSD differed in their receptor binding properties, activation of 5-HT2A and D1 receptors was a common mechanism for eliciting head bob behavior. These findings implicate these two receptors in the mechanism of action of hallucinogens. 相似文献9.
Background
The respiratory tract is the primary route of exposure to inhaled toxicants such as environmental pollutants and tobacco smoke. Metabolic activation of xenobiotics is a contributor to the onset of lung diseases. Enzymes such as CYP1A1/1B1 and CYP2A6/2A13 activate polycyclic aromatic hydrocarbons and nitrosamines, respectively. Yet, few in vitro models retaining both adequate morphology and metabolic activities are currently available to investigate smoke toxicity.Objective
We characterised the expression and activity of the toxicologically relevant metabolic enzymes CYP1A1/1B1 and CYP2A6/2A13 in polarised primary tracheobronchial epithelial cells cultured at the air-liquid interface. Metabolic activity was compared with NCI-H292 and A549, two commonly used lung epithelial cell models.Results
We report that CYP activity and inducibility is conserved in polarised primary tracheobronchial epithelial cells for 7- and 28-days cultured at the air-liquid interface. In comparison, NCI-H292 cells did not show CYP2A6/2A13 activity whilst A549 cells did not display significant metabolic activity for CYP1A1/1B1 or CYP2A6/2A13.Conclusion
Primary tracheobronchial epithelial cells retain both a polarised morphology and significant metabolic activity over a prolonged period of time. On the other hand, although A549 cells and NCI-H292 cells have been extensively used as lung models for toxicological assessment, they lack critical metabolic activation capability. 相似文献10.
11.
Martín-Venegas R Casillas R Jáuregui O Moreno JJ 《Journal of pharmaceutical and biomedical analysis》2011,56(5):976-982
Eicosanoids are oxidized arachidonate-derived lipid products generated by cyclooxygenase, lipoxygenase and cytochrome P-450 pathways. They are involved in diverse processes in health and disease and they are highly bioactive. Gas chromatography and enzyme immunoassays were used to quantify these mediators in the past. However, the recent availability of high-sensitivity liquid chromatography-mass spectrometry has provided a new approach for quantification that minimizes the sample size and the required preparation. This paper describes a rapid and simple technique for the simultaneous quantitative analysis of prostaglandin (PG) E2 and PGJ2; leukotrienes (LT) B4 and D4; 5-, 12-, 15- and 20-hydroxyeicosatetraenoic acids (HETEs); 13-hydroxyoctadecadienoic acid (13-HODE); 5,6-, 8,9-, 11,12- and 14,15-epoxyeicosatrienoic acids (EETs); and 11,12- and 14,15-dihydroxieicosatrienoic acids (DHETs) in cell culture supernatants and urine. We simultaneously analyzed 14 arachidonic acid metabolites representative from the three pathways, together with 13-HODE, a linoleic-derived product. Solid phase extraction was used for the sample preparation. The recoveries obtained ranged from 25% to 100%, depending on the metabolites. The LC/MS/MS method used the gradient on a C18 column and electrospray ionization in negative ion detection mode. The method was optimized for sensitivity and for separation within 20 min. The linear ranges of the calibration curves were 0.1-200 ng/ml for PGE2, PGJ2, LTB4, 5-HETE, 12-HETE, 15-HETE, 13-HODE, 11,12-EET, 11,12-DHET and 14,15-DHET, and 1-200 ng/ml for LTD4, 20-HETE, 5,6-EET, 8,9-EET and 14,15-EET. The advantages of this method include minimal sample preparation, high sensitivity and elimination of the problem associated with thermal instability in gas chromatography analysis. 相似文献
12.
BACKGROUND AND PURPOSE
Lysophosphatidylcholines (lysoPCs) with polyunsaturated acyl chains are known to exert anti-inflammatory actions. 15-Lipoxygeanation is crucial for anti-inflammatory action of polyunsaturated acylated lysoPCs. Here, the anti-inflammatory actions of 1-(15-hydroxyeicosapentaenoyl)-lysoPC (15-HEPE-lysoPC) and its derivatives were examined in a mechanistic analysis.EXPERIMENTAL APPROACH
Anti-inflammatory actions of 15-HEPE-lysoPC in zymosan A-induced peritonitis of mice were examined by measuring plasma leakage and leucocyte infiltration, and determining levels of lipid mediators or cytokines.KEY RESULTS
When each lysoPC, administered i.v., was assessed for its ability to suppress zymosan A-induced plasma leakage, 15-HEPE-lysoPC was found to be more potent than 1-(15-hydroperoxyeicosapentaenoyl)-lysoPC or 1-eicosapentaenoyl-lysoPC. Separately, i.p. administration of 15-HEPE-lysoPC markedly inhibited plasma leakage, in contrast to 15-HEPE, which had only a small effect. 15-HEPE-lysoPC also decreased leucocyte infiltration. Moreover, it reduced the formation of LTC4 and LTB4, 5-lipoxygenation products, as well as the levels of pro-inflammatory cytokines. The time-course study indicated that 15-HEPE-lysoPC might participate in both the early inflammatory phase and resolution phase. Additionally, 15-HEPE-lysoPC administration caused a partial suppression of LTC4-induced plasma leakage and LTB4-induced leucocyte infiltration. In the metabolism study, peritoneal exudate was shown to contain lysoPC-hydrolysing activity, crucial for anti-inflammatory activity, and a system capable of generating lipoxin A from 15-hydroxy eicosanoid precursor.CONCLUSIONS AND IMPLICATIONS
15-HEPE-lysoPC, a precursor for 15-HEPE in target cells, induced anti-inflammatory actions by inhibiting the formation of pro-inflammatory leukotrienes and cytokines, and by enhancing the formation of lipoxin A. 15-HEPE-lysoPC might be one of many potent anti-inflammatory lipids in vivo. 相似文献13.
14.
Background and Purpose
Eicosapentaenoic acid (EPA) has been shown to suppress immune cell responses, such as cytokine production and downstream PG production in vitro. Studies in vivo, however, have used EPA as a minor constituent of fish oil with variable results. We investigated the effects of EPA on systemic inflammatory responses as pure EPA has not been evaluated on immune/inflammatory responses in vivo.Experimental Approach
Rabbits were administered polyinosinic: polycytidylic acid (poly I:C) i.v. before and after oral treatment with EPA for 42 days (given daily). The responses to IL-1β and TNF-α were also studied. Immediately following administration of poly I:C, body temperature was continuously monitored and blood samples were taken. Plasma levels of IL-1β, PGE2 (PGE2), and 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2) were measured by enzyme immunoassay.Key Results
Following EPA treatment, the fever response to poly I:C was markedly suppressed compared with pretreatment responses. This was accompanied by a parallel reduction in the poly I:C-stimulated elevation in plasma levels of IL-1β and PGE2. Paradoxically, the levels of 15d-PGJ2 were higher following EPA treatment. EPA treatment did not significantly alter the fever response or plasma levels of PGE2 in response to either IL-1β or TNF-α.Conclusion and Implications
Oral treatment with EPA can suppress immune/inflammatory responses in vivo via a suppression of upstream cytokine production resulting in a decreased fever response and indirectly reducing circulating levels of PGE2. EPA also enhances the production of the cytoprotective prostanoid 15d-PGJ2 indicating the therapeutic benefit of EPA. 相似文献15.
Background
Methylation of inorganic arsenic (iAs) via one-carbon metabolism is a susceptibility factor for a range of arsenic-related health effects, but there is no data on the importance of arsenic metabolism for effects on child development.Aim
To elucidate the development of arsenic metabolism in early childhood.Methods
We measured iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA), the metabolites of iAs, in spot urine samples of 2400 children at 18 months of age. The children were born to women participating in a population-based longitudinal study of arsenic effects on pregnancy outcomes and child development, carried out in Matlab, a rural area in Bangladesh with a wide range of arsenic concentrations in drinking water. Arsenic metabolism was evaluated in relation to age, sex, anthropometry, socio-economic status and arsenic exposure.Results
Arsenic concentrations in child urine (median 34 μg/L, range 2.4-940 μg/L), adjusted to average specific gravity of 1.009 g/mL, were considerably higher than that measured at 3 months of age, but lower than that in maternal urine. Child urine contained on average 12% iAs, 9.4% MA and 78% DMA, which implies a marked change in metabolite pattern since infancy. In particular, there was a marked increase in urinary %MA, which has been associated with increased risk of health effects.Conclusion
The arsenic metabolite pattern in urine of children at 18 months of age in rural Bangladesh indicates a marked decrease in arsenic methylation efficiency during weaning. 相似文献16.
Mesquita-Santos FP Bakker-Abreu I Luna-Gomes T Bozza PT Diaz BL Bandeira-Melo C 《British journal of pharmacology》2011,162(8):1674-1685
BACKGROUND AND PURPOSE
Prostaglandin (PG) D2 has emerged as a key mediator of allergic inflammatory pathologies and, particularly, PGD2 induces leukotriene (LT) C4 secretion from eosinophils. Here, we have characterized how PGD2 signals to induce LTC4 synthesis in eosinophils.EXPERIMENTAL APPROACH
Antagonists and agonists of DP1 and DP2 prostanoid receptors were used in a model of PGD2-induced eosinophilic inflammation in vivo and with PGD2-stimulated human eosinophils in vitro, to identify PGD2 receptor(s) mediating LTC4 secretion. The signalling pathways involved were also investigated.KEY RESULTS
In vivo and in vitro assays with receptor antagonists showed that PGD2-triggered cysteinyl-LT (cysLT) secretion depends on the activation of both DP1 and DP2 receptors. DP1 and DP2 receptor agonists elicited cysLTs production only after simultaneous activation of both receptors. In eosinophils, LTC4 synthesis, but not LTC4 transport/export, was activated by PGD2 receptor stimulation, and lipid bodies (lipid droplets) were the intracellular compartments of DP1/DP2 receptor-driven LTC4 synthesis. Although not sufficient to trigger LTC4 synthesis by itself, DP1 receptor activation, signalling through protein kinase A, did activate the biogenesis of eosinophil lipid bodies, a process crucial for PGD2-induced LTC4 synthesis. Similarly, concurrent DP2 receptor activation used Pertussis toxin-sensitive and calcium-dependent signalling pathways to achieve effective PGD2-induced LTC4 synthesis.CONCLUSIONS AND IMPLICATIONS
Based on pivotal roles of cysLTs in allergic inflammatory pathogenesis and the collaborative interaction between PGD2 receptors described here, our data suggest that both DP1 and DP2 receptor antagonists might be attractive candidates for anti-allergic therapies.LINKED ARTICLE
This article is commented on by Mackay and Stewart, pp. 1671–1673 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2011.01236.x 相似文献17.
Q Chen K Muramoto N Masaaki Y Ding H Yang M Mackey W Li Y Inoue K Ackermann H Shirota I Matsumoto M Spyvee S Schiller T Sumida F Gusovsky M Lamphier 《British journal of pharmacology》2010,160(2):292-310
Background and purpose:
Rheumatoid arthritis (RA) is an autoimmune disorder involving subsets of activated T cells, in particular T helper (Th) 1 and Th17 cells, which infiltrate and damage tissues and induce inflammation. Prostaglandin E2 (PGE2) enhances the Th17 response, exacerbates collagen-induced arthritis (CIA) and promotes inflammatory pain. The current study investigated whether selective antagonism of the PGE2 EP4 receptor would suppress Th1/Th17 cell development and inflammatory arthritis in animal models of RA.Experimental approach:
Effects of PGE2 and a novel EP4 receptor antagonist ER-819762 on Th1 differentiation, interleukin-23 (IL-23) production by dendritic cells (DCs), and Th17 development were assessed in vitro. The effect of ER-819762 was evaluated in CIA and glucose-6-phosphate isomerase (GPI)-induced arthritis models. In addition, the effects of ER-819762 on pain were evaluated in a model of chronic inflammatory pain induced by complete Freund''s adjuvant (CFA) in the rat.Key results:
Stimulation of the EP4 receptor enhanced Th1 differentiation via phosphatidylinositol 3 kinase signalling, selectively promoted Th17 cell expansion, and induced IL-23 secretion by activated DCs, effects suppressed by ER-819762 or anti-PGE2 antibody. Oral administration of ER-19762 suppressed Th1 and Th17 cytokine production, suppressed disease in collagen- and GPI-induced arthritis in mice, and suppressed CFA-induced inflammatory pain in rats.Conclusion and implications:
PGE2 stimulates EP4 receptors to promote Th1 differentiation and Th17 expansion and is critically involved in development of arthritis in two animal models. Selective suppression of EP4 receptor signalling may have therapeutic value in RA both by modifying inflammatory arthritis and by relieving pain. 相似文献18.
Background and purpose:
Prostaglandin (PG) E2 and interleukin (IL)-8 are simultaneously increased during the inflammation that characterizes numerous pathologies such as inflammatory bowel disease. IL-8 is a potent neutrophil chemo-attractant and activator, and can initiate and/or exacerbate tissue injury. PGE2 signals principally through prostanoid receptors of the EP2 and/or EP4 subtypes to promote cAMP-dependent cellular functions. The aim of this study was to identify the role of the EP2 and EP4 receptor subtype(s) on two human colonic epithelial cell lines (Caco-2 and T84), in regulating PGE2-induced IL-8 production.Experimental approach:
To identify the causative receptor, we knocked-down and over-expressed EP2 and EP4 receptor subtypes in colonic epithelial cells and studied the effect of several selective EP2/EP4 receptor agonists and antagonists. The inductions of IL-8 and EP receptor mRNA and protein expression were determined by real-time PCR and western blot analysis. The affinity of PGE2 and Bmax values for the EP2 and EP4 receptor on colonic epithelial cells were determined by radioligand-binding assays with [3H]PGE2.Key results:
PGE2 had the highest affinity for the EP4 receptor subtype and promoted a robust stimulation of cAMP-dependent IL-8 synthesis. This effect was mimicked by a selective EP4 receptor agonist, ONO-AE1-329, and abolished by silencing the EP4 receptor gene by using siRNA techniques, a selective EP4 receptor antagonist (ONO-AE3-208) and a selective inhibitor (Rp-cAMP) of cAMP-dependent protein kinase.Conclusions and implications:
These findings suggest that initiation and progression of colonic inflammation induced by IL-8 could be mediated, at least in part, by PGE2 acting via the EP4 receptor subtype. 相似文献19.
Background and purpose
P2X7 receptors are potently inhibited by extracellular acidification. The underlying molecular basis remains unknown. This study aimed to examine the role of extracellular histidine, lysine, aspartic acid and glutamic acid residues in the functional inhibition of rat P2X7 receptors by acidic pH.Experimental approach
We introduced point mutations into rat P2X7 receptor by site-directed mutagenesis, expressed wild type (WT) and mutant receptors in human embryonic kidney (HEK293) cells and, using patch clamp recording, characterized the effects of acidic pH on BzATP [2′-3′-O-(4-benzoylbenzoyl) adenosine 5′-triphosphate]-evoked ionic currents.Key results
Reducing extracellular pH, that is, increasing extracellular proton concentrations, inhibited BzATP-evoked currents in cells expressing WT P2X7 receptors, with IC50 value (half-maximal antagonist or inhibitor concentration) for protons of 0.2 µmol·L−1. The major effect of acidification was suppression of the maximal current response without altering the agonist sensitivity. Five residues in the receptor extracellular domain (His85, Lys110, Lys137, Asp197 and His219) were mutated to alanine and current inhibition by protons assessed. Compared with WT, the H85A, H219A, K137A mutants were two- to threefold more sensitive, whereas the K110A and D197A mutants were 2.5- and 9-fold less sensitive. Double-alanine substitution of Lys110 and Asp197 resulted in 23-fold decreased sensitivity to inhibition by protons. Furthermore, charge neutralization (K110M, K110F, D197N and D197F), but not charge conserving mutation (K110R and D197E), attenuated the inhibition of currents by protons.Conclusions and implications
Functional inhibition of rat P2X7 receptors by acidic pH was variably affected by the extracellular His85, Lys110, Lys137, Asp197 and His219 residues, with the Asp197 residue being most critical for this inhibition. 相似文献20.
Zhang Y Guo D Zhao Y Chen X Ma L Jin Y Yan H Wu H Wei L Dong T Chen X 《Antiviral research》2011,92(2):247-254