Distribution of the P2X2 receptor and chemical coding in ileal enteric neurons of obese male mice (ob/ob)

AIM: To investigate the colocalization, density and profile of neuronal areas of enteric neurons in the ileum of male obese mice.METHODS: The small intestinal samples of male mice in an obese group (OG) (C57BL/6J ob/ob) and a control group (CG) (+/+) were used. The tissues were analyzed using a double immunostaining technique for immunoreactivity (ir) of the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT) and calretinin (Calr). Also, we investigated the density and profile of neuronal areas of the NOS-, ChAT- and Calr-ir neurons in the myenteric plexus. Myenteric neurons were labeled using an NADH-diaphorase histochemical staining method.RESULTS: The analysis demonstrated that the P2X2 receptor was expressed in the cytoplasm and in the nuclear and cytoplasmic membranes only in the CG. Neuronal density values (neuron/cm²) decreased 31% (CG: 6579 ± 837; OG: 4556 ± 407) and 16.5% (CG: 7796 ± 528; OG: 6513 ± 610) in the NOS-ir and calretinin-ir neurons in the OG, respectively (P < 0.05). Density of ChAT-ir (CG: 6200 ± 310; OG: 8125 ± 749) neurons significantly increased 31% in the OG (P < 0.05). Neuron size studies demonstrated that NOS, ChAT, and Calr-ir neurons did not differ significantly between the CG and OG groups. The examination of NADH-diaphorase-positive myenteric neurons revealed an overall similarity between the OG and CG.CONCLUSION: Obesity may exert its effects by promoting a decrease in P2X2 receptor expression and modifications in the density of the NOS-ir, ChAT-ir and CalR-ir myenteric neurons.     

Effects of protein deprivation and re-feeding on P2X2 receptors in enteric neurons

AIM:To investigate the effects of malnutrition and refeeding on the P2X2 receptor,nitric oxide synthase(NOS),calretinin,calbindin and choline acetyltransferase(ChAT) in neurons of the rat ileum.METHODS:We analyzed the co-localization,numbers and sizes of P2X2-expressing neurons in relation to NOS-immunoreactive(IR),calbindin-IR,ChAT-IR,and calretinin-IR neurons of the myenteric and submucosal plexus.The experimental groups consisted of:(1) rats maintained on normal feed throughout pregnancy until 42 d post-...     

Purinergic P2X7 receptors regulate secretion of interleukin-1 receptor antagonist and beta cell function and survival

Aims/hypothesis  In obesity, beta cells activate compensatory mechanisms to adapt to the higher insulin demand. Interleukin-1 receptor antagonist (IL-1Ra) prevents obesity-induced hyperglycaemia and is a potent target for the treatment of diabetes, but the mechanisms of its secretion and regulation in obesity are unknown. In the present study, we hypothesise the regulation of IL-1Ra secretion by purinergic P2X₇ receptors in islets. Methods  Production and regulation of P2X₇ were studied in pancreatic sections from lean and obese diabetic patients, non-diabetic controls and in isolated islets. IL-1Ra, IL-1β and insulin secretion, glucose tolerance and beta cell mass were studied in P2x7 (also known as P2Rx7)-knockout mice. Results  P2X₇ levels were elevated in beta cells of obese patients, but downregulated in patients with type 2 diabetes mellitus. Elevated glucose and non-esterified fatty acids rapidly activated P2X₇ and IL-1Ra secretion in human islets, and this was inhibited by P2X₇ blockade. In line with our results in vitro, P2x7-knockout mice had a lower capacity to secrete IL-1Ra. They exhibited severe and rapid hyperglycaemia, glucose intolerance and impaired beta cell function in response to a high-fat/high-sucrose diet, were unable to compensate by increasing their beta cell mass in response to the diet and showed increased beta cell apoptosis. Conclusions/interpretation  Our study shows a tight correlation of P2X₇ activation, IL-1Ra secretion and regulation of beta cell mass and function. The increase in P2X₇ production is one mechanism that may explain how beta cells compensate by adapting to the higher insulin demand. Disturbances within that system may result in the progression of diabetes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

P2X7-induced apoptosis decreases by aging in mice myeloblasts

In the current study, the ability of ATP to promote apoptosis in myeloblasts at different ages was investigated. We have observed that high concentration of extracellular ATP (>1mM), which activates P2X(7) receptor, produced cell shrinkage an increase in the number of events in the sub-G(0)/G(1) region of the cellular cycle and annexin-V/propidium iodide label, which characterizes the apoptotic cell death. In addition, BzATP produced apoptosis, but not ADP and UTP. Gr-1(+) cells express the P2X(7) receptor and oxidized ATP, a specific P2X(7) inhibitor, blocked the ATP-dependent apoptosis. ATP-dependent apoptosis is decreased by aging in myeloblasts of 12 and 22-month-old mice. Furthermore, P2X(7) expression decrease was observed in older mice, explaining apoptosis decrease. This decrease in apoptosis by aging may be related to some diseases in the myelocyte lineage.     

Age-related changes of P2X(1) receptor mRNA in the bladder detrusor from men with and without bladder outlet obstruction

The urinary bladder purinergic system is reported to change with age and with bladder dysfunction. Here, we examined the expression of purinergic P2X(1) receptors in detrusor and mucosa (urothelium+lamina propria) from male control bladder and investigated age-related P2X(1) receptor mRNA expression in control and obstructed detrusor. Biopsy specimens were obtained at cystoscopy from control patients (n=46, age range 30-86years) and patients diagnosed with outlet obstruction (n=29, 46-88years). Calponin expression (measured by RT-PCR) was similar in control and obstructed detrusor and did not change with age. Quantitative competitive RT-PCR was used to measure P2X(1) receptor and GAPDH mRNA in control and obstructed detrusor. P2X(1) receptor mRNA expression was 9-fold (p<0.0001) higher in the detrusor than in the mucosa. Expression of mRNA for the internal control GAPDH remained stable with age and across control and obstructed detrusor. No difference in P2X(1) receptor expression was observed between control and obstructed detrusor (p=0.35). However, an age-related decrease in P2X(1) mRNA expression was observed in control (n=27; p=0.0054; Spearman coefficient r=-0.520) but not obstructed detrusor (n=19; p=0.093; r=-0.396). Downregulation of P2X(1) mRNA expression might occur as a result of an increased component of neural ATP release in the aging bladder.     

Study of the roles of caspase-3 and nuclear factor kappa B in myenteric neurons in a P2X7 receptor knockout mouse model of ulcerative colitis

BACKGROUND The literature indicates that the enteric nervous system is affected in inflammatory bowel diseases(IBDs) and that the P2X7 receptor triggers neuronal death. However, the mechanism by which enteric neurons are lost in IBDs is unknown.AIM To study the role of the caspase-3 and nuclear factor kappa B(NF-κB) pathways in myenteric neurons in a P2X7 receptor knockout(KO) mouse model of IBDs.METHODS Forty male wild-type(WT) C57BL/6 and P2X7 receptor KO mice were euthanized 24 h or 4 d after...     

Enteric nervous system and inflammatory bowel diseases: Correlated impacts and therapeutic approaches through the P2X7 receptor

The enteric nervous system (ENS) consists of thousands of small ganglia arranged in the submucosal and myenteric plexuses, which can be negatively affected by Crohn’s disease and ulcerative colitis - inflammatory bowel diseases (IBDs). IBDs are complex and multifactorial disorders characterized by chronic and recurrent inflammation of the intestine, and the symptoms of IBDs may include abdominal pain, diarrhea, rectal bleeding, and weight loss. The P2X7 receptor has become a promising therapeutic target for IBDs, especially owing to its wide expression and, in the case of other purinergic receptors, in both human and model animal enteric cells. However, little is known about the actual involvement between the activation of the P2X7 receptor and the cascade of subsequent events and how all these activities associated with chemical signals interfere with the functionality of the affected or treated intestine. In this review, an integrated view is provided, correlating the structural organization of the ENS and the effects of IBDs, focusing on cellular constituents and how therapeutic approaches through the P2X7 receptor can assist in both protection from damage and tissue preservation.     

Research progress of P2X7 receptor in inflammatory bowel disease

Inflammatory bowel disease is a chronic nonspecific inflammatory disease of the intestine. Its pathogenesis is not yet fully understood. It may be related to heredity, environmental triggers, infection, immune dysfunction and other factors. Purinergic receptor (P2X7R) ligand-gated ion channel is closely related to inflammation and widely expressed in intestinal cells. Previous studies have shown that ATP/P2X7R signal is involved in the pathogenesis of intestinal inflammation, but its specific mechanism needs further study. This article reviews the research progress of P2X7 receptor in inflammatory bowel disease.     

Denufosol: A review of studies with inhaled P2Y2 agonists that led to Phase 3

Among the most promising of the new therapies being developed for the treatment of Cystic Fibrosis (CF) are those targeted at increasing mucosal hydration on the surface of the airways. One of these therapies, P2Y₂ receptor agonists, bypasses the defective CFTR chloride channel, and activates an alternative chloride channel. This activation results in an increase in airway surface epithelial hydration, and through these actions and effects on cilia beat frequency, increases mucociliary clearance. The pharmacology of P2Y₂ agonists has been confirmed in several preclinical and clinical studies. Denufosol tetrasodium is a novel second-generation, metabolically stable, selective P2Y₂ receptor agonist currently in Phase 3 clinical development. In radiolabelled deposition studies of P2Y₂ agonists in healthy non-smokers and smokers, approximately 7 mg of a 40-mg nebulizer (PARI LC Star) load was deposited in the lungs. In a pharmacokinetic study in healthy volunteers, very limited systemic exposure was observed when doses of 200 mg of denufosol were nebulized. Thus, it appears that high concentrations of denufosol can be achieved in the airways with very low systemic absorption. Denufosol has been generally well-tolerated in healthy volunteers and patients with CF. The most common adverse events were in the respiratory system, with cough having the highest frequency. Doses of 20–60 mg have been evaluated in Phase 2 trials of up to 28 days duration, and superiority relative to placebo on FEV1 has been observed in patients with relatively normal lung function (FEV1 greater than or equal to 75% of predicted). The first Phase 3 trial is a comparison of denufosol 60 mg and placebo in 350 patients with CF with FEV1 at study entry greater than or equal to 75% of predicted.     

The platelet P2Y12 receptor contributes to granule secretion through Ephrin A4 receptor

The main responses of P2Y₁ ligation are platelet shape change and transient aggregation while P2Y₁₂ ligation amplifies P2Y₁-induced aggregation and accelerates aggregation, secretion and thromboxane A₂ production induced by other agonist-receptor complexes. We searched for new targets of P2Y signalling using micro-arrays with 144 peptides representing known phosphosites of protein tyrosine kinases. ADP induced phosphorylation of peptides representing surface receptors, second messenger enzymes and cytoskeletal proteins. Strong phosphorylation was found in peptides representing Ephrin-receptor family members. Blockade of P2Y_1/12 inhibited phosphorylation of EphA4- and EphB1-peptides on micro-arrays. The EphA2/4 inhibitor 2,5-dimethylpyrrolyl benzoic acid derivative interfered with P2Y_1/12-induced EphA4 phosphorylation, left P2Y₁-induced aggregation unchanged but inhibited with P2Y₁₂-induced secretion, second phase aggregation and thrombus formation on collagen at 1600?s^?1. These results show that platelet EphA4 is an important intermediate in P2Y₁₂-induced granule secretion.     

Allosteric interactions between agonists and antagonists within the adenosine A2A receptor-dopamine D2 receptor heterotetramer

Adenosine A_2A receptor (A_2AR)-dopamine D₂ receptor (D₂R) heteromers are key modulators of striatal neuronal function. It has been suggested that the psychostimulant effects of caffeine depend on its ability to block an allosteric modulation within the A_2AR-D₂R heteromer, by which adenosine decreases the affinity and intrinsic efficacy of dopamine at the D₂R. We describe novel unsuspected allosteric mechanisms within the heteromer by which not only A_2AR agonists, but also A_2AR antagonists, decrease the affinity and intrinsic efficacy of D₂R agonists and the affinity of D₂R antagonists. Strikingly, these allosteric modulations disappear on agonist and antagonist coadministration. This can be explained by a model that considers A_2AR-D₂R heteromers as heterotetramers, constituted by A_2AR and D₂R homodimers, as demonstrated by experiments with bioluminescence resonance energy transfer and bimolecular fluorescence and bioluminescence complementation. As predicted by the model, high concentrations of A_2AR antagonists behaved as A_2AR agonists and decreased D₂R function in the brain.Most evidence indicates that G protein-coupled receptors (GPCRs) form homodimers and heteromers. Homodimers seem to be a predominant species, and oligomeric entities can be viewed as multiples of dimers (1). It has been proposed that GPCR heteromers are constituted mainly by heteromers of homodimers (1, 2). Allosteric mechanisms determine a multiplicity of unique pharmacologic properties of GPCR homodimers and heteromers (1, 3). First, binding of a ligand to one of the receptors in the heteromer can modify the affinity of ligands for the other receptor (1, 3, 4). The most widely reproduced allosteric modulation of ligand-binding properties in a GPCR heteromer is the ability of adenosine A_2A receptor (A_2AR) agonists to decrease the affinity of dopamine D₂ receptor (D₂R) agonists in the A_2AR-D₂R heteromer (5). A_2AR-D₂R heteromers have been revealed both in transfected cells (6, 7), striatal neurons in culture (6, 8) and in situ, in mammalian striatum (9, 10), where they play an important role in the modulation of GABAergic striatopallidal neuronal function (9, 11).In addition to ligand-binding properties, unique properties for each GPCR oligomer emerge in relation to the varying intrinsic efficacy of ligands for different signaling pathways (1–3). Intrinsic efficacy refers to the power of the agonist to induce a functional response, independent of its affinity for the receptor. Thus, allosteric modulation of an agonist can potentially involve changes in affinity and/or intrinsic efficacy (1, 3). This principle can be observed in the A_2AR-D₂R heteromer, where a decrease in D₂R agonist affinity cannot alone explain the ability of an A_2AR agonist to abolish the decreased excitability of GABAergic striatopallidal neurons induced by high concentration of a D₂R agonist (9), which should overcome the decrease in affinity. Furthermore, a differential effect of allosteric modulations of different agonist-mediated signaling responses (i.e., functional selectivity) can occur within GPCR heteromers (1, 2, 8). Again, the A_2AR-D₂R heteromer provides a valuable example. A recent study has shown that different levels of intracellular Ca²⁺ exert different modulations of A_2AR-D₂R heteromer signaling (8). This depends on the ability of low and high Ca²⁺ to promote a selective interaction of the heteromer with different Ca²⁺-binding proteins, which differentially modulate allosteric interactions in the heteromer (8).It has been hypothesized that the allosteric interactions between A_2AR and D₂R agonists within the A_2AR-D₂R heteromer provide a mechanism responsible not only for the depressant effects of A_2AR agonists, but also for the psychostimulant effects of adenosine A_2AR antagonists and the nonselective adenosine receptor antagonist caffeine (9, 11, 12), with implications for several neuropsychiatric disorders (13). In fact, the same mechanism has provided the rationale for the use of A_2AR antagonists in patients with Parkinson’s disease (13, 14). The initial aim of the present study was to study in detail the ability of caffeine to counteract allosteric modulations between A_2AR and D₂R agonists (affinity and intrinsic efficacy) within the A_2AR-D₂R heteromer. Unexpectedly, when performing control radioligand-binding experiments, not only an A_2AR agonist, but also caffeine, significantly decreased D₂R agonist binding. However, when coadministered, the A_2AR agonist and caffeine co-counteracted their ability to modulate D₂R agonist binding. By exploring the molecular mechanisms behind these apparent inconsistencies, the present study provides new insight into the quaternary structure and function of A_2AR-D₂R heteromers.     

The active metabolite of prasugrel effectively blocks the platelet P2Y12 receptor and inhibits procoagulant and pro-inflammatory platelet responses

The aim of these studies was to investigate the extent of platelet P2Y₁₂ receptor inhibition by the thienopyridine active metabolite of prasugrel, R-138727. Blood was taken from healthy volunteers and pre-incubated with R-138727 or cangrelor (AR-C66931MX). Platelet aggregation was assessed in platelet rich plasma (PRP) and whole blood (WB). Vasodilator stimulated phosphoprotein (VASP) phosphorylation, platelet procoagulant activity (annexin V binding and microparticle formation) and calcium mobilisation were measured by flow cytometry. Platelet-leukocyte co-aggregate formation and sCD40L release, both pro-inflammatory responses of platelets, were measured by flow cytometry and ELISA, respectively. P2Y₁₂ receptor antagonism was determined using a radioligand binding assay (³³P 2-MeSADP) in resting and stimulated platelets and the effects of clopidogrel administration were also assessed. R-138727 yielded concentration-dependent inhibition of platelet aggregation, VASP phosphorylation inhibition, procoagulant activity and pro-inflammatory responses. In the presence of R-138727 or cangrelor there was increased calcium reuptake following agonist stimulation. R-138727 30 µmol/L and cangrelor 1 µmol/L completely inhibited ³³P 2-MeSADP binding, compared to partial inhibition following clopidogrel administration. Platelet activation and granule secretion did not expose an additional pool of P2Y₁₂ receptors. Prasugrel's active metabolite effectively blocks the P2Y₁₂ receptor with the highest concentrations tested yielding complete inhibition of P2Y₁₂-mediated amplification of several important platelet responses.     

Activation of P2X7 receptors in glial satellite cells reduces pain through downregulation of P2X3 receptors in nociceptive neurons

Purinergic ionotropic P2X7 receptors (P2X7Rs) are closely associated with excitotoxicity and nociception. Inhibition of P2X7R activation has been considered as a potentially useful strategy to improve recovery from spinal cord injury and reduce inflammatory damage to trauma. The physiological functions of P2X7Rs, however, are poorly understood, even though such information is essential for making the P2X7R an effective therapeutic target. We show here that P2X7Rs in satellite cells of dorsal root ganglia tonically inhibit the expression of P2X3Rs in neurons. Reducing P2X7R expression using siRNA or blocking P2X7R activity by antagonists elicits P2X3R up-regulation, increases the activity of sensory neurons responding to painful stimuli, and evokes abnormal nociceptive behaviors in rats. Thus, contrary to the notion that P2X7R activation is cytotoxic, P2X7Rs in satellite cells play a crucial role in maintaining proper P2X3R expression in dorsal root ganglia. Studying the mechanism underlying the P2X7R-P2X3R control, we demonstrate that activation of P2X7Rs evokes ATP release from satellite cells. ATP in turn stimulates P2Y1 receptors in neurons. P2Y1 receptor activation appears to be necessary and sufficient for the inhibitory control of P2X3R expression. We further determine the roles of the P2X7R-P2Y1-P2X3R inhibitory control under injurious conditions. Activation of the inhibitory control effectively prevents the development of allodynia and increases the potency of systemically administered P2X7R agonists in inflamed rats. Thus, direct blocking P2X7Rs, as proposed before, may not be the best strategy for reducing pain or lessening neuronal degeneration because it also disrupts the protective function of P2X7Rs.     

Up-regulation of A 2B adenosine receptor in A 2A adenosine receptor knockout mouse coronary artery

In this study, we looked into possible compensatory changes of other adenosine receptors (ARs) in A_2A genetic knockout mice (A2AKO) as well as the functional role of nitric oxide (NO) in A_2A AR-mediated vasodilation. Gene expression of ARs from coronary arteries of A_2A AR wild type mice (A2AWT) and A2AKO was studied using real-time PCR. Functional studies were carried out in isolated heart and isolated coronary artery preparations. A_2B AR was found to be 4.5 fold higher in A2AKO than in A2AWT, while A_2A AR expression was absent in A2AKO. There was no difference in A₁ and A₃ ARs between WT and KO animals. The concentration-relaxation curve for adenosine-5′-N-ethylcarboxamide (NECA, non-selective AR agonist) in isolated coronary arterial rings in A2AKO was shifted to the left when compared to A2AWT. The concentration-response curve for A_2B selective agonist (BAY 60-6583) was also shifted to the left in A2AKO hearts. L-NAME, a non-specific NO synthase inhibitor, did not affect baseline coronary flow (CF) until the concentration reached 10 µM in A2AWT (76.32 ± 11.35% from baseline, n = 5). In A2AKO, the CF decreased significantly by L-NAME only at a higher concentration (100 µM, 93.32 ± 5.8% from baseline, n = 5). L-NMA (1 µM, n = 4), another non-specific NO synthase inhibitor, also demonstrated similar results in decreasing CF (59.66 ± 3.23% from baseline in A2AWT, while 81.76 ± 8.91% in A2AKO). It was further demonstrated that the increase in CF by 100 µM NECA was significantly blunted with 10 µM L-NAME (377.08 ± 25.23% to 305.41 ± 30.73%, n = 9) in A2AWT but not in A2AKO (153.66 ± 22.7% to 143.88 ± 36.65%, n = 5). Similar results were also found using 50 nM of CGS-21680 instead of NECA in A2AWT (346 ± 22.85 to 277 ± 31.39, n = 6). No change in CF to CGS-21680 was noted in A_2AAKO. Our data demonstrate, for the first time, that coronary A_2B AR was up-regulated in mice deficient in A_2A AR. We also provide direct evidence supporting a role for NO in A_2A AR-mediated coronary vasodilation. The data further support the role for A_2A AR in the regulation of basal coronary tone through the release of NO.     

P2X7 receptor as the regulator of T-cell function in intestinal barrier disruption

The intestinal mucosa is a highly compartmentalized structure that forms a direct barrier between the host intestine and the environment, and its dysfunction could result in a serious disease. As T cells, which are important components of the mucosal immune system, interact with gut microbiota and maintain intestinal homeostasis, they may be involved in the process of intestinal barrier dysfunction. P2X7 receptor (P2X7R), a member of the P2X receptors family, mediates the effects of extracellular adenosine triphosphate and is expressed by most innate or adaptive immune cells, including T cells. Current evidence has demonstrated that P2X7R is involved in inflammation and mediates the survival and differentiation of T lymphocytes, indicating its potential role in the regulation of T cell function. In this review, we summarize the available research about the regulatory role and mechanism of P2X7R on the intestinal mucosa-derived T cells in the setting of intestinal barrier dysfunction.     

Dyspnea in patients treated with P2Y12 receptor antagonists: insights from the GReek AntiPlatElet (GRAPE) registry

In ‘real life’ acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) and receiving contemporary antiplatelet treatment, data on dyspnea occurrence and impact on persistence with treatment are scarce. In a prospective, multicenter, cohort study, ACS patients undergoing PCI were recruited into the GReekAntiPlatElet (GRAPE) registry. During 1-year follow up, overall, 249/1989 (12.5%) patients reported dyspnea, more frequently at 1-month and decreasing thereafter. Multivariate analysis showed that ticagrelor administration (n = 738) at discharge was associated with the occurrence of dyspnea: Odds ratio 2.46 (95% confidence interval, CI, 1.87–3.25), p < 0.001. Older age, lower hematocrit, and prior bleeding event were also associated with dyspnea reports. Persistence, switching, and cessation rates were 68.3%, 20.9%, and 10.8% vs 76.7%, 12.5%, and 10.9% among patients reporting dyspnea compared with those who did not, p for trend = 0.002. In conclusion, in ACS patients undergoing PCI and treated with a P2Y₁₂ receptor antagonist, dyspnea occurs commonly, particularly when ticagrelor is administered. Non-persistence with antiplatelet agents at discharge is more frequently observed among dyspnea-reporters.     

1513A/C polymorphism in the P2X7 receptor gene in chronic lymphocytic leukemia: absence of correlation with clinical outcome

Purinergic P2X7 receptors are ligand-gated cation channels expressed on the cells of the immune and hemopoietic system which have been shown to mediate the ATP-induced apoptotic death of monocytes, macrophages and lymphocytes. A common single nucleotide polymorphism within the P2X7 gene has been described in exon 13 (1513A/C), the gene products encoding fully active and non-functional proteins. We genotyped the P2X7 1513A/C polymorphism using DNA from 111 patients with chronic lymphocytic leukemia (CLL) and 97 healthy controls using polymerase chain reaction (PCR) amplification followed by Hha1 restriction analysis. We found no significant difference in allele frequency between CLL patients and controls. Time periods from diagnosis to initiation of chemotherapy, a surrogate marker for disease progression, were not different in patients displaying the combined 1513A/C and C/C or the 1513A/A genotype (P = 0.97). Similar results were observed in a subgroup analysis of prognostically more favorable CD38-negative and ZAP-70-negative CLL patients. In conclusion, our data do not support a role of the P2X7 genotype as a prognostic marker in B-cell CLL.     

P2X_1受体在急性冠状动脉综合征中的表达

目的观察P2X1受体在急性冠状动脉综合征(ACS)患者血小板中的表达及激活P2X1受体后血小板钙离子浓度的变化,探讨P2X1受体在ACS发生时对血小板功能的调节作用。方法选取70例ACS患者为研究对象,其中急性心肌梗死(AMI)患者30例,不稳定型心绞痛(UA)患者40例,同期入院的健康受试者20例为对照组。应用反转录-聚合酶链反应(RT-PCR)和实时荧光定量PCR方法,观察P2X1受体和血小板膜糖蛋白Ⅱb/Ⅲa(GPⅡb/Ⅲa)受体在对照组和ACS组血小板中的表达情况。以α,β-me ATP(3μmol/L)激活血小板,Fluo-3 AM Ester为标记物在荧光分光光度计下观察血小板钙离子水平变化。结果对照组及ACS组的血小板中均有P2X1受体、GPⅡb/Ⅲa受体的表达,且在ACS组的表达较对照组高(1.62±0.69比0.88±0.04,1.58±0.11比0.85±0.06,P<0.05);ACS组患者钙离子基线水平高于对照组[(418.96±31.85)nmol/L比(307.20±23.37)nmol/L,P<0.05]。结论 P2X1受体在ACS的发生发展过程中起重要作用。