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Most α2-AR agonists derived from dexme-detomidine have few structure differences between them and have no selectivity for α2A/2B-AR or Gi/Gs,that can lead to the side effect of drugs.To get novel and potent α2A-AR agonists,we built the homology model for human α 2A-AR and α2B-AR to find α2A-AR agonists with higher selectivity.Compound P300-2342 and its 3 analogs sig-nificantly decreased the locomotor activity of mice(P＜0.05).Furthermore,P300-2342 and its 3 analogs inhibited the binding of[3H]rauwolscine to α 2A-AR and α 2B-AR respectively.In α2A-AR-HEK293 cells,P300-2342 decre-ased forskolinstimulatedcAMPpruductionwithoutincreas-ing cAMP pruduction,that indicated the P300-2342 acti-vating α2A-AR coupling with Gαi/o pathway without Gαs coupling.P300-2342 had no agonistic and antagonistic activities on α 2B-AR.Similar results were shown in 3 analogs of P300-2342.The docking results showed that P300-2342 formed the π-hydrogen bonds with Y394,V114 of α2A-AR,and with V93 of α2B-AR.3 analogs of P300-2342 formed several π-hydrogen bonds with V114,Y196,F390 of α 2A-AR and with V93 of α 2B-AR.We believe that these molecules can serve as leads for fur-ther optimization of α2A-AR agonists with potentially few side effects.
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Objective To investigate the role of Calcineurin binding protein 1(Cabin1)in renal tubular epithelial cells(RTECs)injury. Methods The male Sprague-Dawley rats were randomly divided into Sham-oper-ated and 5/6 nephrectomized group. Nephrectomized rats were further divided into two groups ,which were 4 and 8 weeks after operation,including 6 rats in each group. Rats were sacrificed at 4 or 8 weeks after nephrectomy,then control or remnant kidneys were harvested. 2μm sections of kidney tissues were collected and stained with Masson's trichrome and were graded for tubulointerstitial lesion score (TILS). RTECs mitochondrial morphology changes were detected by electron microscope. Western blot was applied to detect Cabin1 protein level in the renal tissue. Results At 8 weeks after the operation,plenty of RTECs fell off from the basement membrane,accompanied with interstitial fibrosis and the infiltration of inflammatory cells. Moreover ,TILS were significantly increased in rats at 8 weeks after operation while compared to sham-operated rats(7.16 ± 0.52 vs. 0.00 ± 0.00,P<0.05). RTECs mi-tochondria begun to swell at 4 weeks after 5/6 nephrectomy,while the disruption of cristae could be found in rats at 8 weeks. Cabin1 protein expression apparently increased in the remnant kidney. Cabin1 protein obviously increased in rats at 8 weeks after the surgery compared to sham-operated rats(0.97 ± 0.09 vs. 0.22 ± 0.07,P<0.05)and rats at 4 weeks after nephrectomy(0.97 ± 0.09 vs. 0.45 ± 0.03,P<0.05). Conclusions Cabin1 is overexpressed during RTECs injury in 5/6 nephrectomized rats. It can be a crucial factor regulating the damage of RTECs.
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Objective To investigate the role of Calcineurin binding protein 1(Cabin1)in renal tubular epithelial cells(RTECs)injury. Methods The male Sprague-Dawley rats were randomly divided into Sham-oper-ated and 5/6 nephrectomized group. Nephrectomized rats were further divided into two groups ,which were 4 and 8 weeks after operation,including 6 rats in each group. Rats were sacrificed at 4 or 8 weeks after nephrectomy,then control or remnant kidneys were harvested. 2μm sections of kidney tissues were collected and stained with Masson's trichrome and were graded for tubulointerstitial lesion score (TILS). RTECs mitochondrial morphology changes were detected by electron microscope. Western blot was applied to detect Cabin1 protein level in the renal tissue. Results At 8 weeks after the operation,plenty of RTECs fell off from the basement membrane,accompanied with interstitial fibrosis and the infiltration of inflammatory cells. Moreover ,TILS were significantly increased in rats at 8 weeks after operation while compared to sham-operated rats(7.16 ± 0.52 vs. 0.00 ± 0.00,P<0.05). RTECs mi-tochondria begun to swell at 4 weeks after 5/6 nephrectomy,while the disruption of cristae could be found in rats at 8 weeks. Cabin1 protein expression apparently increased in the remnant kidney. Cabin1 protein obviously increased in rats at 8 weeks after the surgery compared to sham-operated rats(0.97 ± 0.09 vs. 0.22 ± 0.07,P<0.05)and rats at 4 weeks after nephrectomy(0.97 ± 0.09 vs. 0.45 ± 0.03,P<0.05). Conclusions Cabin1 is overexpressed during RTECs injury in 5/6 nephrectomized rats. It can be a crucial factor regulating the damage of RTECs.
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Objective To investigate the function and molecular mechanism of tacrolimus in podocyte injury and restoration.Methods Cultured podocytes were stimulated by Angiotensin Ⅱ (Ang Ⅱ) or Ang Ⅱ plus tacrolimus.Cells were collected at different time points (0 h,12 h and 24 h).The distribution of F-actin was observed after immunofluorescence staining,and the protein expression of nephrin and podocin were detected by Western Blot (WB).Results In normal control podocytes,F-actin was arranged in cytoplasm powerfully.Ang Ⅱ induced the disruption and discontinuity of F-actin.Tacrolimus inhibited the effect of Ang Ⅱ,stabilized the regular arrangement the F-actin.Compared to normal cells,the protein expression of nephrin in Ang Ⅱ group significantly decreased at 24 h after stimulation (0.76 ± 0.32 in AngⅡ group vs.1.18 ± 0.40 in normal group,P ＜ 0.05).And tacrolimus stabilized the expression of nephrin protein (1.00 ± 0.19 in treatment group vs.0.76 ± 0.32 in Ang Ⅱ group,P ＜ 0.05).Ang Ⅱ and tacrolimus did not affect the expression of podocin protein.Conclusion Tacrolimus inhibits podocyte injury induced by Ang Ⅱ,stabilizes the regular arrangement of cytoskeleton and protein expression of nephrin.
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OBJECTIVE To establish a new cell line that can stably express humanα2A-adrenoceptor (α2A- AR). METHODS Recombinant plasmid of α2A- AR with hygromycin B (Hygro) resistance (pcDNA3.1/Hygro-HA-α2A-AR)was stably transfected into Chinese hamster ovary(CHO)cells which had expressed protein kinase A catalytic subunits(PKAcat) with labeling of enhanced green fluorescent protein(EGFP)by a Lipofectamine based method. A single positive clone expressingα2A-AR was selected through cultivation in the presence of 200 mg · L-1 hygromycin B followed by PKA redistribution assay. The transcriptional expression ofα2A-AR was detected by quantitative real-time PCR(qRT-PCR). Time-resolved fluorescence resonance energy transfer immunoassay was used to identify the function of inhibiting cAMP accumulation of α2A-AR. RESULTS The CHO-PKAcat-α2A-AR cell line No.7 exhibited stable response in PKA redistribution assay. qRT-PCR analysis demonstrated that the high expression ofα2A-AR in the cell line remained stable after a few generations compared with CHO-PKAcat-EGFP cells (P<0.01). The cAMP accumulation caused by forskolin was significantly inhibited by α2A-AR agonist in CHO-PKAcat-α2A-AR cells(P<0.01). CONCLUSION CHO-PKAcat-α2A-AR cell line is constructed successfully, which provides an effective model for drug screening and studies of mechanisms.
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Hypoxia refers to the reduction in tissue oxygen supply or utilization. It occurs in various pathological symptoms like embolism,anthracemia,and chronic obstructive sleep. At high altitude, lower partial pressure of oxygen compromises the supply of adequate oxygen to the tissues and leads to many clinical syndromes,such as acute mountain sickness,high-altitude cerebral edema,and high-altitude pulmonary edema. Histamine H3 receptor, primarily as a presynaptic receptor, is widely expressed in the central and peripheral systems. Histamine,dopamine,acetylcholine and many other neurotransmitters are regulated by histamine H3 receptor. Studies have shown that histamine H3 receptor is involved in the hypoxic response of the respiratory network. In addition,histamine,espe?cially histamine H3 receptor,participates in the regulation of cerebral ischemia in the central nervous system. In this paper,we reviewed the structure and functions of histamine H3 receptor and explained its role in the regulation of hypoxia so as to evaluate the possibility of histamine H3 receptor as a drug target for the therapy of hypoxia-induced injuries.
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Opioid receptors, as an important member of G protein coupled receptors (GPCR), are the binding targets of endogenous opioid peptides and exogenous opiates. The activation of opioid receptors influences the nervous system, immune physiology and endocrine system. However, prolonged activation of opioid receptors is likely to produce opioid tolerance, leading to opioid addiction. Receptor endocytosis and sorting into the recycling pathway contribute to recovery of cellular opioid responsiveness. Recent studies have revealed that GPCR can be modulated by ubiquitination which plays a unique roles in governing GPCR trafficking. Moreover, ubiquitination of the opioid receptors (μ, κand δ) is increased after stimulation of most opioid agonists. Mutation of the ubiquitin sites affects the internalization and degradation of opioid receptors, which contributes to changes in signal pathways and regulation of opioid receptors. ln this paper, ubiquitination of opioid receptors and the fundamental role of ubiquitination in trafficking of opioid receptors are reviewed.
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OBJECTIVE Toestablisharecombinantcelllinethatcanstablyexpressratpurinergic P2receptorP2X4(rP2X4R).METHODS ToconstructgreenfluorescentproteinandrP2X4recombinant plasmid (pEGFP-N1-rP2X4),lipofectamine was used to transfect pEGFP-N1-rP2X4 into human embry-onic kidney (HEK293)cells that were screened with G41 8 (1 g·L-1 ).The quantitative expression of rP2X4 receptor was verified by qRT-PCR and Western blotting analysis.Whole-cell patch clamp record-ing was used to investigate the function of the stably expressed rP2X4 receptor. RESULTS The sequence of plasmid pEGFP-N1-rP2X4 was verified by PubMed Blastn comparison.qRT-PCR and Western blotting analysis demonstrated that the expression of rP2X4 receptor in HEK293-pEGFP-N1-rP2X4 cell lines remained stable after 25 generations (P1 ,P3,P5,P10,P15,P20 and P25).Whole-cell patch clamp recording experiments showed that the rP2X4 receptor agonist,purine-5′-triphosphate (ATP,3.0 μmol·L-1 ),could activate rP2X4 receptors in HEK293-pEGFP-N1-rP2X4 cell lines.Specific activating current could be blocked by non-selective rP2X4 receptor antagonist TNP-ATP (30.0μmol·L-1).CONCLUSION rP2X4receptorisstablyexpressedinHEK293-pEGFP-N1-rP2X4cell line and maintains stable expression and function within 25 continuous generations.The establish ment of HEK293-pEGFP-N1-rP2X4 cell line can contribute to further investigations of the roles of rP2X4 receptors in neuropathic pain.
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Aim To evaluate the antinociception of ω-SO3,a novel Omega-superfamily conotoxin,in rat formalin test.Methods Potency and duration of ω-SO3 antinociception compared with morphine were investigated in rat formalin test after acute intrathecal administration.Development of tolerance or cross tolerance to analgesia of ω-SO3 and morphine was tested in formalin test after chronic intrathecal administration.Locomotor activity of rat after acute intrathecal administration was tested to evaluate possible central side effects.Results In rat formalin test after intrathecal bolus injection,ω-SO3 produced dose-and time-dependent antinociception by suppressing acute(ED_(50),1.79 ng·g~(-1))and tonic phases(ED_(50),0.41 ng·g~(-1)),which was approximately 10-fold potency and twice longer-acting of morphine in blocking tonic phase responses.After repeated intrathecal injections twice daily for 5 consecutive days,ω-SO3 produced analgesia without loss of potency whereas morphine produced analgesia tolerance in rat formalin test;further,ω-SO3 still produced potent analgesia in morphine-tolerant rats.No changes in motor function were seen in rats receiving above antinociceptive doses.Conclusion sNovel ω-SO3 produces potent and long-acting spinal antinociception without observable motor dysfunction and after chronic intrathecal administration.ω-SO3 produces neither tolerance nor cross-tolerance to morphine analgesia.
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The C-terminal tail of opioid receptor is important for opioid receptor phosphorylation,desensitization and internalization after opioid agonists treatment.The C-terminal point mutant and truncated mutant of amino acid residues of ?opioid receptors such as T394A,T383A,T357A,S355A affect the function of the opioid receptor obviously.The identical results could be seen in the C-terminal point mutant S363A of ?opioid receptor and S369A of ?opioid receptor.It is well known that opioid receptor requires interaction with other proteins for function,regulation and trafficking.Although proteins such as PPL,FilaminA,PLD2,PKCI,GASP and EBP50/NHERF have been identified to interact with C-terminals of opioid receptors,the role of interaction of these proteins with opioid receptor in the dependence,tolerance and addiction of opioids is dubious.Therefore,looking for the proteins specifically interacting with the C-terminals of opioid receptor may be important to understand the mechanism of opioids addiction.