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1.
Calcium-activated chloride channels play important roles in the pathological processes in asthma with mucus overproduction and a series of airway inflammation. The function of calcium-activated chloride channels depends on their structure and characterization. The members of chloride channels, calcium activated (CLCA) family of proteins and in particular murine mCLCA3 (alias Gob-5) are possible initial factors of mucus overproduction in asthma. Regulation of mCLCA3 is relevant with cytokines secreted by Th2 cells. Over-expression of Gob-5 and hCLCA1 increase the translation of MUC5AC gene, which upregulates the secretion of goblet cells. Further study on the function and structure of calcium activated chloride channels may provide new evidence for understanding the pathogenesis of asthma.  相似文献   

2.
AIM：To investigate the type of chloride channel activated by cisplatin in poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z cells). METHODS：The technique of whole-cell patch-clamp was used to investigate the role of Ca2+ in the activation of cisplatin-activated chloride currents and to analyze the effect of hypertonic stress on these currents in CNE-2Z cells. RESULTS：Chloride currents were induced when the cells were exposed to the calcium-free cisplatin solution, showing the similar density to the currents induced by cisplatin with the presence of extracellular calcium. However, the latency and the peak time of cisplatin-activated currents in the absence of extracellular calcium were prolonged. The activation of cisplatin-activated chloride currents was insensitive to the depletion of intra- and extracellular calcium. Calcium channel antagonist nifedipine had no effect on the cisplatin-activated chloride currents, while hypertonic solution completely inhibited those currents. CONCLUSION：The cisplatin-activated chloride currents are independent on intra/extracellular calcium. The chloride channels activated by cisplatin are not calcium-activated chloride channels, but are probably volume-sensitive chloride channels.  相似文献   

3.
ClC-3 channel is one of voltage-gated chloride channels for chloride ion transmembrane, and participates in a variety of physiological and pathological processes, such as cell volume regulation, proliferation, migration, apoptosis, organic release and acidification of synaptic vesicle. The ClC-3 channel is controlled by many factors, including phosphorylation and dephosphorylation, to regulate the opening and closing. PKA(protein kinase A), PKB, PKC and calcium calmodulin kinaseⅡ are the key kinases in cell signal transduction pathway, which take part in the processes of ClC-3 channel phosphorylation and regulate their functions. The study of ClC-3 phosphorylation and functions are helpful to understand the importance of ClC-3 in physiological and pathological processes and are premise to exploit the channel drugs for clinical therapy.  相似文献   

4.
AIM: To investigate the role of intracellular free Ca2+ concentration (［Ca2+］i) in the regulation of calcium-activated chloride (ClCa) channels in pulmonary artery smooth muscle cells (PASMCs) of rats under normoxic, acute and chronic hypoxic conditions. METHODS: Acute hypoxia-induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusion in vitro. The fluorescence Ca2+ indicator Fura-2/AM was used to observe ［Ca2+］i of rat PASMCs in normal and chronic hypoxic condition. The influences of ClCa channels on PASMCs proliferation were assessed by MTT assay. RESULTS: (1) The ClCa channel blockers niflumic acid (NFA) and indaryloxyacetic acid (IAA-94) produced inhibitory effects on acute hypoxia-evoked contractions in pulmonary artery. (2) Under chronic hypoxic condition, ［Ca2+］i was increased. In normoxic condition, ［Ca2+］i was (123.63±18.98) nmol/L, and in hypoxic condition, ［Ca2+］i was (281.75±16.48)nmol/L (P<0.01). (3) In normoxic condition, ［Ca2+］i had no significant change and no effect on ClCa channels was observed (P>0.05). (4) Chronic hypoxic increased ［Ca2+］i which opened ClCa channels. The NFA and IAA-94 blocked them and decreased ［Ca2+］i from (281.75±16.48)nmol/L to (117.66±15.36)nmol/L (P<0.01). (5) MTT assay showed that in chronic hypoxic condition NFA and IAA-94 decreased the value of absorbing light degree (A value) from 0.459±0.058 to 0.224±0.025 (P<0.01). CONCLUSION: Hypoxia increased ［Ca2+］i which opened ClCa channels and had a positive-feedback to ［Ca2+］i. This may play an important role in hypoxic pulmonary hypertension. In chronic hypoxic condition, ClCa channel may play a role in the regulation of PASMCs proliferation.  相似文献   

5.
AIM: To investigate the role of potassium channels in the regulation of intracellular free calcium concentration ( [Ca2+]i) of pulmonary artery smooth muscle cells (PASMCs) in rats. METHODS: The fluorescence Ca2+ indicator Fura-2/AM was used to observe [Ca2+]i of rat PASMCs in normal and chronic hypoxic condition. The influences of potassium channels on PASMCs proliferation were assessed by MTT assay. RESULTS: 1. In normoxic condition, [Ca2+]i was (156.91±8.60) nmol/L, and in hypoxic condition, [Ca2+]i was (294.01±16.81) nmol/L. 2. In normoxic condition, the voltage-dependent K+-channel antagonist 4-aminopyridine (4AP), but not the Ca2+-activated K+-channel antagonist tetraethylammonium (TEA) and the ATP-sensitive K+-channel antagonist glibenclamide (Glib) increased [Ca2+]i. 3. In hypoxic condition, 4AP and TEA caused the rise in [Ca2+]i , but Glib had no effect on [Ca2+]i. 4. MTT assay showed that 4AP increased the value of absorbing light degree (A value) in normoxic and hypoxic condition (0.582±0.062,0.873±0.043,respectively, P＜0.01), TEA increased A value only in hypoxic condition, and Glib had no effect on the proliferation of PASMCs. CONCLUSIONS: KV plays an important role in the regulation of [Ca2+]i and proliferation of PASMCs. KCa serves as distinct responsive roles in the regulation of proliferation of PASMCs in hypoxic condition. KATP has no effect on [Ca2+]i and proliferation of PASMCs in normoxic and hypoxic conditions.  相似文献   

6.
AIM: To investigate the activation of chloride channels induced by bufalin and the properties of the channels in poorly differentiated nasopharyngeal carcinoma (CNE-2Z) cells. METHODS: The technique of whole-cell patch clamp was used to record the chloride currents and to analyze the characteristics of the currents in CNE-2Z cells.RESULTS: A chloride current was slowly activated by extracellular application of bufalin (1 μmol/L). The activation of the current was slower than that of the volume-activated chloride current, with an activation latency of(12.1±6.4) min. The reversal potential of the current was close to the calculated Cl- equilibrium potential (ECl =-0.9 mV). The chloride current was outward-rectified and did not show significant time-dependent or voltage-dependent inactivation. The chloride channel blocker tamoxifen completely inhibited the outward and inward currents. The current was also completely inhibited by extra-cellular application of 47% hypertonic solution. CONCLUSION: Bufalin activates chloride channels and induces a chloride current in CNE-2Z cells. Compared with the volume-activated chloride current in CNE-2Z cells, the activation latency of the bufalin-induced current is longer and the outward rectification is more obvious.  相似文献   

7.
AIM：To study the effects and mechanisms of ethanol on chloride channels in poorly differentiated nasopharyngeal carcinoma CNE-2Z cells. METHODS：The effect of ethanol on the cell growth was analyzed by MTT assay. The technique of whole-cell patch-clamp was used to detect the chloride current. The characteristics of the chloride current were analyzed by using the chloride channel blockers. The siRNA technique was used to analyze the molecular basis of the ethanol-sensitive chloride channels. RESULTS：Under isotonic conditions, the background current was weak and stable. Ethanol at concentrations of 0.17~170 mmol/L activated a chloride current in a concentration-dependent manner (an inverted U-shape), with a maximum effect at the concentration of 17 mmol/L. The currents showed obviously outward rectification and were susceptible to extracellular hypertonicity and the chloride channel blocker, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). ClC-3 siRNA obviously decreased the currents activated by ethanol. CONCLUSION：Extracellular ethanol induces chloride currents through activating the ClC-3 chloride channels.  相似文献   

8.
AIM: To characterize the chloride current activated by extracellular hypotonic stress in human acute lymphoblastic leukemia Molt4 cells.METHODS: The technique of whole-cell patch clamp recording was used to detect the volume-activated Cl- current in Molt4 cells. The characteristics of the current were investigated.RESULTS: The background Cl- current was weak and stable under isotonic condition. However, a large Cl- current was induced by exposure of the cells to 47% hypotonic solution. The current showed a characteristic of outward rectification. No voltage-dependent inactivation and time-dependent inactivation were observed. The current was sensitive to the change of cell volume and was inhibited by extracellular hypertonic solution. Extracellular tamoxifen, which is one of the chloride channel blockers, significantly inhibited the current. The effects of tamoxifen were almost equal for both inward and outward currents (P>0.05).CONCLUSION: There are volume-activated chloride channels on the cell membrane of Molt4 cells. Exposure of the cells to a hypotonic solution activates the chloride channels and induces a volume-activated chloride current. The volume-activated Cl- channels are sensitive to tamoxifen in Molt4 cells.  相似文献   

9.
AIM:To observe the influence of captopril on intracellular free calcium concentration (［Ca2+］ i) and the involved ion channels mechanisms in cardiac myocytes of the neonatal rat undergone anoxia-reoxygenation injury.METHODS:The anoxia-reoxygenation model in cultured neonatal rat ventricular myocytes was established.Groups were divided into ① normal;② anoxia-reoxygenation;③anoxia-preconditioning (5 min anoxia+5 min reoxygenation);④ captopril preconditioning.Flou-3 /AM loading and flow cytometry technique were used to observe the ［Ca2+］i,and whole-cell patch clamp technique was used to record the L-type calcium current and Na+/Ca2+ exchange current.RESULTS:① Compared to normal group,［Ca2+］i in anoxia -reoxygenation group was increased significantly (789.42±9.05 vs 414.08±37.40,P<0.01),L-type calcium current density was decreased (P<0.01),the current-voltage curve was moved up,the inactivation curve was moved left and Na+/Ca2+ exchange current was increased in anoxia-deoxygenating.② Compared to anoxia-reoxygenation group,anoxia and captopril preconditioning resulted in a significant decrease in ［Ca2+］i (593.84±5.06,507.08±31.89 vs 789.42±9.05,P<0.01),and a significant increase in L-type calcium current density (P<0.01),the current-voltage curve was moved down,the inactivation curve was moved right and Na+/Ca2+ exchange current was decreased ③ Compared to normal oxygen condition,the anoxia and captopril precondition resulted in a lightly increase in ［Ca2+］i (507.08±31.89 vs 414.08±37.40,P<0.05) and Na+/Ca2+ exchange current.④ Compared to anoxia-preconditioning group,captopril-preconditioning resulted in no significant difference in all the markers mentioned above.CONCLUSIONS:The anoxia-reoxygenation injury in cardiac myocytes results in ［Ca2+］i abnormal increase and calcium overload by increasing Na+/Ca2+ exchange current.Late preconditioning in cardiac myocytes is triggered by transient and repeated anoxia and captopril,which slightly increases Na+/Ca2+ exchange current and ［Ca2+］i and restraines the abnormal increasing of Na+/Ca2+ exchange current and calcium overload induced by subsequenced anoxia-reoxygenation injury,so it plays an delayed protective role in cardiac myocytes.L-typed calcium passage is not involved in calcium overloaded and late preconditioning of calcium in myocytes during reperfusion.  相似文献   

10.
Ca2+-activated chloride channels (CaCC, CLCA) are a new family of chloride channels discovered recently, which are related to Ca2+-sensitive chloride ions transport, and there were several members identified currently in different biologic bodies. New studies have shown that its member gob-5 in murine （its human counterpart is CaCC1） plays a pivotal role in airway goblet cell metaplasia, mucus overproduction, MUC5AC gene expression as well as airway hyperresponsiveness (AHR) in asthma, and is a key molecule in the induction of murine asthma and an asthma-related gene. Inhibition of their function and/or their signaling pathway may therefore provide a new therapeutic strategy for asthma.  相似文献   

11.
AIM: To observe the effect of thyroxine on the expression of T-type calcium channels Cav3.1, Cav3.2 and Cav3.3 in rat myocardium, and to explore the possible biological mechanism between the changes of the expression of T-type calcium channels and the arrhythmia in hyperthyroid heart disease. METHODS: Healthy SD rats (n=20) were randomly divided into normal control group (n=10) and hyperthyroid heart disease group (n=10). The animal model was established by intraperitoneal injection of levothyroxine for 35 d. The contents of T3 and T4 in serum, the heart-to-body weight ratio, the diameter of cardiac myocytes and electrocardiograph were measured to evaluate hyperthyroid heart disease. Moreover, the mRNA and protein expression levels of T-type calcium channels in the myocardium were measured by RT-PCR, immunohistochemistry and Western blot. RESULTS: After intraperitoneal injection of levothyroxine for 35 d, compared with the normal control group, the serum contents of T3 and T4, the heart-to-body weight ratio and the diameter of cardiac myocytes were significantly increased in hyperthyroid heart disease group (P<0.05), and arrhythmia occurred in hyperthyroid heart disease group. By immunohistochemistry and Western blot, the protein expression of Cav3.1 increased significantly (P<0.05), while the protein expression of Cav3.2 decreased significantly (P<0.01). However, no change of the Cav3.3 protein was observed. The results of RT-PCR were the same as immunohistochemistry and Western blot. CONCLUSION: Thyroxine promotes the expression of Cav3.1 in the myocardium but inhibits the expression of Cav3.2 at mRNA and protein levels, which might be involved in arrhythmia in hyperthyroid heart disease.  相似文献   

12.
AIM: The research was to investigate the effects of the Tian ma gou teng decoction on the electric physiology feature of L-type calcium channels in the vascular smooth muscle cells in spontaneously hypertensive rats (SHR), and to further explain the mechanism of the Tian ma gou teng decoction in the intervention of blood pressure.METHODS: 12-week-old SHRs were assigned randomly into five groups：group A (treated with Tian ma gou teng decoction), group B (treated with Tian ma gou teng decoction with subtraction concha haliotidis), group C (treated with nifedipine), group D (treated with concha haliotidis), group E (treated with normal saline as control), each group consisted of 9 rats. After treatments were conducted for 4 weeks, the free calcium concentration in serum was measured. The electric physiology feature of L-type calcium channels in the vascular smooth muscle cells was analyzed by patch clamp technique (PCT).RESULTS: No significant difference between group A and group C was observed in the serum free calcium concentration (P>0.05). There were significant differences among group B, group D and group E (P<0.05), compared to before treatment, the change in group E was the most obvious. A decrease in the L-type calcium channel current of vascular smooth muscle cells was observed in group A and group C. The function of group D was feeble, no decrease in the L-type calcium channels current of vascular smooth muscle cells was observed in group B and group E.CONCLUSION: Tian ma gou teng decoction can increase the serum free calcium concentration and block the L-type calcium channel current in vascular smooth muscle cells, indicating one of the mechanism of intervention of blood pressure.  相似文献   

13.
AIM: To investigate the effects of adipose tissue-derived mesenchymal stem cells (ADMSCs) on calcium channels of pulmonary artery in monocrotaline (MCT)-induced pulmonary hypertensive rats.METHODS: ADMSCs were isolated from adipose tissue by collagenase digestion. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups: normal control (Ctr) group, pulmonary arterial hypertension (PAH) group and ADMSCs transplantation group. Mean pulmonary arterial pressure (MPAP) was measured by catheterization, and right ventricular hypertrophy index (RVHI) was calculated. The expression of voltage-gated calcium channel α1c subunit (CaVα1c), sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA-2a), inositol 1,4,5-triphosphate receptor 1(IP3R-1), transient receptor potential channel 1 (TRPC1) and TRPC6 at mRNA and protein levels in the pulmonary trunks was determined by RT-PCR and Western blotting, respectively.RESULTS: MPAP and RVHI were higher in PAH group than those in Ctr group, while those in ADMSCs group were significantly decreased as compared with PAH group. The expression of CaVα1c, TRPC1 and TRPC6 at mRNA and protein levels was obviously increased in PAH group as compared with Ctr group, while that in ADMSCs group was significantly decreased as compared with PAH group. Compared with Ctr group, the expression of SERCA-2a and IP3R-1 at mRNA and protein levels was obviously decreased in PAH group, while that in ADMSCs group was significantly increased as compared with PAH group.CONCLUSION: MPAP and RVHI are attenuated by ADMSCs in MCT-induced pulmonary hypertensive rats. The reduction of pulmonary arterial pressure by ADMSCs transplantation in MCT-induced pulmonary hypertensive rats may be related to the changes of calcium channels.  相似文献   

14.
AIM:To investigate the volume-activated chloride currents and regulatory volume decrease(RVD) induced by hypotonic challenges in rat embryonic myocardial cell line H9c2. METHODS:The technique of whole-cell patch-clamp was used to record the chloride currents induced by hypotonic challenges and to clarify the properties of the currents in H9c2 cells. The changes of cell volume were observed by the technique of real-time living cell imaging, and the roles of chloride channels in RVD were analyzed. RESULTS:A weak background current was recorded in H9c2 cells under isotonic condition. Extracellular application of 47% hypotonic solution rapidly activated an outward rectified current, which did not exhibit time-and voltage-dependent inactivation with the current density of(47.77±3.80) pA/pF at +80 mV and(-33.36±2.80) pA/pF at-80 mV. The reversal potential was(-9.02±0.61) mV, closed to the calculated equilibrium potential for Cl-(-0.9 mV). The current was volume-sensitive and was completely suppressed by 47% hypertonic solution. In addition, chloride channel blockers tamoxifen(20 μmol/L), 5-nitro-2-(3-phenylpropylamino) benzoic acid(NPPB,100 μmol/L) and ATP(10 mmol/L) significantly inhibited the current with different inhibitory ratios. The phenomenon of RVD was also observed in H9c2 cells under the condition of perfusion with 47% hypotonic solution. The chloride channel blocker NPPB at concentration of 100 μmol/L completely inhibited the RVD process. CONCLUSION:The volume-activated chloride channels, which are activated by extracellular hypotonic challenges, play an important role in the process of regulatory volume decrease in H9c2 cells.  相似文献   

15.
YANG Xi  YANG Zhuo  ZHANG Tao 《园艺学报》2009,25(2):401-404
The CaV 2.3 encoded Ca2+ channel is one of the least well-known voltage-gated calcium channels in terms of physiology, pharmacology and clinical relevance. Epilepsy is a family of neurological disorders that are common and harmful to human health. More and more studies such as gene knock-out experiment have demonstrated that the channel is related to epileptic seizure, including participating to plateau potential generation, regulating intracellular Ca2+ concentration, CaV 2.3 splice variant, interacting with some muteins. In addition, some antiepileptic drugs inhibit the epileptiform discharges by targeting CaV 2.3 voltage-gated calcium channel.  相似文献   

16.
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17.
AIM:To investigate whether glycine receptor is involved in the protection of glycine against anoxia/reoxygenation injury in cardiomyocytes by detecting oxygen free radical metabolism, apoptosis and intracellular calcium overload. METHODS:The neonatal rat cardiomyocytes were cultured and exposed to anoxia and reoxygenation (A/R) in the presence of glycine receptor antagonist, glycine or in free chloride buffer. The superoxide dismutase (SOD) activity, the contents of malondialdehyde (MDA) and nitric oxide (NO), the intracellular free calcium concentration and the apoptotic rate in the cardiomyocytes were determined. RESULTS:SOD activity and NO content in cardiomyocytes were lower, but MDA content, intracellular free calcium concentration and apoptotic rate in cardiomyocytes were higher in A/R group than those in control. Pretreatment with glycine inhibited the above changes caused by A/R, which was reversed by strychnine treatment and in the free chloride medium. CONCLUSIONS:Glycine inhibits free radical production, attenuates calcium overload, decreases apoptotic rate and increases SOD activity and NO release in cardiomyocytes exposed to A/R. These findings suggest that glycine exerts a protective effect against A/R injury via glycine receptor and glycine protects the neonatal rat cardiomycytes from A/R-induced injury in a chloride-dependent manner.  相似文献   

18.
AIM: To study the activation and the properties of chloride channels activated by the antineoplastic agent cisplatin (cDDP) in nasopharyngeal carcinoma (CNE-2Z) cells. METHODS: The whole-cell patch clamp technique was used to record chloride currents. The characteristics of the channel were investigated using ion-exchange and pharmacological methods. RESULTS: A chloride current was activated by extracellular application of cDDP (5 μmol/L). The current showed significant outward rectification. The reversal potential of the current was close to the calculated equilibrium potential for Cl-(ECl=-0.9 mV). The activation of the chloride channel was dependent on the existence of the intracellular ATP. The permeability sequence of the four anions was I-≥Br->Cl->gluconate. The current was almost completely inhibited by extracellular application of chloride channel blocker tamoxifen (30 μmol/L). CONCLUSION: Antineoplastic agent cDDP can activate a chloride channel with characteristics similar to the volume-activated chloride channel in CNE-2Z cells.  相似文献   

19.
15 years ago, Noma first applicated the patch clamp technique to CN-treated mamammalian heart cells, e-vealed specific K+ channels which were depressed by intracellular ATP at level greater than 1 mNl.He suggested the ATP-sensitive channels are important for regulating cellular energy metabolism in the control of membrane exitability. Recent studies supported the hypothesis and suggested that ATP- sensitive channels play an important role in hypoxia, myocardial ischemia/reperfusion and is chemic preconditioning  相似文献   

20.
AIM: To investigate the roles of ClC-3 chloride channels in the regulation of cell cycle and the relationship between ClC-3 chloride channels and the cell cycle regulators, such as cyclin D1, cyclin-dependent kinase (CDK)4, CDK6, P21 and P27 in the HeLa cells.METHODS: ClC-3 genes were silenced by the siRNA technique in the HeLa cells. The transfection efficiency of ClC-3 siRNA was detected by real-time PCR. The cell cycle distribution was analyzed by the flow cytometry. The protein expression of ClC-3, P21, P27, CDK4, CDK6 and cyclin D1 was determined by Western blot.RESULTS: ClC-3 was knocked down by ClC-3 siRNA in the HeLa cells. Transfection of the cells with ClC-3 siRNA arrested the cells at G0/G1 phases, decreased the expression of cyclin D1, CDK4 and CDK6, and increased the expression of P21 and P27.CONCLUSION: ClC-3 plays an important role in the cell cycle of HeLa cells through the G1-S transition point. ClC-3 may regulate the cell cycle progression by up-regulation of cyclin D1, CDK4 and CDK6 expression and/or by down-regulation of P21 and P27 expression.  相似文献   

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