共查询到20条相似文献，搜索用时 656 毫秒
1.
AIM: To explore the pathophysiological bases in the pathogenesis of the lasting emotional behavioral disorders following posttraumatic stress disorder(PTSD). METHODS: 240 male Wistar rats were divided randomly into 3 groups. Group SE(n =96) for rats with PTSD-like behavior by constant pulsating current of 100 μA with intratrain frequencies of 16 Hz, pulsating duration of 1 ms, train duration of 10 s and interstimulus interval of 7 min for 5 days with 8 times per day. Group CE(n =96) for control with electrode implanted in hippocampus without stimulation, and Group NC(n =48) for normal control. The activities of Na+-K+-ATPase and Ca2+ -ATPase, levels of intracellular calcium and free calmodulin(CaM), and the total CaM expression were detected in hippocampi of experimental rats. RESULTS: The activities of Na+-K+-ATPase and Ca2+ -ATPase in mitochondria of hippocampal cells in Group SE rats were significantly decreased at 48 h and 72 h after the last stimulation, respectively. The intracellular free calcium levels were increased, and the mean channel fluorescence of intracellular free CaM decreased remarkably at 72 h poststimulation, while the expression of total CaM was significantly elevated at 48 h after the last stimulation in hippocampi of Group SE rats. CONCLUSION: The lasting increased levels of intracellular free calcium and expression of Ca2+ -CaM in hippocampus, as well as the dysfunction of Na+-K+ pump and Ca2+ -ATPase in mitochondria may play important roles in the long-term neuropsychological sequelae in PTSD. 相似文献
2.
AIM: To determine whether nuclear Ca2+ is independently regulated from the cytosolic Ca2+ and nuclear Ca2+ oscillation induced by many modulating factors in cultured rat neonatal myocytes and its mechanism. METHODS: Rat neonatal cardiac myocytes were cultured, and fluo-4/AM was loaded as calcium probe. The changes of cytosolic and nuclear Ca2+ were observed by confocal laser microscopy. RESULTS: Calcium fluorescent intensity oscillated slightly in myocardiocytes and the average intensity was much higher in the nucleus than that in the cytosole. Ca2+ oscillation in nucleus and cytosole induced by norepinephrine, isoproperenol, ATP were completely blocked by Ca2+-ATPase antagonist thapsigargin (10-6 mol/L),L-type Ca2+ channel blocker verapermil (500 μmol/L) and KCl (20 mmol/L). Ca2+-ATPase antagonist thapsigargin completely blocked the propagation of Ca2+ waves and simutaneouly induced a temporary Ca2+ increase followed by a magnificient drop and loss of response to norepinephrine. CONCLUSIONS: The results suggested that generation and maintenance of calcium oscillation both in cytosole and nucleus depended on extracellular Ca2+ influx, membrane potential, Ca2+ release and uptake of cytosolic and nuclear calcium stores. The difference between cytosolic calcium and nuclear calcium indicated that calcium regulating system relatively independent of cytosole may exist in nucleus. 相似文献
3.
AIM: To study the effects of fructose-1,6-diphosphate (FDP) on adriamycin (ADR)-induced calcium and sarcoplasmic reticulum Ca2+-ATPase activity in cardiomyocytes of rats. METHODS: Rats were treated with ADR by intraperitoneal injection (2.5 mg·kg-1 body weight) once every two days for 11 days, and then ADR-treated rats were intervened by FDP at different dosages (ip) once every other day for 41 days. Enzyme linked immune absorption assay (ELISA) was employed to detect froponin I (CTnI). CK-MB was examined by monoclonal antibody. Intracellular free calcium concentration was measured on fluorescent spectrophotometry and SRCa2+-ATPase activity was examined by inorganic phosphate. RESULTS: FDP (300, 600, 1 200 mg·kg-1) significantly reduced the levels of CTnI and CK-MB in serum. Decreased calcium and increased SRCa2+-ATPase activity in cardiomyocytes were also observed when ADR-treated rats were intervened by FDP (P＜0.01). CONCLUSION: FDP reduced the injury of cardiotoxicity induced by ADR via decreasing intracellular free calcium and increasing SRCa2+-ATPase activity in cardiomyocytes. 相似文献
4.
AIM:To investigate the effect of lipopolysaccharide (LPS) priming on macrophage(MΦ).METHODS:Macrophage cell line RAW264.7 were pretreated with or without LPS for 1 h, then challenged with PMA, or LPS, muramyl dipeptide(MDP), Zymosan, formyl-methionyl-leucyl-phenylalanine(FMLP) for 1 h. O2- production in supernatants and intracellular free calcium([Ca2+]i) were measured, and changes in [Ca2+]i and LPS induced O2- production were compared.RESULTS:LPS pretreatment significantly increased O2- production in RAW264.7 cells challenged with the stimuli, and in a certain extent, both O2- production and increase of resting intracellular [Ca2+]i were dose- and time-dependent on LPS pretreatment.Furthermore, the peak [Ca2+]i was significantly higher in LPS pretreated groups than that of LPS unpretreated groups when challenged with PMA. Pretreatment with Ca2+ inophore A23187 mimicked the LPS priming effects on O2- production, but pretreatment with Ca2+ chelator BAPTA and EGTA blocked this priming effect.CONCLUSION:LPS-induced MΦ priming effect on O2- production is dependent on elevation of resting intracellular [Ca2+]i. 相似文献
5.
AIM: To investigate the role of reactive oxygen species (ROS) and calcium overload in the apoptosis of MC3T3-E1 cells induced by high glucose. METHODS: Cultured mouse skull bone-derived osteoblast cell line MC3T3-E1 was treated with high concentration of D-glucose to induce apoptosis. The proliferation of MC3T3-E1 cells was detected by MTT assay after treated with different concentrations of D-glucose for 24 h and 48 h. The apoptotic rate and the intracellular levels of calcium and ROS were also measured after the cells were treated with high glucose (35 mmol/L) for 24 h. RESULTS: After high glucose treatment, the cell proliferation was inhibited. The early apoptosis and total cell death increased to (24.16?3.53)% and (63.74?4.32)%,respectively. High glucose treatment significantly increased intracellular levels of ROS and Ca2+. The increased apoptotic rate was reduced by addition of antioxidant N-acetylcysteine and calcium chelator BAPTA-AM. Inhibition of store-operated Ca2+ channels by La3+ also decreased the intracellular level of Ca2+ and cell apoptosis induced by high glucose. CONCLUSION: High glucose increases intracellular ROS level and the release of Ca2+ through the store-operated Ca2+ channels, thus resulting in intracellular Ca2+ overload and leading to apoptosis of osteoblasts. 相似文献
6.
AIM:To study alterations of cardiac sarcoplasmic reticulum (SR) function in vitamin D3-induced calcium overload rats. METHODS: The Ca-overload rat models were prepared by vitamin D3 plus nicotine. Cardiac SR was seperated by centrifuging. The measurement of SR Ca2+uptake and Ca2+ release activities were preformed by the Millimore filtration technique. Specific SR -ryanodine binding capacity was measured by radioligand method. RESULTS: Compared with control,myocardial calcium content in calcium overload rats increased by 78%(P＜0.01), SR Ca2+ uptake and Ca2+ release activities decreased by 64% and 40% respectively(P＜0.01),and in the meantime ,the Ca2+-ATPase activity decreased by 65%(P＜0.01).Maxmum value for -ryanodine binding decreased by 51%(P＜0.01). CONCLUSION:The function of cardiac SR in calcium-overload rats was decreased. 相似文献
7.
AIM: To observe the effect of Shenmai injection on the acute myocardial ischemia/ reperfusion injury in rats. METHODS: The left-anterior coronary artery was ligated for 10 minutes and then loosed for 15 minutes to establish the animal model of acute myocardial ischemia/reperfusion injury. During the process, electrocardiogram was traced continuously to observe the arrhythmia caused by reperfusion. The levels of SOD, MDA, Na+, K+-ATPase and Ca2+ -ATPase in ventricular myocardium were measured. The mitochondria was observed through electron microscope. RESULTS: Shenmai injection decreased the incidence of arrhythmia caused by reperfusion and shortened its duration. Shenmai injection improved the activity of SOD, Na+, K+-ATPase and Ca2+ -ATPase, decreased the content of MDA in myocardium and relieved the injury of mitochondria. CONCLUSION: Shenmai injection had a protective effect on acute myocardial ischemia/reperfusion injury in rats. The mechanism may be related to relieving the injury caused by oxygen free radical and calcium overload. 相似文献
8.
AIM: To explore regulation of lipopolysaccharide (LPS)-induced elevation of Ca2+ intracellular level in alveolar macrophages(AMs) from patients with chronic bronchitis by Angelica Sinensis and nifedipine.METHODS:AMs was obtained from 7 patients with chronic bronchitis and 6 normal controls by bronchoalveolar lavage and intracellular Calevel was detected after adding Angelica Sinensis, nifedipine or LPS to the supernatant of AMs loaded by Fura-2. RESULTS: In contrast with normal control group (99.65±32.21 nmol/L), intracellular Ca2+ level in AMs from chronic bronchitis group (189.47±23.69 nmol/L) was increased significantly in the absence of extracellular Ca2+ but not 1 mmol/L. Intracellular Ca2+ level in AMs from chronic bronchitis group were significantly increased by adding 10 μg/mL LPS to the supernatant of AMs. LPS-induced elevation of intracellular Ca2+ level in AMs from chronic bronchitis group was completely inhibited by Angelica Sinensis or nifedipine.CONCLUSION: Both Anelica Sinensis and nifedipine may inhibit activation of AMs from patients with chronic bronchitis by reducing LPS-induced elevation of intracellular Ca2+ level in AMs, suggested that these two medicines may inhibit non-specific inflammation of airways in chronic bronchitis. 相似文献
9.
AIM: Nitroxyl(HNO) increases myofilament Ca2+ responsiveness relative to increases in intracellular Ca2+ in cardiac muscle. In this study, we further investigated this effect of HNO on trabecular muscles from phospholamban knockout(PLB-KO) and wide-type(WT) mice using a novel HNO donor, 1-nitrosocyclohexyl acetate(NCA). METHODS: Trabecular muscles were dissected from the right ventricles of the rat hearts and mounted between a force transducer and a motor arm. The muscles were superfused with K-H solution(pH 7.4) at room temperature. Fura-2 was loaded into the trabecular muscles via electrophoresis. The length of the sarcomere was set to 2.2~2.3μm. During steady-state activations, the maximal Ca2+-activated force and Ca2+ required for 50% activation were measured. RESULTS: The intracellular Ca2+ transients and force of the PLB-KO muscles at baseline were higher than those of the WT muscles and exhibited a negative force-frequency relationship(FFR). NCA(2.5μmol/L) increased systolic force in both PLB-KO group and WT group at any given[Ca2+]o. However, there was more dramatic increase in the force development due to moderate increases in the intracellular Ca2+ transients in the WT muscles when external Ca2+ increased from 1.5 to 4.5 mmol/L under NCA. NCA did not affect the negative FFR in PLB-KO muscle. Steady-state force-Ca2+ relations obtained from skinned muscles were not different between the 2 groups, while NCA increased Ca2+ responsiveness in skinned muscles from both PLB-KO and WT mice.CONCLUSION: HNO increases force development in both PLB-KO and WT muscles as a result of increases in myofilament Ca2+ responsiveness. The increased intracellular Ca2+ transients are accompanied by greater force development in WT mice, suggesting that HNO improves Ca2+ activation and establishes HNO as a positive inotropic agent with novel mechanisms. 相似文献
10.
AIM:To investigate different intracellular concentration of Ca2+ in uterine myometrial cells at term and non-term.METHODS:The living cells suspensions were made to measure intracellular Ca2+ concentrations after stainned by calcium fluorescent indicator Fluo-3 AM, then examined by laser scanning confocal microscope (LSCM).RESULTS:Intracelluar Ca2+ showed very stronger red positive signal in myometrial cells at term than that in non-term cells. [Ca2+]i were (35±8.1) nmol/L at non term and (75±7.3) nmol/L at term, which had significant difference compared with each other (P＜0.05).CONCLUSION:Increase in [Ca2+]i in myometrial cells might play a very important role labor. 相似文献
11.
AIM: To investigate the alteration of sarcoplasmic reticulum (SR) Ca2+ transport proteins including sarcoplasmic reticulum Ca2+-ATPase 2a(SERCA2a) and phospholamban(PLB) mRNA expression as well as the alteration of myocardial SR Ca2+-ATPase activity in neonatal hypothyroid rats, and to explore the effect of levothyroxine(L-T4) substitution therapy on the above indexes.METHODS: Hypothyroidism was induced by the administration of propylthiouracil (PTU, 50 mg/d) to the pregnant SD rats by gavage beginning on embryonic day 15 and continuing throughout the lactational period. A subgroup of neonatal hypothyroid rats were intraperitoneally injected with L-T4 levothroxine (20 μg/kg BW daily), starting from the day of birth. Other pregnant SD rats received normal saline instead of PTU. The samples of the rats in all 3 groups were harvested at postnatal day 3, 5 and 7 respectively (n=10). After measurement of serum thyroid hormone levels, the hearts were removed and the ventricles were weighed (HW). The concentration of calcium in ventricular myocardium(ventricular myoCa2+) was detected by fluorospectrophotometry and the activity of SR Ca2+-ATPase was determined by the inorganic phosphorus method. The mRNA expression of SERCA2a and PLB was also detected by real-time PCR. RESULTS: Neonatal hypothyroid rats had a significant lower level of SERCA2a mRNA (P<0.05) and a higher level of PLB mRNA (P<0.01), and subsequent lower SERCA2a/PLB at each postnatal day (P<0.01) was observed. Compared with hypothyroid group, the mRNA expression of SERCA2a significantly increased (P<0.05) and that of PLB significantly decreased (P<0.05) in L-T4 treatment group. The concentration of ventricular MyoCa2+ in hypothyroid group was significantly higher than that in control group (P<0.01), and that in L-T4 treatment group showed a significant decrease as compared with hypothyroid group (P<0.05). The activity of sarcoplasmic reticulum Ca2+-ATPase in hypothyroid group was significantly lower than that in control group (P<0.01), and that in L-T4 treatment group showed a significant increase as compared to hypothyroid group (P<0.05). CONCLUSION: The deficiency of thyroid hormone, resulting in decreased expression of SERCA2a mRNA as well as increased PLB mRNA, contributes to the reduction of SR Ca2+-ATPase activity in neonatal rats. This may be one of the most important mechanisms of myocardial systolic and diastolic dysfunctions. 相似文献
12.
AIM: To investigate the effect of interleukin-2(IL-2) on the intracellular calcium in electrically stimulated adult rat ventricular myocytes during anoxia and reoxygenation. METHODS: The isolated cardiac ventricular myocytes were exposed to 5 min anoxia followed by 10 min reoxygenation. Chemical anoxia was introduced by Krebs-Henseleit(K-H) solution containing 10-3 mol/L sodium dithionite. The spectrofluorometric method was used to verify intracellular calcium transient with fura-2/AM as calcium fluorescence probe. RESULTS: It was shown that during anoxia, the amplitude of Ca2+ transient was decreased, diastolic [Ca2+]i, time to peak and time to relaxation of Ca2+ transient were increased. All the parameters were got back but did not returned to the pre-anoxia level during reoxygenation. IL-2 at 2×105 U/L administrated during anoxia aggravated the effect of rexoxygenation on [Ca2+]i transient. Pretreatment with a specific κ opioid antagonist, nor-BNI(10-8 mol/L), abolished the effect induced by IL-2 during anoxia on the [Ca2+]i transients, whereas specific δ opioid antagonist, naltrindole(10-6 mol/L), did not cancel the effect. CONCLUSION: It is concluded that administration of IL-2 during anoxia aggravated the effect of reoxygenation on the [Ca2+]i transients of isolated ventricular myocytes, which was mediated by cardiac κ opioid receptor pathway. 相似文献
13.
AIM:To investigate the change in myocardial mitochondrial Ca2＋ concentration ( [Ca2+]m) and its mechanism in the early stage of severe burn. METHODS:An experimental model of 30%TBSA full-thickness skin scalding was reproduced in rats. [Ca2+]m, cytosolic Ca2＋ concentration ( c) and mitochondrial Ca2＋ transport velocity were determined. RESULTS: ① [Ca2+]m increased evidently at 1st hour postburn, and continuously at 3rd hour, reached the peak at 6th hour postburn, then, it decreased at 12th and 24th hour, but remained in higher level than that of the control. ② There was no significant difference in c between 1st hour postburn and the control, but c increased evidently at 3rd, 6th, 12th, 24th hour postburn. ③ mitochondrial Ca2＋ uptake velocity at 1st hour postburn was higher than that of control, and Ca2＋ release velocity didn't change obviously, but both of them were decreased at 3rd, 6th, 12th, 24th hour postburn. ④ [Ca2+]m was positive correlated with c after burn, and negative correlated with mitochondrial Ca2＋ release velocity at 3rd, 6th, 12th, 24th hour postburn, respectively. CONCLUSION: There was obvious Ca2＋ overload in myocardial mitochondria after severe burn, the mechanism of which might include ascent of c and disorder of Ca2＋ transport in mitochondria. 相似文献
14.
AIM: To study the effects of cyproheptadine (Cyp) and anisodamine (Ani) on the changes of intracellular free Ca2+ concentration ([Ca2+]i) induced by tumor necrosis factor (TNFα) in single endothelial cells, and to explore the mechanisms of TNFα mediated shock and antishock actions of Cyp and Ani. METHODS: Human umbilical vein endothelial cell strains (ECV304) were seed in 35 mm tissue culture dish with 2 mL DMEM culture medium. The cultured cells were loaded by Fluo-3/AM. The spatial distribution and the dynamic changes of [Ca2+]i in single endothelial cell was determined by laser scanning confocal microscopy (LSCM). RESULTS: [Ca2+]i in single endothelial cell after stimulation of TNFα rapidly increased in a dose-dependent manner and approached the peak value within 60 seconds, afterwards, decreased and kept above the basal level. The confocal scanning image showed that [Ca2+]i elevation was more obvious in nuclear than in cytoplasma, and decreased slowly. Cyp (3×10-5, 6×10-5 mol/L) and Ani (2×10-5, 4×10-5 mol·L-1) markedly inhibited TNFα (1.2×10-9 mol·L-1)-induced [Ca2+]i elevation. CONCLUSIONS: TNFα markedly induces elevation of [Ca2+]i in single endothelial cell, it may be an important mechanism of TNFα-induced shock and tissue injury. Cyp and Ani obviously suppress TNFα-induced [Ca2+]i elevation, which probably is one of the mechanisms of their antishock effects. 相似文献
15.
AIM: To investigate the effect of hesperetin on hypoxia/reoxygenation (H/R)-induced apoptosis in the H9c2 cells and to clarify the underlying mechanism. METHODS: The H/R model was established and the H9c2 cells were pretreated with hesperetin for 4 h. The cell viability and cell damage were measured by CCK-8 assay and lactate dehydrogenase (LDH) detection. The apoptosis was analyzed by Hoechst 33258 staining and flow cytometry. The intracellular calcium fluorescence intensity was measured by fluorescence microscopy and flow cytometry. The calcium-ATPase activity and the level of adenosine triphosphate (ATP) were measured by ELISA. The mitochondrial membrane potential was measured by JC-1 staining. The protein expression levels of Bcl-2, Bax and cytochrome C (Cyt-C) were determined by Western blot. RESULTS: Hesperetin reduced the apoptosis of the H9c2 cells induced by H/R, decreased intracellular Ca2+ fluorescence intensity, elevated Ca2+-ATPase activity, inhibited the mitochondrial membrane potential depolarization and increased the level of ATP (P<0.05). In addition, hesperetin significantly reduced the release of Cyt-C protein from mitochondria to cytoplasma and increased the Bcl-2/Bax ratio (P<0.05). After using the calcium ion inhibitor nimodipine, the percentage of the cells with mitochondrial membrane depolarization was decreased, the ATP level was increased and the protein expression of mitochondrion-related apoptosis molecules were decreased (P<0.05). CONCLUSION: Hesperetin reduces the apoptosis of the H9c2 cells induced by H/R, which may be related to inhibition of calcium overload and improvement of mitochondrial function. 相似文献
16.
AIM: To investigate the heterogeneity of basal intracellular free calcium concentration([Ca2+]i) in peritoneal macrophages(PM) and whether it is relative to the reactivity of PM at the single cell level. METHODS:[Ca2+]iimplicated stimulated were measured by fluorescent microscopic imaging system after loading with fluorescent probe fura-2/AM. Superoxide(O2-)produced by single PM was determined by modified NBT test. RESULTS: The values of basal[Ca2+]idetermined in 392 PMs of 7 mice showed normal distribution [(54±24) nmol/L, n=392] with wide range(less than 20 nmol/L to more than 100 nmol/L), among which about 50% were in the range of 40-60 nmol/L. When stimulated with PMA or fMLP,[Ca2+]iwas increased, the peak values were positively correlated with the basal[Ca2+]iin one mouse(PMA stimulated cells: r=0.52, P<0.01, n=58; fMLP stimulated cells:r=0.59, P<0.01, n=44. Both of the experiments were repeated in 3 mice, the results in the other 2 mice were similar). The O2- in PMA stimulated PMs were also positively correlated with the basal i(r=0.42, P<0.01, n=43, repeated in 4 mice, the results in the other 3 mice were similar). CONCLUSION: Basal[Ca2+]iin murine PM is heterogeneous, and the value of basal[Ca2+]iis tightly correlated to the reactivity of PM stimulated by proinflammatory factors. 相似文献
17.
AIM: To investigate the protective effect of calcium antagonists on anoxia/reoxygenation (A/R) injury of cardiomyocytes. METHODS: Primary-cultured cardiomyocytes were divided into four groups, namely A/R, A/R+nifedipine (Nif), A/R+ruthenium red (Ru)+heparin (Hep) and control groups. The following parameters were measured in all groups: intracellular calcium concentration (i), cardiac cell viability, ATP content, lactate dehydrogenase (LDH) activity in the medium, PKC and MAPK activity and 3[H]-Leucine (3[H]-Leu) incorporation. RESULTS: In comparison with A/R group,A/R+nifedipine (Nif) and A/R+ruthenium red (Ru)+heparin (Hep) groups showed a marked decrease in[Ca2+]i and LDH content,and a significant increase in cell viability, ATP content, activity of PKC and MAPK and [3H]-Leu incorporation (P<0.05 or P<0.01). CONCLUSION: A/R mediated Ca2+ overload resulted in cardiomyocyte injury, which could be attenuated by blocking Ca2+ entry and release. 相似文献
18.
AIM:To study the effect of salvia miltiorrhiza (SM) on cell contraction and intracellular calcium of enzymatically isolated rat ventricular myocytes during normoxia and anoxia/reoxygenation.METHODS:Contraction and intracel ular calcium were determined with video tracking system and spectrofluorometric method,and the chemical anoxic method was employed. RESULTS:The ±dL/dtmax, dL of cell contraction and the amplitude of [Ca2+]i in the cardiomyocytes following SM treatment were decreased in a dose-dependent manner. During anoxia, the ±dL/dtmax, dL and amplitude of [Ca2+]i were decreased, while the diastolic Ca2+ level was elevated compared with control group. All the contractile parameters and the diastolic Ca2+ level were back toward pretreatment values during reoxygenation, but could not return to control level. After the treatment with SM (3 g/L), ±dL/dtmax and dL of cell contraction and the amplitude of [Ca2+]i were higher and the diastolic Ca2+ level was lower than those in anoxia/reoxygenation group. CONCLUSION:SM antagonized effects of anoxia and reoxygenation on cell contraction and intracellular calcium in isolated ventricular myocytes. 相似文献
19.
AIM: To observe the effects of irbesartan and perindopril on pressure-overload cardiac hypertrophy in rats. METHODS: 40 male adult Sprague Dawley rats were divided into 5 groups. One was sham operation group, other four were aortic banding groups. One week after operation, all rats were gavaged with normal saline, perindopril, irbesartan or combination of perindopril and irbesartan. Morphometric determination, calcineurin (CaN) expression, CaN and sarcoplasmic reticulum (SR) Ca2+-ATPase activity were performed at the end of 6 weeks of drug intervention. RESULTS: Left ventricular mass index (LVMI), transverse diameter of myocardical cell (TDM), CaN activity were remarkably decreased after drug intervention and this decrease was most remarkable in the combination group. SR Ca2+-ATPase activity increased after drug intervention, especially in the combination group. CaN expression in myocardium were remarkably decreased after drug intervention. LVMI was positively correlated with TDM and CaN, negatively correlated with SR Ca2+-ATPase. CONCLUSION: Both irbesartan and perindopril decrease CaN activity, increase SR Ca2+-ATPase activity and combination of them has synergic effects on regressing of ventricular hypertrophy. 相似文献
20.
AIM: To study the roles and mechanisms of ERKs and intracellular free calcium in cardiomyocyte hypertrophic response induced by endothelin-1(ET-1). METHODS: (1) Neonatal rat cardiomyocyte hypertrophic response was assayed by measuring cell surface area and protein content; (2) ERKs activity was determined by Whatman Paper Filter method; (3) Intracellular free calcium concentration ([Ca2+]i) was measured using Fura-2/AM as a fluorescent indicator. RESULTS:(1)ET-1 could increase total protein production,surface area,ERKs activity and[Ca2+]i in cultured cardiomyocyte in dose-dependent manner at concentrations ranging from 10-9to 10-7mol/L.And this effect could be abolished by BQ123,an antagonist of ETA receptor,partly inhibited by PTX,but not by BQ788,an antagonist of ETB receptor.(2)The activation of ERKs and the increase of[Ca2+]i induced by ET-1 were obviously in hibited by PD98059,a selective ERKs kinase inhibitor,and nifedipine,a calcium channel blocker,respectively.Both antagonists partialy inhibited ET-1-stimulated cardiomyocyte hypertrophic response.(3)Staurosporine,a selective PKC inhibitor,could inhibit ET-1-stimulated cardiomyocyte hypertrophic response and increase of[Ca2+]i,but not af ect the activation of ERKs.CONCLUSION: Cardiomyocyte hypertrophic response induced by ET-1 is mediated by ETA receptor coupled to PTX-sensitive G-protein, which involves at least two signalling pathways: PKC-mediated increase of [Ca2+]i , and PKC-independent activation of ERKs. 相似文献