Bio-effects of salusins on isolated rat heart and neonatal cardiomyocytes

AIM: To investigate the bio-effects of salusins on rat heart and cardiomyocytes. METHODS: The cardiac function was determined by multipurpose polygraph in isolated rat heart treated with various concentrations of salusin-α or salusin-β.[⁴⁵Ca²⁺] and[³H]-Leu incorporation were determined in cultured neonatal rat cardiomyocytes with β-liquid scintillation counter. RESULTS: 10^-12-10^-7mol/L salusin-α and salusin-β had no effects on isolated rat cardiac function. However, salusin-α and salusin-β stimulated uptake and[³H]-Leu incorporation. The [⁴⁵Ca²⁺] uptake induced by salusins were inhibited by nicardipine, and were synergistically increased by endothelin-1. The[³H]-Leu incorporation induced by salusin-α and salusin-β was inhibited by nicardipine, FK506 (a special inhibitor of carcineulin), PD₉₈₀₅₉ (inhibitor of MAPK) and chelerthine (inhibitor of PKC). The effects of salusin-β[⁴⁵Ca²⁺] on uptake was stronger than those of salusin-α. But there were no statistical difference in[³H]-Leu incorporation between salusin-α and salusin-β. CONCLUSIONS: Salusin-α and salusin-β did not affect directly cardiac function in rat hearts. But salusins improved calcium uptake and protein synthesize in neonatal rat cardiomyocytes. Those effects of salusins were related with calcium channel, carcinuelin, MAPK and PKC signal pathways. Salusins may be the regulatory factors for myocardium growth and hypertrophy.     

Effects of three kinds of calcium activator on the proliferation of cultured vascular smooth muscle cells in rats

AIM: To investigate the effects of intracellular free calcium ([Ca²⁺]i) from different resources on the proliferation mediated by mitogen activated protein kinase (MAPK) in vascular smooth muscle cells (VSMCs). METHODS: Cultured VSMCs were used in all experiments. Calcium influx was stimulated by angiotension Ⅱ(Ang Ⅱ). The release of intracellular calcium stores was induced by inositol trisphosphate (IP₃) and ryanodine (RY). MAPK activity was measured by [γ-³²P]-ATP incorporation MAPK protein expression by western blot, VSMCs proliferation by [³H]-Leucine ([³H]-Leu) and [³H]-Thymidine ([³H]-TdR) incorporation. RESULTS: Compared to the control VSMCs, Ang Ⅱ, IP₃ and RY significantly increased [Ca²⁺]i concentration activity of MAPK and its protein content in VSMCs. The promotion of [³H]-Leu and [³H]-TdR incorporation in VSMCs was also observed (P<0.01). CONCLUSION: The study indicated that calcium activator-induced increase in the activity and protein content of MAPK was involved in the proliferation of VSMCs, which was closely related to the [Ca²⁺]i concentration but independent to its origin.     

Effect of fibronectin on proliferation and collagen synthesis in cardiac fibroblasts from spontaneously hypertensive rats

AIM:To investigate the effects of fibronectin (FN) on the proliferation and collagen synthesis in cultured rat cardiac fibroblasts (CFb) derived from SHR (CFb_SHR) and WKY (CFb_WKY). METHODS:CFb derived from 12-week-old spontaneously hypertensive rat (SHR) and WKY was cultured by outgrowth of tissue block. Cell proliferation of CFb was measured by cell number counting and[³H]-TdR incorporation using 24-well plates pre-coated with 5 μg/cm² of FN. Collagen synthesis was determined by [³H]-proline incorporation. RESULTS:As compared with control, the cell number of fibroblasts derived from SHR and WKY were significantly increased to 163.75% and 170.42% respectively after 72 h incubation with FN in the presence of 0.4% FCS from a intial cell density of 1×10⁴ cells/mL. DNA synthesis of CFb was markedly promoted by FN. FN induced an increased in [³H]-proline incorporation in both CFb_SHR and CFb_WKY. CONCLUSION:FN is able to promote cell proliferation and collagen synthesis of CFb derived both from SHR and WKY.     

Taurine attenuated β-glycerophosphate-stimulated calcification in cultured rat vascular smooth muscle cells

AIM: To investigate the effect of taurine on calcification of vascular smooth muscle cells (VSMCs).METHODS: Calcified VSMCs of rat in vitro were induced by β-glycerophosphate. Cellular calcium content, alkaline phosphatase(ALP) activities and [⁴⁵Ca]accumulation were measured. DNA synthesis were evaluated by [³H]-thymidine ( [³H]-TdR) incorporation. RESULTS: Calcium content, ALP activities and [⁴⁵Ca]uptake of calcified VSMCs stimulated by taurine (5-20 mmol/L) were greatly decreased in a concentration-dependent manner as compared with calcified group (P＜0.01). Taurine also inhibited the proliferation of calcified cells in a concentration-dependent manner. Cell countingz, [³H]-TdR incorporation of calcified cells stimulated by taurine were greatly decreased as compared with calcified VSMCs (P＜0.01). CONCLUSION: It was demonstrated that calcification of VSMCs may be alleviated by taurine.     

Changes of intracellular Ca2+ in living brain slices during focal cerebral ischemia/reperfusion

AIM: The purpose of the present study was to detect intracellular Ca²⁺changes in living brain slices during focal cerebral ischemia/reperfusion (I/R) and reveal the role of intracellular Ca²⁺in the cerebral I/R injury. METHODS: The model of focal cerebral I/R was established in rats by reversible inserting a nylon thread, and dynamic change of intracellular Ca²⁺in brain slices was determined using laser confocal imaging system. RESULTS: ① Ca²⁺gradually enhanced with increase in ischemic time in cortex and striatum. ②At1h ischemia/10min reperfusion, Ca²⁺increased significantly in striatum, but Ca²⁺decreased at 3 h reperfusion compared with10min reperfusion. ③ Ca²⁺markedly enhanced at 6 h ischemia compared with1h ischemia, and after 3 h reperfusion Ca²⁺decreased, but was still higher than that in sham-operation group. ④The striatum is more sensitive than cortex to ischemia/reperfusion. CONCLUSION: Ca²⁺overload in the area of cortex and striatum may play an important role in cerebral ischemia/reperfusion injury in rats.     

Changes of myocardial nuclear membrane Ca2+-ATPase function in ischemia/reperfusion injury

AIM: The changes of myocardial nuclear membrane Ca²⁺ -ATPase function was investigated in ischemia/reperfusion injury. METHODS: The model of myocardial ischemia/reperfusion injury was established in rats. Myocardial nuclei were purified with sucrose density centrifugation, the activity of Ca²⁺ -ATPase was measured and calcium uptake was assayed with [⁴⁵ Ca²⁺ ] . RESULTS: Plasma levels of malondialdehyde (MDA) and free fatty acid (FFA) in myocardial ischemia/reperfusion injury increased significantly( P<0.01 vs control). Ca²⁺ -ATPase activity and [⁴⁵ Ca²⁺ ] uptake was lower than normal at below 10 μmol/L, while higher at 50 μmol/L. CONCLUSION:These data indicate dysfunction of nuclear menbrane calcium pump and [⁴⁵ Ca²⁺ ] uptake function in myocardial ischemia/reperfusion injury.     

Cyclosporine A suppresses the hypertrophic effect of neuropeptide Y in rat cardiomyocytes

AIM:To investigate the effect of cyclosporine A on rat cardiomyocyte hypertrophy caused by neuropeptide Y (NPY).METHODS:Cardiomyocytes of neonatal Wistar rats were cultured with NPY or NPY together with CsA. For assessing protein synthesis rate and c-jun mRNA expression in cardiomyocytes, the methods of [³H]-Leu incorporation and RT-PCR were used.RESULTS:(1) [³H]-Leu incorporation in cardiomyocytes: [³H]-Leu incorporation in NPY (10 nmol/L) group was higher than that in control group, but there were no distinct changes between two groups. To compare with control group, [³H]-Leu incorporation in NPY (100 nmol/L) group were increased significantly (P＜0.05). There was no significant change between control group and CsA group; (2) c-jun mRNA expression in cardiomyocytes: RT-PCR production of c-jun mRNA in NPY group was enhanced considerably compared with CsA group and control group (P＜0.01). There was no significant change between CsA group and control group.CONCLUSIONS:NPY can induce cardiomyocyte hypertrophy. Cyclosporine A (inhibitor of CaN) can blunt the effect of NPY, suggesting that the Ca²⁺/CaM-dependent calcineurin (CaN) signaling pathway plays an important role in it.     

Inhibitory effect of Salidroside on the proliferation of rabbit pulmonary artery smooth muscle cells under hypoxia

AIM: To investigate the effect of Salidroside on the proliferation, DNA synthesis, intracellular Ca²⁺ content of rabbit PASMC (pulmonary artery smooth muscle cells) under hypoxia. METHODS: Techniques of cell culture, MTT test, [³H][³H][³H]-TdR incorporation, fluo-3 and confocal laser scanning microscopy were used. RESULTS: The A value of MTT and [³H][³H]-TdR incorporation of PASMC increased significantly by 62% (P＜0.05) and 138% (P＜0.01) after 24 h hypoxia. Salidroside (32×10^-5 mol/L) inhibited the action of hypoxia on the proliferation of PASMC, the A value of MTT and [³H][³H]-TdR incorporation declined significantly by 29% (P＜0.05) and 37% (P＜0.01) compared with hypoxia group. A calcium channel blocker, verapamil could also inhibit the accelerative effect of hypoxia on the proliferation of PASMC. The intracelluler Ca²⁺ content of PASMC raised markedly under hypoxia, but the effect of hypoxia on the intracelluler Ca²⁺ content could be inhibited by Salidroside. CONCLUSION: Salidroside inhibited the proliferation, DNA synthesis of PASMC induced by hypoxia. The inhibitory action of Salidroside on the increase in intracellular Ca²⁺ concentration under hypoxia might be one of the mechenisms.     

Metallothionein inhibits rat vascular fibroblasts activation induced by homocysteine

AIM:To study the effects of exogenous metallothionein (MT) and ZnCl₂-induced MT production on biological action of homocysteine(HCY)in vascular fibroblasts.METHODS:[³H]-TdR, [³H]-Pro incorporation and LDH leakage were measured, the cellular viabilities were calculated by trypan blue exclusion test and the intracellular contents of MT were assayed by [¹⁰⁹Cd]-hemoglobin saturation method in cultured rat vascular fibroblasts.RESULTS:Proliferation, collagen production of vascular fibroblasts in HCY-treated group were significantly increased compared with control group in a concentration-depedant manner. HCY (500 μmol/L) increased LDH leakage and decreased the cellular viabilities (P＜0.05 or P＜0.01). [³H]-TdR incorporation, [³H]-Pro incorporation, collagen secretion and LDH leakage were all decreased in MT (1×10^-5 mol/L, 1×10^-4mol/L) plus HCY(500 μmol/L) incubated group, compared with HCY alone group, respectively (P＜0.05 or P＜0.01). MT content in ZnCl₂ pretreatment group was increased compared with control group. Proliferation, collagen production and LDH leakage in HCY group pretreated with ZnCl₂ were decreased whereas the cellular viabilities were increased compared with HCY alone group.CONCLUSIONS:The results shows that HCY induces proliferation and collagen production of vascular fibroblasts. Both exogenous MT and endogenous MT induced by ZnCl₂ inhibite the above-mentioned effects of HCY on vascular fibroblasts. MT inhibites vascular fibroblast activation induced by HCY, which may be related to its vascular protection.     

Effects of adrenomedullin on proliferation of vascular smooth muscle cells induced by urotensin Ⅱ

AIM:To observe the effect of adrenomedullin(ADM)on proliferation of vascular smooth muscle cells(VSMC) induced by urotensin Ⅱ(UⅡ). METHODS:DNA synthesis of cultured rat aortic VSMC was measured by [³H]-TdR incorporation. The activities of mitogen activated protein kinase(MAPK) were determined by isotope tagged with [γ-³²P]-ATP. RESULTS:UⅡ(10^-8mol/L) significantly increased [³H]-TdR incorporation of VSMC and MAPK activities by 38%(P＜0.05) and 260%(P＜0.01) respectively compared with control group. Compared with UⅡ group, 10^-10,10^-9,10^-8mol/L ADM decreased [³H]-TdR incorporation of VSMC by 7%(P＞0.05), 32%(P＜0.05)and 41%(P＜0.01),respectively, and diminished MAPK activities by 24%(P＞0.05), 32%(P＜0.05)and 36%(P＜0.05),respectively. CONCLUSION:ADM inhibits proliferation of VSMC induced by urotensin Ⅱ through inhibiting MAPK activation.     

Role of cellular paracrine in the mechanism of cardiomyocyte hypertrophy induced by stretch

AIM: To investigate the role of cellular paracrine in the mechanism of cardiomyocyte hypertrophy induced by stretch. METHODS: [³H]-leu incorporation into cultured cardiomyocytes was measured when stimulated by conditioned-media of myocardial fibroblast and microvascular endothelial cell after stretch. RESULTS: [³H]-leu incorporation rate were both elevated significantly stimulated by conditioned-media of myocardial fibroblast and microvascular endothelial cell. And angiotensin II and endothelin of conditioned-media of myocardial fibroblast and microvascular endothelial cell were also elevated significantly. And [³H]-leu incorporation rate were inhibited significantly when the specific angiotensin II and endothelin receptor antagonist losartan(1μmol/L) and BQ123(1μmol/L) were added. [³H]-leu incorporation rate were inhibited over 80% when losartan(1μmol/L) and BQ123(1μmol/L) were added together.CONCLUSION: The activation of myocardial fibroblast and microvascular endothelial cell endocrine stimulated by stretch play a role through paracrine in the pathogenesis of pressure-overload heart hypertrophy.     

Yangxue qingnao-containing serum inhibits rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid

AIM: To observe the effects of Yangxue qingnao-containing serum on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). METHODS: The [³H]-TdR incorporation and mitogen-activated protein kinasc (MAPK) activity were measured in cultured VSMC. End product of lipid peroxidation-MDA levels were also detected. RESULTS: 1×10^－9,1×10^－8 and 1×10^－7 mol/L LPA enhanced the cultured VSMC [³H]-TdR incorporation, increased MAPK activity and MDA content in a concentration-dependent manner. 5％, 10％ and 15％ Yangxue qingnao-containing serum concentration-dependently inhibited the increase in VSMC [³H]-TdR incorporation, MAPK activity and MDA content induced by LPA. CONCLUSIONS: LPA has a stimulating effect on VSMC proliferation. The LPA-induced intracellular signal transduction may be related to MAPK activity. Yangxue-qingnao can efficiently inhibit LPA -induced VSMC proliferation,MAPK activity and lipid peroxidation.     

Protective effect of magnesium on brain with acute ischemia and reperfusion injury

AIM: To dynamically observe the protective effect of magnesium on the brain with ischemia and reperfusion injury in the middle cerebral artery occlusion (MCAO) rat model using the device of laser Doppler flowmetry (LDF) .METHODS: Twenty-four Sprague-Dawley male rats (280-300 g) were used to establish MCAO model with the conventional line-embolism method.The rats were divided into 4 groups according to the initial time of peritoneal injection of magnesium sulfate (MgSO₄).The rats in MgSO₄ groups were treated with 25% MgSO₄ at 160 mg/kg at time points of 20 min, 30 min and 40 min after ischemia.The rats in control group were treated with the same volume of normal saline.The real-time fluctuation of the local cerebral blood flow (CBF) was dynamically monitored by LDF.The degree of nervous functional defect was evaluated by calculating the neurological impairment score of the rats after suffered from 2 h ischemia and followed with 24 h reperfusion.All the rats were killed with an end breaking method, and the volumes of brain infarction were evaluated by TTC staining at the brain slices obtained by autopsy.RESULTS: The fluctuating features in 3 MgSO₄ treatment groups were as follows: when reperfusion began, the local CBF appeared and increased smoothly, then approached to its baseline step by step, and kept at the stable level in the whole reperfusion period.The CBF in control group fluctuated sharply in the whole reperfusion period associated with the heart beating, which was significantly different from those in MgSO₄ treatment groups.The average volume of brain infarction in MgSO₄ treatment groups was 26.5%, 36.5% and 24.5%, respectively, and was 54.0% in control group.The local nervous defect scores in MgSO₄ treatment groups were 5.670±1.003, 8.670±1.211 and 7.170±1.472, respectively, and was 11.170±0.983 in control group.CONCLUSION: Vasomotor functional improvement might be one of the protective mechanisms of magnesium on the brain with cerebral ischemia and reperfusion injury in acute ischemic stroke.     

番茄E8启动子乙烯应答元件克隆及DNA序列分析

E8启动子是常用的番茄果实特异表达启动子之一，是指番茄E8基因5’侧翼近2．2kb的DNA序列。前人的研究表明，E8基因5’侧翼-2181～-1088区段的删除使E8基因表达量大幅度下降(仅为完整E8启动子的1／10)，同时该区段还是E8基因对乙烯应答的充分必要区域；这说明了该区段是E8基因表达调控的重要元件。     

Effects of thyroid hormone on the myosin heavy chain mRNA expression in cardiac myocytes induced by angiotensin Ⅱ

AIM: To study the effect of thyroid hormone on the expressional change of myosin heavy chain(MHC) gene in cardiomyocyte induced by angiotensinⅡ(AngⅡ) and its potential mechanism. METHODS: Cardiac myocyte was cultured according to the method of Simpson. 10^-8 mol/L T₃ and 10^-7 mol/L AngⅡ were added to the culture medium, respectively or synchronously. After 48 h, the expression of α and β-MHC mRNA in myocytes were detected by RT-PCR. The protein kinase C activation were detected by PepTag non-radioactive PKC assay. The incorporation of -Leucine and [³H]-thymine to test the protein and DNA synthesis in myocytes were also performed. RESULTS: AngⅡalone increased the incorporation of [³H]-Leucine of myocytes while it had no effect on the incorporation of [³H]-thy mine. The expression of β-MHC mRNA was increased and the expression of α-MHC mRNA was decreased significantly at the condition of AngⅡ. The enhanced PKC activation was induced by AngⅡalso. When AngⅡand T₃ were added to the culture medium synchronously, though the incorporation of [³H]-leucine and [³H]-thymine were not changed compared with AngⅡ treated alone. The α-MHC mRNA expression was increased and the β-MHC mRNA expression was decreased significantly. The PKC activation of the myocytes also was decreased. CONCLUSIONS: T₃ inhibited the expressional change of myosin heavy chain gene in cardiac myocytes induced by AngⅡ. The effect of T₃ on the change of PKC activation in cardiac myocytes may be one of its mechanisms.     

Effects of acute and chronic hypoxia on rat brain mitochondrial translation activity

AIM: To investigate the effect of simulated high altitude hypoxia on rat brain mitochondrial translation activity. METHODS: Animals were continuously exposed to simulated 4 000 m high altitude in hypobaric chamber for three days and forty days. Mitochondria of rat brain were isolated by homogenizing brain tissue and following centrifuging program. Protein translation activity in isolated mitochondria in vitro was measured with [³H]-Lencine incorporation method. Products labeled with [³⁵S]-methionine in isolated mitochondrial protein synthesis system in vitro were separated on SDS-PAGE and identified by autoradiography. RESULTS: Mitochondrial translation activity in vitro in acute hypoxia exposure were significantly lower than control(P< 0.01). Mitochondrial translation activity in chronic hypoxia exposure were significantly higher than that in acute hypoxia exposure(P< 0.05), but showed no statistical difference between chronic and control. No differences in electrophoretic-autoradiography pattern of -methionine incorporation into translational products was observed among three groups. CONCLUSION: These results indicated that acute hypoxia exposure depressed synthesis of mitochondrial protein encoded by mitochondrial DNA in vitro and the changes in mitochondrial protein synthesis were related with hypoxia exposure time.     

Effect of trichosanthes injection on expression of proliferating cell nuclear antigen of vascular smooth muscle cell in rabbit

AIM: To observe the effect of thichosanthes injection on the expression of proliferating cell nuclear antigen (PCNA) of vascular smooth muscle cell (SMC). METHODS: The expression of PCNA of cultured rabbit aortic SMC was examined with LSAB immunohistochemical technique, and [³H]-thymidine( [³H]-TdR) incorporation data of SMC and the contents of superoxide dismutase (SOD), lipid peroxide (LPO), prostacyclin (PGI₂) and cyclic AMP (cAMP) in medium were simultaneously determined. RESULTS: Thichosanthes injection has an effects of increasing SOD activity, decreasing LPO, elevating PGI₂ and cAMP, reducing [³H]-TdR incorporation and expression of PCNA (all P＜0.05,P＜0.01). CONCLUSION: Thichosanthes could inhibit SMC proliferation.     

Effects of Astragalus injection on neuronal apoptosis and expression of JNK3 in rat hippocampus after cerebral ischemia reperfusion

AIM:To investigate the effects of Astragalus injection on neuronal apoptosis and expression of c-Jun N-terminal kinase 3(JNK3) in the rat hippocampus after cerebral ischemia reperfusion. METHODS:The rat model of cerebral ischemia reperfusion was set up by a four-vessel occlusion method. The SD rats were randomly divided into 4 groups:sham operation group, cerebral ischemia reperfusion group(model group), cerebral ischemia reperfusion+Astragalus injection group(Astragalus injection group) and cerebral ischemia reperfusion+vehicle group(vehicle group). The rats in model group, Astragalus injection group and vehicle group after transient global cerebral ischemia(30 min) were then divided into 7 subgroups according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. The apoptosis of the neuron in the hippocampus was measured by the method of TUNEL staining. The expression of JNK3 at mRNA and protein levels was determined by real-time PCR and Western blotting,respectively. RESULTS:Compared with sham operation group, the number of apoptotic neurons increased in model group(P<0.05). Compared with model group, the number of apoptotic neurons decreased obviously in Astragalus injection group(P<0.05). Compared with sham operation group, the expression of JNK3 at mRNA and protein levels in the hippocampus increased obviously in model group at all time points except 120 h(P<0.05). Compared with model group, the expression of JNK3 at mRNA and protein levels in the hippocampus decreased obviously in Astragalus injection group at all time points except 120 h(P<0.05). CONCLUSION:Astragalus injection decreases neuronal apoptosis in rat hippocampus after cerebral ischemia reperfusion by inhibiting the expression of JNK3 at mRNA and protein levels.     

Effects of salvianolic acid B on the energy metabolism and hydrocephalus in mice with cerebral ischemia

AIM: To explore the effects of salvianolic acid B (SalB) on the energy metabolism and hydrocephalus in mice with cerebral ischemia.METHODS: NIH mice were randomly divided into four groups: sham-operated group,cerebral ischemia group,SalB-treated group and nimodipine-treated group.The brain tissue energy charge (EC),phosphocreatine (PCr),the activity of ATPase,excitability amino acid (EAA) content and water content of brain were measured when cerebral ischemia for 30 min.RESULTS: EC (0.520±0.034),PCr content ［(98.344±13.249) μmol/g］,the activity of Na⁺-K⁺-ATPase ［(0.593±0.013)×10³ U/g］ and Ca²⁺-ATPase ［(0.484±0.053)×10³ U/g］ in SalB-treated group were significantly higher than those in cerebral ischemia group {EC (0.465±0.037),PCr content ［(81.614±9.919) μmol/g］ ,the activity of Na⁺-K⁺-ATPase ［(0.244±0.065)×10³ U/g］,the activity of Ca²⁺-ATPase ［(0.321±0.086)×10³ U/g］} (P<0.01).The glutamate (Glu) content ［(0.405±0.110) μmol/g］,aspartate (Asp) content ［(0.141±0.020) μmol/g］ and water content of brain ［(38.1±0.1)%］ in SalB-treated group were markedly lower than those in cerebral ischemia group ［ Glu content (0.550±0.140) μmol/g,Asp content (0.287±0.050) μmol/g,water content of brain (44.1±0.1)%］ (P<0.05,P<0.01).CONCLUSION: The increase in cerebral energy metabolism and the activity of ATPase,and decrease in EAA content in brain tissue are the mechanism of SalB alleviating hydrocephalus at the early stage of cerebral ischemia in mice.     

Influence of caveolin-1 on the ET-1-induced VSMC proliferation

AIM: To investigate the effect of caveolin-1 on the endothelin-1 (ET-1)-induced vascular smooth muscle cells (VSMC) proliferation. METHODS: The [³H]-thymidine ([³H]TdR) incorporation, immunofluorescence assays and western blotting were used in this study. RESULTS:The ETA receptor specific antagonist BQ123 inhibited the increase in[³H]TdR incorporation in response to ET-1 on VSMC.Immunofluorescence assays showed that caveolin-1 was mostly distributed in plasmalemma of VSMC.After 24 h treatment of VSMC with ET-1,the expression of caveolin-1 in VSMC was significantly decreased.Western blotting showed that ET-1 inhibited the expression of caveolin-1 in VSMC,BQ123 reversed the effect of ET-1.CONCLUSION: Caveolin-1 was mostly distributed in plasmalemma of VSMC. ET-1 downregulated caveolin-1 expression in VSMC via ETA receptor.