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AIM: To observe the effect of β3-adrenoceptor (AR) on ventricle fibrillation threshold (VFT) and effective refractory period (ERP) in rats with heart failure.METHODS: Rats were randomized into control group and heart failure group. The expression of β3- AR mRNA was detected with RT-PCR. The VFT, ERP, left ventricle end-systolic pressure(LVESP),left ventricle end-diastolic pressure(LVEDP), +dp/dtmax and -dp/dtmax were measured at the same time with administration of BRL37344 (β3-AR agonist).RESULTS: ① Both the expression of β3-AR mRNA and the proportion (β3/β1+β2+β3) were increased in failure rats comparied with those in control rats (0.028 vs 0.011 and 5.4% vs 1.2%, P<0.05). ② ERP was longer in rats with heart failure than that in control group (70.5 ms±5.5 ms vs 59.5 ms±6.4 ms, P<0.05). No difference in ERP in rats with heart failure was observed before and after administration of BRL37344 (73.0 ms±4.8 ms vs 70.5 ms±5.5 ms, P>0.05). ③ VFT was lower in rats with heart failure than that in control group (10.9 mV±0.8 mV vs 30.5 mV±1.3 mV, P<0.05) and decreased obviously in rats with heart failure after administration of BRL37344 (7.1 mV±0.6 mV vs 10.9 mV±0.8 mV, P<0.05). The decrease in VFT correlated with the effect of LVESP, +dp/dtmax, -dp/dtmax with BRL37344 and the expression of β3-AR mRNA (correlation coefficient: 0.788, 0.708, 0.759, 0.787; P<0.05). CONCLUSION: The expression of β3-AR mRNA in left ventricle is obviously increased in rats with heart failure. The activation of β3-AR has no effect on ERP but can decrease VFT which correlates with the effect of β3-AR on LVESP, +dp/dtmax, -dp/dtmax and the expression of β3-AR mRNA.  相似文献   

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AIM:To determine the effects of catestatin (CST) on ventricular arrhythmia (VA) in isolated rat hearts with chronic heart failure (CHF). METHODS:Fifty-one male rats were randomly divided into 2 groups: control (CTL) group (n=17) and CHF group (n=34), which were injected with 0.9% normal saline (1 mL·kg-1·d-1, ip) and isoproterenol (ISO, 5 mg·kg-1·d-1, ip) for 7 d,respectively. The echocardiography was used to assess the cardiac functions 2 weeks after the end of modeling in both groups. The CHF rats were divided into non-treatment group (n=17) and CST treatment group (CST group, n=17). The rats in CST group was given CST (2 nmol·kg-1·d-1, ip) for 3 weeks, while 0.9% normal saline (1 mL·kg-1·d-1, ip) was applied to the rats in non-treatment group. To all the whole Langendorff-perfused hearts, the monophasic action potential (MAP) and the ventricular effective refractory period (VERP) were recorded and measured in left anterior free wall (LAF). The programmed electrical stimulation and burst pacing were used to induce action potential duration (APD) alternans (ALT) and VA in the LAF, respectively. The car-diac myocytes of LAF were enzymatically isolated and the technique of whole-cell patch clamp was used to record L-type Ca2+ current (ICa-L). RESULTS:Compared with CTL group, the peak ICa-L density, 90% of MAP duration (MAPD90), VERP, median of maximum pacing cycle length (PCLmax) inducing APD-ALT and incidence of VA (83.33% vs 1667%) were significantly increased in non-treatment group (all P<0.01). Compared with non-treatment group, the peak ICa-L density, MAPD90, VERP, median of PCLmax inducing APD-ALT and incidence of VA were significantly decreased in CST group (all P<0.05). CONCLUSION: Treatment with CST reduces the incidence of VA in CHF rats, which might be associated with the inhibition of ICa-L.  相似文献   

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AIM: To explore the effects of pentoxifylline (PTX) on ventricular remodeling and cardiac function in dilated cardiomyopathy (DCM) rats.METHODS: Lewis rats were randomly allocated to a myocin-induced dilated cardiomyopathy (DCM) group receiving saline (n=10), a DCM group receiving PTX (PTX group; 25 mg·kg-1·d-1, ip, for 30 days, n=10) or healthy control group (n=10). The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10 in the blood plasma were analyzed by ELISA. The extent of fibrosis was estimated using Massons staining and immunohistochemistry analyses. Cardiac structure and function were measured by echocardiography.RESULTS: PTX decreased plasma levels of TNF-α and IL-6, and increased IL-10 level in DCM animals compared with DCM group ［TNF-α: (7.21±0.24) μg/L vs (19.30±1.31) μg/L, P<0.01; IL-6: (119.60±36.58) ng/L vs (189.50±13.25) ng/L, P<0.05; IL-10: (41.26±3.27) μg/L vs (32.45±4.32) μg/L, P<0.05］. Collagen volume fraction (CVF), perivascular collagen area (PVCA) and collagen Ⅰ/Ⅲ ratio were lower in PTX group than those in DCM group ［CVF: (16.45±3.01)% vs (23.33±4.43)%, P<0.05; PVCA: 4.58±2.10 vs 13.74±4.29, P<0.05; Ⅰ/Ⅲ ratio: 2.84±0.67 vs 4.22±0.54, P<0.01］. Left ventricular end-diastolic dimension reduced ［(6.11±0.51) mm vs (6.46±0.28) mm, P<0.05］ and left ventricular ejection fraction elevated ［(77.29±5.20)% vs (62.73±10.11)%, P<0.01］ by PTX compared with DCM.CONCLUSION: PTX modulates plasma levels of inflammatory cytokines, delays the ventricle remodeling and improves the heart function in DCM rats.  相似文献   

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AIM: To study urinary concentration of aquaporin-2 water channel protein(AQP2) at different stages of chronic heart failure(CHF) rats and its relation to hyponatremia. METHODS: Male Sprague-Dawley rats(200~250 g) underwent either a left coronary artery ligation (a model of CHF) or a sham-operation. At different stage after surgery, urinary AQP2 concentration was measured by Western blot. 24-hours urine volume, serum sodium and urine osmolality were measured at the same time. RESULTS: There were two peaks of urinary excretion of AQP2 in severe heart failure rats model: one was the third day after operation, the other was the 9th week. Serum sodium and urine osmolality were significantly different in CHF rats as compared with sham-operated rats. Seven weeks after surgery, urinary AQP2 concentration was increased significantly insevere CHF rats compared with the mild ones and the control ones(365%±103% vs 179%±81% and 99%±48%, P＜0.01).CONCLUSION: The variation of urinary AQP2 excretion at different stages after ligation showed that the expression of AQP2 gene was increased obviously in CHF rats, and its expression level was higher as the heart failure became more severe.This is the important reason of heart failure with hyponatremia.  相似文献   

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AIM: To investigate the changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy. METHODS: Ventricular hypertrophy was induced by a partial constriction of the abdominal aorta in rabbits. Myocytes were isolated by a two steps enzymological method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from other region (midmyocardium, Mid) with a razor. Whole cell patch clamp technique was used to record the action potential and ion currents. RESULTS: The action potentials duration at 90% repolarization (APD90) of Epi, Mid and Endo were all prolonged significantly in hypertrophy group compared to control group. This prolongation of APD90 was more pronounced in Mid (26.0%±2.7%) than that in Epi (14.0%±1.6%) and Endo (10.0%±1.1%). The transmural repolarization heterogeneity was increased significantly in the hypertrophy group. The IKs and Ito density in Epi, Mid and Endo was decreased significantly in hypertrophy group compared to those in control group. This decrease in IKs and Ito density was more pronounced in Mid than in Epi and Endo. No significantly difference of ICa,L and IKr density between hypertrophy group and control group in three layers was observed. The IK1 density decreased significantly in hypertrophy group compared to control group, but the extent of the decrease had no differences among the three layers. CONCLUSIONS: The transmural repolarization heterogeneity increases significantly in rabbit hypertrophied ventricle. The decrease in transmural heterogeneity of Ito and IKs is the main causes.  相似文献   

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AIM: To investigate the changes of intrarenal endothelin system in the course of congestive heart failure. METHODS: A canine congestive heart failure model induced by rapid right ventricular pacing was used in the present study. Twenty-one mongrel dogs divided randomly into 3 groups: control, congestive heart failure 2 weeks (CHF2) and congestive heart failure 4 weeks (CHF4). The severity of heart failure was evaluated by means of hemodynamic measurement. The concentration of plasma endothelin was detected via RIA, and the expression of endothelin was detected by RT-PCR. RESULTS: The concentration of plasma endothelin in both of CHF2 and CHF4 elevated significantly. In CHF2, the expression of endothelin receptor B(ETB) in renal medulla increased significantly. And in CHF4, the expression of preproendothelin, endothelin receptor A (ETA) and ETB increased both in renal cortex and medulla. Furthermore, in cortex, the expression of ETA increased more significantly than ETB, while in medulla, ETB expressed much more than ETA. CONCLUSION: The changes of renal endothelin system expression plays a role in the regulation of water and electrolyte balance during the progress of congestive heart failure.  相似文献   

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AIM:To observe the effects of sodium restricted or supplemented on atrial natriuretic polypeptide (ANP) and cardiac function of rats with congestive heart failure (CHF).METHODS:CHF rats were divided into three groups with sham operation rats group as control. Radioimmunassay was used to determine the ANP contents of plasma and myocardium, at the same time cardiac function was measured. RESULTS:In sodium restricted group, the plasma sodium and atrial ANP and left ventricular systolic pressure and artery pressure were obviously lower than those in CHF group, while the plasma and ventricular ANP and the right atrial pressure were remarkably higher; In sodium supplemented group, the plasma sodium and arterial pressure had no obvious change compared with the control, the plasma and myocardium ANP and the right atrial pressure had no difference as compared with CHF group, while the left ventricular end diastolic pressure was remarkably lower and the left ventricular systolic pressure were obviously higher. CONCLUSION:Keeping the balance of plasma sodium by an appropriate supplement of sodium intake after CHF might be beneficial to the ANP biological effects and the cardiac function.  相似文献   

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There are two type of cardiac calcium channel current, both are inward current: (1) L-type Ca2+channel current (Ica-L), plays a major role in determining myocyte action potential plateau characteristics as well as initiating the myocyte excitation-contraction coupling; (2) T-type Ca2+ channel current (Ica-T), probably plays an important role in pacemaker activity. The alterations of L-type calcium channel abundance and function in cardiac hypertrophy and heart failure are determined by the the species difference, especially by the stage of the disease process and the degree of the disease. Both abundance and function of L-type calcium channel decrease in severe hypertrophy and heart failure.  相似文献   

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AIM: To observe ventricular remodeling induced by ischemic heart failure in the mice at different ages.METHODS: Three-month-old (young group, n=50) and 18-month-old (old group, n=50) male C57BL/6J mice were selected in the study. Forty mice underwent ligation of left coronary artery with certain infarct size, and 10 were sham-operated for control. Echocardiography was performed after 8 weeks of infarction. All mice were killed and the hearts were collected for examinations. Masson trichrome staining was used to detect myocardial fibrosis. The expression of type I and type Ⅲ collagens was measured by the method of immunohistochemistry.RESULTS: The incidences of cardiac rupture (18% vs 10%, P<0.05) and heart failure (22% vs 10%, P<0.05) were significantly higher in aged mice than those in young mice. The degrees of left ventricular dilation, contractile dysfunction and heart rate were significantly higher in aged mice than those in young mice (P<0.05). The left ventricular mass index, collagen volume fraction, the expression of type I collagen and ratio of type Ⅰ/Ⅲ collagens were significantly increased in aged mice as compared with young mice (P<0.05).CONCLUSION: After heart failure, aged mice show abnormal collagen distribution, and suffer from worse cardiac functions and more serious ventricular remodeling.  相似文献   

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AIM: To explore the probable mechanisms of diabetes-induced arrhythmias. METHODS: Diabetes was induced in male SD rats, using a single injection of alloxan into tail vein. Untreated age-matched animals were used as controls. All animals were observed by 2, 4, 6 and 8 weeks, respectively. Transmembrane potentials were recorded with conventional glass microelectrodes. RESULTS: Action potential duration(APD) at all level (APD10, APD20, APD30, APD50, APD70, APD90) was significantly lengthened in right ventricular papillary muscle from week 2 of diabetes. At week 8, APD was more lengthened at any level of repolarization than that at week 2. No differences were observed in the maximum rate of depolarization(Vmax), overshoot(OS) and action potential amplitude(APA) as well as the resting membrane potential(RP) from the 2th to 8th week of diabetes. CONCLUSION: The results indicate that prolongation of APD may be prominently responsible for the increased incidence of cardiac re-entry-arrhythmias and sudden death, especially at late stages of diabetes.  相似文献   

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CHEN Shi-jian  WEI Ni-na  LI Yan 《园艺学报》2013,29(11):2097-2099
AIM: To determine the effects of action potential duration restitution (APDR) on ventricular arrhythmia (VA) in Langendorff-perfused chronic heart failure (CHF) rabbit hearts. METHODS:Twenty male New Zea-land rabbits were equally divided into 2 groups randomly: control (CTL) group and CHF group. CHF was induced by abdominal aortic banding for 14 d. The echocardiography was applied to assess the cardiac function and structural change in both groups 4 weeks after the end of modeling. In the whole Langendorff-perfused hearts, the monophasic action potential (MAP) and the effective refractory period (ERP) were recorded and measured in ventricular chamber, and the action potential duration (APD) curves were also constructed in both groups. The burst pacing was used to induce APD alternans and VA. RESULTS: Compared with the same sites of CTL group, the 90% of MAP duration (MAPD90), the ERP, the maximal slope (Smax) of APDR curves were increased in CHF group (all P<0.05). The VAs in CHF group were easier to be induced than those in CTL group (all P<0.05). The coefficients of variation of Smax (COV-Smax) of APDR curves in CHF group were greater than those in CTL group (all P<0.05).CONCLUSION: Both Smax and COV-Smax of APDR curves increase during CHF to facilitate the ventricular arrhythmia.  相似文献   

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AIM: To study the changes of endothelin system during chronic heart failure (CHF) and imply the relationship between endothelin system and the course of CHF by observing the mRNA expression of endothelin receptors (ETAR and ETBR) and PreproET1 in early stage and later stage of CHF caused by left coronary artery ligation. METHODS: The mRNA expression of ETA, ETB receptors and PreproET1 were detected by RT-PCR technique. The plasma concentrations of ET1 and ANP were determined by RIA method. RESULTS: The plasma concentrations of ET1 and ANP, and the mRNA expression of ET receptors and PreproET1 in the lefe ventricle increased significantly in early stage (myocardial infarction 10 d). While the plasma concentrations of ET1 and ANP in later stage (myocardial infarction 70 d) were higher than those in the early stage. However, the mRNA expression of ETAR, ETBR and PreproET1 decreased significantly. The mRNA expression of ETAR in myocardial infarction (MI) 70 d rats had no difference with those in sham-operated rats and the mRNA expression of ETBR and PreproET1 in MI 70 d rats was lower significantly than those in MI 10 d rats, but significantly higher than those in sham-operated rats. CONCLUSION: The changes of ET receptors and PreproET1 mRNA expression are involved in the cardiac function modulation during the different stages in chronic heart failure.  相似文献   

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AIM: To investigate the effect of gene transfection of FKBP12.6 (FK12.6 binding protein) on the canine failing heart induced by rapid ventricular pacing. METHODS: Three weeks after onset of rapid ventricular pacing (250 bpm), 28 canines were divided into 4 groups. Either pcDNA3.1-FKBP12.6 plasmid encoding human FKBP12.6 gene (transfection groupⅠ,Ⅱ; observed at the 4th or 14th days respectively after transfection) or empty vector (controlⅠ,Ⅱ) was transferred into myocardium under ultrasonic microbubble destruction. After transfection, maintenance pacing at a reduced rate (190 beats/min) was continued until end-point of experiment. Echocadiographic, hemodynamic and plasmic ANP (atrial natriuretic peptide), BNP (brain natriuretic peptide) data were collected three times (before pacing, before transfection and endpoint). Semiquantative RT-PCR was used to identify FKBP12.6 expression in myocardium. RESULTS: Gene transfection of FKBP12.6 elevated expression of FKBP12.6 mRNA 3.5 folds at day 4, and 1.7 folds at day 14 respectively, compared with control group. Significant improvements of cardiac function, hemodynamics and plasmic concentrations of ANP, BNP were observed in transfection groupⅠ and these effects were stable for at least 2 weeks. Cardiac output (CO), ejection fraction (EF) and fractional shortening (FS) were still lower than pre-pacing although they increased in transfection groups. Left ventricular end-diastolic diameter (LVEDD) and left ventricular end-diastolic volume (LVEDV) decreased at day 14 but LVEDD remained unchanged at day 4 compared with pre-transfection. CONCLUSION: Gene transfection of FKBP12.6 improves cardiac functions in the failing heart and reverses myocyte remodeling. This might be a novel therapeutic application for treating human heart failure.  相似文献   

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AIM: To establish the experimental acute pulmonary embolism(APE) model and observe the left and right ventricular pressure-volume relationship in different overload situations. METHODS: The present study consisted of seven anesthetized mongrel dogs that were divided into the control group, moderate APE group and severe APE group according to the various phase and different pressure load during the experiment. APE model was induced by suture piece injection through right cardiac catheterization. The hemodynamic indexes were measured by the simultaneous cardiac catheterization and echocardiography.RESULTS: (1) In the group with moderate APE, the pressure-volume relationship of right ventricle tended to right-upward shift, the area of chart increased, the shape of chart transformed form triangle to rectangle. The mild parallel leftward shift, the area of chart decreased mildly and no change of chart shape was observed in the pressure-volume relationship of left ventricle. (2) In the group with severe APE, the chart of right ventricular pressure-volume relationship tended to right-upward shift continuously, the area of chart decreased. The chart of the left ventricle tended to left-downward shift and no change of chart shape was observed in the pressure-volume relationship of left ventricle, the area of chart decreased. The erose shape of charts was also found.CONCLUSION: The chart of ventricular pressure-volume relationships is a practical and reliable method to evaluate left and right ventricular hemodynamic in APE.  相似文献   

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AIM:This study was designed to investigate the effects of sodium restriction and sodium supplementation on the expression of angiotensinogen mRNA in myocardium of rats with congestive heart failure(CHF).METHODS:Radioimmunassay and in situ hybridization techniques were used to determine the angiotensin Ⅱ(AngⅡ)contents and the expression of angiotensinogen(ANG)mRNA in myocardium, respectively.RESULTS: In sodium restricted group, the plasma sodium was obviously lower than that in CHF group(P＜0.05), while the contents of AngⅡ,the expression of ANG mRNA in myocardium and the ratio of heart weight/body weight(HW/BW)were significantly higher than those in CHF group (P＜0.05 or P＜0.01). It was also found that the AngⅡ, the mRNA contents in rat myocardium and the ratio of HW/BW were not significantly changed in case of sodium supplementation. CONCLUSION:Restriction of sodium intake can further activate the local renin-angiotensin system in CHF heart.  相似文献   

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