Relaxation effect of isoliensinine on isolated mouse airway smooth muscle

AIM: To study the relaxation effect of isoliensinine on high K⁺-induced isolated mouse airway smooth muscle (ASM) and the underlying mechanism. METHODS: The muscle tension transducer was used to detect the effects of isoliensinine on high K⁺-induced precontraction and Ca²⁺ influx in ASM. The technique of patch-clamp and calcium imaging system were respectively used to examine the effects of isoliensinine on LVDCC currents and[Ca²⁺]_i of the ASM cells (ASMCs). RESULTS: Isoliensinine significantly relaxed precontracted ASM induced by high K⁺ in a concentration-dependent manner. The maximum relaxation ratio was(95.3±3.9)% by isoliensinine at 100 μmol/L. In addition, LVDCC currents were measured using the whole-cell patch-clamp technique, which were abolished by isoliensinine. High K⁺-induced 340/380 nm fluorescence ratio of Fura-2 was 0.63±0.10 in ASMCs, while it decreased to 0.36±0.05 after the addition of isoliensinine (P<0.01). When isoliensinine was added at the peak point of[Ca²⁺]_i, the ratio rapidly decreased from 0.74±0.02 to 0.42±0.05 (P<0.01). Moreover, isoliensinine inhibited high K⁺-induced Ca²⁺ influx-mediated contraction of ASM. CONCLUSION: Isoliensinine inhibits LVDCC currents, terminates Ca²⁺ influx and reduces[Ca²⁺]_i, eventually resulting in relaxation of the ASM, indicating isoliensinine might be a potential bronchodilator.     

Role of K+ channels in hypoxic pulmonary vasoconstriction in normal and chronic hypoxic rats

AIM:To investigate the role of K⁺ channels in the decreased hypoxic pulmonary vasoconstriction(HPV) in chronic hypoxic rats. METHODS:Blockers of three kinds of K⁺ channels, 4-AP(voltage dependent K⁺ channel blocker), TEA(Ca²⁺ activated K⁺ channel blocker), GLIB(ATP sensitive K⁺ channel blocker) were used in isolated perfused rat lungs to detect the role of K⁺ channels in HPV. RESULTS:In normal rats, 4-AP and TEA, but not GLIB, both elicited a significant increase in pulmonary artery baseline pressure, and also potentiated the acute hypoxic pulmonary vasoconstriction. In chronic hypoxic rats, the HPV is significantly decreased, while 4-AP, TEA, GLIB all elicited a significant but smaller increase in pulmonary artery baseline pressure. Additionally, all these three blockers potentiated the HPV stronger in chronic hypoxic rats than in control rats. CONCLUSION:The opening of Kv, K_Ca, K_ATP might modulate the hypoxic pulmonary vasoconstriction in isolated rat lungs, and the increase in this modulation by potassium channel in chronic hypoxic rats might play a role in its decrease in HPV.     

The discovery of the interaction between augmenter of liver regeneration and Na+, K+-ATPase with yeast two-hybrid system

AIM:To screen the proteins interacting with human augmenter of liver regeneration (hALR) by yeast two-hybrid system and to study the mechanism of hALR action. METHODS:hALR bait plasmid was constructed by ligating the gene of hALR into pGBKT7, then transformed into yeast AH109. The yeast strain AH109 containing pGBKT7-hALR was mated with yeast Y187 containing human liver cDNA library plasmid. Diploid yeast was plated on SD/-trp-leu-his-ade (QDO) for screening and on QDO containing X-α-gal for further selection.The AD/library inserts were amplified by PCR and the PCR products were characterized by digesting with Sau3AⅠ and HaeⅢ restriction enzyme to eliminate the duplicates. After sequencing, the positive clones were analysed by bioinformatics. RESULTS:Several positive clones were obtaind. The sequencing and analysis shown that one of them is 669 bp DNA fragment encoding β subunit of Na⁺, K⁺-ATPase. The 224 bp 3'terminal DNA fragment is non-encoder region, and the 445 bp 5'terminal DNA encodes C-terminal 147 amino acid residues of Na⁺, K⁺-ATPase β subunit. CONCLUSION:The results of screening proteins using yeast two-hybrid system showed that hALR could interact directly with Na⁺, K⁺-ATPase in the yeast cell.     

Effects of hypothermia on the contents of neuropetides and other active substances in rat plasma and different brain regions

AIM: To study the effects of hypothermia on the contents of AVP,Ang Ⅱ,L-EK,cAMP,Mg²⁺and Ca²⁺in rat plasma and different brain regions.METHODS: The model of experimental hypothermia rat was established and treated in groups randomly.At the end of the experiment,samples of plasma and braintissues were taken and the contents of L-EK,cAMP,AVP,Ang Ⅱ were determined by RIA methods,Mg²⁺and Ca²⁺by atom absorption methods.RESULTS: The contents of Ang Ⅱ,AVP increased significantly in the plasma of Ⅰ,Ⅲ group(P<0.01),while that of group Ⅱ decreased obviously (P<0.01);the contents of Ang Ⅱ,AVP decreased in the hypothalamus and truncus encephalicus of Ⅰ,Ⅲ group(P<0.01),and that of group Ⅱ increased (P<0.01).CONCLUSION: L-EK,cAMP,AVP,Ang Ⅱ,Mg²⁺and Ca²⁺might be involved in body temperature regulation during hypothermia.     

Role of potassium channels in the regulation of intracellular free Ca2+ concentration of pulmonary artery smooth muscle cells in rats

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: K_V plays an important role in the regulation of [Ca²⁺]_i and proliferation of PASMCs. K_Ca serves as distinct responsive roles in the regulation of proliferation of PASMCs in hypoxic condition. K_ATP has no effect on [Ca²⁺]_i and proliferation of PASMCs in normoxic and hypoxic conditions.     

The alteration of extracellular sodium and potassium ionic activities of hippocampal neurons in epileptiform rats kindled by coriaria lactone

AIM and METHODS: The sodium ion Na⁺ and potassium ion K⁺ selective microelectrodes were used to measure changes of ionic activity of extracellular sodium and potassium( [Na⁺]_o, [K⁺]_o) in hippocampus and hippocampal slice during epieptic seizure induced by intrahippocampal microinjection of coriaria lactone(CL) in rats and perfusing hippocampal slice with CL. RESULTS:30 s, 1min and 2min after injection of CL into hippocampus, the [Na⁺]_o decreased 27.7 mmol/L, 50.3 mmol/L, 57.8 mmol/L respectively and the [K⁺]_o increased 2.3 mmol/L, 2.4 mmol/L, 2.9 mmol/L respectively compared with control values(P＜0.01). The [K⁺]_o returned to the control level 3min after local application of CL, but the[Na⁺] _o was still lower than that of control group(P＜0.01). The [Na⁺]_o and the [K⁺]_o were measured also in hippocampal silces and results are similar to those of experiments in vivo. CONCLUSION: The influx of Na⁺and the flux of K⁺occurred during epileptiform discharges of hippocampal neurons induced by administration of CL.     

Blocking effects of extracellular Cd2+ on the inward rectifier potassium channel

AIM:To study the blocking effects of extracellular Cd²⁺ on the inward rectifier potassium channel (IRK1) expressed in the Xenopus oocytes. METHODS:Two-microelectrode voltage clamp (TEV) method was used. RESULTS:Cd²⁺ can concentration-, time- and voltage dependently block IRK1 instantaneous currents ( 1.5 ms after voltage applied ) when external Cd²⁺ concentration is 0, 0.1, 0.15, 0.3, 0.9, 2.7 or 5.4 mmol/L with K⁺ concentration fixed to 90 mmol/L. Cd²⁺ almost has no effect on the gating property and outward currents of IRK1. Cd²⁺ can concentration-dependently increase the normalized conductance of IRK1. IRK1 can not permeate Cd²⁺ because reverse potential did not change. Three exponential fitting analyze indicates that time constant is not changed with the change in Cd²⁺ concentration. This shows that the inhibitory effects of Cd²⁺ may be caused by surface potential or the blocking site of Cd²⁺ is at the surface of the channel. Because external Cd²⁺ can not inhibit IRK1 macroscopic currents more powerfully when external Cd²⁺ concentration is lower. These mean that external Cd²⁺ does not work through surface potential mechanism.CONCLUSION:Cd²⁺ is considered as one of the fast open channel blockers of IRK1 and its blocking site is at the surface of the channel.     

Plant water stress and K starvation reduce absorption of foliar applied K by olive leaves

Three-month-old mist-rooted ‘Picual’ olive cuttings were transplanted into 2-l plastics pots containing perlite as substrate and fertigated with a complete nutrient solution containing 0.05, 0.1 or 2.5 mM KCl depending on the experiment. In the first experiment, plants were sprayed with RbCl (Rb⁺ is a K⁺ analog) at a rate of 4% at 63 days after transplanting (DAT). Foliar Rb⁺ uptake through leaves increased with K⁺ concentration in the nutrient solution, indicating that foliar Rb⁺ uptake was lower when plants were K⁺ deficient than when they were adequate. On the contrary, it was observed that translocation of Rb⁺ from leaves to other organs of the plant was higher under K⁺ deficiency conditions. In the second and third experiments, when differences appeared on shoot length due to K⁺ nutritional status (0.05 or 2.5 mM KCl) at 63 DAT, a group of plants were subjected to water stress during 7 weeks. On the other hand, another group of plants (control plants) did not receive any water stress treatment during the experiments. After this period of 7 weeks, all plants were sprayed with RbCl at 4%. Leaf K⁺ concentration diminished in water-stressed plants independently of plants nutritional status. Foliar Rb⁺ uptake through leaves was restricted by water stress either in plants with low K⁺ (0.05 mM KCl) or plants with high K⁺ (2.5 mM KCl). Translocation of Rb⁺ from leaves was greater under water stress conditions in both K⁺ nutritional statuses. In conclusion, the results obtained could explain the irregular response in olive trees to foliar K⁺ sprays, particularly, when they grow in rainfed orchards.     

Relationship of CTCs with CD4+/CD8+, NLR,TTV and tumor stage in patients with primary hepatocellular carcinoma

AIM: To explore the relationship of circulating tumor cells (CTCs) with CD4⁺/CD8⁺, neutrophil-to-lymphocyte ratio (NLR), total tumor volume (TTV) and tumor stage in the patients with primary hepatocellular carcinoma.METHODS: We selected 80 cases of histologically diagnosed primary hepatocellular carcinoma in the study. The method of CanPatrol^TM was used, which was developed by SurExam biotechnology company to identify CTCs in the blood. CD4⁺ T cells and CD8⁺ T cells were counted by flow cytometry. The patients were divided into 2 groups according to the levels of CD4⁺/CD8⁺ ratio, NLR and TTV. The patients were also divided into Ⅰ＋ Ⅱstage group and Ⅲ＋ Ⅳ stage group according to the seventh edition of TMN staging criteria.RESULTS: The numbers of peripheral blood CTCs and mesenchymal CTCs in high CD4⁺/CD8⁺ ratio group were significantly lower than those in low CD4⁺/CD8⁺ ratio group (P < 0.05). The numbers of peripheral blood CTCs, mesenchymal CTCs and hybrid CTCs in high TTV group were significantly higher than those in low TTV group (P < 0.05). The numbers of peripheral blood CTCs, mesenchymal CTCs and hybrid CTCs in I＋ II stage group were significantly lower than those in III＋ IV stage group (P < 0.05). The numbers of peripheral blood CTCs, mesenchymal CTCs, hybrid CTCs and epithelial CTCs between high NLR group and low NLR group had no statistical difference.CONCLUSION: CTCs exist in the peripheral blood of the patients with primary hepatocellular carcinoma. The peripheral blood CTCs have significant correlations with TTV, tumor stage and T-cell immunity.The worse cell immune function, the larger TTV and the later tumor stage a patient has, the more the peripheral blood CTCs are.     

Activation of myocyte voltage-gated K+ channels is involved in HSYA-induced rat coronary arterial relaxation

AIM: To observe the effects of hydroxysafflor yellow A (HSYA) on the relaxation of isolated rat coronary artery (RCA) rings and its relationship with voltage-gated K⁺ (Kv) channels. METHODS: The vascular tension was recorded with a wire myograph. The Kv currents of freshly isolated RCA smooth muscle cells were assessed with whole-cell patch clamp. The protein expression levels of Kv1.2 and Kv1.5 in RCA smooth muscle cells were assayed by Western blot. RESULTS: HSYA (10 μmol/L and 30 μmol/L) led to relaxation of RCA precontracted by 60 mmol/L KCl or 0.1 mmol/L U46619 (P<0.05), but the effect showed no statistical difference between endothelium-intact and endothelium-denuded groups (P>0.05). HSYA (3 μmol/L, 10 μmol/L and 30 μmol/L) significantly increased the maximal Kv currents of RCA smooth muscle cells (P<0.05). HSYA (10 μmol/L and 30 μmol/L) increased the protein expression of Kv1.2 and Kv1.5 (P<0.05). CONCLUSION: HSYA relaxes isolated RCA in an endothelium-independent manner. The vasodilatory effect of HSYA may be related to activation of the myocyte Kv channels.     

Inhibitors of CaMKⅡ suppress the expression of TNF-α, TGF-β1 and collagen I,III in cardiac fibroblasts treated with angiotensin II or electrical field stimulation

AIM: To observe the role of calcium/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) in the proliferation, released cytokines and expression of collagen Ⅰ and Ⅲ in rat cardiac fibroblasts induced by angiotensin Ⅱ (AngⅡ) or electrical field stimulation (EFS).METHODS: The cultured cardiac fibroblasts were isolated from the neonatal rats of 1-3 days and used in the 3rd passage. The cells were divided into 10 groups: control group, 0.1 μmol/L AngⅡ group, 0.1 μmol/L AngⅡ+0.5 μmol/L KN92 group, 0.1 μmol/L AngⅡ+0.5 μmol/L KN93 group, 0.1 μmol/L AngⅡ+0.5 μmol/L AIP group; 10V 1.0 Hz EFS group, 10 V 1.0 Hz EFS+0.5 μmol/L KN92 group, 10 V 1.0 Hz EFS+0.5 μmol/L KN93 group, 10 V 1.0 Hz EFS+0.5 μmol/L AIP group, 10 V 1.0 Hz EFS+0.1 μmol/L AngⅡ group.MTT was used to detect the proliferation of cardiac fibroblasts. The release of cytokines was measured by ELISA. The mRNA expression of TNF-α, TGF-β₁ and collagen Ⅰ, Ⅲ was determined by RT-PCR.RESULTS: CaMKⅡ inhibitors (0.5 μmol/L KN93 or 0.5 μmol/L AIP) prevented the proliferation and the increase in the expression of TGF-β₁ and TNF-α in cardiac fibroblasts induced by AngⅡ (0.1 μmol/L) or EFS (10 V 1.0 Hz). CaMKⅡ inhibitors (0.5 μmol/L AIP or 1.0 μmol/L AIP) also prevented the increase in mRNA expression of collagen Ⅰ and Ⅲ induced by 0.1 μmol/L AngⅡ. CONCLUSION: Inhibition of CaMKⅡ prevents the proliferation of cardiac fibroblasts induced by AngⅡ or EFS. The possible mechanism of CaMKⅡ inhibitors may be involved in preventing the mRNA expression and release of cytokines (TGF-β₁ and TNF-α), and regulating collagen I and III expression.     

Changes of dendritic cells subsets and their HLA-DR expression in peripheral blood of breast cancer patients

AIM: To explore the changes of the subsets and HLA-DR expression of dendritic cells and their concerning cytokine levels in peripheral blood of patients with breast cancer. METHODS: The subsets of the precussors of dendritic cells (pDC) in the peripheral blood of 57 cases of patients with breast cancer before operation and a week or six months after operation and 20 cases of healthy controls were analyzed by four-color FCM. The levels of IL-12p40, IL-10, IFN-γ and IL-4 in the plasmas were tested by ELISA. RESULTS: Among 57 cases of patients with breast cancer, 2 cases in Ⅲ phase and 4 cases in Ⅳphase expressed deficiency of pDC, the ratios of pDC₁/pDC₂ in the other cases inⅠ, Ⅱ, Ⅲ, Ⅳ phase were respectively 1.62±0.59, 1.41±0.63, 0.91±0.32, 0.81±0.29 before operation, which were markedly lower than those in controls (1.94±0.44). The ratios of pDC₁/pDC₂ in the cases inⅠ, Ⅱ, Ⅲ phase were 1.71±0.47, 1.52±0.54, 1.04±0.36 a week after operation, which were the same as those in pre-operation, but markedly lower than those in controls. The ratios of pDC₁/pDC₂ in the cases inⅠ, Ⅱ, Ⅲ phase were 1.92±0.72, 1.63±0.65, 1.28±0.34 six months after operation, which were markedly higher than those in pre-operation, meanwhile, to compare with controls, those were still lower for patients in Ⅱ, Ⅲ phase except in Ⅰphase. No difference between patients and controls in the expression of HLA-DR of pDCs and the levels of IL-12p40, IL-10, IFN-γ, IL-4 in plasmas and the ratios of IL-12p40/ IL-10, IFN-γ/ IL-4 was observed. CONCLUSION: The ratios of pDC₁/pDC₂ in peripheral blood of patients with breast cancer inⅠ-Ⅳ phase are decreased. Parts of patients in Ⅲ, Ⅳ phase are deficiency of pDCs. HLA-DR expression of DCs and the ability of DCs which secret the concerning cytokines do not change as pDC subsets change. pDC subsets improve markedly inⅡ, Ⅲ phase patients and recover to the normal level inⅠphase patients after operation.     

自由基清除剂对几种蔬菜衰老种子活力的影响

用外源自由基清除剂ＳＢＮ（１、２ｍｍｏｌ／Ｌ）和ＧＳＨ（０．００１、０．００５ｋｇ／Ｌ）浸种西瓜、甜瓜和萝卜衰老种子能显著促进其萌发，而ＡｓＡ（５、１０、１５ｍｍｏｌ／Ｌ）浸种效果不明显，上述处理要不同程度地提高衰老种子中ＣＡＴ和ＳＯＤ活性，降低Ｏ２＾－产生速率，减轻膜脂过氧化作用。     

Effect of 2, 3-butanedione monoxime (BDM) on myocardial protection in cold cardioplegia

AIM: The effects of BDM on isolated rat heart in cold cardioplegia were studied. METHODS: Rat heart were subjected to cold cardioplegia at 4℃ for 8, 18 and 24 h.Then each heart was perfused (90 cm H₂O) in Langendorff model at 37℃ for 40 min. In the high K⁺ group(n=24) the hearts were preserved in St.Thomas cardioplegic solution, in BDM group(n=24) hearts were preserved in K-H solution with BDM 30 mmoL/L. RESULTS: After 18 h, heart rate and the coronary flow in BDM group were significantly higher than in high K⁺ group(P＜0.05). Activity of Na⁺-K⁺-ATPase in cell membrane and in mitochondrial membrane in the BDM group was significantly higher than high K⁺ group(P＜0.01). After 24 h, all hearts in high K⁺ group were dead, but were alive in BDM group. CONCLUSION: Under given experiment conditions, BDM did enhance the tolerance to cold ischemia significantly. The results showed that BDM may become a useful agent for prolong the storage period of heart in cold cardioglegia.     

Effects of Shenmai injection on acute myocardial ischemia/reperfusion injury in rats

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.     

Study on hyper methylation of p15INK4B gene in multiple myeloma

AIM: To study the characteristics and regulations of p15 (MST INK4B) methylation in multiple myeloma (MM). METHODS: Method of methylation-specific PCR was applied in 23 cases of MM about the methylation rate of p15 gene. RESULTS: Methyaltion rate in MM was 73.5%(17/23). The PCR product was a fragment of 148 bp. In four stageⅠcases of MM with plasma cell-typed bone marrow profile, p15^INK4B gene was non-methylated; In one case of stag ⅡMM and one case of stage Ⅲ MM with mature plasma typed bone marrow profile, p15^INK4B gene was no-methylated, too, while in many cases of stageⅠ、stage Ⅱand stage Ⅲ with naive plasma cell in bone marrow profile which were plasma cell-typed or mixed typed, p15^INK4B gene methylation was frequently detected. The methylation rates for stageⅠ、stage Ⅱand stage Ⅲ MM were respectively 55%(5/9),100%(7/7) and 71.4%(5/7). CONCLUSION: p15 gene methylation was a possible pathogenic factor,and might be related to the progression and prognosis of the disease.     

Effect of amiodarone and metoprolol on platelet activation,fibrinolytic activity and vasoactive mediators in acute myocardial infarction in rabbits

AIM:To explore the significance of platelet activation, fibrinolytic activity and the changes of vasoactive mediators in acute myocardial infarction in rabbits and the intervention of amiodarone and metoprolol.METHODS:Fifty New Zealand white rabbits were randomly assigned to five groups, ten for each. Group Ⅰ: sham group, group Ⅱ: acute myocardial infarction(AMI) group, group Ⅲ: AMI and lidocaine group, group Ⅳ: AMI and amiodarone group, group Ⅴ: AMI and metoprolol group.The middle point of left ventricular coronary artery was ligated (groupⅡ,Ⅲ, Ⅳ and Ⅴ ) or a sham ligation(group Ⅰ). Four hours later, blood was collected for measuring plasma concentration of TXB₂, 6-Keto-PGF_1α, ET, NO, plasma activity of t-Pa and PAI.After that, the heart was taken out to evaluate the infarction size(IS).RESULTS:Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly higher in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01), but the plasma concentration of 6-Keto-PGF_1α and plasma activity of t-Pa were remarkably lower in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01). There were no difference in plasma concentration of TXB₂, 6-Keto-PGF_1α, t-Pa activity and infarction size in group Ⅱ,Ⅲ and Ⅳ(P＞0.05).Compared to group Ⅱ, plasma concentration of ET, NO and PAI activity were significantly decresed (P＜0.01)in group Ⅳ. Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly lower in groupⅤ than those in group Ⅱ(P＜0.01). Conversely, plasma concentration of 6-Keto-PGF1 and plasma activity of t-Pa were remarkably higher in group Ⅴ than those in group Ⅱ(P＜0.01). The infarction size was remarkly decrease(P＜0.01)in group Ⅴ.CONCLUSIONS:Amiodarone inhibited PAI avtivity, decreased release of ET and NO in AMI in rabbits. Metoprolol inhibited platelet activation, improved fibrinolytic, decreased release of ET and NO, and reduced myocardial infarction size in AMI in rabbits; Lidocaine had no effect above.