新书推荐：《中国花卉病虫原色图鉴》

AIM: To observe the influence of serum contained Tongmai herbal medicine on calcium overload of the anoxic myocardial cells. METHODS: Serum contained Tongmai herbal medicine was prepared with the serum pharmacological method and the model of anoxic myocardial cells was established. The intracellular free calcium concentration and the expression of the L-type calcium channel were determined with Fura-2/AM and RT-PCR, respectively. RESULTS: The serum contained Tongmai herbal medicine and levo-anlodipine decreased the intracellular free calcium concentration in the anoxic myocardial cells. The serum contained Tongmai herbal medicine also suppressed the expression of L-type calcium channel in the anoxic myocardial cells, but levo-anlodipine had no effect on the expression of L-type calcium channel. CONCLUSION: Tongmai herbal medicine can attenuate calcium overload in anoxic my-ocardial cells.     

Influence of Sini decoction on the proliferation and apoptosis of artery smooth muscle cells after balloon injury

AIM: To investigate the influence of Sini decoction (SND) on the proliferation and apoptosis of rabbit abdominal aorta smooth muscle cells after ballon injury and discuss the effect of vascular smooth muscle cell's (VSMCs) proliferation and apoptosis in post-percutaneous coronary intervention (PCI) restenosis (RS) and the feasibility of SND preventing post-PCI RS. METHODS: The animal model of rabbit abdominal aorta ballon injury was set up and the therapertic group was treated with SND. The shape of proliferative and apoptotic cell were investigated by electron microscope. Immunohistochemistry staining was performed using α-actin,PCNA and Cyclin E monoclonal antibodies. In situ Cell Death Detection Kit was used to identify apoptotic cells. Abdomial aorta angiography was operated in the 84th day subgroup and the stenosis degree was evalued by quantitative angiographic analysis. RESULTS: As compared with the control group, the therapeutic group displayed a lower proliferative percentage and a higher apoptosic percentage (P<0.05). Moreover, the apoptosic peek time was on the 14th day after operation,which was longer than the control group. CONCLUSION: SND effectly inhibited the proliferation of VSMCs and iuduced apoptosis in VSMCs.     

Effects of chronic hypoxia on intracellular calcium concentration in pulmonary arterial smooth muscle cells

AIM:To study the effect of chronic hypoxia (CH) on the intracellular calcium (［²⁺］_i) in pulmonary artery smooth muscle cells (PASMCs) and the role of L-type calcium channel and calcium store. METHODS:The rat chronic hypoxia model was set up and intervene the PASMCs with normal PSS, calcium-free PSS, nifedipine, and heparine respectively. The resting ［Ca²⁺］_i was determined with the Fura-2/AM calcium imaging technique. RESULTS:(1) The ［Ca²⁺］_i in CH group in normal PSS was higher than that in control group in normal PSS (P<0.05). The ［Ca²⁺］_i in CH group in normal PSS was higher than that in calcium-free PSS (P<0.05). (2) No obvious change of ［Ca²⁺］_i before and after application of nifedipine in PASMCs of CH groups was observed. (3) No difference of ［Ca²⁺］_i before and after application of heparine in PASMCs of CH groups was detected. CONCLUSION:Chronic hypoxia increased the ［Ca²⁺］_i in PASMCs. Chronic hypoxia induced increase in ［Ca²⁺］_i may relate to the influx of extracellular calcium, but not due to the L-type calcium channel or the IP3R modulation only.     

Effect of autophagy on L-type calcium channel current induced by gp120V3 in hippocampus neurons

AIM: To observe the influence of autophagy on L-type calcium channel current induced by gp120V3 loop in hippocampal neurons.METHODS: Hippocampal neurons were exteriorized from the newborn rats within 1 d and primarily cultured for 7 d. The neurons were divided into 2 parallel groups, namely control group, gp120V3 group, autophagy inhibitor 3-MA group, gp120V3 + 3-MA group; control group, gp120V3 group, autophagy activator rapamycin group, gp120V3 + rapamycin group. Whole-cell pathch-clamp was used to record L-type calcium channel current. RESULTS: Compared with control group, the density of L-type calcium channel current increased in gp120V3 group and 3-MA group(P<0.05). Compared with gp120V3 group, the density of L-type calcium channel current increased in gp120V3 + 3-MA group(P<0.05). Compared with control group, the density of L-type calcium channel current decreased in rapamycin group(P<0.05). Compared with gp120V3 group, the density of L-type calcium channel current increased in gp120V3 + rapamycin group(P<0.05).CONCLUSION: Autophagy may be involved in the gp120V3 loop-mediated L-type calcium channels in hippocampus neurons.     

Effects of She xiang bao xin wan (SXBXW) on phenotype transformation of vascular smooth muscle cells

AIM: To observe the effects of She xiang bao xin wan (SXBXW) of Chinese patent drug on the phenotype transformation of vascular smooth muscle cells.METHODS: The vascular smooth muscle cell line RASMC P8 was used as the cell model in this experiment. The cells were treated with SXBXW at the doses of 0.25 g/L, 0.50 g/L, 1.0 g/L and 2.0 g/L, respectively, and control cells were treated with the same volume of culture medium without SXBXW. The expression of α-smooth muscle actin (α-SMA) and the smooth muscle myosin heavy chain (SM-MHC), which served as specific molecular markers of vascular smooth muscle contraction in RASMC P8 cells, was analyzed by flow cytometry. RESULTS: The percentages of α-SMA and SM-MHC negative cells in SXBXW treated groups were lower than those in control group. Meanwhile, the percentages of α-SMA and SM-MHC positive cells were increased in RASMC P8 cells treated with SXBXW, indicating that SXBXW prompted the transformation of RASMC P8 cells from synthetic to contractile phenotype.CONCLUSION: Chinese patent drug SXBXW plays a role in transforming the cell phenotype from synthetic to the contraction in vascular smooth muscle.     

Influence of captopril on intracellular free calcium concentration and involved ion channels mechanisms in cardiac myocytes of the neonatal rat undergone anoxia-reoxygenation injury

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

Effects of the Bushen Ningxin Chinese herb-containing serum on the adherence of human monocytes to endothelial cells

AIM: To study effect of the Bushen Ningxin decoction, a Chinese medicine, on the adherence of monocytes to endothelial cells and its mechanism. METHODS: Using cultured human umbilical vein endothelial cells (HUVECs) as target cells, oxidized low density lipoprotein (ox-LDL) was added to the endothelial cell culture to prepare the model of human endothelial cell injury. The serum of rabbits having been treated with Bushen Ningxin decoction was added to trial architecture, the adherence of monocyte-like cell line U937 to HUVECs was analyzed using Rose Bengal staining. In addition, the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1(VCAM-1) and E-selectin in HUVECs was measured by flow cytometry. RESULTS: Treatment of HUVEC with ox-LDL (100 mg/L) for 24 hours significantly increased adhesion of U937 to HUVECs. If serum of the animal treated with Bushen Ningxin decoction was added to trial architecture, the adhesion decreased significantly. The flow cytometry analysis showed that ox-LDL could induce the expression of ICAM-1, VCAM-1 and E-selectin in HUVECs. Serum of the animal treated with Bushen Ningxin decoction significantly decreased the expression of ICAM-1, VCAM-1 and E-selectin in HUVECs. CONCLUSION: The Bushen Ningxin Chinese herb-containing serum has an inhibitory effect on the adherence of monocytes to endothelial cells, probably by way of down-regulating the expression of ICAM-1, VCAM-1 and E -selectin in endothelial cells.     

An approach to calcium signal transmission between L-type calcium channel and sarcoplasmic reticulum of atrial myocytes during atrial fibrillation

AIM: To inquire into the Ca2+ signal transmission from L-type calcium channel to the sarcoplasma reticulum in atrial fibrillation. METHODS: Ten adult cross-bred dogs were used in the experiment. Five dogs underwent continuous rapid atrial pacing (500±20 beats/min) for twenty-four weeks to create persistent atrial fibrillation. Another group of size-matched dogs (n=5) without pacemaker implantation was used as a control group. Canine atrial myocytes were isolated by enzymatic dissociation. The Ca2+ cytosolic transient in atrial myocytes was analyzed by confocal imaging after loading myocytes with the acetoxymethyl ester of fluo-3 (Fluo-3/AM). Ca2+ signal transmission from L-type Ca2+ channels in the plasma membrane to the sarcoplasma reticular IP3R and RyR in atrial myocytes during atria fibrillation were measured. RESULTS: (1) Ca2+ signal transmission from L-type calcium channel to IP3R in the sarcoplasma reticulum:intracellular Ca2+concentration was slightly increased in two groups after blocking T-type calcium channel and RyR, but showed no statistic significance (P＞0.05) between them. (2) Ca2+ signal transmission from L-type calcium channel to RyR in the sarcoplasma reticulum: intracellular Ca2+concentration was risen (1.5576±0.1989) in control groups after blocking T-type calcium channel and IP3R, and no significance was observed (P＞0.05) compared with that in atrial fibrillation group (1.5372±0.2952). CONCLUSIONS: Ca2+ signal transmission possibly exists from L-type calcium channel to RyR and IP3R in the sarcoplasma reticulum, but it does not play an important role in intracellular Ca2+-overload and abnormal Ca2+ signal transmission during atrial fibrillation.     

Changes of large-conductance calcium-activated potassium channel in gastric smooth muscle cells of diabetic gastroparesis rats

AIM: To discuss the relevance between the pathogenesis of diabetic gastroparesis and the large-conductance calcium-activated potassium channels (BK_Ca) in gastric smooth muscle cells. METHODS: The SD rats were randomly divided into control group and model group. The gastric smooth muscle cells of the SD rats were enzymatically isolated in a low calcium solution containing papain. The current was recorded by patch clamp single channel recording technique. The expression of KCNMA and KCNMB1 were observed by the method of immunohistochemistry. RESULTS: The value of BK_Ca single channel conductance was (220.10±10.90) pS; the channels had distinct voltage dependent and calcium dependent characteristics. In outside-out patch (Vm =+30 mV), the activation of BK_Ca was blocked by 200 nmol/L IbTX completely. Compared with control group, the open probability and amplitude of current in model group significantly increased, while the mean open time and mean close time significantly decreased. Compared with control group, the expression of KCNMB1 in model group was significantly increased. CONCLUSION: Up-regulation of β1-subunit and increase in BK_Ca functional activities may be associated with diabetes gastroparesis in rats.     

Cx43 is involved in electrical remodeling of atrial myocytes through regulating L-type calcium current

AIM: To investigate whether the association of connexin 43(Cx43) and L-type calcium channel involved in the pathogenesis of atrial fibrillation (AF). METHODS: The biochemical assays and whole-cell patch-clamp technique were used to study the expression of Cx43 in human atrial tissue. The co-localization of Cx43 and L -type calcium channel, and the regulation of L-type calcium current in atrial myocytes were investigated. RESULTS: The expression of Cx43 at mRNA and protein levels was decreased in human atrial tissues of AF patients. In cultured atrium-derived myocytes (HL-1 cells), knockdown of Cx43 significantly inhibited the mRNA expression of L-type calcium channel α1c subunit, as well as L-type calcium current. Co-localization of Cx43 with L-type calcium channel α1c subunit in mouse atrial myocytes was observed. CONCLUSION: The decrease in Cx43 is involved in the pathogenesis of AF, probably through reducing the L-type calcium current in atrial myoctyes by co-localization with L-type calcium channel, thus representing the potential pathogenesis in atrial fibrillation.     

Progress of STIM1, a dynamic calcium signal transducer, #br# in cardiovascular diseases

Stromal interaction molecule 1 (STIM1) is a transmembrane protein of the endoplasmic reticulum (ER), a Ca²⁺ transducer in ER that activates the store-operated calcium channel. Through Orai1 protein, STIM1 adjusts the intracellular and extracellular calcium concentration. This way is called a store-operated Ca²⁺ entry. STIM1 plays a key role in phenotypic transformation of vascular smooth muscle cells, proliferation of endothelial cells, myocardial hypertrophy and myocardial fibrosis to regulate lots of cardiovascular diseases, such as atherosclerosis, congestive heart failure and systemic hypertension. STIM1 is closely related to cardiovascular diseases through calcium signal. The research progress of STIM1 in cardiovascular diseases is mainly discussed in this article.     

The disturbance of calcium metabolism of vascular smooth muscle in the late phase of septic shock and the underlying mechanism

AIM: To evaluate the alterations in calcium metabolism of the vascular smooth muscle in the late phase of septic shock and test the hypothesis that nitric oxide might be involved in sepsis-induced vascular hyporeactivity. METHODS: Male Sprague-Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). 18 hours post CLP, rat aortic rings were employed for measurement of contractile responses by using organ bath technique. RESULTS: In endothelium-denuded aortic rings from CLP rats, concentration-contraction curves to phenylephrine (PE) and KCl were significantly decreased when compared to that from sham control rats. The transient contraction induced by PE in calcium-free Krebs solution and the concentration-dependent contraction to CaCl₂ in KCl-depolarized medium were also markedly reduced. The hyporeactivity was partially reversed by treatment with aminoguanidine, a selective inducible nitric oxide synthase inhibitor. CONCLUSION: An impairment in calcium handling in vascular smooth muscle is involved in the vascular hyporeactivity during the late phase of septic shock, in which an excessive nitric oxide production might be the major mechanism.     

Effect of AT2 receptor on the proliferation and the NOS expression in cultured adult rat VSMC

AIM: To observe the effect of angiotensinⅡ subtype 2 receptor (AT2 receptor) on the cultured rat aortic vascular smooth muscle cells. METHODS: The plasmid contained the cDNA of AT2 receptor was transfected into cultured rat vascular smooth muscle cells. The effects of AngⅡ, Ang Ⅱ＋losartan, Ang Ⅱ+PD123319 on the expression of PCNA, the NOS activity and the cell number were observed. RESULTS: The cell number and the expression of PCNA decreased after the cells were treated with losartan. When treated with PD123319, the cell number and the expression of PCNA increased, but the expression of NOS decreased. CONCLUSIONS: These data suggest that when being activated, AT2 receptor inhibits the proliferation of vascular smooth muscle cells and antagonizes the effect of AT1 receptor, such an effect may be related to the activation of NOS.     

“中国园艺学会第七届青年学术讨论会”

中国园艺学会第九届第8次常务理事扩大会决定，“中国园艺学会第七届青年学术讨论会”由山东农业大学园艺科学与工程学院和山东省园艺学会承办，将于2006年7月或8月在山东泰安举行。     

Mechanisms of calcium regulating lymphatic contraction

Lymphatic system plays vital roles in fluid homeostasis, nutrition absorption and immunological surveillance, replying on the spontaneous cyclical contraction of lymphatic smooth muscle cells. The calcium ion is the key factor of various smooth muscle cell motion.Beginning with the molecular elements of lymphatic contraction,the present article reviews the mechanisms of calcium ion regulating lymphatic contraction from the aspects of pacemaker system, contractile myofilaments, calcium dependence and calcium sensitivity, thus providing a novel approach for treatment of lymphatic dysfunction disease through calaium regulation.     

Ca2+-activated Cl- channels and pulmonary hypertension induced by high pulmonary blood flow

Pulmonary hypertension induced by high pulmonary blood flow involves a variety of complex mechanisms, including endothelial damage, pulmonary artery smooth muscle relaxation-contraction disorder and vascular remodeling. Besides, the factor of ion channels in pulmonary artery smooth muscle cells is also highly correlated to vasoconstriction. In recent years, many studies have shown that activation of Ca²⁺-activated Cl^- channels is responsible for the membrane depolarization of pulmonary artery smooth muscle cells, and plays an important role in the regulation of vascular tone and vasoconstriction. This article reviews the biophysical and pharmacological characteristics of Ca²⁺-activated Cl^- channels as well as the influence of Ca²⁺-activated Cl^- channels in high pulmonary blood flow-induced pulmonary hypertension.     

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.     

The signal transducers involved in the regulation of calcium sensitivity of vascular smooth muscle in hemorrhagic shock

AIM: To observe the regulatory effects of Rho-kinase, PKC and PKG on calcium sensitivity of vascular smooth muscle in hemorrhagic shock in rats. METHODS: The superior mesenteric artery (SMA) from hemorrhagic shock model of rat was adopted to assay the calcium sensitivity via observing the contraction initiated by Ca2+ under depolarizing conditions (120 mmol/L K+) with isolated organ perfusion system. Rho-kinase agonist Ang-Ⅱ and inhibitor fasudil, PKC agonist PMA and inhibitor staurosporine, PKG agonist 8Br-cGMP and inhibitor KT-5823 were used as tool agents to study the regulatory effect of Rho-kinase, PKC and PKG on the calcium sensitivity of SMA following shock. RESULTS: Ang-Ⅱ, PMA and KT-5823 improved the calcium sensitivity of SMA and made the cumulative dose-response curve of SMA to Ca2+ shift to the left, their Emax of Ca2+ (at 3×10-2 mol/L) was 0.630 g/mg, 0.595 g/mg and 0.624 g/mg, respectively, which were all higher than that in shock control (0.377 g/mg) (P<0.05, P<0.01). Fasudil, staurosporine and 8Br-cGMP delimitated the calcium sensitivity of SMA and made the cumulative dose-response curve of Ca2+ shift to the right, their Emax at 3×10-2 mol/L of Ca2+ was 0.242 g/mg, 0.230 g/mg and 0.256 g/mg, respectively, which were all lower than that in shock control (0.377 g/mg) (P<0.05, P<0.01). CONCLUSION: Rho-kinase, PKC, PKG play important roles in the regulation of calcium sensitivity of vascular smooth muscle in hemorrhagic shock.