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Pharmacology is the bridge of preclinical and clinical medicine,as well as medical science and pharmaceutical sciences.Guiding students to grasp some memory method will make for inspiring student's thinking and increasing their interest in pharmacology teaching.And it will also help to improve the effect of pharmacology teaching.
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Aim To investigate the effects of YMⅢ,a derivative of naftopidil, on the vascular contractive activities in rabbit aorta and to explore its vasodilative mechanisms.Methods The isotonic contractions of the thoracic aorta strips from rabbits were recorded, and the effects of YMⅢ on the concentration-response curves of noradrenaline(NA),high potassium and 5-hydroxytryptamine(5-HT)were observed.Intracellular free Ca2+([Ca2+]i)was investigated in the pressence of and the absence of YMⅢ in different conditions.Results YMⅢ(10-8,5?10-8,10-7 mol?L-1)shifted the concentration-response curve of NA with a parallel manner to right, the maximum response was unchanged and the pA2 value was 8.00; YMⅢ (10-5 mol?L-1)also shifted the concentration-response curve induced by high potassium to right but with non-parallel manner,the response was depressed and the pD′2 value was 4.26. However, YMⅢ(10-7,10-6,10-5 mol?L-1)had no statistical influence on the concentration-response curve induced by 5-HT, although it tended to depress the response of the curve at 10-5 mol?L-1.In Ca2+-free medium,YMⅢ (10-8,5?10-8 and 10-7mol?L-1) significantly inhibited the transient contraction induced by NA and the long-lasting one induced by addition of Ca2+ with a concentration-dependent manner.But even at 10-5 mol?L-1,it did not inhibit the contraction induced by caffeine.Conclusions YMⅢ may be ?-adrenergic receptor blocker.Its vasodilative mechanism may be related to:blocking ?-adrenergic receptor on cell membrane resulting in the inhibition on the influx of extracellular Ca2+ and the release of intracellular calcium.
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Aim To study the effect of naftopidil(Naf) on noradrenalin(NA)-induced proliferation of rats vascular smooth muscle cells (VSMCs),and explore its mechanisms. Methods The cultured VSMCs was induced to proliferate by NA,and effects of Naf on the VSMCs proliferation was tested by MTT assay and cell counting method respectively. The intra-cellular calcium concentration is investigated by fluorimetry,and the expressions of c-myc,c-fos and hypertension related gene-1(HRG-1) mRNA were tested by Real-Time RT-PCR. Results The proliferation of VSMCs induced by NA was inhibited by Naf(10-7~10-6mol?L-1),which diminished clearly VSMCs [Ca2+]i and decreased mRNA expressions of c-myc,c-fos and increased the expression of HRG-1 mRNA. Conclusions Proliferation of VSMCs induced by NA can be inhibited clearly by Naf. The mechanisms may be related to diminishing [Ca2+]i,antagonizing the up-regulation of c-myc and c-fos mRNA expressions by NA and antagonizing the down-regulation of HRG-1 mRNA expression.
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Aim To investigate the effect of Isorhynchophylline(Isorhy)on platelet aggregation or thrombosis,and explore the mechanism of it's action.Methods Rat platelet aggregation was determined.cAMP contents were assessed by Born's method and radioimmunoassay respectively.The effect of Isorhy on rat's thrombosis was observed with the thrombogenesis model of artery-vein bypass.Results Isorhy(0.65 mmol?L-1,1.30 mmol?L-1)was shown to markedly inhibit the rat's platelet aggregation induced by ADP or thrombin in a concentration-dependent manner(P
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Aim To study the role of calcineurin signal transduction pathway in the anti-hypertrophic effect of L-arginine in vivo and in vitro.Methods The hypertrophic effects was assayed by calculating the right ventricular hypertrophy index(RVHI=right ventricle weight/left ventricle and septum weight),and atrial natriuretic peptide(ANP)mRNA expression in rat right ventricle hypertrophy model induced by monocrotaline(MCT) or by measuring the cell diameter,protein content,and ANP mRNA expression in hypertrophic cardiomyocyte induced by prostaglandin F2?(PGF2?).For mechanism studies,the intracellular free calcium concentration([Ca2+]i) in cultured cardiomyocytes was measured by using Fura 2/AM as a fluorescent indicator.ANP and CaN mRNA expressions,and expressions of CaN and its downstream effectors,NFAT3 and GATA4 proteins were assayed by RT-PCR and Western blot,respectively,in vivo and in vitro.Results In MCT-hypertrophic model,prevention-and treatment-administration of L-arginine,a nitric oxide(NO) precursor,200 mg?kg-1?d-1,could obviously inhibit the elevated RVHI and ANP mRNA expression;similar to that found in vivo.Addition of L-arginine 1 mmol?L-1 could markedly inhibit the increased cell diameter,protein content and the expression of ANP mRNA in the hypertrophic cardiomyocyte induced by PGF2? 100 nmol?L-1,and it could also decrease the elevated [Ca2+]i in vitro;notably,the above dose or concentration of L-arginine could blunt the elevated expressions of calcineurin mRNA and the calcineurin-,NFAT3-,GATA4-proteins induced by MCT or by PGF2?.These effects of L-arginine were blocked by NG-nitro-L-arginine-methyl ester,a NO synthase inhibitor,in vivo and in vitro.Conclusion These results suggest that calcineurin signal transduction pathway may play an important role in the NO-induced inhibition of cardiac hypertrophy.The anti-hypertrophic effects of L-arginine may involve the decrease of [Ca2+]i,and then inhibit the activated calcineurin pathway,through the release of NO.
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Objective To study the effect of protopine (Pro) on the intracellular free calcium ions of the smooth muscular cells of the thoracic aorta in rats. Methods The procedure of calcium absence-calcium addition was designed to observe the changes of the level of calcium ions in the strips of the smooth muscle of the thoracic aorta indirectly. The concentration of calcium ions in the smooth muscle of the thoracic aorta was determined with Fura-2/AM loaded SMCs. The elevation of calcium ions was induced with norepinephrine (NE). The concentration of potassium ions was observed in the presence of Pro. Results Pro significantly inhibited the NE-induced transient contract of the smooth muscle of the thoracic aorta in calcium-free medium and long-lasting contraction after the addition of calcium ions in a concentration-dependent manner. In Fura-2/AM loaded SMCs, Pro (50 ?mol/L or 100 ?mol/L) exerted no effect on the resting calcium ions but obvious effect on the NE-induced and high potassium level-induced elevation of calcium ions. In the presence of extracellular calcium ions, Pro (50 ?mol/L) decreased the NE-induced elevation of calcium ions but showed no effect on potassium-induced elevation of calcium. Pro (100 ?mol/L) significantly decreased NE-induced and high potassium level-induced elevation of calcium ions. Conclusion Pro reduces NE-induced or high potassium level-induced elevation of calcium ions in the smooth muscle of the thoracic aorta through its effect on calcium release and/or calcium influx.
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Aim To study the protective effects of Rhynchophyll a of total alkaloids ( RTA ) on cerebral ischemia/reperfusion injury and the possi ble mechanism of action. Methods The effects of RTA on decapit ated gasping model and model of middle cerebral artery ischemia 2 h/reperfusion 22 h were observed. The neurological scores, cerebral infarct volume and cerebr al water content after ischemia/reperfusion were observed in rats respectively. The activities of NOS and SOD and the content of MDA in rat's brain tissue were measured. Neuron apoptosis in ischemia penumbral area were detected by terminal depoxynucleotidyl transferase mediated dUTP-biotin nick end labeling ( TUNEL ) . Results The average gasping times in mice treated with RTA 50 , 75 mg?kg -1 was significantly prolonged. The cerebral infarct volume and cerebral water content in rats treated with RTA 40, 60 mg?kg -1 were sign ificantly decreased in ischemic rats. RTA 40, 60 mg?kg -1 increased the ac tivity of SOD ,and decreased the activity of NOS and the content of MDA in the i schemic brains of rats. The number of apoptotic neurons in ischemia penumbral ar ea of cerebral tissue of rats treated with RTA 40, 60 mg?kg -1 was signif icantly lower than that in control rats. Conclusions RTA has pr otective effect on cerebral ischemia/reperfusion injury; this may be related to inhibit the activity of NOS and lipoperoxidation, and increasing the activity of SOD and decreasing neuron apoptosis.
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Aim To observe the effects of Breviscapine (Bre) on the contractions induced by noradrenaline (NA) and high potassium in rabbit aorta strips and to investigate the relationships of these effects to the changes of intracellular free calcium( i). Methods The effects of Bre on the concentration-response curves for NA and high potassium, and on the transient contractions induced by NA and caffeine in Ca 2+-free medium and the sustained contraction by NA after replenishing Ca 2+ were surveyed using rabbit aorta strips; the changes of i increased by NA and high potassium in the presence of Bre were determined using fura-2/AM loaded cultured smooth muscle cells of rabbit aorta. Results Bre shifted the concentration-response curve for NA to right in a dose-dependent manner , but shifted that for high potassium to left; it inhibited the transient contraction induced by NA and caffeine in the Ca 2+-free medium and the sustained contraction induced by NA after replenishing Ca 2+; Bre inhibited the i increased by NA, but enhanced that increased by high potassium in the smooth muscle cells of rabbit aorta. Conclusion Bre inhibits the contraction induced by NA through its inhibition effects on Ca 2+-influx and Ca 2+-release ; it enhances the Ca 2+-influx induced by high potassium, but the mechanism by which Bre enhances the high potassium inducing Ca 2+ -influx is not known.
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AIM:To study the role of prostaglandin F2?(PGF2?) in cardiac hypertrophy and its relation with calcineurin(CaN) signal transduction pathway in vitro.METHODS:The cultured neonatal rat cardiomyocyte was used to observe the hypertrophic effect of PGF2?,and the hypertrophic response was assayed by measuring the cell diameter,protein content and atrial natriuretic factor(ANF) mRNA expression.For mechanism studies,the intracellular free calcium concentration([Ca2+]i) in cultured cardiomyocytes was measured by using Fura-2/AM as a fluorescent indicator.ANF and CaN mRNA expressions,and the expressions of CaN and its downstream effectors,NFAT3 and GATA4 proteins were assayed by RT-PCR and Western blotting,respectively.RESULTS:In cultured cardiomyocytes,PGF2? induced profound hypertrophic morphology change and the significant increase in cell diameter,and protein content in a concentration-dependent manner compared with those in vehicle control(P
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AIM To study the distrubution and excretion of protopine in rats. METHODS Reversed phase high performance liquid chromatographic method (RP HPLC) was developed for determining the level of protopine in rats. The analytical column were packed with 5 ?m C 18 . The mobile phase was a mixture of methanol, water and 10% acetic acid (80∶20∶2), in which the pH was modulated to 5 6 with 15% ammonia. Protopine biological samples were isolated well, in which two extraction with ether under basical condition and an extraction with 0 02 mol?L -1 sulfuric acid were performed, respectively. The content of protopine in the biological sample was measured by an UV detector at 285 nm. The distrubution and excetion of protopine have been investigated in rats after intravenous administration 10 mg?kg -1 . RESULTS Protopine distrubuted in many tissues after iv a dose of 10 mg?kg -1 . The higher level of protopine was found in lung, kidney, spleen and brain, and the highest was observed in lung at 5, 15 minutes after administration. However the top level tissue was testicle at 3 h, which may be due to small blood circulation. The excretion of the parent compound in urine was 36 87% of dose, but the excretion of the parent compound in feces and bile was less than 1% of dose. Plasma protein binding was less than 5%. CONCLUSION The distrubution of protopine is extensive and the parent compoud was mainly excreted by urine and plasma protein binding was low.
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The effects of Rhynchophylline (Rhy) and Isorhychophyiline (Isorhy), the alkaloids abstracted from the Chinese traditional herb Uncaria rhynchophyllia (Miq) Jackson, on the 45Ca-influx and efflux were investigated in rabbit aorta. Both Rhy and Isorhy (10 ?mol? L-1) inhibited the 45Ca-influx induced by high K+(77. 0 mmol ? L-1), but neither significant-ly influenced the 45Ca-influx and efflux induced by noradrenaline (10 ?mol ? L-1). The results suggest that these alkaloids block the Voltage-dependent calcium channel.
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Aim To study the effect of ginsenoside Rg1(Rg1)on cardio myocyte hypertrophy induced by prostaglandin F2?(PGF2?),and to probe primarily into its mechanism.Methods The cultured neonatal rat cardiomyocyte hypertrophic response and the antihypertrophic effects of Rg1 were observed by measuring the cell diameter,protein content and the expression of atrial natriuretic factor(ANF) mRNA,which was assayed by real-time PCR.For mechanism studies,the intracellular free calcium concentration(i) in cultured cardiomyocytes was measured by using Fura-2/AM as a fluorescent indicator,nitric oxide(NO) metabolite level in the culture medium was tested by using Nitric Oxide Synthase Detection Kit.Results PGF2? 0.1 ?mol?L-1 caused the increases in the cardiomyocyte cell diameter,protein content and the expression of ANF mRNA.It could increase the i in cultured cardiomyocytes.Rg1 15.6、31.2、62.4 ?mol?L-1 could concentration-dependently inhibit the cardiomyocyte hypertrophy induced by PGF2?,and the cell diameter of cardiomyocyte treated by PGF2? was decreased by 18.4%、32.7%、43.8%(P