The effects of trichlorphon on ganglionic transmission of the isolated superior cervical, ganglia of the guinea pig were investigated by means of intracellular recording techniques. At the concentration of 0.05 ?mol/L or less, trichlorphon increased the amplitude and duration of the fast excitatory postsynaptic potential ( f-KPSP ) and the membrane apolarization induced by application of acetylcholine ( ACh), but not carbachol ( CaCh ) . At the concentration of 0.1 mmol/L or more, trichlorphon reversibly depressed the f-EPSP and depolarization evoked by superfusion of either ACh or CaCh. Furthermore, the depressant effect of trichlorphon persisted in a low Ca/ high Mg solution. The membrane potential and membrane resistance of the sympathetic neurons were not significantly altered by trichlorphon.The results indicate that the facilitatory action of trichlorphon appears to be related to its anticholinesterase activity,whereas trich-lorphon-induced blockade of transmission may be explained by a direct action of trichlorphon on the postsynaptic membrane.

BACKGROUND: The rare earth elements (Res) have multiple bio-activities and some extent neurotoxicity, Because of their distinct physical and chemical properties. The studies on neuromuscular junction and sympathet ic ganglia have shown that some Res, such as lanthanum(La), gadolinium (Gd),etc, exert considerable effects on synaptic transmission, but the effects and mechanism of Samarium on synaptic transmission are still unknown.OBJECTIVE: To investigate the effects and impossible mechanism of Samarium Chloride (SmCl3) on the nicotinic transmission in the isolated sympathetic ganglia, superior cervical ganglion (SCG) of rats.DESIGN: Controlled experimental study based on cells.SETTING: Department of Pharmacology, Guangxi Medical University. MATERIALS: Totally 40 adult Wistar rats (weighing 250-300 g) of either sex, provided by the Experimental Animal Center of Guangxi Medical University, were used in this study. SmCl3 was made by the chlorination of Samarium Oxide with purity 99.5% and relative molecule mass 348.7, presented by Professor Liu Da-yuan, Guangxi Medical University. Acetylcholine chloride (Ach) and carbachol (Carb) were purchased from Sigma.METHODS: The experiment was completed at the neuropharmacology lab of the experimental center of Guangxi Medical University from September 2001 to December 2002. After sacrificing animals by acute exsanguination,SCG together with their preganglionic nerve trunks were isolated rapidly,then transferred to the recording chamber, the preganglionic nerve trunk was drawn into a suction electrode for orthodromic stimulation. The ganglia were superfused continuously with a Krebs solution, saturated with 950 mL/L 02 and 5mL/L CO2, pH 7.4±0.05, (34±0.5) ℃.The fiber containing glass microelectrodes filled with 3 mol/L KC1 (30-60 MΩ tip resistance) were used to impaled cells and do intracellular recording. The fast excitatory postsynaptic potentials (FEPSPs) were evoked in SCG neurons by single pulse stimulations (0.2-0.5 Hz, 0.5-1.0 ms, 2-10 V)on preganglionic nerve trunk. The remarkable membrane depolarization would be recorded in SCG neurons by superfusing ganglia with exogenous Ach (0.1 mmol/L) or Carb(0.1 mmol/L) for 30-60 s. The effects of 1×(10-7-10-4) mol/L SmCl3 on FEPSPs, membrane potentials, membrane resistance, exogenous Ach and Carb-induced membrane depolarization of SCG neurons were investigated in this experiment.The effects of SmCl3 on the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs were also be observed, namely, first superfusing the ganglia with high Ca2+ (10 mmol/L)to facilitate FEPSPs, then superfusing the ganglia with Ca2+(10 mmol/L)contained SmCl3. All the drugs were solved in Krebs solution or improved Krebs solution and applied to ganglia by superfusion in known concentration.The bioelectricity difference before and after the drug superfusion were analyzed by paired Student's t test.MAIN OUTCOME MESURES: ①Effects of SmCl3 on FEPSPs.②Effects of SmCl3 on membrane potentials and membrane resistances. ③Effects of SmCl3 on exogenous Ach and Carb-induced membrane depolarization. ④Effects of SmCl3 on the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs.RESULTS: ① 1 ×(10-7-10-4)mol/L SmCl3 could reversibly depressed the FEPSPs of rats SCG neurons [the amplitude inhibitory percentage of FEPSPs of l×10-4, 1×10-5, 1×10-6, 1×107 mol/L SmCl3 was (49.78±13.85)%(n=20),(39.05±4.05)%(n=10),(29.83±9.73)%(n=10)and (16.30±2.16)%(n=10)respectively (P ＜ 0.05-0.01)].1×10-4 mol/L SmCl3 could chang Aps into FEPSPs (n=5).②The membrane depolarization induced by Ach (n=5) and Carb (n=7) were not significantly changed by 1×10-4 mol/L SmCl3(P ＞ 0.05).③The membrane potential and membrane resistance were not significantly altered by 1×(10-7-10-4)mol/L SmCl3(n=67), P ＞ 0.05. ④1×10-4 mol/L SmCl3 could antagonized the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs (n=5), P ＜ 0.01.CONCLUSION: SmCl3 can depresses nicotinic transmission in rats sympathetic ganglia by presynaptic mechanisms, perhaps due to its inhibition on Ca2+ influx.

Aim To investigate the antagonistic action o f total saponins of panaxnotoginseng(PNS) on cardiac hypertrophy and its nervous mechanism.Methods (1)cardiac hypertrophy of rats due to pressure overload was induced by constricting of abdominal aorta. There were five groups in the experiments. The rats in Group A(control group)were sham operated . Group B was aorta-constricted group.The rats in Group C,D,E were given ip PNS 50,100,150 mg?kg?d -1 for three weeks respectively. Three weeks later, We measured the heart-weight(HW),left ventricular weight(LVW), the ratio of HW/BW,LVW/BW (LVI) and the cardiomyocyte diameters(MD) after dyeing by HE color.(2)The effects of PNS on the fast excitatory postsynaptic potential(f-EPSP),membrane depolarization induced by application of acetylcholine (ACh),membrane potential and membrane resistance of the isolated Stellate ganglion(SG)of the rats were investigated by means of intracellular recording techniques. Results (1)HW/BW, LVI and MD of Group E were significantly lower than that of Group B(P0.05).(2)At the concentration of 0.10 ～0.16 g?L -1, PNS reversibly depressed the amplitude of f-EPSP, but the ACh depolarization,membrane potential and membrane resistance were not significantly altered by PNS. Conclusion PNS can prevent cardiac hypertrophy due to pressure overload in rats and this action may underline its inhibitory action on presyn aptic effect of regulating calcium influx.

Aim To study effects of morphine tolerance and dependence on the fast excitatory synaptic transmission in sympathetic ganglia of rats.Methods The isolated sympathetic ganglia,superior cervical ganglia(SCG), were made from control and morphine tolerant and dependent rats respectively.Effects of morphine tolerance and dependence on the fast excitatory synaptic transmission in rat sympathetic ganglia were studied by means of intracellular recording technique.Results ① Morphine(0.1～1.0 mmol?L~(-1))reversibly inhibited the amplitude of the fast excitatory postsynaptic potentials(f-EPSPs) in SCG neurons of control rats.② Compared with control group,inhibitory effects of morphine(0.5 mmol?L~(-1) and 1.0 mmol?L~(-1)) on f-EPSPs in SCG neurons of morphine tolerant and dependent rats were obviously decreased;③ Naloxone(0.1 mmol?L~(-1)),which had no significantly effect on f-EPSPs in SCG neurons of control rats,could reversibly facilitate the amplitude of f-EPSPs in SCG neurons of morphine tolerant and dependent rats;④ No significant difference of RMP and Rm was founded between SCG neurons of control and morphine tolerant and dependent rats.Conclusion The morphine tolerant and dependent of the fast excitatory synaptic transmission in rat sympathetic ganglia has been formed in morphine tolerant and dependent rats.

Aim To study the effects of chronic morphine treatment on the contents of cAMP and cGMP in sympathetic ganglia,superior cervical ganglia(SCG) of rats.Methods The chronic morphine dependent model of rats was established by subcutaneous injection of morphine in gradually increasing doses for 5 days,the dependence and the tolerance of the model was estimated by naloxone precipitation test and 55℃ tail-flick trail test respectively.The contents of cAMP and cGMP in SCG were detected by means of 125I radioimmunoassay.Results ① Compared with control group,the content of cAMP in SCG of morphine-acute group rats was descended(P0.05;compared with morphine-acute,P0.05).Conclusion There was an up-regulation of cAMP in sympathetic ganglia of chronic morphine treated rats.

Objective To evaluate the effect of sildenafil on the expression of tumor necrosis factor-alpha (TNF-α) in lung tissues of rats with pulmonary hypertension.Methods Twenty-four male Sprague-Dawley rats,aged 8 weeks,weighing 180-220 g,were randomly divided into 3 groups (n =8 each) using a random number table:control group (group C),pulmonary hypertension group (group PH),and sildenafil group (group S).Sildenafil 50 mg/kg was injected through a gastric tube into stomach once a day for 35 consecutive days starting from 1 day after lelf pneumonectomy in group S.Pulmonary hypertension was induced by left pneumonectomy and subcutaneous monocrotaline injected at 7 days after operation in PH and S groups.At 35 days after operation,mean pulmonary arterial pressure (mPAP),relative medial thickness of pulmonary artery (RMT),right ventricular systolic pressure (RVSP),and muscularization of small pulmonary arteries were measured in the lung.The ratio of the right ventricular weight to the sum of the weights of the left ventricle and septum (RV/(LV + S)) was calculated.The expression of TNF-α mRNA and protein was determined using RT-PCR and Western blot analysis,respectively.Results Compared with group C,mPAP,RVSP,muscularization of small pulmonary arteries,RMT and RV/(LV + S) ratio were significantly increased,and the expression of TNF-α mRNA and protein was upregulated in group PH,and RVSP,muscularization of small pulmonary arteries and RV/(LV + S) ratio were increased in group S.Compared with group PH,mPAP,RVSP,muscularization of small pulmonary arteries,RMT and RV/(LV + S) ratio were significantly decreased,and the expression of TNF-α mRNA and protein was downregulated in group S.Conclusion Sildenafil can down-regulate the expression of TNF-α in lung tissues of rats with pulmonary hypertension,inhibit reconstruction of pulmonary artery,and decrease the pulmonary arterial pressure.

AIM: To study the effects of tumor necrosis factor-α (TNF-α) on the transcriptional activity of nuclear factor-erythroid 2-related factor 2 (Nrf2) in pulmonary microvascular endothelial cells. METHODS: Rat pulmonary micro-vascular endothelial cells (PMVECs) were cultured by lung tissue block pasted methods, and identified immunocytochemically using Ⅷ factor-related antigen. The cells were treated with different doses TNF-α (prepared in serum-free medium) for 4 h. Subcellular localization and levels of Nrf2 in PMVECs were observed with immunocytochemical methods. Nuclear extract were obtained to assayed transcriptional activity of Nrf2 with EMSA. Total RNA were isolated to assay the mRNA expression of Nrf2 by RT-PCR. RESULTS: The protein level of Nrf2 in the nuclei and transcriptional activity increased dose-dependently in PMVECs after treated with TNF-α at concentrations of 2.5, 5.0 or 10.0 μg/L. However, the protein level of Nrf2 in nuclei and transcriptional activity decreased dose-dependently in PMVECs after treated with TNF-α at concentrations of 20 or 40 μg/L. No different mRNA expression of Nrf2 in PMVECs treated with TNF-α at all concentration above was observed. CONCLUSION: Transcriptional activity of Nrf2 increases in PMVECs treated with low or moderate doses of TNF-α and decreases in PMVECs treated with high doses of TNF-α.

Objective To explore the association of transforming growth factor-beta 1(TGF-β1) polymorphisms with coronary heart disease(CHD).Methods The 509C/T polymorphisms of TGF-β1 gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) in 300 patients of CHD and 300 healthy individuals,the levels of serum lipids and hsCRP were also studied.Results The levels of hsCRP、TC 、LDL、ApoB in serum and the frequencies of C、T allele at position-509 of TGF-β1 gene were statistically significant higher than the controls(P＜0.01,P＜0.05).Conclusion The polymorphisms of TGFβ1-509C/T were associated with CHD.C allele should be the susceptibility gene in the occurence of CHD.

Objective To investigate the effects of Panax notoginseng saponins(PNS)on both the excitatory and inhibitory synaptic transmission in the pyramidal neurons in hippocampal CA1 region of rats.Methods Wistar male rats(3—4 weeks)were killed by cervical dislocation and hippocampal slices(400 ?m)were prepared,blind whole-cell voltage-clamp recordings were performed on the CA1 pyramidal cells in hippocampal slices to examine and analyze the effects of PNS(0.05—0.4 g/L)on CA1 afferent fiber-evoked excitatory postsynaptic currents(EPSCs)and inhibitory postsynaptic currents(IPSCs),respectively.Moreover,the Schaffer collateral/commissural pathway was stimulated with paired pulses(interpulse interval was 50 ms)and the paired-pulse facilitation(PPF)was analyzed by EPSC2/EPSC1(P2/P1)ratio.Results PNS(0.1—0.4 g/L)significantly depressed amplitude of EPSCs in neurons in the hippocampal CA1 region(P0.05).Conclusion The inhibitory effect of PNS on EPSCs in hippocampal CA1 pyramidal neurons is not due to the reinforcement of the inhibiting interneurons.It may be a result of direct inhibition on excitatory synaptic transmission.The increasing of P2/P1 ratio after PNS application suggests that PNS depresses the excitatory synaptic transmission by presynaptic mechanism.

In this study, we constructed a yeast consortium surface-display expression system by using Flo1 as an anchor protein. Endoglucanase II (EGII) and cellobiohydrolase II (CBHII) from Trichoderma reesei, and β3-glucosidase 1 (BGLI) from Aspergillus aculeatus were immobilized on Saccharomyces cerevisiae Y5. We constructed the cellulose-displaying expression yeast consortium (Y5/fEGII:Y5/fCBHII:Y5/fBGLI = 1:1:1) and investigated the enzymatic ability and ethanol fermentation. The displayed cellulolytic enzymes was stabile during the 96-h fermentation. The yeast consortium produced 0.77 g/L ethanol from 10 g/L phosphoric acid swollen cellulose (PASC) within 96 h. The yield (in grams of ethanol produced per gram of carbohydrate consumed) was 0.35 g/g, which correspond to 68.6% of the theoretical yield.
Aspergillus ; enzymology ; Cellulase ; genetics ; Cellulose ; metabolism ; Cellulose 1,4-beta-Cellobiosidase ; genetics ; Enzymes, Immobilized ; genetics ; Ethanol ; metabolism ; Fermentation ; Glucosidases ; genetics ; Mannose-Binding Lectins ; metabolism ; Protein Binding ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; metabolism ; Trichoderma ; enzymology