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AIM: To study the effect of caffeine on the large conductance calcium activated potassium (K_(Ca)) channels by patch-clamp technique on smooth muscle cells enzymatically isolated from the porcine coronary artery (PCASMC),and to investigate the effect of ryanodine on K_(Ca) being activated by caffeine.METHODS: Using the single channel patch-clamp technique,single PCASMC was isolated by collagenase,the activity of single K_(Ca) channel was recorded in porcine coronary artery smooth muscle cells.RESULTS: Caffeine (0.1-10 mmol/L) enhanced the open probability (Po) of K_(Ca) channels in a dose-dependent manner in the intracellular side of inside-out patches and its effect was almost completely abolished by washout. Caffeine decreased the mean close time markedly,but had no effect on the amplitude of K_(Ca) channels. However,ryanodine (10-40 μmol/L) decreased Po of K_(Ca) channels activated by caffeine in a dose-dependent manner in cell-attached patches. The mean open time also decreased.CONCLUSION: Caffeine directly activates K_(Ca) channels of porcine coronary artery smooth muscle cells in inside-out patches,the activity of single K_(Ca) channel is inhibited by ryanodine indirectly in cell-attached patches.
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Objective To prepare the bivalent immunoglobulin yolk (lgY) against eobra and viper venom and to detect its activities as the foundation for production and application of polyvalent . Methods The venom of Naja atra Cantor and Daboia russellii siamensis injected alternately into the leghorn hen. Biva-lent lgY was extraeted by water dilution. The biological activity of bivalent lgY were deteeted in several as-pects, sueh as the potency ( by indireet ELISA assay), the cross immunity ( by double immunodiffusion), the membrane lysis activity ( by experiments of vitelline membrane lysis) and 50% lethal activity ( LD50 ). Results Bivalent IgY was extracted from eggs yolk in 28-42 days after the first immunization. The titers of bivalent lgY against cobra and viper venom were 1:12 800 and 1: 6400. The cross immunologic reactions of bivalent IgY were found obviously with six kinds of snake venoms from Elapinae and Viperinae. There were not immunologic precipitation lines between bivalent IgY and four kinds of snake venoms from Crotalinae. Bi- valent lgY obviously deereased the vitelline membrane lysis activity of cobra and viper venom and prolonged the average survival time of mice with cobra or viper envenomation (P < 0.05). Moreover, with the same dose of bivalent IgY, the survival rate of mice with cobra venom envenomation was higher than those with vi-per venom envenomation. Conclusion Bivalent lgY could signifieantly neutralize biologieal activities of co-bra and viper venom, protect animals with cobra or viper envenomation.
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AIM To investigate the protection of plicamycin on apoptosis in cerebellar granule neurons (CGN) of rat. METHODS TUNEL, Hoechst 33258 staining, agarose gel electrophoresis and fluorescein diacetate staining were used to detect morphological and biochemical characteristics of apoptosis in primary rat CGN. RESULTS Being pre-incubated with plicamycin for 1 h and lasting for 24 h, rat CGN apoptosis induced by low potassium basal modified Eagle′s medium for 24 h was inhibited in a plicamycin concentration-dependent manner. This effective concentrations of plicamycin were from 50 to 200 nmol·L-1, and the maximum inhibitory rate of plicamycin on CGN apoptosis was near 80% at 200 nmol·L-1. CONCLUSIONPlicamycin inhibits rat CGN apoptosis induced by low potassium.
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Purpose:To investigate the effect of antineoplastic polypeptide from Buthus martensii venom (APBMV) on the cultured human promyelocytic leukemia cells HL 60 and hepatoma cell line SMMC 7721 and hepatoma H 22 bearing mice.Methods:MTT colorimetric method, growth inhibiting test and colony formation assay were used in the in vitro test. H 22 bearing mice were applied in the in vivo experiment. Through measuring tumor growth inhibitory rate(IR),white blood cell (WBC) number and spleen index (SI) ,we explored the influence of APBMV on H 22 bearing mice.Results:APBMV possessed stronger cytotoxicity on HL 60 cells and SMMC 7721 cells, and IC 50 was 10.74 ?g/ml and 11.33 ?g/ml , respectively. APBMV could dramatically inhibit their growths. There were obvious dosage response correlations. The IC 50 of HL 60 and SMMC 7721 at 24h, 48h and 96h were 19.41 ?g/ml, 9.90 ?g/ml, 11.41 ?g/ml and 15.87 ?g/ml, 13.05 ?g/ml, 8.70 ?g/ml, respectively. When the concentration of APBMV exceeded 8 ?g/ml, the colony formation rate of SMMC 7721 cells decreased dramatically ( P 0.05).Tumor growth of H 22 bearing mice was markedly inhibited by APBMV,the growth inhibiting rate was reached 40.30% ( P
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AIM:The different effect of bivalent immunoglobulin Yolk(IgY) was evaluated against snake venom between intragastric administration and intraperitoneal injection in mice with cobra or viper envenomation.METHODS:The venom of naja and viper was injected alternately into the leghorn hen.Bivalent anti-snake venom IgY was extracted by water dilution.The concentration of bivalent IgY in plasma was observed in indirect ELISA assay after bivalent anti-snake venom IgY taken orally.The gastric emptying function test was used for determining optimization time after gastric administration of IgY.The protective effect of bivalent anti-snake venom IgY was compared between intragastric administration and intraperitoneal injection in mice with cobra or viper envenomation.RESULTS:Bivalent anti-snake venom IgY was extracted from eggs laid in 28-42 d after the first immunization.The titers of Bivalent IgY against cobra and viper venom were 1:12 800 and 1:6 400.At the time of 2.5-3.5 h after bivalent anti-snake venom IgY was taken orally in three concentrations(75 mg,150 mg,300 mg?0.5 mL-1?20 g-1 BW),the gastric evacuation rate of mice was above 68.9%,with the plasma concentration of bivalent IgY in peak.The survival time of mice envenomation with snake venom was extremely prolonged(P
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AIM: To observe the inhibitory effects of polypeptide from Buthus martensii venom (PBMV) on human tumor cell lines and the influence of PBMV on cell cycle migration, expression of tumor-suppressor gene p53 and the membrane potential of CNE-2Z cells. METHODS: MTT colorimetric method, the colony formation and mitosis index, flow cytometry assay and intracellular recording with glass microelectrodes were used. RESULTS: PBMV had obvious cytotoxicity on several tumor cell lines. The cells grow was inhibited by PBMV, colony formation rate and mitotic index of tumor cells were reduced and the number of polykaryocyte was decreased. CNE-2Z cells in S phase were reduced evidently after they were treated with PBMV (P
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AIM: To observe the growth inhibiting effect of antineoplastic polypeptide from Buthus Martensii venom(APBMV)on liver neoplasm METHODS: MTT calorimetric method, trypin blue exclusion,colony formation and H 22 -bearing mouse model RESULTS: The ability to metabolize MTT of SMMC-7721 cells was lower than control distinctly after the cells were treated by APBMV The IC 50 of APBMV was 11 3 ?g/mL The growth of SMMC-7721 cells was inhibited obviously by APBMV and the dose-response relationship was clear, the IC 50 were 15 87 ?g/mL,13 05 ?g/mL and 8 70 ?g/mL respectively The colony formation rate of SMMC-7721 cells was also decreased evidently compared with control when treated concentrations of APBMV were higher than 8 ?g/mL Tumor growth of H 22 -bearing mice was inhibited by APBMV evidently, the growth inhibiting rate was reached 37 31%( P
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The cultured human esophageal cancer cell line——Eca109 cells was incubated with the scorpion venom crude (SVC) collected from Buthus Martensii Karshiin Henan Province. The growth inhibition and cytotoxicity of SVC on Eca109 cells were detected. The results showed that Eca109 cell growth was inhibited by SVC. while Eca 109 cells were incubated with SVC for 24, 48, 72hrs. The rates of inhibition were 35.6%, 39.5, 36.9% respectively, the concention of SVC used was 0.017?g/ml. The mitochondrial dehydrogenase of Eca109 cells were also inhibited by SVC, Which had the cytotoxic effect on Eca109 cells. When the concentrations of SVC were 0.017?g/ml, 0.034?g/ml, 0.085?g/ml, the cytotoxicity were 63%, 56% and 59%, respectively. The effect and mechanism of cytotoxicity of SVC on the tumor cells are worth further studies.
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AIM:To study the effect of caffeine on the large conductance calcium activated potassium (KCa) channels by patch-clamp technique on smooth muscle cells enzymatically isolated from the porcine coronary artery (PCASMC),and to investigate the effect of ryanodine on KCa being activated by caffeine.METHODS:Using the single channel patch-clamp technique,single PCASMC was isolated by collagenase,the activity of single KCa channel was recorded in porcine coronary artery smooth muscle cells.RESULTS:Caffeine (0.1-10 mmol/L) enhanced the open probability (Po) of KCa channels in a dose-dependent manner in the intracellular side of inside-out patches and its effect was almost completely abolished by washout. Caffeine decreased the mean close time markedly,but had no effect on the amplitude of KCa channels. However,ryanodine (10-40 ?mol/L) decreased Po of KCa channels activated by caffeine in a dose-dependent manner in cell-attached patches. The mean open time also decreased.CONCLUSION:Caffeine directly activates KCa channels of porcine coronary artery smooth muscle cells in inside-out patches,the activity of single KCa channel is inhibited by ryanodine indirectly in cell-attached patches.