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PubMed1969

Metabolism of Bacillus thuringiensis in relation to spore and crystal formation.

A general pattern of metabolism was determined for Bacillus thuringiensis grown in a glucose-yeast extract-salts medium. The pattern did not differ significantly from that of B. cereus grown in a similar medium. Acetic acid produced from glucose during exponential growth was further catabolized in the early sporulation phase of growth, at which time the specific activity of aconitate hydratase increased markedly. Fluoroacetate and alpha-picolinate prevented the removal of accumulated acid, and the resulting low pH inhibited spore and crystal synthesis. Neither crystal-related antigens nor insect toxicity was shown by cells whose crystal synthesis was inhibited in this way. alpha-Picolinate prevented the normal increase in specific activity of aconitate hydratase without inhibiting exponential growth. It also inhibited aconitate hydratase in vitro, but only if preincubated with the enzyme. alpha-Picolinate did not inhibit the increase in specific activity of aconitate hydratase or spore and crystal synthesis in a medium buffered near neutrality. Chloramphenicol and actinomycin D inhibited crystal enlargement and sporulation when added to cells in which small crystals had already begun to form. Typical messenger ribonucleic acid-dependent protein synthesis, rather than the type associated with peptide antibiotic synthesis, is thus indicated for the synthesis of crystal peptide subunits.

Bacillus↗
PubMed1973

Transport of tricarboxylic acids in Salmonella typhimurium.

Salmonella typhimurium possesses at least three inducible transport systems for the tricarboxylic acids (citric, isocitric, cis-aconitic, and tricarballylic). The first system was induced by citrate, isocitrate, or cis-aconitate, and transported citric acid and isocitric acid. The second system was also induced by the same acids as in the first system and transported cis-aconitic acid. This system required Mg(2+) ions and was stable at pH 8.4 but unstable at pH 7.0. The metal ion was replaced with Sr(2+) or Ca(2+) ions but not with Ba(2+) ions. The third system was induced by tricarballylate and transported citric acid, cis-aconitic acid, and tricarballylic acid.

Aconitum↗
PubMed1995

Expression of major histocompatibility complex in mouse peritoneal macrophages increasingly depends on plasma corticosterone levels: stimulation by aconitine.

Influence of aconite extract and a main component of aconite, aconitine were investigated on the plasma corticosterone level for the expression of major histocompatibility complex class II (Ia antigen) of macrophage. In peritoneal macrophage exposed to corticosterone (2.9-87 microns) in vitro the interferon (IFN)-gamma (0.1 unit/ml)-induced Ia antigen expression was inhibited in a dose-dependent manner. Ia antigen expression in macrophages harvested from the corticosterone (1.25mg/mouse/d, i.m., 4d)-excessive mice and aconitine (3 micrograms/kg, i.p., 7d)-treated mice was significantly stimulated, whereas that of adrenalectomized (7d) mice was inhibited. In macrophage exposed to aconitine up to 46.5 microns in culture Ia antigen expressed was not affected. Administration of aconite extract (3 mg/kg, i.p., 7d) and aconitine (3 micrograms/kg, i.p., 7d) increased plasma corticosterone levels. These result demonstrate that high levels of corticosterone increases the macrophage response to ifn-gamma on Ia antigen expression and that low levels of corticosterone decrease it. Aconite extract and aconitine stimulate the response to IFN-gamma-activated expression of Ia antigen by macrophages which is caused by increasing the plasma corticosterone level.

Aconitine↗
PubMed2002

Incidence of herb-induced aconitine poisoning in Hong Kong: impact of publicity measures to promote awareness among the herbalists and the public.

BACKGROUND: In Hong Kong 'chuanwu' (the main root of Aconitum carmichaeli) and 'caowu' (the root of Aconitum kusnezoffii) are used by herbalists to treat patients with various musculoskeletal disorders. These aconite roots contain aconitine, mesaconitine and hypaconitine, which are neurotoxins and cardiotoxins. During 1989 to 1991, 31 patients were treated in public hospitals because of poisoning by aconite roots and there were two deaths from ventricular arrhythmias. In late 1991, healthcare officials together with cardiologists held a press conference to warn the public, healthcare professionals and herbalists of the potential toxicity of aconite roots. The risk of ventricular arrhythmias and the need for urgent medical attention were highlighted. An information leaflet was also sent to hospital doctors. Since 1992, the topic was covered periodically in the local newspapers, medical journals and continuing medical education programmes. OBJECTIVE: The objective of this study was to assess the impact of these publicity measures on the incidence of herb-induced aconitine poisoning in the New Territories East, based on the number of admissions to the Prince of Wales Hospital. METHODS: During 1989 to 1993 and 1996 to 1998, all patients admitted to our medical wards because of herb-induced aconitine poisoning were identified by on-going surveillance of medical patients, searching our computerised medical record system and reviewing reports received by the 24-hour Drug and Poisons Information Bureau. RESULTS: The number of hospitalisations due to aconitine poisoning markedly decreased from four to six per year in 1989 to 1991 to one to two per year in 1992 to 1993. The annual incidence of aconitine poisoning showed a marked decrease from 0.49 to 0.69 [overall 0.60, 95% confidence intervals (CI) 0.34 to 0.99] to 0.10 to 0.22 (overall 0.16, 95% CI 0.03 to 0.46) per 100,000 population (p = 0.024). During 1996 to 1998, herb-induced aconitine poisoning remained uncommon, with zero to two hospital admissions per year or an annual incidence of zero to 0.33 (overall 0.17, 95% CI 0.05 to 0.43) per 100,000 population (p = 0.016). DISCUSSION: It is possible that the herbalists could have used smaller doses of 'chuanwu' and 'caowu' than before. Patients could be more compliant with the instructions on how to prepare the herbal decoction at home. However, our experience suggested that publicity measures to promote awareness, among the herbalists and the public, may reduce the incidence of poisoning due to toxic herbs such as aconite roots.

Aconitine↗
PubMed1997

[Determination of organic acids and inorganic anions by gradient ion chromatography].

The chromatographic conditions for separation and detection of organic acids and inorganic anions by gradient ion chromatography with suppressed conductivity detection were studied. The optimized gradient programs were established. Ion chromatography were performed with a DX-100 chromatograph (DIONEX). The separation column is IonPac-AS11. Compared with NaHCO3/Na2CO3 and Na2B4O7, NaOH was the optimal eluent. The effect of organic modifier was also studied. Among methanol, 2-propanol and acetonitrile, methanol can make ion pairs such as malate and succinate, malonate and tartrate gaining baseline resolution. By using ion exchange separation, Cl-, NO3-, malate, succinate, malonate, tartrate, SO4(2-), oxalate were eluted between 5 mmol/L NaOH-16% CH3OH and 10 mmol/L NaOH-16% CH3OH in 25 min. A mobile phase composed of 30 mmol/L NaOH, 50% CH3OH and D.I. water was chosen to elute two groups of organic acids and inorganic anions: (1) quinate, formate, Cl-, malate, malonate, oxalate, citrate, isocitrate, aconitate; (2) lactate, Cl-, SO4(2-), tartrate, PO4(3-), citrate, isocitrate, aconitate. The detection limits (S/N = 3) were 0.1625 (quinate), 0.0691 (formate), 0.0115 (Cl-), 0.0886 (malate), 0.0591 (malonate), 0.0263 (oxalate), 0.1147 (citrate), 0.2017 (isocitrate), 0.3656 (cis-aconitate), 0.1045 (trans-aconitate), 0.1950 (lactate), 0.0729 (tartrate), 0.0224 (SO4(2-)) and 0.0692 (PO4(3-)) mg/L. The relative standard deviations were lower than 11.9% (n = 7) and the correlation coefficients ranged from 0.9212 for Cl- to 0.9999 for formate. The method was applied to determine the organic acids and inorganic anions of beverages and citric acids fermenting-medium. The results were satisfactory.

Anions↗
PubMed1995

Steric and conformational features of the aconitase mechanism.

Crystal structures of mitochondrial aconitase with alpha-methylisocitrate and with sulfate bound have been solved and refined at 2.0 A resolution with R factors of 18.2 and 16.8%, respectively. The steric factors and conformational effects observed in both new structures support the proposed mechanism for the overall reaction catalyzed by aconitase. The alternate substrate alpha-methylisocitrate is derived from alpha-methyl-cis-aconitate during crystallization and is observed to bind in the active site in a manner very similar to that observed for isocitrate. The methyl group is accommodated by favorable contact with Ile-425. However, the other potential hydration product of alpha-methyl-cis-aconitate, alpha-methylcitrate, cannot be accommodated in the active site due to steric conflict of the methyl group with Asp-165. The results are consistent with the requirement that cis-aconitate must bind in two ways, in the citrate mode and in the isocitrate mode. Crystals of aconitase with sulfate bound are isomorphous to those with isocitrate bound. However, the structure displays significant conformational changes, providing a model for the substrate-free state of enzyme. Three water molecules bind in place of the C alpha- and C beta-hydroxyl and carboxyl groups of isocitrate, while sulfate binds in place of the C gamma-carboxyl group. Side chains of Ser-642 and Arg-447 in the active site rotate to pair with other side chains in the absence of substrate. The new conformation of Arg-447 triggers a concerted set of shifts which transmits conformational change to the surface of the protein, 30 A from the active site. In the absence of substrate, a chain segment containing the [4Fe-4S] ligand Cys-358 also shifts, resulting in the net translation and reorientation of the Fe-S cluster.

Aconitate Hydratase↗
PubMed1994

Studies on compounds promoting the in vitro transformation of Trypanosoma brucei from bloodstream to procyclic forms.

In vitro differentiation of pleomorphic blood-stream forms of Trypanosoma brucei to procyclic culture forms occurred rapidly and at high rates at 27 degrees C in a culture medium containing 1 mM cis-aconitate as the transformation-inducing agent. Citrate was required at a much higher concentration (10 mM) to produce a similar transformation rate. The highest percentage of transformed cells was obtained when bloodstream-form trypanosomes were treated with pronase in the absence of a feeder-cell layer. However, under these conditions, the amount of procyclic forms obtained after 72 h was lower than that obtained in the presence of cis-aconitate. Trypsin was also capable of inducing transformation in the absence of a feeder-cell layer, but this treatment again resulted in low numbers of transformed cells. Blood-stream-form trypanosomes were incapable of taking up citrate to any significant extent and the citrate content of these stages was negligible. After 72 h of exposure to citrate (3 mM), intracellular levels of this compound remained very low (< 1 nmol (10(9) cells)-1), increasing in established procyclic stages to approximately 1.7 nmol (10(9) cells)-1. These observations suggest that the tricarboxylic acid (TCA)-cycle metabolite-dependent transformation may be initiated externally to the trypanosome cell membrane. The ability of both citrate and cis-aconitate to bind calcium and, thus, to reduce the concentration of this cation in the culture medium was found not to be responsible for the triggering effect on trypanosome transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aconitic Acid↗
PubMed1991

Inhibition of protein synthesis results in super-induction of procyclin (PARP) RNA levels.

Procyclin is an abundant surface antigen found exclusively on the procyclic forms of African trypanosomes. We are interested in the induction of procyclin gene expression during differentiation from bloodstream forms. We find that increased levels of procyclin RNA are evident as early as 15 min after triggering differentiation. The increase in procyclin RNA levels requires the temperature shift from 37 degrees C to 27 degrees C and is aided by addition of the tricarboxylic acid cycle intermediate cis-aconitate. Maximal induction is observed with a combination of three triggers of differentiation: citrate, cis-aconitate and the temperature shift. Protein synthesis does not appear to be required for induction of procyclin RNA during differentiation. In fact, addition of protein synthesis inhibitors results in super-induction of procyclin RNA levels, even under conditions where no induction is normally observed (i.e., at 37 degrees C in the absence of citrate and cis-aconitate). This super-induction was observed with four different protein synthesis inhibitors that affect different stages of translation. Thus, the accumulation of procyclin transcripts may be under the control of a negative regulator whose effective levels are reduced during differentiation from bloodstream to procyclic forms.

Aconitic Acid↗
PubMed1990

17O, 1H, and 2H electron nuclear double resonance characterization of solvent, substrate, and inhibitor binding to the [4Fe-4S]+ cluster of aconitase.

17O electron nuclear double resonance (ENDOR) studies at X-band (9-GHz) and Q-band (35-GHz) microwave frequencies reveal that the [4Fe-4S]+ cluster of substrate-free aconitase [citrate (isocitrate) hydro-lyase, EC 4.2.1.3] binds solvent, HxO (x = 1, 2). Previous 17O ENDOR studies [Telser et al. (1986) J. Biol. Chem. 261, 4840-4846] had disclosed that Hx17O binds to the enzyme-substrate complex and also to complexes of enzyme with the substrate analogues trans-aconitate and nitroisocitrate (1-hydroxy-2-nitro-1,3-propanedicarboxylate). We have used 1H and 2H ENDOR to characterize these solvent species. We propose that the fourth ligand of Fea in substrate-free enzyme is a hydroxyl ion from the solvent; upon binding of substrate or substrate analogues at this Fea site, the solvent species becomes protonated to form a water molecule. Previous 17O and 13C ENDOR studies [Kennedy et al. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 8854-8858] showed that only a single carboxyl, at C-2 of the propane backbone of cis-aconitate or at C-1 of the inhibitor nitroisocitrate, coordinates to the cluster. Together, these results imply that enzyme-catalyzed interconversion of citrate and isocitrate does not involve displacement of an endogenous fourth ligand, but rather addition of the anionic carboxylate ligand and a change in protonation state of a solvent species bound to Fea. We further report the 17O hyperfine tensor parameters of the C-2 carboxyl oxygen of substrate bound to the cluster as determined by the field dependence of the 17O ENDOR signals. 17O ENDOR studies also show that the carboxyl group of the inhibitor trans-aconitate binds similarly to that of substrate.

Aconitate Hydratase↗
PubMed2006

Kinetics and product analysis of the reaction catalysed by recombinant homoaconitase from Thermus thermophilus.

HACN (homoaconitase) is a member of a family of [4Fe-4S] cluster-dependent enzymes that catalyse hydration/dehydration reactions. The best characterized example of this family is the ubiquitous ACN (aconitase), which catalyses the dehydration of citrate to cis-aconitate, and the subsequent hydration of cis-aconitate to isocitrate. HACN is an enzyme from the alpha-aminoadipate pathway of lysine biosynthesis, and has been identified in higher fungi and several archaea and one thermophilic species of bacteria, Thermus thermophilus. HACN catalyses the hydration of cis-homoaconitate to (2R,3S)-homoisocitrate, but the HACN-catalysed dehydration of (R)-homocitrate to cis-homoaconitate has not been observed in vitro. We have synthesized the substrates and putative substrates for this enzyme, and in the present study report the first steady-state kinetic data for recombinant HACN from T. thermophilus using a (2R,3S)-homoisocitrate dehydrogenase-coupled assay. We have also examined the products of the reaction using HPLC. We do not observe HACN-catalysed 'homocitrate dehydratase' activity; however, we have observed that ACN can catalyse the dehydration of (R)-homocitrate to cis-homoaconitate, but HACN is required for subsequent conversion of cis-homoaconitate into homoisocitrate. This suggests that the in vivo process for conversion of homocitrate into homoisocitrate requires two enzymes, in simile with the propionate utilization pathway from Escherichia coli. Surprisingly, HACN does not show any activity when cis-aconitate is substituted for the substrate, even though other enzymes from the alpha-aminoadipate pathway can accept analogous tricarboxylic acid-cycle substrates. The enzyme shows no apparent feedback inhibition by L-lysine.

Aconitate Hydratase↗
PubMed1996

The reaction of fluorocitrate with aconitase and the crystal structure of the enzyme-inhibitor complex.

It has been known for many years that fluoroacetate and fluorocitrate when metabolized are highly toxic, and that at least one effect of fluorocitrate is to inactivate aconitase. In this paper we present evidence supporting the hypothesis that the (-)-erythro diastereomer of 2-fluorocitrate acts as a mechanism based inhibitor of aconitase by first being converted to fluoro-cis-aconitate, followed by addition of hydroxide and with loss of fluoride to form 4-hydroxy-trans-aconitate (HTn), which binds very tightly, but not covalently, to the enzyme. Formation of HTn by these reactions is in accord with the working model for the enzyme mechanism. That HTn is the product of fluorocitrate inhibition is supported by the crystal structure of the enzyme-inhibitor complex at 2.05-A resolution, release of fluoride stoichiometric with total enzyme when (-)-erythro-2-fluorocitrate is added, HPLC analysis of the product, slow displacement of HTn by 10(6)-fold excess of isocitrate, and previously published Mössbauer experiments. When (+)-erythro-2-fluorocitrate is added to aconitase, the release of fluoride is stoichiometric with total substrate added, and HPLC analysis of the products indicates the formation of oxalosuccinate, and its derivative alpha-ketoglutarate. This is consistent with the proposed mechanism, as is the formation of HTn from (-)-erythro-2-fluorocitrate. The structure of the inhibited complex reveals that HTn binds like the inhibitor trans-aconitate while providing all the interactions of the natural substrate, isocitrate. The structure exhibits four hydrogen bonds < 2.7 A in length involving HTn, H2O bound to the [4Fe-4S] cluster, Asp-165 and His-167, as well as low temperature factors for these moieties, consistent with the observed very tight binding of the inhibitor.

Aconitate Hydratase↗
PubMed2004

The acnD genes of Shewenella oneidensis and Vibrio cholerae encode a new Fe/S-dependent 2-methylcitrate dehydratase enzyme that requires prpF function in vivo.

The propionate utilization operons of several bacteria differ from each other in the occurrence of two genes, acnD and prpF, in place of or in addition to the prpD gene encoding an Fe/S-independent 2-methylcitrate dehydratase enzyme. We cloned the acnD and prpF genes from two organisms, Shewanella oneidensis and Vibrio cholerae, and found that, together, the AcnD and PrpF proteins restored the ability of a prpD mutant strain of Salmonella enterica to grow on propionate as a source of carbon and energy. However, neither acnD nor prpF alone was able to substitute for prpD. The AcnD and PrpF proteins were isolated and biochemically analyzed. The AcnD protein required reconstitution of an Fe/S cluster for activity. All detectable AcnD activity was lost after incubation with iron-chelating agents, and no AcnD activity was observed after attempted reconstitution without iron. Nuclear magnetic resonance spectroscopy and in vitro activity assay data showed that AcnD dehydrated 2-methylcitrate and citrate to 2-methyl-cis-aconitate and cis-aconitate, respectively; AcnD also hydrated cis-aconitate. However, 2-methylisocitrate and isocitrate were not substrates for AcnD, indicating that AcnD only catalyzes the first half of the aconitase-like dehydration reactions. No aconitase-like activity was found for PrpF. It is hypothesized that, in vivo, PrpF is an accessory protein required to prevent oxidative damage of the Fe/S center of active AcnD enzyme or that it may be involved in synthesis or repair of the Fe/S cluster present in AcnD.

Aconitate Hydratase↗
PubMed1977

Identification of D-threo-alpha-methylisocitrate as stereochemically specific substrate for bovine heart aconitase and inhibitor of TPN-linked isocitrate dehydrogenase.

DL-threo-alpha-Methylisocitrate (3-hydroxy-1,2,3-butanetricarboxylate) is a substrate for bovine heart aconitase and an inhibitor of TPN-linked isocitrate dehydrogenase from liver and heart. The isomer of alpha-methylisocitrate formed from alpha-methyl-cis-aconitate (cis-2-butane-1,2,3-tricarboxylate) by aconitase inhibits TPN-linked isocitrate dehydrogenase and has been identified as D-threo-alpha-methylisocitrate (2S,3R)-3-hydroxy-1,2,3-butanetricarboxylate) by optical rotation and circular dichroism studies. Mitochondrial bovine heart aconitase catalyzes a reversible reaction between D-threo-alpha-methylisocitrate (Km, 0.2 mM) and alpha-methyl-cis-aconitate (Km, 0.05 mM) at pH 7.4. However, formation of methylcitrate (2-hydroxy-1,2,3-butanetricarboxylate) from these substrates or utilization of synthetic methylcitrate for formation of these products could not be demonstrated with bovine heart aconitase. DL-threo-alpha-Methylisocitrate is also a substrate for aconitase from rat liver cytosol (Km, 0.1 mM); Vmax with citrate is approximately 1.4 times that with DL-threo-alpha-methylisocitrate. The ratio of activities for these substrates observed with the bovine heart enzyme is about 5. Formation of alpha-methyl-cis-aconitate from synthetic methylcitrate could not be detected spectrophotometrically with the liver aconitase; if it occurs with either the liver or the heart enzyme, the rate would be less than 0.1% that obtained with DL-threo-alpha-methylisocitrate. A new synthesis of methylcitric acid in good yields from diethyl alpha-methyl-beta-ketoglutarate (diethyl 2-methyl-3-oxoglutarate) and cyanide has been described. NMR spectroscopy indicates that this synthetic methylcitric acid contains the two racemic pairs of diastereoisomers.

Aconitate Hydratase↗
PubMed2003

Determination of tricarboxylic acid cycle acids and other related substances in cultured mammalian cells by gradient ion-exchange chromatography with suppressed conductivity detection.

An ion-exchange chromatography method was established for simultaneously analyzing the tricarboxylic acid (TCA) cycle acids and other related substances in cultured mammalian cells, including citrate, cis-aconitate, isocitrate, alpha-ketoglutarate, succinate, malate, fumarate, oxaloacetate, trans-aconitate, phosphate, lactate and pyruvate. A Dionex 600 ion chromatograph with an ion suppressor and a conductivity detector, and an IonPac AS11-HC analytical column were employed. An NaOH gradient elution containing 13.5% methanol contributed to sufficient separation of target substances. The stability of carboxylic acids was investigated and oxaloacetate was found to be extremely unstable especially at pH 3. TCA cycle acids and other related substances in Chinese hamster ovary (CHO) cells were separated completely, and lactate, malate, phosphate, citrate and cis-aconitate were quantified due to their higher concentrations. In the quantification of the five substances, detection limits (S/N=3) ranged from 0.12 to 0.48 microM, the correlation coefficients from 0.9982 to 1.0000 in their linear ranges of concentration, and the recoveries from 87 to 95%. The metabolic status of CHO cells was analyzed on the basis of the intracellular concentrations of TCA cycle acids.

Animals↗
PubMed2002

[Determination of aconitine alkaloids in a pesticide--0.25% aconitine alkaloids mixed with emulsion by high performance liquid chromatography].

The raw root of Aconitum, an important Chinese traditional medicine, contains some very toxic alkaloids such as aconitine, mesaconitine and hypaconitine etc. They are usually processed to lower the alkaloid content before used as a drug. The extract of crude drug (aconite) can be made into a plant pesticide by means of mixing with some emulsion. In order to evaluate the quality of the pesticide, we developed a rapid, specific and precise method using high performance liquid chromatography (HPLC) for the separation and quantitation of the alkaloids in the aconite extract and the mixed products (the aconite extract is mixed with emulsion). Before the determination by HPLC, the sample must be acidified with 2% (mass percentage) HCl at first. Extract the acid liquid with CHCl3. Alkalize the extract with ammonia, and add a little of 0.1 mol/L NaHCO3 and 0.1 mol/L Na2CO3 till pH 9. Extract it with CHCl3. Evaporate the extract and add a certain amount of methanol. Add the internal standard into the sample. Inject the combined sample solution onto a column of chemically bonded octadecylsilane phase and develop the chromatogram with MeOH-H2O-CHCl3-triethylamine (68:32:2:0.1, volume ratio). Aconitine, mesaconitine, hypaconitine and medroxyprogesteroni acetas (internal standard) were on base line separated. Quantify the alkaloids by peak area ratio (aconitine alkaloids vs internal standard). This method has high recovery (> 92%) and good reproducibility (RSD < 3.2%).

Aconitine↗
PubMed2004

[Effects of the extracts from decoction for resuscitation and its component herbs on PGI2, TXA2 and NO release from rat vascular endothelial cells under hypoxia in vitro].

OBJECTIVE: To compare the effect of the extracts from Decoction for resuscitation (DRE) and its component herbs on prostacyclin (PGI2), thromboxane A2 (TXA2) and nitric oxide (NO) release from rat vascular endothelial cells under hypoxia. METHOD: After treatment with the extracts from DRE and its component herbs, the contents of 6-keto-prostaglandin F1alpha(6-keto-PGF1alpha), thromboxane B2 (TXB2) as well as nitrite (NO), which were degradation products of PGI2, TXA2 and NO respectively, in culture medium of rat vascular endothelial cells under hypoxia were measured with radioimmunoassay and Griess Reaction. RESULT: Compared with the control group, the results indicated that DRE, prepared licorice root extract (LE), dried ginger extract (GE), aconite root extract (AE), extracts of aconite root and prepared licorice root (ALE), extracts of aconite root and dried ginger (AGE) increased significantly the content of 6-keto-PGF1alpha and the ratio of 6-keto-PGF1alpha/TXB2, but had no effect on the content of TXB2 in culture medium of rat vascular endothelial cells under hypoxia. The content of 6-keto-PGF1alpha in the DRE group was higher than that in the groups of LE, GE, AE, ALE, AGE. The ratio of 6-keto-PGF1alpha/TXB2 in the DRE group was higher than that of the groups of GE, AE, ALE. Compared with the control group, DRE, LE, GE, AE, ALE, AGE increased significantly the content of NO2- in culture medium of rat vascular endothelial cells under hypoxia. Moreover, the content of NO2- in the DRE group was higher than that of the groups of GE, AE, ALE. CONCLUSION: The results suggested that DRE increased significantly the content of PGI2 and the ratio of PGI2/TXA2 as well as the content of NO. The effect of DRE on the parameters in culture medium of rat vascular endothelial cells under hypoxia was better than that of the extracts from its component herbs.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

[Effect of lithium hydroxybutyrate and lithium chloride on heart rhythm disorders of various origins].

It has been shown in experiments on anesthetized cats and dogs that lithium hydroxybutyrate produces antiarrhythmic action in central aconitic and strophanthine arrhythmias, prevents the development of ventricular fibrillation, and shows antiarrhythmic activity in strong occlusion on the coronary artery. The drug does not remove the atrial and aconitic patterns of arrhythmia. Lithium chloride also exhibits antiarrhythmic action in central aconitic arrhythmia, being inferior to lithium hydroxybutyrate. The drug does not influence central strophanthine arrhythmia and does not show antifibrillation activity.

Animals↗
PubMed1978

[Prevention of ventricular fibrillation with the aid of protopine in animal experiments].

The anti-arrhythmic activity of protopin, quinidine and novocainamide infused intravenously as a preventive and relieving measure was studied in acute experiments on rats with calcium chloride and aconitic arrhythmia. In myocardial fibrillation induced by calcium chloride the contents in the rat heart of adrenalin, noradrenaline, dopa and dopamine were studied by spectrofluorimetry before and after the use of protopin. It was established that in the size of its minimum effective doses which arrest or prevent calcium chloride and aconitic arrhythmias in rats protopin is two to three times more potent than quinidine and novocainamide. The mechanism of the anti-arrhythmic effect of protopin in calcium chloride and aconitic arrhythmias is complex and is due to the suppression of the foci of heterotopic stimulation, decrease in excitability of the myocardial cells and normalization of the catecholamine content in the myocardium.

Alkaloids↗