Astragalus membranaceus saponins (AMS) 50-200 micrograms/ml had a positive inotropic action on the isolated working heart of rats, but in the case of 30 micrograms/ml the inotropic action turned negative. The contractility recovered after washing out the AMS. Strophanthin K performed in a similar manner as AMS. AMS 500 micrograms/ml decreased the resting potential of cultured rat heart cells by 10 mV. The results suggest that AMS plays its inotropic role through influencing the Na-K-ATPase.

92 patients suffering from ischemic heart disease was successfully treated with Astragalus membranaceus (AM). The effect of the treatment was compared with that of Nifedipine and Tab. Salviae miltiorrhizae. The clinical practice showed that the group treated with AM yielded better results. After having administered the drug, the patients were markedly relieved from angina pectoris (heart stroke). Meanwhile the improvement of clinical objective index such as electrocardiogram (EKG) and impedance cardiogram can also be observed. The effective rate of EKG improvement was 82.6%. The treatment of ischemic heart disease with AM was significantly more effective in comparing with control group (P < 0.05).

The body surface signal-averaged electrocardiogram (SAECG) was recorded on 316 cardiac patients, 84% (266 patients) of whom were also taken 24-hour Holter ECG. VLPs were detected positively in 6.1%, 25%, 25.7%, 14.3% and 5.5% of patients with angina pectoris, myocardial infarction, myocarditis, cardiomyopathy and arrhythmia of unknown origin respectively, and the patients with complex ventricular arrhythmia had more VLPs positive determination definitely (P less than 0.05). The specificity of VLPs in the prediction of complex ventricular arrhythmia was greater than 80%, and the positive predictive accuracy was 70-80%. 5, 5 and 10 patients with VLPs were treated with Mexiletini Hydrochloridum, Lidocaini Hydrochloridum and Injection of Astragalus membranaceus respectively. As a result of treatment, the transfer of VLPs positive to negative was unsuccessful, but only the intervention of Astragalus membranaceus Injection made the duration of VLPs shortened significantly (39.8 +/- 3.3 ms versus 44.5 +/- 5.9 ms, P less than 0.01).

Principal component analysis (PCA) and correlation analysis (CA) were applied to analyze the correlation of the main chemical components in Astragalus membranaceus var. mongholicus and ecological factors. The results showed that the contents of astragaloside, campanulin, ononin, kaempferol and astragalus polysaccharides (APS) of A. membranaceus var. mongholicus produced. in Shanxi were significantly higher than in Inner Mongolia and Gansu. The main climatic factors for affecting the contents of chemical ingredients in A. membranaceus var. mongholicus were annual average relative humidity, sunshine hours and average July temperature. Calcium was the main factor in the soil affecting the chemical ingredient contents, and calcium was negatively correlated with the contents of calycosin glycosides, kaempferol, ononin, quercetin and APS in A. membranaceus var. mongholicus within a certain range.

A murine model system for observing the effect of Astragalus Membranaceus (AM) on experimental myocarditis caused by Coxsackie B-3 virus (CB3V) was developed in 4-week-old male BALB/C mice. Gross, histopathologic and ultrastructural examinations of the infected-AM treated group showed that the severity and involved area of the myocardial lesions became milder and smaller than those in the infected-NS treated mice. The total lesion area, and the total lesion area/total myocardial area examined (%) and virus titer in the former group were also smaller and lower than those in the latter group. The results suggest that AM is effective in the inhibition of Coxsackie B virus propagation and protection of myocardium in mouse myocarditis.

OBJECTIVE

To study the effects of heavy metals on germination and antioxidant systems of the seeds of Astragalus membranaceus.

METHODS

The seeds were treated with three different heavy metals (Cu, Pb, Cd) and the germination rate, germination energy, germination index, seedling root length, seedling fresh weight, soluble protein, antioxidant enzyme systems, electrical conductivity were detected and analyzed.

RESULTS

The results indicated that all of the three kinds of heavy metals had a significant effect on the seed germination index at different levels of concentrations except germinating ability. Different kinds of heavy metals could also enhance the vitality of POD and CAT, increase the electrical conductivity and the concentration of soluble protein.

CONCLUSIONS

It can be concluded that heavy metals have a significant effect on the growth and antioxidant system of the seed.

Twelve cyclolanstane-type saponins including six new ones, astrolanosaponins A1 (1), A2 (2), B (3), C (4), D (5), and E (6) were obtained from the stem of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao, and their structures were elucidated by chemical and spectroscopic methods. Of the known ones, cycloastragenol-3-O-β-D-glucopyranoside (7), astraverrucin II (8), cycloaraloside E (9), huangqiyenin A (10), and huangqiyenin B (11) were isolated from the species first. Meanwhile, compounds 1-3, 5-9, and aleksandroside I (12) showed inhibitory effects on triglyceride accumulation in HepG2 cells.

Astragalus membranaceus (webbed astragalus) for more than two millennia has been used in traditional Chinese medicine as a means of slowing down the aging process and increasing longevity. The article analyzes the data of experimental and clinical studies of recent years, identifying possible mechanisms of the anti-aging effects of the plant. It is noted that the extract or various groups of chemical compounds of this plant activate telomerase, inhibit the processes of replicative senescence, have antioxidant activity, have a neuroprotective effect, affect age-related macular degeneration, skin photoaging and alopecia.

This work is to establish the fingerprint of Astragalus membranaceus var. mongholicus by HPLC-ELSD method, and to analyze the simulated wildness degree of A. membranaceus var. mongholicus in the genuine region of Inner Mongolia, Ningxia and Gansu. Compared with wild A. membranaceus var. mongholicus, the quality differences of A. membranaceus var. mongholicus in the genuine region were analyzed by identification of chromatographic peaks and similarity evaluation, cluster analysis(CA), principal components analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). HPLC fingerprints of A. membranaceus var. mongholicus in different genuine regions are established. The qualitative analysis of mass spectrometry identified 18 components. The similarity evaluation shows that the similarity of 32 batches of A. membranaceus var. mongholicus samples was 0.688-0.993. Among them, the similarity of samples in Shanxi, Inner Mongolia, Ningxia is 0.688-0.993, 0.835-0.989, 0.934-0.988, respectively and the similarity of samples in Gansu is 0.729-0.876 except No. 25 sample. The results of CA show that the samples of A. membranaceus var. mongholicus can be grouped into four categories according to the production area except the No. 11 and No. 25 samples. The results of PCA indicate that 32 batches of A. membranaceus var. mongholicus samples can be clustered according to quality and origin, and the quality of A. membranaceus var. mongholicus in Inner Mongolia is the closest to the wild breed. The results of OPLS-DA indicate that there are six components that can distinguish the wild and domestic A. membranaceus var. mongholicus, which are malonylastragaloside Ⅰ, astragaloside Ⅰ, calycosin-7-O-β-D-glycoside-6″-O-malonate, calycosin-7-O-β-D-glycoside, formononetin-7-O-β-D-glycoside-6″-O-malonate, and astrapterocarpan-3-O-β-D-glycoside-6″-O-malonate. The established method can be used to analyze differences between A. membranaceus var. mongholicus origin and planting environment, and can provide references for the protection and replacement of wild A. membranaceus var. mongholicus resources, and the cultivation, processing and production of A. membranaceus var. mongholicus.

Keywords: Astragalus membranaceus var.mongholicus; cluster analysis; fingerprint; orthogonal partial least squares discriminant analysis; principal component analysis.

OBJECTIVE

To define the effects of Astragalus membranaceus on the atrial dynamics and ANP secretion in the perfused beating rabbit atria.

METHODS

The experiments have been done in isolated perfused beating rabbit atria. ANP was measured by radioimmunoassay in the atrial perfusate in real-time base.

RESULTS

A. membranaceus (2.0, 2.5, 3.0 g L(-1)) could increase atria stroke volume from (694.70 +/- 0.01) microL g(-1) (P<0.05) to (1,003.00 +/- 8.80) microL g(-1) (P<0.001); (1,120.00 +/- 17.71) microL g(-1) and (1,195.00 +/- 8.21) microL g(-1) (P<0.001), respectively, and its could difference increase atrial pulse pressure from (0.82 +/- 0.01) kPa to (0.86 +/- 0.01) kPa (P<0.01); (0.96 +/- 0.01) kPa (P<0.001) and (1.02 +/- 0.01) kPa (P<0.001), respectively; A. membranaceus obviously increased rabbit atrial dynamics with dose-dependent manner. Simultaneously, A. membranaceus inhibited ANP secretion. Nifedipine (1.0 micromol L(-1)), a L-type Ca2+ channel inhibitor, and KB-R 7943 (10.0 micromol L(-1)), an inhibitor of reversed Na+ -Ca2+ exchanger, blocked the effects of A. membranaceus-induced augmentation of atrial dynamics but failed to modulation the inhibition of A. membranaceus on ANP secretion.

CONCLUSIONS

A. membranaceus increases the atrial dynamics via Na+ -Ca2+ exchanger and L-type Ca2+ channel and negatively modulates ANP secretion in beating rabbit atria.

The purpose of the study was to evaluate the effect of Astragalus membranaceus extract and ligustrazine combination on ameliorating inflammation in cerebral ischemic rats that have undergone thrombolysis. Astragalus membranaceus and ligustrazine per se, or a combination of A. membranaceus and ligustrazine was administered by intraperitoneal injection immediately after surgery and sham surgery. After the induction of thrombolysis, the neurological function was measured and cerebral lesion volume was determined. The regulatory T cells in the spleen were measured by flow cytometry. To explore the protective effects of the combination drug on the neurological function and inflammation, the expression of transcription factor Foxp3 and cytokines, including transforming growth factor beta 1, interleukin 10, interleukin 4, interleukin 1 beta, interferon gamma, interleukin 17, in damaged brain was examined using reverse transcription polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay. The cerebral lesion volume was markedly reduced in the combination drug-treated rats compared to the rats treated with either A. membranaceus or ligustrazine alone (P < 0.05). The neurological function, regulatory T cells, transcription factor Foxp3, transforming growth factor beta 1, interleukin 10, and interleukin 4 were markedly elevated in the rats treated with combination drugs (P < 0.05). The expression of interleukin 1 beta, interferon gamma, and interleukin 17 was reduced in the rats treated with combination drug therapy (P < 0.05). Treatment with a combination of A. membranaceus and ligustrazine can ameliorate inflammation after thrombolysis and regulate the related cytokines by elevating the expression of endogenous regulatory T cells.

Astragalus membranaceus (Ast) and ligustrazine (Lig) have a protective effect on lower hemorrhagic transformation induced by pharmaceutical thrombolysis. The cerebral ischemia rat model was induced with autologous blood clot injections. A combination of Ast and Lig, or a protein kinase C delta (PKCδ) inhibitor-rottlerin, or a combination of Ast, Lig, and rottlerin was administered immediately after recombinant tissue plasminogen activator injection. The cerebral infarct area, neurological deficits, cerebral hemorrhage status, neuronal damage and tight junctions' changes in cerebral vessels, and the messenger RNA and protein levels of PKCδ, myristoylated alanine-rich C kinase substrate (Marcks), and matrix metallopeptidase 9 (MMP9) were determined after 3 h and 24 h of thrombolysis. The ultrastructure of the neuronal damage and tight junctions was examined under a transmission electron microscope. The expression levels of PKCδ, Marcks, and MMP9 were assessed by immunohistochemistry, western blot, and quantitative real-time polymerase chain reaction . Administration of Ast and Lig not only significantly decreased neurological deficit scores, infarct volumes, and cerebral hemorrhage but also inhibited the disruption due to neuronal dysfunction and the tight junction integrity in the cerebral vessel. Treatment with a combination of Ast and Lig effectively protected ischemia-induced microhemorrhage transformation through PKCδ/Marcks pathway suppression.

Keywords: Astragalus membranaceus; PKCδ/MARCKS; cerebral ischemia; hemorrhage transformation; ligustrazine.

A murine model for observing the effect of Astragalus membranaceus (AM) on electrophysiological activity of the right ventricular myocardium was developed in 4 week-old male BALB/c mice infected with Coxsackie B3 virus (CB3V). The conventional microelectrode technique and real-time microcomputer data processor system was used. The survival rate in infected-AM treated mice was significantly higher and the percentage of abnormal action potential was much lower than those in control mice (P < 0.05 and < 0.01 respectively). Some abnormal electrophysiological parameters, such as APA, OS and Vmax in infected myocardium were found to be improved by AM treatment. Single dose of AM did not show beneficial effect in murine myocardium infected with CB3V. The results suggested that AM might be valuable in the prevention and treatment of acute myocarditis involving Coxsackie B3 virus.

A murine model for observing the effect of Astragalus membranaceus (AM) on electrophysiological action of the right ventricular myocardium was developed in 4-week-old male BALB/c mice infected with coxsackie B-3 virus (CB3V). The conventional microelectrode technique and a real-time data processor system were used. The survival rate in AM-treated mice was much higher and the percentage of abnormal action potential was much lower than those in infected control mice (P < 0.05, P < 0.01, respectively). Some abnormal electrophysiological parameters, such as APA, OS and Vmax, in infected myocardium were found to be improved by AM treatment. The results suggest that AM may be valuable in the prevention and treatment of acute viral myocarditis involving coxsackie B viruses.

OBJECTIVE

To investigate the effect of Astragalus membranaceus (APS) on the proliferation, osteogenic capacity and structure of periodontal ligament cells (PDLCs) in vitro.

METHODS

PDLCs were cultured in vitro with APS of 0.08, 0.1, 0.2, 0.4 mg x mL(-1). Methyl thiazolyl tetrazolium (MTr), alkaline phosphatase (ALP) and cell structure were detected to determine the proliferation and differentiation of PDLCs proliferation and differentiation.

RESULTS

When the APS was 0.2 mg x mL(-1), the absorbance of MTT and ALP exhibit significantly increased as compared to the control (P < 0.05). The cells cultured in vitro with APS of 0.2 mg x mL(-1) had the normal structure.

CONCLUSIONS

APS with proper concentration in short-term culture may promote the proliferation and differentiation of PDLCs.

Antiviral activity of Astragalus membranaceus aqueous and methanol root extracts was determined against Avian influenza H9 virus. Toxicity profile of extracts was evaluated using chicken embryos and BHK-21 cell line. Different concentrations (400, 200, 100, 50, 25. 12.5, 6.25 and 3.12μg/mL) of both aqueous and methanol extracts were mixed with standard virus inoculum (4HAunits) and incubated for 30minutes at 37°C prior to inject the chicken embryos. Chorioallantoic fluid harvested 72 hours post inoculation and evaluated for virus growth using hemagglutination assay. Same concentrations of both extracts without virus were injected in chicken embryos to evaluate embryo toxic activity as well. The cytotoxic activity of aqueous and methanol extracts was determined by MTT colorimetric assay using BHK-21 cells. Three concentrations (400, 200 and 100μg/mL) of aqueous and five concentrations (400, 200, 100, 50 and 25μg/mL) of methanol extract showed antiviral activity. None of the tested concentrations of aqueous and methanol A. membranaceus root extracts caused chicken embryo mortality. Cell survival percentage of aqueous extract was higher than 50 at all of the tested concentrations except 400μg/mL. Two concentrations (400 and 200μg/mL) of methanol extract showed cytotoxicity. It was concluded that aqueous and methanol roots extracts of A. membranaceus have antiviral activity and concentrations which were safe may be used for treatment of Avian influenza H₉ virus infections.

Therapeutic effect of the glucoside extracted from the root of Astragalus Membranaceus (AM) was studied in guinea pigs intoxicated with 600 mg/kg doses of Dimethoate (D). Four groups of guinea pigs, each consisting of two males and two females, were treated with (a) D, (b) D + Atropine, and (c) D + AM, (d) D + Atropine + AM. The survival time of the animals increased from an average of 70 minutes without AM to an average of 235 minutes with AM. Severe changes in ECG were observed prior to respiratory distress in groups without AM, and Atropine did not modify such changes. Differently, severe ECG disorders appeared only after respiratory distress in groups treated with AM. Prolongation of the Q-T interval and changing of the T wave configuration were significantly mitigated in the AM treated animals, while, arrhythmias were minimized and postponed. Moreover, muscular fasciculation and fibrillation, seizures and secretion in the respiratory tract were also significantly reduced by AM treatment. Results have shown that AM could be a promising drug to be used after cholinergic crisis in the treatment of cardiac complications with severe organophosphate intoxication.

OBJECTIVE

To investigate the effect of Astragalus membranaceus (AM) on endothelial-dependent (EDV) and non- dependent (EIV) vascular relaxation in ex vivo thoracic aortic rings of obese rats.

METHODS

Fifteen SD rats were randomized into 3 equal groups, namely the control group fed with normal chow, obese group with high-fat chow, and AM intervention group fed with high-fat chow and daily AM gavage. The rats were sacrificed after 6 weeks of feeding, and the aortic rings were dissected and cut into 3-mm rings. The response to acethylcholine (Ach) and sodium nitroprusside (SNP) were examined in organ bath. In ex vivo study, the aortic rings obtained from the control group and obese group were incubated with AM or vehicle for 3 h in organ bath before testing the EDV and EIV. The body weight and weight of the visceral fat in each group were recorded.

RESULTS

The weight of visceral fat was greater in the obese group than in the control group, and a 6-week AM treatment significantly reduced the fat tissue due to high-fat diet. The maximum EDV value was (87.0 - or + 3.5)% in the control group, (54.8 - or + 7.8)% in the obese group, and (69.8 - or + 5.7)% in AM intervention group; the EIV values were comparable between the 3 groups. After incubation with AM, the maximum EDV values of aortic rings obtained from the obese group were significantly increased from (55.6 - or + 8.3)% to (85.1 - or + 4.5)%.

CONCLUSIONS

AM can improve endothelial dysfunction in obese rats, and the mechanism involves improved insulin resistance and increased endothelium-derived NO productor function.

Erythrocytes play an essential role in transporting O2 and CO2 for respiration in fish. However, erythrocytes continuously suffer from reactive oxygen species (ROS) -induced oxidative stress and apoptosis. Thus, it is essential to expand our knowledge of how to protect erythrocytes against ROS-induced oxidative stress and apoptosis in fish. In this study, we explored the cytotoxicity and the effects of butylated hydroxyanisole (BHA), ethyl ether extracts, ethyl acetate extracts, acetone extracts (AE), ethanol extracts, and aqueous extracts of Astragalus membranaceus (EAm) on hydroxyl radical (•OH)-induced apoptosis in carp erythrocytes. The rat hepatocytes and carp erythrocytes were incubated with different concentrations of BHA or EAm(0.125 to 1 mg/mL). The toxicity in rat hepatocytes and carp erythrocytes was then measured using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and a haemolysis assay, respectively. The carp erythrocytes were treated with BHA or EAm in the presence of 40 μmol/L FeSO4 and 20 μmol/L H2O2 at 37 °C, except for the control group. Oxidative stress and apoptosis parameters in the carp erythrocytes were then evaluated using the commercial kit. The results indicated that at high concentrations, BHA and EAm could induce toxicity in rat hepatocytes and fish erythrocytes. However, BHA was more toxic than EAm at the same concentrations. Moreover, the toxicity order of BHA and EAm in the fish erythrocytes approximately agreed with that for the rat hepatocytes. Butylated hydroxyanisole and EAm suppressed the •OH-induced phosphatidylserine exposure and DNA fragmentation (the biomarkers of apoptosis) by decreasing the generation of ROS, inhibiting the oxidation of cellular components, and restoring the activities of antioxidants in carp erythrocytes. Of all of the examined EAm, the AE showed the strongest effects. The effects of AE on superoxide anion, H2O2, met-haemoglobin and reduced glutathione levels, as well as glutathione reductase activity and apoptosis were equivalent to or stronger than those of BHA. These results revealed that the AE of Astragalus membranaceus could be used as a potential natural antioxidant or apoptosis inhibitor in fish erythrocytes.

OBJECTIVE

To observe the effect of Astragalus membranaceus (AM) on insulin-like growth factor 1 (IGF-1) expression in a rat model of olivo-cerebellar degeneration and assess the neuroprotective actions of AM meanwhile.

METHODS

Rats model of olivo-cerebellar degeneration was established by using 3-acetylpyridine. The effect of AM on the expression of Calbindin D-28K in inferior olive (IO) neurons by immunohistochemistry, the serum IGF-1 level by Elisa, the IGF-1 mRNA level in the cerebellum by RT-PCR were detected respectively.

RESULTS

AM effectively improve the serum IGF-1 level, Cerebellar IGF-1 mRNA level and the survival of the 10 neurons in a rat model of olivo-cerebellar degeneration, even at a lower dose (9 g x kg(-1)), and the effect was in a dose-dependent manner.

CONCLUSIONS

AM could effectively upregulate the IGF-1 expression in the rat model of olivo-cerebellar degeneration, and have neuroprotective effect on IO neurons.

The effect of Astragalus membranaceus (AM) on Ca2+ influx across the myocardial plasma membrane and coxsackie virus B3(CVB3)-RNA replication in cultured neonatal rat heart cells infected with CVB3 was investigated. It was found that the Ca2+ influx could be inhibited significantly (P < 0.01) by AM after infection of heart cells for 48 h. In addition, when the cultured heart cells infected with CVB3 and treated with AM for 48 h, the Ca2+ influx of infected heart cells also could be inhibited by AM (P < 0.05) and the amounts of CVB3-RNA in myocytes were significantly decreased than that in infected control group (P < 0.001). These phenomena suggested that AM could exert the effects of decreasing the secondary Ca2+ damages, and improving the abnormal myocardial electric activity, and inhibiting replication of CVB3-RNA in myocardium. Thus, it is a rational choice to treat patients with AM in viral myocarditis.

This study aimed to explore the effects of Astragalus membranaceus polysaccharide (AMP) on the growth and innate immunity of crucian carp (Carassius auratus). Crucian carps were randomly divided into a control group (fed with basal diet) and three AMP groups (received basal diet supplemented with 50, 100 and 150 mg/kg AMP). After 60 days of culture, the crucian carps from each group were weighed, and their immune indexes were measured. Another batch crucian carps from each group was injected with 0.15 ml of 10⁷ CFU/ml Aeromonas hydrophila. The body weight gain, feed conversion rate, specific growth rate and digestive enzyme activity of the crucian carps in the low and middle doses of AMP groups were higher than those in the control group. The AMP groups had significantly higher survival rate and alkaline phosphatase level but lower glutamic-oxaloacetic transaminase, glutamic-alanine transaminase and serum bacteria number compared with the control group. The optimal dose of dietary AMP required for the maximum growth of crucian carp was 100 mg/kg. These results showed that AMP could promote the growth of crucian carps, improve their disease resistance and thus may be developed as a dietary supplement.

In this study, the effects of Astragalus membranaceus oral solution on lifespan and learning and memory abilities of honey bees were evaluated. Two groups of bees were fed with sucrose syrup (50%) containing low dose (1.33%) and high dose (13.3%) of A. membranaceus oral solution, respectively. The proboscis extension response (PER) analysis was applied to examine the learning and memory capabilities of bees. Two genes related to memory formation in honey bees were determined by real-time PCR. High dose (13.3%) of A. membranaceus significantly decreased the mean lifespan of bees compared to the bees fed with low dose (1.33%) and control bees. No significant differences in lifespan of bees were found between low-dose-fed bees and control bees. The results of PER experiments showed apparent improvement in the memorizing ability of the high-dose group (in comparison with the control group). Moreover, the relative expression levels of Nmdar1 in the low-dose group and control group were significantly lower than those in the high-dose group. It is preliminarily concluded that A. membranaceus has an adverse effect on the mean lifespan of honey bees but might be helpful in strengthening memories.

OBJECTIVE

To investigate the effect of Astragalus membranaceus(AM) on vascular circles and the underlying mechanisms.

METHODS

The study was performed with the model of isolate rat thoracic aorta rings in organ bath. When the endothelium of rat thoracic aorta was removed,the effect of accumulated AM on aorta rings in resting tension, or pre-constricted with KCl, or pre-constricted with phenylephrine (PE) was observed. And to explove the mechanism, the aorta rings were incubated with Ca(2+)-free medium alone, or Ca(2+)-free medium plus heparin, or propranolol alone before pre-contraction with PE.

RESULTS

AM had no significant effects on aorta rings in resting tension or pre-constricted with KCl. When the concentration of AM was cumulated to 10(-1), 3 x 10(-1),10(0), 3 x 10(0) g/L, it caused concentration-dependent relaxation while aorta rings were pre-constricted with PE(3 x 10(-7)mol/L), compared with the control [(90.4 +/-4.2)% compared with (94.7 +/-2.4)%,(86.1 +/-5.0)% compared with (92.6 +/-3.2)%, (82.3 +/-5.9)% compared with (90.4 +/-3.6) %, (78.3 +/-6.0)% compared with (88.1 +/-4.0)%]. This effect was not inhibited by Ca(2+)-free medium or propranolol alone. However, the effect was attenuated by the co-incubation with heparin and Ca(2+)-free medium [without heparin:(76.2+/-4.3)% compared with (92.3 +/-5.9)%, with heparin: (95.3+/-0.5)% compared with (95.1+/-0.6)%].

CONCLUSIONS

The results indicate that AM can relax the rat thoracic aorta rings without endothelium. The mechanism may include the inhibition of intracellular calcium ions release by the 1,4,5-triphosphate inositol-receptor-dependent pathway in vascular smooth muscle cells.