[Advances in the relationship between lung cancer and microbiota]

Interaction exists in lung cancer and microbiota. Lung microecological homeostasis can improve the immune tolerance, enhance immune suppression, and inhibit inflammatory responses, to reduce the lung cancer; while lung cancer can lead to pulmonary microecological imbalance, change the lung environment, and promote tumor cell proliferation. Therefore, modulating microbial flora and microecological immunotherapy may be a potential and preventive treatment for lung cancer, to restore tumor immunosuppression and improve patient survival. However, the individual differences in the lung microecology, because of different genetics, ethnic characteristics, and dietary habits, increasing the difficulty of precise diagnosis and treatment, which is also the current bottleneck in the application of microecological immunotherapy. Otherwise, the effectiveness of regulatory measures such as probiotics, prebiotics or antimicrobials is questionable. The research on microbial flora is still in its infancy, and further exploration is needed to form a standardized, effective, and precise treatment plan. So, standardized, effective, and precise microbial flora treatment strategies need to be further explored.

[Clinical study of circulating tumor cells in monitoring the efficacy of neoadjuvant immunotherapy for non-small cell lung cancer]

Objective: To investigate the changes of CTCs and the correlation between the changes of CTCs and the clinical efficacy of neoadjuvant immunotherapy for non-small cell lung cancer (NSCLC). Methods: A retrospective case-control study was conducted to collect the data of 23 patients with NSCLC who received neoadjuvant immunotherapy in the Third Xiangya Hospital from June 2018 to December 2019. They were 35-76 years old with a median age of 52 years old, including 13 male patients and 10 female patients. The CTCs value, evaluation results from response evaluation criteria in solid tumor (RECIST) and major pathological response were evaluated before treatment, after neoadjuvant immunotherapy and after operation. Mann Whitney U test was used for the comparison between the two groups, Wilcoxon test was used for the comparison of association samples, and Kruskal Wallis test was used for the comparison between multiple samples. Results: The CTCs value was positively correlated with tumor progression, that the CTCs value of ⅡB group, ⅢA group and ⅢB group was 10.69 (3.87) FU/3 ml, 12.90 (2.24) FU/3 ml and 16.04 (3.43) FU/3 ml, and the difference was statistically significant (χ²=7.829, P=0.020). Then CTCs decreased to 7.60(4.79) FU/3 ml significantly (Z=4.197,P=0.000), and decreased to 6.22(2.80) FU/3 ml significantly again after surgery(Z=-2.950,P=0.005). In RECIST results, the CTCs value of CR group, PR group and SD group was 12.90(3.79)FU/3 ml, 12.52(3.96) FU/3 ml and 13.58(5.11) FU/3 ml,and no significant difference before treatment (χ²=1.806, P=0.405). After neoadjuvant immunotherapy, the CTCs of CR group decreased to 6.22(3.87) FU/3 ml significantly (Z=-4.950, P= 0.000), and also PR group to7.32(4.31) FU/3 ml (Z=-3.180, P=0.001) or SD group to (Z=-2.023, P=0.043). There was no significant difference between CR group and PR group (Z=-0.838, P=0.402), but significant difference between SD group and CR/PR group (Z=-1.922, P=0.050). After operation, the CTCs of CR, PR and SD group decreased to 6.09(3.43) FU/3 ml, 6.40(1.82) FU/3 ml and 9.20(5.16) FU/3 ml,and there was no significant difference to preparation in CR group and PR group, but significant difference in SD group (Z=-2.023, P=0.043). There was no significant difference between CR group and PR group (Z=-1.134, P=0.257), but significant difference between SD group and CR/PR group (Z=-1.624, P=0.014). Before treatment,CTCs of MPR group and non-MPR group were 11.98(4.14) FU/3 ml and 13.54(4.76) FU/3 ml,and there was no significant difference between them (Z=-1.354, P=0.176). After neoadjuvant immunotherapy, the CTCs of MPR group decreased to 6.36(2.65) FU/3 ml significantly (Z=-2.934, P=0.001) and also in non-MPR group to 10.88(2.80) FU/3 ml (Z=-2.840, P=0.003); but there was significant difference between MPR group and non-MPR group (Z=-3.693, P=0.000), and also the change of CTCs between two groups (Z=-2.770, P=0.006). After operation, the CTCs of MPR group decreased to 5.40(1.33) FU/3 ml insignificantly (Z=-0.533, P=0.594) but significantly to 7.05(3.80) FU/3 ml in non-MPR group (Z=-2.734, P=0.030), and significant difference between them (Z=-1.900, P=0.011). Conclusion: The value of CTCs is negatively correlated with the efficacy (RECIST and MPR) of neoadjuvant immunotherapy for NSCLC, which can be used for clinical efficacy evaluation of neoadjuvant immunotherapy.

Molecular cytogenetic characterization and phylogenetic analysis of four Miscanthus species (Poaceae)

Chromosomes of four Miscanthus (Andersson, 1855) species including M. sinensis (Andersson, 1855), M. floridulus (Schumann & Lauterb, 1901), M. sacchariflorus (Hackel, 1882) and M. lutarioriparius (Chen & Renvoize, 2005) were analyzed using sequentially combined PI and DAPI (CPD) staining and fluorescence in situ hybridization (FISH) with 45S rDNA probe. To elucidate the phylogenetic relationship among the four Miscanthus species, the homology of repetitive sequences among the four species was analyzed by comparative genomic in situ hybridization (cGISH). Subsequently four Miscanthus species were clustered based on the internal transcribed spacer (ITS) of 45S rDNA. Molecular cytogenetic karyotypes of the four Miscanthus species were established for the first time using chromosome measurements, fluorochrome bands and 45S rDNA FISH signals, which will provide a cytogenetic tool for the identification of these four species. All the four have the karyotype formula of Miscanthus species, which is 2n = 2x = 38 = 34m(2SAT) + 4sm, and one pair of 45S rDNA sites. The latter were shown as strong red bands by CPD staining. A non-rDNA CPD band emerged in M. floridulus and some blue DAPI bands appeared in M. sinensis and M. floridulus. The hybridization signals of M. floridulus genomic DNA to the chromosomes of M. sinensis and M. lutarioriparius genomic DNA to the chromosomes of M. sacchariflorus were stronger and more evenly distributed than other combinations. Molecular phylogenetic trees showed that M. sinensis and M. floridulus were closest relatives, and M. sacchariflorus and M. lutarioriparius were also closely related. These findings were consistent with the phylogenetic relationships inferred from the cGISH patterns.

Lactobacillus paracasei PS23 reduced early-life stress abnormalities in maternal separation mouse model

Maternal separation (MS) has been developed as a model for inducing stress and depression in studies using rodents. The concept of the gut-brain axis suggests that gut health is essential for brain health. Here, we present the effects of administration of a probiotic, Lactobacillus paracasei PS23 (PS23), to MS mice against psychological traits including anxiety and depression. The administration of live and heat-killed PS23 cells showed positive behavioural effects on MS animals, where exploratory tendencies and mobility were increased in behavioural tests, indicating reduced anxiety and depression compared to the negative control mice (P<0.05). Mice administered with both live and heat-killed PS23 cells also showed lower serum corticosterone levels accompanied by higher serum anti-inflammatory interleukin 10 (IL-10) levels, compared to MS separated mice (P<0.05), indicating a stress-elicited response affiliated with increased immunomodulatory properties. Assessment of neurotransmitters in the brain hippocampal region revealed that PS23 affected the concentrations of dopaminergic metabolites differently than the control, suggesting that PS23 may have improved MS-induced stress levels via neurotransmitter pathways, such as dopamine or other mechanisms not addressed in the current study. Our study illustrates the potential of a probiotic in reversing abnormalities induced by early life stress and could be an alternative for brain health along the gut-brain axis.

An evaluation study of research efficiency of the Guangzhou institute of respiratory diseases based on malmquist index

BACKGROUND

This study aimed to analyze the dynamic changes of the scientific research innovation efficiency of Guangzhou Institute of Respiratory Diseases (GIRD) during the year 2009-2013 to explore the reason for these changes and give some suggestions on how to improve the overall efficiency of the Institute.

METHODS

The panel data used in this study were taken from 19 research teams of GIRD during 2009 to 2013. Data envelopment analysis (DEA) based on Malmquist index (MI) was used to analyze the performance of each research team in terms of productivity changes over time. Data were analyzed using DEAP 2.1 software.

RESULTS

The annual average increase rate of total factor productivity (TFP), technological progress, technical efficiency, pure technical efficiency, and scale efficiency was 30.4%, 22.5%, 6.4%, 0.9%, and 5.4%, respectively from 2009 to 2013. The scientific research innovation efficiency of the GIRD was generally high and kept on growing. The increase of TFP was mainly caused by the progress of tech, the descending of TFP in some teams should be mainly attributable to the declining pure technical efficiency, and scale efficiency on the whole, maintaining a stable growth at a low speed.

CONCLUSIONS

To achieve higher scientific research innovation, GIRD not only needs to further improve the management level and introduce advanced management mode, but also needs to focus on optimization of resource allocation, as well as to strengthen the talent introduction, and continue to maintain the absorption of new technologies and innovation.

2-Methoxystypandrone represses RANKL-mediated osteoclastogenesis by down-regulating formation of TRAF6-TAK1 signalling complexes

BACKGROUND AND PURPOSE

2-Methoxystypandrone (2-MS) is a naphthoquinone isolated from Polygonum cuspidatum, a Chinese herb used to treat bone diseases. Here we have determined whether 2-MS antagonised osteoclast development and bone resorption.

EXPERIMENTAL APPROACH

RAW264.7 cells were treated with receptor activator of nuclear factor kappaB (NF-kappaB) ligand (RANKL) to induce differentiation into osteoclasts. RT-PCR and Western blot were used to analyse osteoclast-associated gene expression and signalling pathways.

KEY RESULTS

The number of multinuclear osteoclasts, actin rings and resorption pit formation were markedly inhibited by 2-MS, targeting osteoclast differentiation at an early stage and without significant cytotoxicity. The anti-resorption effect of 2-MS was accompanied by decreasing dendritic cell-specific transmembrane protein and matrix metalloproteinase-9 (MMP-9) mRNA expression. RANKL-increased MMP-9 gelatinolytic activity was also attenuated by concurrent, but not by subsequent addition of 2-MS. 2-MS markedly inhibited not only the RANKL-triggered nuclear translocations of NF-kappaB, c-Fos and nuclear factor of activated T cells c1 (NFATc1), but also the subsequent NFATc1 induction. Degradation of IkappaB and phosphorylation of mitogen-activated protein kinases were also suppressed. RANKL facilitated the formation of signaling complexes of tumour necrosis factor receptor-associated factor 6 and transforming growth factor beta-activated kinase 1 (TRAF6-TAK1), important for osteoclastogenesis and formation of such signalling complexes was prevented by 2-MS.

CONCLUSIONS AND IMPLICATIONS

The anti-osteoclastogenic effects of 2-MS could reflect the block of RANKL-induced association of TRAF6-TAK1 complexes with consequent decrease of IkappaB-mediated NF-kappaB and mitogen-activated protein kinases-mediated c-Fos activation pathways and suppression of NFATc1 and other gene expression, essential for bone resorption.

Evaluation of anti-Wnt/β-catenin signaling agents by pGL4-TOP transfected stable cells with a luciferase reporter system

Refractory and relapsed leukemia is a major problem during cancer therapy, which is due to the aberrant activation of Wnt/β-catenin signaling pathway. Activation of this pathway is promoted by wingless (Wnt) proteins and induces co-activator β-catenin binding to lymphoid enhancer factor (LEF)/T-cell factor protein (TCF). To provide a convenient system for the screening of anti-Wnt/β-catenin agents, we designed a bi-functional pGL4-TOP reporter plasmid that contained 3X β-catenin/LEF/TCF binding sites and a selectable marker. After transfection and hygromycin B selection, HEK 293-TOP and Jurkat-TOP stable clones were established. The luciferase activity in the stable clone was enhanced by the recombinant Wnt-3A (rWnt-3A; 100-400 ng/mL) and GSK3β inhibitor (2'Z,3'E)-6-bromoindirubin-3'-oxime (BIO; 5 µM) but was inhibited by aspirin (5 mM). Using this reporter model, we found that norcantharidin (NCTD; 100 µM) reduced 80% of rWnt-3A-induced luciferase activity. Furthermore, 50 µM NCTD inhibited 38% of BIO-induced luciferase activity in Jurkat-TOP stable cells. Employing ³H-thymidine uptake assay and Western blot analysis, we confirmed that NCTD (50 µM) significantly inhibited proliferation of Jurkat cells by 64%, which are the dominant β-catenin signaling cells and decreased β-catenin protein in a concentration-dependent manner. Thus, we established a stable HEK 293-TOP clone and successfully used it to identify the Wnt/β-catenin signaling inhibitor NCTD.

Risk factors for periodic breathing in acute stroke: tracheobronchial infection

BACKGROUND AND PURPOSE

Despite evidence from clinical and population studies, the aim of the present study was to suggest that multiple factors contribute to periodic breathing (PB). However, little information has been focused on episodes of tracheobronchial infections (TBI) preceding PB onset.

METHODS

Thirty subjects with acute stroke who had PB and 41 subjects with acute stroke that of a sex- and age-matched control group without PB were retrospectively evaluated. Stroke location, extent of stroke (demonstrated on CT or MRI), and characteristics of TBI before PB were assessed. PB diagnosis was carried out using a portable device and a pulse oximeter. Risk factors for patients with PB were compared with those without PB by univariate and multivariate analysis.

RESULTS

Twenty-four TBI in 30 patients with PB and 11 TBI in 41 patients with non-PB were diagnosed. There was no significant difference in age, sex, body mass index, stroke type, stroke location, or underlying diseases between the two groups (P > 0.05). There was a significant difference in snoring, first recurrent stroke, Glasgow Coma Scale, congestive heart failure, TBI, and inflammatory responses between the PB and non-PB group (P < 0.05). Multiple logistic regression analyses showed a difference in the prevalence of snoring (OR = 10.813, CI = 2.131-54.866, P < 0.01), TBI (OR = 5.313, CI = 1.241-22.740, P < 0.05), and inflammatory responses (OR = 7.315, CI = 1.253-43.123, P < 0.05) between the two groups.

CONCLUSIONS

In addition to snoring, TBI and inflammatory responses are the two independent predictors for PB in patients with acute stroke. Clinicians should be encouraged to systematically evaluate TBI and inflammatory responses before PB in patients with acute stroke.

Protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin B(1)-induced genotoxicities

To evaluate the protective effects of baicalein and wogonin against benzo[a]pyrene- and aflatoxin (AF) B(1)-induced toxicities, the effects of these flavonoids on the genotoxicities and oxidation of benzo[a]pyrene and AFB(1) were studied in C57BL/6J mice. Baicalein and wogonin reduced benzo[a]pyrene and AFB(1) genotoxicities as monitored by the umuC gene expression response in Salmonella typhimurium TA1535/pSK1002. Baicalein added in vitro decreased liver microsomal benzo[a]pyrene hydroxylation (AHH) activity with an ic(50) of 33.9 +/- 1.4 microM at 100 microM benzo[a]pyrene. Baicalein also inhibited AFQ(1) and AFB(1)-epoxide formation from AFB(1) (50 microM) oxidation (AFO) with ic(50) values of 22.8 +/- 1.4 and 5.3 +/- 0.8 microM, respectively. However, the in vitro inhibitory effects of wogonin on AHH and AFO activities in liver microsomes were less than those of baicalein as inhibition by 500 microM wogonin was only about 51-65%. Treatment of mice with liquid diets containing 5 mM baicalein and wogonin resulted in 22 and 49% decreases in hepatic AHH activities, respectively. Baicalein treatment resulted in 39 and 32% decreases in AFQ(1) and AFB(1)-epoxide formation from liver microsomal AFO, respectively. Wogonin treatment resulted in 39 and 47% decreases in AFQ(1) and AFB(1)-epoxide formation, respectively. A 1-week pretreatment with wogonin significantly decreased hepatic DNA adduct formation in mice treated with 200 mg/kg of benzo[a]pyrene via gastrogavage. These in vitro and in vivo effects suggested that baicalein and wogonin might have beneficial effects against benzo[a]pyrene- and AFB(1)-induced hepatic toxicities and that wogonin had a stronger protective effect in vivo.

Spasmolytic effects of three harmala alkaloids on guinea-pig isolated trachea

The present study examined and compared the spasmolytic effects of 3 harmala alkaloids, harmine, harman, and harmaline, on carbachol-, histamine-, and KCl-induced contractions of guinea-pig isolated tracheal preparations. All 3 compounds relaxed the tracheal preparations contracted by these spasmogens with similar or different EC50 values, harmine being the most potent one. The cumulative concentration-response curves of all 3 compounds for carbachol-induced contraction were shifted to the right by propranolol (1 microM) pretreatment, indicating the involvement of the activation on the beta-adrenoceptors. All 3 compounds shifted the concentration-response curves of carbachol to the right in a parallel manner with the pA2 values comparable with their relaxation EC50 values, indicating a competitive antagonism at the muscarinic receptors. Receptor binding assays indicated that all 3 compounds interacted with lung muscarinic receptors (Ki = 11-13 microM), histamine H1 receptors (Ki = 27-107 microM), and beta2-adrenoceptors (Ki = 20-51 microM). Therefore, in addition to their actions on receptor-linked and voltage-dependent Ca2+ channels as reported in other types of smooth muscle, the present study suggests that the actions on muscarinic receptors, histamine H1 receptors, and beta2-adrenoceptors are also involved in their spasmolytic effects on airway smooth muscles.

Calcium channel blockade in vascular smooth muscle cells: major hypotensive mechanism of S-petasin, a hypotensive sesquiterpene from Petasites formosanus

In vivo and in vitro studies were carried out to examine the putative hypotensive actions of S-petasin, a sesquiterpene extracted from the medicinal plant Petasites formosanus. Intravenous S-petasin (0.1-1.5 mg/kg) in anesthetized rats produced a dose-dependent hypotensive effect. In isolated aortic ring, isometric contraction elicited by KCl or the L-type Ca2+ channel agonist Bay K 8644 was reduced by S-petasin (0.1-100 microM), an action not affected by the cyclooxygenase inhibitor indomethacin, nitric-oxide synthase inhibitor N(omega)-nitro-L-arginine, guanylyl cyclase inhibitor methylene blue, or removal of vascular endothelium. Pretreatment with S-petasin for 10 min shifted the concentration-response curve for KCl (15-90 mM)-induced contraction to the right and reduced the maximal response. In Ca2+-depleted and high K+-depolarized aortic rings preincubation with S-petasin attenuated the Ca2+-induced contraction in a concentration-dependent manner, suggesting that S-petasin reduced Ca2+ influx into vascular smooth muscle cells (VSMCs). Moreover, in cultured VSMCs, whole-cell patch-clamp recording indicated that S-petasin (1-50 microM) inhibited the L-type voltage-dependent Ca2+ channel (VDCC) activities. Intracellular Ca2+ concentration ([Ca2+[(i)) estimation using the fluorescent probe 1-[2-(5-carboxyoxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2'-amino-5'-methylphenoxy)-ethane-N,N,N,N-tetraacetic acid pentaacetoxymethyl ester indicated that S-petasin (10, 100 microM) suppressed the KCl-stimulated increase in ([Ca2+[(i)). Taken together, the results suggested that a direct Ca2+ antagonism of L-type VDCC in vascular smooth muscle may account, at least in part, for the hypotensive action of S-petasin.

Comparative study on the vasorelaxant effects of three harmala alkaloids in vitro

Three psychological active principles from the seeds of Peganum harmala L., harmine, harmaline and harmalol, showed vasorelaxant activities in isolated rat thoracic aorta preparations precontracted by phenylephrine or KCl with rank order of relaxation potency of harmine > harmaline > harmalol. The vasorelaxant effects of harmine and harmaline (but not harmalol) were attenuated by endothelium removal or pretreatment with a nitric oxide (NO) synthase Nomega-nitro-L-arginine methyl ester. In cultured rat aortic endothelial cells, harmine and harmaline (but not harmalol) increased NO release, which was dependent on the presence of external Ca2+. In endothelium-denuded preparations, pretreatment of harmine, harmaline or harmalol (3-30 microM) inhibited phenylephrine-induced contractions in a non-competitive manner. Receptor binding assays indicated that all 3 compounds interacted with cardiac alpha1-adrenoceptors with comparable affinities (Ki value around 31 - 36 microM), but only harmine weakly interacted with the cardiac 1,4-dihydropyridine binding site of L-type Ca2+ channels (Ki value of 408 microM). Therefore, the present results suggested that the vasorelaxant effects of harmine and harmaline are attributed to their actions on the endothelial cells to release NO and on the vascular smooth muscles to inhibit the contractions induced by the activation of receptor-linked and voltage-dependent Ca2+ channels. The vasorelaxant effect of harmalol was not endothelium-dependent.

Dehydroevodiamine attenuates beta-amyloid peptide-induced amnesia in mice

Dehydroevodiamine has been reported to have anticholinesterase activity and an anti-amnesic effect. This study examined the effects of dehydroevodiamine on scopolamine- and beta-amyloid peptide-(25--35)-induced amnesia in mice, using a step-through passive avoidance test. Similarly to the cholinesterase inhibitor, physostigmine (0.03--0.3 mg/kg, i.p.), dehydroevodiamine (0.75--12.0 mg/kg, i.p.) administered 30 min before the training trial, immediately after the training trial, and 30 min before the retention test significantly improved scopolamine- and beta-amyloid peptide-(25--35)-induced amnesia. In beta-amyloid peptide-(25--35)-induced amnesia, the rank order of anti-amnesic potency in these three administration schedules for dehydroevodiamine was different from that for physostigmine. Furthermore, dehydroevodiamine was more potent to improve beta-amyloid peptide-(25--35)-induced amnesia than scopolamine-induced amnesia when administered before the training trial. These results suggested that dehydroevodiamine may have an action other than that of an anticholinesterase and may be a novel and effective ligand for improvement of beta-amyloid type amnesia.

Anticonvulsant effect of water extract of Scutellariae radix in mice

Since a previous study indicated that the water extract of Scutellariae radix (SR) had high affinity for the benzodiazepine (BDZ) binding site of GABA(A) receptors, the present study examined whether SR water extract has an anticonvulsant effect in vivo and an enhancing effect on gamma-amino-n-butyric acid (GABA)-stimulated uptake of 36Cl(-) in cortex preparation in vitro in mice. The results showed that SR water extract had little effect on pentylenetetrazol (PTZ, 85 mg/kg, s.c.)-induced clonic seizures but significantly inhibited maximal electroshock-induced tonic seizures with an ED(50) of 3.6 g/kg. The BDZ agonist chlordiazepoxide (10 mg/kg, i.p.) had anticonvulsant activity on both types of seizures. In 36Cl(-) uptake assay, SR water extract (1-500 microg/ml) had no significant effect on 25 microM GABA-stimulated 36Cl(-) uptake, whereas chlordiazepoxide (10 microM) increased the 36Cl(-) uptake to 125% of control. Therefore, the present results showed for the first time that SR water extract had anticonvulsant activity against maximal electroshock-induced tonic seizures, and suggested that this anticonvulsant effect might be not via the activation of the BDZ binding site of GABA(A) receptors, but probably via the prevention of seizure spread.

Anti-diarrheal effect of water extract of Evodiae fructus in mice

Our previous study showed that Evodiae fructus (the dried, unripe fruit of Evodia rutaecarpa) has an inhibitory effect on the intestinal transit (anti-transit effect) in mice. In the present study, a water extract of Evodiae fructus was used to examine its effect on castor oil-induced diarrhea and to compare with its anti-transit effect in mice. The results indicated that Evodiae fructus had both anti-transit and anti-diarrheal effects with comparable ID(50) (the dose for 50% inhibition) values of 54+/-7 and 76+/-17 mg/kg. The time-courses of Evodiae fructus pretreatment for both anti-transit and anti-diarrheal effects were very similar. Because no significant influences of both nitric oxide (NO) precursor L-arginine (600 mg/kg, i.p.) and NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (25 mg/kg, i.p.) pretreatment, the NO system was not involved in both the anti-transit and anti-diarrheal effects of Evodiae fructus. Like Evodiae fructus, a muscarinic acetylcholine receptor antagonist atropine inhibited castor oil-induced increase in fecal weight and loss of body weight. However, the potencies or time-courses of atropine pretreatment for both anti-transit and anti-diarrheal effects were different. Furthermore, the anti-diarrheal effect of atropine was independent of its anti-transit effect at the lower dose (0.5 mg/kg, i.p.). Therefore, the action of Evodiae fructus appeared to be something different from atropine, suggesting that an action other than the anti-muscarinic action, as previously proposed for Evodiae fructus, may be involved.

Effects of baicalein and wogonin on drug-metabolizing enzymes in C57BL/6J mice

Effects of baicalein and wogonin, the major flavonoids of Scutellariae radix, on cytochrome P450 (CYP), UDP-glucuronosyl transferase (UGT), and glutathione S-transferase (GST) were studied in C57BL/6J mice. One-week treatment of mice with a liquid diet containing 5 mM baicalein resulted in 29%, 14%, 36%, 28%, and 46% decreases of hepatic benzo(a)pyrene hydroxylation (AHH), benzphetamine N-demethylation (BDM), N-nitrosodimethylamine N-demethylation (NDM), nifedipine oxidation (NFO), and erythromycin N-demethylation (EMDM) activities, respectively. Treatment with a liquid diet containing 5 mM wogonin resulted in 43%, 22%, 21%, 24%, and 35% decreases of hepatic AHH, BDM, NDM, NFO, and EMDM activities, respectively. However, hepatic 7-methoxyresorufin O-demethylation (MROD) activity was increased and decreased by baicalein- and wogonin-treatments, respectively. Similar modulation was observed with caffeine 3-demethylation (CDM) activity. Immunoblot analysis showed that the levels of hepatic CYP2E1 and CYP3A proteins were decreased by both baicalein- and wogonin-treatments. Hepatic CYP1A2 protein level was increased by baicalein but decreased by wogonin. In extrahepatic tissues, renal AHH activity was decreased by wogonin whereas pulmonary AHH, 7-ethoxyresorufin O-deethylation (EROD), and MROD activities were increased by both flavonoids. Both baicalein and wogonin strongly increased CYP1A protein level in mouse lung. Hepatic and renal UGT activities toward p-nitrophenol were suppressed by baicalein- and wogonin-treatments. However, cytosolic GST activity was not affected by flavonoids. These results suggest that ingestion of baicalein or wogonin can modulate drug-metabolizing enzymes and the modulation shows tissue specificity.

Vasorelaxant effect of harman

The in vivo cardiovascular effect and in vitro vasorelaxant effect of harman, one of harmala alkaloids isolated from Peganum harmala, were examined in this study. Harman (1-10 mg/kg, i.v.) dose-dependently produced transient hypotension and long-lasting bradycardia in pentobarbital-anesthetized rats, which were attenuated by N(G)-nitro-L-arginine pretreatment. In isolated rat endothelium-intact thoracic aortic rings, harman concentration dependently relaxed phenylepherine-induced contractions with an IC(50) value around 9 microM. This vasorelaxant effect was attenuated by endothelium removal or N(omega)-nitro-L-arginine methyl ester pretreatment, but not by tetraethylammonium or indomethacin pretreatment. In cultured rat aortic endothelial cells, harman (1-100 microM) concentration dependently increased nitric oxide (NO) release, which was dependent on the presence of external Ca(2+). Harman pretreatment (3-30 microM) also concentration dependently inhibited the contractions induced by phenylephrine, 5-hydroxytryptamine (5-HT), and KCl in endothelium-denuded aortic rings in a non-competitive manner. In addition, harman pretreatment reduced both phasic and tonic phases of phenylephrine-induced contractions. Receptor binding assays further indicated that harman (K(i) values around 5-141 microM) interacted with the cardiac alpha(1)-adrenoceptors, brain 5-HT(2) receptors, and cardiac 1, 4-dihydropyridine binding site of L-type Ca(2+) channels. Therefore, the present results suggested that the vasorelaxant effect of harman was attributed to its actions on the endothelial cells to release NO and on the vascular smooth muscles to inhibit the contractions induced by the activation of receptor-linked and voltage-dependent Ca(2+) channels. The vasorelaxant effect may be involved in the hypotensive effect of harman.

In vitro and in vivo effects of naringin on cytochrome P450-dependent monooxygenase in mouse liver

In vitro and in vivo effects of naringin on microsomal monooxygenase were studied to evaluate the drug interaction of this flavonoid. In vitro addition of naringin up to 500 microM had no effects on benzo(a)pyrene hydroxylase (AHH) activity of mouse liver microsomes. In contrast, the aglycone naringenin at 300 to 500 microM decreased AHH activity by 50% to 60%. Analysis of Lineweaver-Burk and Dixon plots indicated that naringenin competitively inhibited AHH activity with an estimated Ki of 39 microM. Naringenin at 100 microM also reduced metabolic activation of benzo(a)pyrene to genotoxic products as monitored by umuC gene expression response in Salmonella typhimurium TA1535/pSK1002. In the presence of equimolar naringenin and benzo(a)pyrene, umuC gene expression presented as beta-galactosidase activity was reduced to a level similar to the control value. Administration of a liquid diet containing 10 mg/ml naringin for 7 days caused 38% and 49% decreases of AHH and 7-methoxyresorufin O-demethylase activities, respectively. In contrast, the administration had no effects on cytochrome P450 (P450)-catalyzed oxidations of 7-ethoxyresorufin, 7-ethoxycoumarin, N-nitrosodimethylamine, nifedipine, erythromycin and testosterone. Microsomal P450 and cytochrome b5 contents and NADPH-P450 reductase activity were not affected. Immunoblot analysis using MAb 1-7-1, which immunoreacted with both P450 1A1 and 1A2, revealed that the level of P450 1A2 protein was decreased by 38%. These results demonstrate that naringenin is a potent inhibitor of AHH activity in vitro and naringin reduces the P450 1A2 protein level in vivo. These effects may indicate a chemopreventive role of naringin against protoxicants activated by P450 1A2.

Binding of dimemorfan to sigma-1 receptor and its anticonvulsant and locomotor effects in mice, compared with dextromethorphan and dextrorphan

Dextromethorphan ((+)-3-methoxy-N-methylmorphinan, DM) has been shown to have both anticonvulsant and neuroprotective effects. The mechanisms of these CNS effects of DM have been suggested to be associated with the low-affinity, noncompetitive, N-methyl-d-aspartate (NMDA) antagonism of DM and/or the high-affinity DM/sigma receptors. DM is largely O-demethylated into the phencyclidine (PCP)-like compound dextrorphan (DR), which may limit its therapeutic use by producing PCP-like adverse effects, such as hyperlocomotion. Dimemorfan ((+)-3-methyl-N-methylmorphinan, DF), an analog of DM, which has been safely used as an antitussive for more than 20 years, is also known not to form DR. This study therefore characterized the binding of DF to the sigma receptors and NMDA-linked PCP sites and examined the anticonvulsant as well as locomotor effects of DF in mice in comparison with those of DM and DR. We found that DF, DM, and DR were relative high-affinity ligands at sigma-1 receptors (Ki=151, 205, 144 nM, respectively) while all of them were with low affinity at sigma-2 receptors (Ki=4-11 microM). Only DR exhibited moderate affinity for PCP sites (Ki=0.9 microM), whereas DF (Ki=17 microM) and DM (Ki=7 microM) were much less active. DF, DM and DR produced prominent anticonvulsant effects in mice as measured by the supramaximal electroshock test with comparable potency (ED50 approximately 70 micromol/kg, i.p.). At the tested doses (20-260 micromol/kg, i.p.), DM and DR exhibited biphasic effects on the locomotor activity whereas DF produced a consistent dose-dependent decrease. These results revealed that, unlike DM and DR, DF did not cause a PCP-like hyperlocomotion adverse effect that is parallel with the PCP sites binding data. Furthermore, since they have equipotent anticonvulsant effects and similar binding affinities to sigma-1 receptors, the very low affinity of DF at PCP sites may suggest that acting on the PCP sites may not be the requisite for mediating the anticonvulsant activity of these DM analogs. With the history of safety and relative less adverse effects, DF appears to be worth further studying on its CNS effects other than the antitussive effect.

Kinetic model of folate metabolism in nonpregnant women consuming [2H2]folic acid: isotopic labeling of urinary folate and the catabolite para-acetamidobenzoylglutamate indicates slow, intake-dependent, turnover of folate pools

In a 10-wk study of folate metabolism in nonpregnant women (21-27 y, n -6 per group), subjects were fed a diet containing approximately 68 nmol/d (30 microg/d) folate from food. The remainder of the ingested folate was provided as folic acid in apple juice (as nonlabeled during wk 1-2, as [2H2]folic acid during wk 3-10) to yield a constant intake of 454, 680 or 907 nmol/d (200, 300 or 400 microg/d). Isotopic enrichment of total urinary folate and the primary catabolite para-acetamidobenzoylglutamate (ApABG) was determined. Isotopic enrichment of ApABG served as an indicator of labeling of tissue folates. A kinetic model consisting of fast- and slow-turnover nonsaturable pools and a saturable slow-turnover pool, with provisions for urinary and fecal excretion, catabolism and enterohepatic circulation, yielded a close fit to the data. Mean residence times for total body folate were 212, 169 and 124 d for folate intakes of 454, 680, and 907 nmol/d, respectively. The model predicted that variation in folate intake over this range had little effect on the mass of the large saturable folate pool; however, the fast-turnover nonsaturable pools increased in proportion to folate intake, whereas the slow nonsaturable pool also tended to increase. This model will aid in evaluation of folate turnover and in predicting kinetic consequences of physiologic conditions associated with altered folate requirements.

Benzodiazepine binding site-interactive flavones from Scutellaria baicalensis root

A benzodiazepine binding assay directed separation led to the identification of 3 flavones baicalein (1), oroxylin A (2), and skullcapflavone II (3) from the water extract of Scutellaria baicalensis root. Compounds 1, 2, and 3 interacted with the benzodiazepine binding site of GABAA receptors with a Ki value of 13.1, 14.6 and 0.36 micromol/L, respectively.

Central inhibitory effects of water extract of Acori graminei rhizoma in mice

The present study evaluated in mice the central inhibitory effects of a water extract of shichangpu (Acori graminei rhizoma (AGR), the dry rhizome of Acorus gramineus Soland. (Araceae)). AGR (0.5-5.0 g/kg) dose-dependently decreased the locomotor activity and increased the pentobarbital-induced sleeping time, but had no significant effect on the treadmill performance. AGR also dose-dependently inhibited the intensity of apomorphine-induced stereotypic behavior. At the highest dose (5.0 g/kg), AGR had a weak anticonvulsant effect on the pentylenetetrazol-induced seizures. Receptor binding assays showed that AGR competed with [3H]SCH-23390 and [3H]YM-09151-2 for specific binding to striatal dopamine D1 and D2 receptors with Ki values of 5.6 and 4.2 mg/ml, respectively. AGR also competed with [3H]muscimol for specific binding to the gamma-aminobutyric acid (GABA) binding site of cortex GABA(A) receptors with a Ki value of 0.31 mg/ml. It also increased the specific binding of [3H]flunitrazepam to the benzodiazepine binding site of the GABA(A) receptors, suggesting a GABA agonist-like action. These results suggested that the central inhibitory effects of AGR were probably effected through an action on the central dopamine receptors and GABA(A) receptors. The principle of AGR acting at these ligand binding sites was not alpha-asarone, one of the important principles of AGR, since that alpha-asarone (10(-6)-10(-4) M) had no significant interactions with these binding sites.

6-Methoxy-N-methyl-1,2,3,4-tetrahydro-beta-carboline from Evodiae Fructus

A receptor binding assay directed separation has led to the identification of a minor alkaloid 6-methoxy- N-methyl-1,2, 3,4-tetrahydro-beta-carboline (1) from the Chinese herbal drug Evodiae Fructus [EF, the dried, unripe fruit of Evodia rutaecarpa Look. f. et Thomas (Rutaceae)]. The structure of compound 1 was elucidated by means of spectroscopic methods and a comparison with synthetic materials. Compound 1 interacted with 5-HT (1A) and 5-HT (2) receptors with a moderate K (i) value of 78 and 1.2 microM, respectively. Compound 1 is found in EF and the genus Evodiae for the first time.

Inhibitory effect of dehydroevodiamine and evodiamine on nitric oxide production in cultured murine macrophages

Possible antiinflammatory effects of dehydroevodiamine (1) and evodiamine (2) were examined by assessing their effects on NO production in the murine macrophage-like cell line RAW 264.7. The results indicated that both 1 and 2 inhibited the IFN-gamma/LPS-stimulated NO production in a concentration-dependent manner. However, 1 appeared to inhibit NO production by interfering not only with the priming signal initiated by IFN-gamma but also with iNOS protein synthesis, while 2 affected the former only.

Spasmolytic effect of water extract of Stemonae radix on the guinea-pig tracheal smooth muscle in vitro

The present study examined the relaxing effect of a water extract of Baibu (Stemonae radix, the root tuber of Semona sessilifolia (Miq.) Franch. et Sav.) on carbachol-, histamine- and KCl-induced contractions of the guinea-pig isolated tracheal preparations. The results showed that Baibu (1-50 mg/ml) concentration-dependently relaxed the tracheal preparations contracted by these spasmogens with an IC50 value (mg/ml) of 2.0 +/- 0.1 for carbachol, 41.2 +/- 0.8 for histamine and 18.6 +/- 0.9 for KCl. The effect of Baibu was not affected by the pretreatment with a beta-adrenoceptor antagonist propranolol (10(-6) M), indicating that Baibu's effect was not due to an activation on beta-adrenoceptors. Baibu shifted the concentration-response curve of carbachol to the right in a parallel manner without changing the maximal response, having a pA2 value of 0.16 +/- 0.07 mg/ml (equivalent to a KB = 0.70 +/- 0.11 mg/ml). This indicates a competitive antagonism at the muscarinic receptors. Receptor binding assay indicated that Baibu interacted with the muscarinic receptors (Ki = 0.51 +/- 0.12 mg/ml) and the dihydropyridine (DHP) binding site of L-type Ca2+ channels (Ki = 8.0 +/- 1.9 mg/ml), but not with the histamine H1 receptors. Therefore, the present study demonstrates that Baibu contains the principle(s) acting on the muscarinic receptors and DHP binding sites, which contribute its relaxation effect on the airway smooth muscles.

Studies of the cellular mechanisms underlying the vasorelaxant effects of rutaecarpine, a bioactive component extracted from an herbal drug

We conducted studies to investigate the nature and underlying mechanisms of the vascular effects of rutaecarpine (Rut), an alkaloid isolated from the Chinese herbal drug Evodia rutaecarpa. By using largely the effects on phenylephrine (PE)-induced contraction in the isolated rat aorta as the experimental index and by comparison with several known vascular muscle relaxants such as acetylcholine (ACh), histamine, and A23187, Rut relaxed PE-precontracted aorta in concentration-(10(-7)-10(-4) M) and endothelium-dependent manners. Studies with appropriate antagonists indicated that this was coupled to nitric oxide (NO) and guanylyl cyclase. Extracellular Ca2+ removal and treatment with the intracellular Ca2+ antagonist, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), suggested that influx of extracellular Ca2+ was the major factor contributing to the action of Rut. Pertussis toxin suppressed the relaxation potency of histamine but had no effects on the actions of Rut. NaF, the G proteins activator, attenuated the actions of ACh, but only minimally affected Na-NP, A23187, and Rut. 1-[6-{[17 beta-3-methoxyestra-1,2,3(10)-trien-17-yl]amino} hexyl]-1H-pyrrole-2,5-dione (U73122), the phospholipase C inhibitor, again suppressed the actions of ACh but had few effects on A23187 and Rut. Taken together, these results suggest that these vasorelaxants had different cellular mechanisms and that neither pertussis toxin-sensitive Gi protein, other G proteins, nor phospholipase C activation was involved in the cellular response to rutaecarpine.

Mechanisms of vasorelaxant effect of dehydroevodiamine: a bioactive isoquinazolinocarboline alkaloid of plant origin

We examined the mechanisms underlying the vasorelaxant effect of dehydroevodiamine (DeHE), one of the bioactive components of the Chinese herbal drug Evodia rutaecarpa that has been shown to produce vasorelaxant and hypotension. DeHE (10(-7)-10(-4) M) concentration-dependently relaxed isolated rat mesenteric arteries precontracted with phenylephrine (PE). This vasorelaxant potency was diminished by 15% by endothelial removal, L-NG-nitro arginine, or methylene blue (MB), but not indomethacin treatment, indicating that the vasorelaxant effect of DeHE was partially endothelium dependent and mediated by nitric oxide (NO) and the cyclic GMP pathway. In endothelium-denuded preparations, DeHE caused a rightward shift of the contractile concentration-response curve (CRC) to PE in a dose-dependent manner with a pA2 value of 6.15. Maximal response was unaffected. Receptor binding assay indicated that DeHE competed with alpha 1-adrenoceptor ligand prazosin with a Ki value of 3.57 microM. Potassium channel activity-attenuating conditions such as increased level of extracellular K+ (20 mM) and treatment with the antagonist tetraethylammonium (TEA) significantly inhibited DeHE's effect, suggesting a mode of action similar to that of a potassium channel activator. In addition, high concentrations of DeHE (3 x 10(-5) and 10(-4) M) relaxed high K+ (80 mM)-evoked contraction, indicating that DeHE might possess K+ channel blocking properties. Multiple-action mechanisms, including endothelium dependence, alpha 1-adrenoceptor blockade, K+ channel activation, and Ca2+ channel blockade were probably involved in the vasorelaxant effects of DeHE.

Comparative study of the vasodilatory effects of three quinazoline alkaloids isolated from Evodia rutaecarpa

The vasoreactivity of dehydroevodiamine (1), evodiamine (2), and rutaecarpine (3), quinazoline alkaloids isolated from Evodia rutaecarpa, to aorta smooth muscle demonstrated that they produce a vasodilatory effect on endothelium-intact rat aorta with equal potency. Compound 3 produced a full (100%) nitric oxide-dependent vasodilatation, whereas 2 and 1 produced a partially endothelium-dependent effect, 50% and 10%, respectively. At the same time, I and 2 may also act by other mechanisms, including probably an alpha1-adrenoceptor blocking action and a 5-HT antagonizing action, respectively.

Evaluation with receptor binding assay on the water extracts of ten CNS-active Chinese herbal drugs

In the present study, we established receptor binding assays to evaluate the water extracts of ten central nervous system (CNS)-active Chinese herbal drugs. These ten herbal drugs are Chaihu (Radix Bupleuri), Chuanxiong (Rhizoma Chuanxiong), Danggui (Radix Angelicae sinensis), Danshen (Radix Salviae miltiorrhizae), Duhuo (Radix Angelicae pubescentis), Hangqin (Radix Scutellariae), Qinjiao (Radix Gentianae macrophyllae), Shengma (Rhizoma Cimicifugae), Suanzaoren (Semen Zizphi spinose), and Yangjihua (Flos Daturae). The results indicated that these water extracts contained the principles acting on the dopamine (D1 & D2), muscarinice acetylcholine (M1), or 5-HT (5-HT1A & 5-HT2) receptors, or the benzodiazepine and the gamma-amino-n-butyric acid (GABA) binding sites of GABAA receptors as determined by receptor binding assays. The receptors or binding sites which predominantly acted by each water extract are listed as follows: Chaihu: D2, 5-HT1A, GABA; Chuanxiong: GABA, 5-HT1A; Danggui: GABA, 5-HT1A; Danshen: BDZ; Duhuo: GABA, 5-HT1A, D2, D1; Hangqin: BDZ, D1, 5-HT1A; Qinjiao: GABA, BDZ, 5-HT1A, D2; Shengma: 5-HT1A; Suanzaoren: 5-HT1A, 5-HT2, GABA; Yangjihua: M1, 5-HT1A, 5-HT2. These results provided evidence to explain the CNS effects of these herbal drugs at the receptor level. Furthermore, these results provided information to direct the isolation and purification of receptor-interactive compounds from these herbal drugs.

Effect of the crude extract of Evodiae Fructus on the intestinal transit in mice

One of the uses of Evodiae Fructus (EF, the dried, unripe fruit of Evodia rutaecarpa) in Chinese medicine is recommended in diarrhea, but its underlying mechanism has not yet been studied. The present study examined the effect of an aqueous extract of EF on the intestinal transit in mice by the charcoal meal method. Intraperitoneal administration (i.p.) of EF (1.9-30 g/kg) significantly inhibited the intestinal transit in a dose- and time-dependent manner. This inhibitory effect of EF was not attenuated by the i.p. pretreatment with an alpha 2-, alpha 1-, or beta-adrenoceptor antagonist, i.e. yohimbine (10 mg/kg), prazosin (2 mg/kg), or propranolol (6 mg/kg), respectively. In the isolated mouse duodenum, jejunum, and ileum preparations, EF (10-50 mg/ml) concentration-dependently abolished 10 microM carbachol-induced contraction with an IC50 of 9.9, 11.7, and 16.3 mg/ml, respectively. This inhibitory effect was not competitive. Receptor binding assay showed that EF (1-50 mg/ml) significantly competed with [3H]-N-methylscopolamine for specific binding to muscarinic receptors on the duodenum, jejunum, and ileum membrane preparations with a Ki value of 7.1, 8.4, and 14.4 mg/ml, respectively. Therefore, the above results suggested that the inhibitory effect of EF on intestinal transit was probably via an action directly on the muscarinic receptors but not on the alpha 2, alpha 1-, and beta-adrenoceptors in the small intestine.

The mechanism of the vasodilator effect of rutaecarpine, an alkaloid isolated from Evodia rutaecarpa

The mechanisms underlying the rutaecarpine-induced vasodilatation were studied using isolated rat mesenteric arterial ring segments. The results showed that rutaecarpine (0.1 microM to 0.1 mM) produced a dose-dependent vasorelaxing response in our preparations, which were precontracted with phenylephrine. This vasodilator effect was significantly attenuated by removal of the endothelium, treatment with L-NG-nitro-arginine, a nitric oxide synthase inhibitor, and methylene blue, a guanylyl cyclase inhibitor, but not by treatment with atropine, triprolidine and yohimbine. Rutaecarpine pretreatment (1 microM to 0.1 mM) reduced both the phasic (fast) and tonic (slow) phases of phenylephrine-induced contractions, suggesting that a reduction in intracellular calcium might be involved. It is thus concluded that while the vasorelaxing effect of rutaecarpine appeared to be endothelium-dependent and to involve nitric oxide and guanylyl cyclase, neither muscarinic receptors, histamine H1 receptors nor alpha 2-adrenoceptors are involved. Moreover, a direct effect on the vascular smooth muscle cell, possibly through a reduction in intracellular Ca2+, can not be excluded.

Study on the vascular reactivity and alpha 1-adrenoceptors of portal hypertensive rats

1. Vascular hyporesponsiveness in portal hypertension has been demonstrated to various vasoconstrictors including noradrenaline (NA). The present study aimed to determine whether the attenuated vascular responsiveness to NA is due to a change in the affinity or the number of alpha 1-adrenoceptors. 2. Partial portal vein ligation (PVL) was performed in Sprague-Dawley rats to produce portal hypertension. Vascular responsiveness to NA was assayed in portal vein, mesenteric artery or tail artery. The affinity and number of alpha 1-adrenoceptors were determined by specific binding of [125I]-HEAT (2-beta-4-hydroxy-3-iodophenyethyl-aminomethyltetralone). 3. In the presence of yohimbine (10(-7) M, an alpha 2-adrenoceptor antagonist), propranolol (10(-6) M, a beta-adrenoceptor antagonist), and two catecholamine uptake inhibitors, desipramine (10(-7) M) and normetanephrine (10(-6) M), the maximum responses to NA were decreased in all three blood vessels of PVL rats: 45% decrease in portal vein, 25% in mesenteric artery and 18% in tail artery. 4. The EC50 values of NA and the pA2 values of prazosin, an alpha 1-adrenoceptor antagonist, in all three blood vessels were not significantly different between sham-operated and PVL rats. 5. The KD and Bmax values for specific binding of [125I]-HEAT or the Ki values for NA in the crude membrane preparations of either mesenteric artery or tail artery were also not significantly different between the two groups. 6. It is concluded that the vascular hyporesponsiveness to NA in the mesenteric artery or tail artery of PVL rats is not due to changes in the affinity or number of alpha 1-adrenoceptors.

Characterization of agonist-induced internalization and down-regulation of beta-adrenergic receptors in isolated rat lung and heart preparations

Using isolated lung and heart preparations from male Sprague-Dawley rats, this study characterizes whether the beta-adrenergic receptor (BAR) agonist isoproterenol (ISO) can induce internalization and down-regulation of BAR in these tissues. The results showed that ISO-induced BAR internalization was time- and concentration-dependent in the lung preparations. When the lung and heart preparations were compared, however, the same ISO (10 microM, 30 min) treatment only induced BAR internalization in the lung but not in the heart preparations. Pretreatment of hypertonic sucrose medium (0.45-0.6 M) for 30 min inhibited about 50% of ISO-induced BAR internalization in the lung preparations. Treatment of either ISO (10 microM) or terbutaline (10 microM) for 3 hr or 12 hr did not significantly decrease the number of BAR in both tissue preparations. However, ISO (10 microM, 12 hr) increased the KD value of the radioligand [125I]-iodocyanopindolol for BAR in the heart homogenates. This ISO-induced KD change was not observed in the presence of cycloheximide (20 micrograms/ml), a protein synthesis inhibitor. In the presence of cycloheximide (20 micrograms/ml), ISO also did not decrease the BAR number in either tissue preparation.

Differential effects of antimycin A on endocytosis and exocytosis of transferrin also are observed for internalization and externalization of beta-adrenergic receptors

In many cells catecholamines induce a translocation of beta-adrenergic receptors from the cell surface to intracellular vesicular sites. We have postulated that the translocation event is the result of ligand-induced endocytosis of the receptor, probably via clathrin-coated pits. Previously, we demonstrated that reduction of cellular ATP content with antimycin A completely blocked endocytosis of epidermal growth factor and translocation of beta-adrenergic receptors in 1321N1 astrocytoma cells. However, the effect of reduction in ATP content on endocytosis remains controversial. In the present report, we demonstrate that reduction of ATP content to a level < 5% of that in control cells is sufficient to prevent endocytosis of [125I]iodotransferrin and translocation of beta-adrenergic receptors. The further demonstration that reactions leading to the return of internalized transferrin or beta-adrenergic receptors to the cell surface are blocked after relatively modest reductions in ATP content provides further evidence of the similarity in the processes subserving diacytosis of beta-adrenergic receptors and transferrin. The differential requirement for ATP of the two arms of diacytosis provides the basis for an explanation of the controversy regarding a requirement for ATP in endocytosis via clathrin-coated pits.

Regulation of glucose transporters by connective tissue activating peptide-III isoforms

Connective tissue activating peptide-III (CTAP-III) is a component of platelet alpha-granules which elicits a series of responses in connective tissue cells referred to as activation, including increased glucose consumption and mitogenesis and increased secretion of hyaluronic acid and glycosaminoglycans. As anticipated by a requirement for glucose or glucose precursors in the activation process, an early event following CTAP-III activation of connective tissue cells is an increase in glucose transport. The present study investigates the molecular basis for this increase in glucose transport. Murine 3T3-F442A fibroblasts were found to respond to CTAP-III in a manner similar to human connective tissue cells (synovial cells, chondrocytes, skin fibroblasts). CTAP-III increases the rate of glucose transport to similar extents at 4 and 24 h, and at physiologic (micrograms/ml) concentrations of CTAP-III. A proteolytic cleavage product of recombinant CTAP-III (rCTAP-III-Leu-21 (des-1-15)), also known as neutrophil-activating peptide-2 (NAP-2), was found to be equally effective as CTAP-III, whereas NAP-1/interleukin-8, another member of the CTAP-III super-family, was ineffective in stimulating glucose transport. This contrasts with neutrophil chemotaxis, in which CTAP-III (des-1-15)/NAP-2 acts similarly to NAP-1/interleukin 8 while CTAP-III is ineffective. CTAP-III appears to elicit a different type of glucose transport response than many other growth factors in that its response is sustained (greater than or equal to 24 h) rather than transient (peak approximately 4 h) in confluent as well as in subconfluent cells. Western blot analysis using antibodies to the GLUT-1 glucose transporter revealed an increased level of GLUT-1 protein in response to CTAP-III isoforms that corresponded in magnitude (on a percentage basis) to the increased level of glucose transport. The increased levels of GLUT-1 protein in response to CTAP-III and rCTAP-III-Leu-21 (des-1-15)/NAP-2 were accompanied by an increase in levels of GLUT-1 mRNA of a magnitude sufficient to account for observed increased levels of GLUT-1. These results are consistent with CTAP-III isoforms stimulating glucose transport in connective tissue cells by increasing levels of GLUT-1 mRNA and is one of the few known instances in which increases in levels of GLUT-1 mRNA and protein are sufficient to account for observed increases in glucose transport. They also provide further evidence that CTAP-III (des-1-15)/NAP-2 binds to more than one type of receptor and that CTAP-III acts in a manner different than other well characterized growth factors (e.g. platelet-derived growth factor, transforming growth factor-beta) in that it causes a sustained (greater than or equal to 24 h) elevation in glucose transport in confluent as well as subconfluent cells.

Pharmacokinetics of glycyrrhizin after intravenous administration to rats

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of glycyrrhizin in the rat after bolus intravenous administration at a dose of 20, 50, or 100 mg/kg. The decline in the concentration of glycyrrhizin in plasma was generally biexponential at each dose, but the terminal disposition became much slower as the dose was increased. A greater-than-proportional increase in the glycyrrhizin concentration in plasma was observed with an increase in the dose, a result suggesting a dose-dependent glycyrrhizin disposition. The disposition of drug in plasma at each dose fitted well to a two-compartment pharmacokinetic model. The apparent total body clearance decreased significantly with increases in the dose. On the other hand, the apparent distribution volume after intravenous administration was unaffected by the dose. The results indicate that the pharmacokinetics of glycyrrhizin is nonlinear.

Differential regulation of two glucose transporters by chronic growth hormone treatment of cultured 3T3-F442A adipose cells

New methods for the analysis of glucose transporters were used to analyze the molecular mechanisms involved in the insulin-antagonistic effects of growth hormone (GH), which is known as a diabetogenic hormone. The ability of GH to alter the number and mRNA levels of two different glucose transporters in cultured 3T3-F442A adipocytes was investigated using specific antibodies and cDNA probes. At concentrations of GH as low as 0.5 and 5 ng/ml and at incubation times as short as 4 h, GH decreased rates of 2-deoxyglucose uptake in 3T3-F442A adipocytes. 3-O-Methyl-D-glucose uptake was inhibited to an extent similar to that of 2-deoxyglucose uptake (60-80%) after a 24-h incubation with GH (500 ng/ml), indicating that GH inhibits glucose metabolism specifically at the step of glucose transport. To determine whether reduced rates of glucose transport might result from reduced numbers of glucose transporters, whole cell lysates were prepared from GH-treated cells and subjected to immunoblotting using antibodies that identify Glut 1 (HepG2/rat brain) and Glut 4 (muscle/adipose) transporters. GH caused a time- and dose-dependent decrease in the number of Glut 1 transporters in the cell. Northern and slot-blot analyses showed a GH-induced dose-dependent decrease in levels of Glut 1 mRNA. In contrast, levels of Glut 4 transporter and mRNA were unchanged by GH. These data suggest that GH regulates Glut 1 and Glut 4 transporters differentially and that it exerts its inhibitory effect on glucose uptake at least in part by decreasing the synthesis of Glut 1 transporters. These studies provide the first evidence that GH regulates a key gene in metabolic regulation and can interfere with gene expression.

Cardiovascular effects of matrine isolated from the Chinese herb Shan-dou-gen

Matrine, a pure compound isolated from the Chinese herb Shan-don-Gen (Sophora subprostrata), was studied for its effects on the cardiovascular system of the rat. Intravenous injections of matrine at doses from 5 mg to 20 mg/kg body weight exhibited dose-dependent hypotensive and bradycardiac effects. These effects lasted only 1 to 3 min. In the isolated atria and ventricle preparations, matrine at doses from 50 micrograms to 200 micrograms/ml increased the amplitudes of spontaneous contraction of the atria and electrically induced contraction of the ventricle, whereas the frequency of the spontaneous beating of the atria was reduced. The dose-dependent effects of matrine on the isolated preparations persisted as long as the compound was present. Tachyphylaxis was not observed with repeated applications of this compound to the isolated preparations. The positive inotropic effects on both atria and ventricle and the negative chronotropic effect on spontaneous beating of the atria by matrine were not blocked by diphenhydramine, atropine, phenoxybenzamine, propranolol, trifluoperazine, or methysergide. In contrast, verapamil significantly reduced the positive inotropic effect of matrine on the ventricle. In the isolated aortic strip preparation, matrine at a dose of 200 micrograms/ml led to a slight increase in muscle tone. The same dose of matrine induced a 35% increase of perfusion pressure in the hindleg perfusion model. These results suggest that the in vivo transient hypotensive effect of matrine is likely associated with a decrease in heart rate itself, since positive inotropic effects on both the atria and the ventricle, and vasoconstriction of some vascular beds could not be the cause of hypotension.(ABSTRACT TRUNCATED AT 250 WORDS)

Participation of regional sympathetic outflows in the centrogenic pulmonary pathology

In anesthetized and vagotomized rats, a mechanical cerebral compression (CC) evoked systemic arterial hypertension (SAH) and pulmonary venous hypertension (PVH) followed by massive pulmonary hemorrhagic edema (PHE). The hemodynamic and pulmonary changes induced by CC were more pronounced in the right heart bypass (RHB) preparation (venous return to reservoir and constant pulmonary inflow). Additional observations in RHB included a marked reduction in reservoir volume (RV) without significant change in pulmonary vascular resistance (PVR). In either natural circulation or RHB, an upper thoracic sympathectomy did not affect the SAH, RV reduction, and PVR change, but reduced the PVH and PHE by approximately one-third. Such effects were not attributed to cardiac denervation, because beta 1-adrenergic blockade (metaprolol) did not alter the CC-induced PHE. Splanchnic denervation greatly diminished the SAH and prevented the RV reduction, PVH, and PHE. The results suggest that the centrogenic PHE is initiated from an intense arteriolar constriction, principally in the splanchnic beds. The latter causes left heart failure leading to volume and pressure loading and blood loss in the lungs. Direct sympathetic impulses to the lungs do not affect the PVR and RV changes and are not essential for the genesis of PHE. However, they may alter the vascular compliance and thereby exacerbate the PVH and PHE when passive accumulation of blood is produced in the lungs.