脑5-HT1A/1B、α2受体及腺苷酸环化酶参与了胍丁胺的抗抑郁作用

为了在单胺受体及受体后腺苷酸环化酶(adenylate cyclase,AC)水平探讨胍丁胺(agmatine,AGM)抗抑郁作用的精细机制,采用小鼠悬尾实验和强迫游泳实验观察AGM抗抑郁行为改变。采用放射免疫方法测定大鼠前额皮层突触膜蛋白AC活性。结果表明,AGM(5～40 mg·kg^-1,ig)在小鼠悬尾实验和强迫游泳实验模型上均有显著抗抑郁活性。同时伍用β受体/5-HT_1A/1B受体阻断剂吲哚洛尔(pindolol, PIN, 20 mg·kg^-1, ip)、 α₂肾上腺素受体拮抗剂育亨宾(yohimbine, YOH, 5～10 mg·kg^-1, ip)或咪唑克生(idazoxan, IDA, 4 mg·kg^-1, ip)对AGM(40 mg·kg^-1, ig)的抗抑郁活性具有显著拮抗效应; 而β受体阻断剂普萘洛尔(propranolol, PRO, 5～20 mg·kg^-1, ip)或5-HT₃受体拮抗剂曲匹西隆(tropisetron, TRO, 5～40 mg·kg^-1, ip)对AGM(40 mg·kg^-1, ig)的抗抑郁活性无显著影响。AGM(0.1～6.4 μmol·L^-1)与大鼠前额皮层提取的突触膜共孵可剂量依赖地激活AC活性, 而PIN(1 μmol·L^-1)或YOH(0.25～1 μmol·L^-1)均显著拮抗AGM(6.4 μmol·L^-1)对AC的激活作用; 慢性给予大鼠AGM(10 mg·kg^-1, ig, bid)或氟西汀(fluoxetine, FLU, 10 mg·kg^-1, ig, bid) 2 w也显著增强大鼠前额皮层基础及Gpp(NH)p 预激活的AC活性。本研究表明, 调节脑内5-HT_1A/1B和α₂等受体功能, 并激活前额皮层AC可能是AGM抗抑郁活性的重要机制之一。     

溴泰君(W198)在大鼠和比格狗体内的药代动力学

目的研究溴泰君(W198)在大鼠和比格狗的药代动力学。方法采用HPLC紫外检测方法测定大鼠及比格狗注射W198后血清药物浓度。结果大鼠iv W198 10,20和40 mg·kg^-1 3个剂量的T_1/2β分别为6.60,7.36和6.77 h,AUC_0-24h分别为3.797,7.371和15.192 mg·h·L^-1,V_d分别为7.14,4.33和4.13 L·kg^-1,CL分别为2.83,2.60和2.71 L·(kg·h)^-1。大鼠im W198 20 mg·kg^-1后T_1/2β为11.61 h,AUC_0-24h为4.191 mg·h·L^-1,im的生物利用度为56.9%。比格狗iv W198 5 mg·kg^-1,T_1/2β为11.72 h,AUC_0-24h为12.646 mg·h·L^-1,V_d为0.70 L·kg^-1,CL为0.46 L·(kg·h)^-1。W198与人血浆蛋白的结合率平均为78.0%。结论W198 im的T_1/2β比iv的略长,其生物利用度为56.9%。在10～40 mg·kg^-1剂量内的吸收呈现一级动力学特征。     

Kappa-晒化卡拉胶对实验动物的抗心律失常作用

Kappa-硒化卡拉胶是一含硒有机化合物。ip 9 mg·kg^-1·d^-1×5d或单次ig 35,70,140mg·kg^-1能显著提高乌头碱致大鼠HA的阈剂量,此作用可与Na₂SeO₃ 1 mg·kg^-1·d^-1×5d ip比拟.随着Kappa-硒化卡拉胶ig剂量增加,尚可提高乌头碱所致VE,VT和VF的阈剂量。ip 9mg·kg^-1·d^-1×5 d或ig 70mg·kg^-1能提高BaCl₂致大鼠或哇巴因致豚鼠HA的阈剂量。对BaCl₂致大鼠VF或哇巴因致豚鼠VE的阈剂量,分别在ig70mg·kg^-1与140mg·kg^-1时有提高,而ipNa₂SeO₃ 1 mg·kg^-1·d^-1×5d无此明显影响。     

蛇床子素在兔体内药物代谢动力学

目的研究蛇床子素在兔体内的药物代谢动力学。方法用高效液相色谱法,以丹皮酚为内标,以甲醇-水(80∶20)为流动相,测定兔血液中蛇床子素(iv,10 mg·kg^-1)的含量。采用3P87程序计算药物代谢动力学参数。结果蛇床子素iv药代动力学符合二房室开放模型,T_1/2α=5.81 min,T_1/2β=42.2 min,K21=0.036 0·min^-1,K₁₂=0.045 0·min^-1,K₁₀=0.054 0·min^-1,AUC=235 mg·min·L^-1,CLs=0.043 0 L·min^-1·kg^-1,V_C=0.780 L·kg^-1。结论蛇床子素在兔体内分布及消除较快     

利福平及异烟肼对家兔体内地西泮药代动力学的影响

用HPLC测定方法,研究了家兔多次ig利福平(100mg·kg^-1·d^-1×4)及异烟肼(50mg·kg^-1×4)后,对iv地西泮的药代动力学。结果表明,给药后利福平组肝微粒体细胞色素P-450含量增加98.1%,使地西泮的T_1/2β由98.77±19.38min减少到40.08±17.75min;AUC由143.52±41.41mg·min·L^-1减少到79.10±11.46mg·min·L^-1;CL由22.41±8.12ml·min^-1·kg^-1增加到43.96±10.38ml·kg^-1·min^-1。异烟肼组则表现出相反的作用。而利福平与异烟肼合用组对P-450含量及地西泮的动力学均无显著影响。提示利福平诱导家兔肝药酶的作用可加速地西泮的体内代谢过程,异烟肼抑制肝药酶减低地西泮的代谢。     

HPLC法同时测定复方三维右旋泛酸钙糖浆中4中维生素的含量

目的 建立高效液相色谱(HPLC)法同时测定复方三维右旋泛酸钙糖浆中维生素B₁、维生素B₂、维生素B₆和烟酰胺的含量。方法 采用外标法进行测定,色谱柱为Thermo Betasil C₁₈ Analytical(4.6 mm×250 mm, 5 μm),流动相为乙腈-5 mmol·L^-1十二烷基硫酸钠（含0.05%甲酸）水溶液梯度洗脱,流速1.0 mL·min^-1,检测波长260 nm,柱温30 ℃。分别测定10批复方三维右旋泛酸钙糖浆。结果 维生素B₁、维生素B₂、维生素B₆、烟酰胺4种成分的线性范围分别为5.76~115.2 μg·mL^-1(r=0.999 9)、1.16~23.20 μg·mL^-1(r=0.999 9)、1.72~34.4 μg·mL^-1(r=0.999 6)和5.76~115.2 μg·mL^-1(r=0.999 9),平均加样回收率为96.2%~98.4%(RSD为2.14%~3.42%)。不同批次复方三维右旋泛酸钙糖浆中维生素B₁、维生素B₂、维生素B₆、烟酰胺含量范围分别为0.133 7~0.155 9、0.027 86~0.030 71、0.039 05~0.047 7、0.138 7~0.148 2 mg·g^-1。结论 该方法为完善复方三维右旋泛酸钙糖浆的质量标准和加强质量控制提供了新的方法和依据。     

聚氧乙烯醚类表面活性剂对大鼠体内细胞色素P450 3A活性的影响

为研究药用辅料对大鼠体内细胞色素P450 3A(CYP3A)药酶活性的影响， 大鼠分别灌胃生理盐水、 酮康唑(75 mg·kg^-1·d^-1)， 曲拉通X-100(30 mg·kg^-1·d^-1)、 聚氧乙烯蓖麻油(EL35, 150 mg·kg^-1·d^-1)、 聚氧乙烯氢化蓖麻油(RH40, 150 mg·kg^-1·d^-1) 5 d后， 12 h禁食再经十二指肠给予上述试药， 20 min后给予咪哒唑仑作为探针。分别测定咪哒唑仑及其代谢物1′-羟基咪哒唑仑在大鼠体内的血药浓度并计算其药代动力学参数， 比较曲拉通X-100、 EL35和RH40处理组与生理盐水组的药代动力学差异。结果显示， 阳性对照药酮康唑对CYP3A有明显的抑制作用； 而曲拉通X-100、 EL35和RH40使1′-羟基咪哒唑仑与咪哒唑仑的AUC_0-∞比值分别从1.14降至0.90、 1.03和0.64，统计学分析表明曲拉通X-100和EL35对CYP3A没有明显的抑制作用， 而RH40对CYP3A有明显的抑制作用。因此， 在药物制剂研究及临床应用中， RH40有可能影响经细胞色素P450 3A转化的药物代谢及处置， 增加药物的生物利用度， 对药物的临床应用产生显著影响。     

联苯双酯对大鼠黄曲霉毒素B1代谢及肝毒性的影响

目的研究抗肝炎药联苯双酯对大鼠黄曲霉毒素B1代谢和肝毒性的影响.方法大鼠po联苯双酯300 mg*kg-1*d-1, 连服3 d后ip黄曲霉毒素B1 1.5 mg*kg-1.给黄曲霉毒素B1 16 h后测定血清ALT和AST水平,观察联苯双酯对黄曲霉毒素B1引起肝损伤的保护作用以及对体外代谢的影响.结果联苯双酯(300 mg*kg-1*d-1,连服3 d)可明显降低黄曲霉毒素B1引起的大鼠血清转氨酶升高,增加低毒代谢产物AFM1的生成.联苯双酯还可增加大鼠肝脏细胞色素P450总量和胞浆GSH含量,诱导P450 2B1介导的PROD和GST的活性.此外,联苯双酯对P450 3A介导的红霉素脱甲基酶和P450 1A介导的EROD也有一定的诱导作用.结论联苯双酯可通过增加大鼠肝脏对AFB1代谢的解毒功能起到肝保护作用.     

乙酰基蝙蝠葛苏林碱抗缺血性脑损伤作用

用细胞培养方法和大鼠脑缺血损伤模型,研究乙酰基蝙蝠葛苏林碱(O,O-acetyldaurisoline,Adau)对缺血性脑损伤的保护作用。结果表明,Adau对低钾、高钾、Bay K 8644及去甲肾上腺素所引起PC12细胞内游离钙浓度增加有抑制作用,其IC₅₀分别为4.63±0.72,0.15±0.02,93.7±17.6和10.0±1.4μmol·L^-1。Adau在整体大鼠双动脉结扎(2.5,5,10mg·kg^-1,iv)和四动脉结扎(5,10mg·kg^-1,iv)模型上,均能降低缺血脑组织脂质过氧化物含量,增加超氧物歧化酶(SOD)活性。提示Adau对脑缺血损伤有明显的保护作用。     

流动注射化学发光法测定维生素B2

目的建立一种简便、快速、灵敏度高的流动注射抑制化学发光测定维生素B₂的新方法。方法 以维生素B₂对luminol-K₃Fe(CN)₆化学发光体系的抑制作用为基础,在流动注射系统中用固定化试剂技术完成对试样的测定。结果测定的线性范围为0.01～1.0 μg·mL^-1,检测限为4.0 ng·mL^-1 (3σ),RSD小于3.0%(n=7)。并对药品和生物材料中的常见干扰物质进行了试验。结论维生素B₂化学发光传感器可连续使用450次以上,并成功地用于药物中维生素B₂的测定。     

双环醇对大鼠黄曲霉毒素B1代谢和肝毒性的影响

目的:研究抗肝炎新药双环醇对大鼠黄曲霉毒素B_1(AFB_1)代谢和肝毒性的影响.方法:大鼠灌胃双环醇300 mg·kg~(-1)·d~(-1),连服三日后腹腔注射黄曲霉毒素B_1 1.5 mg·kg~(-1).给黄曲霉毒素B_1 16小时后观察双环醇对黄曲霉毒素B_1引起肝损伤的防护作用以及对体外代谢的影响.结果:双环醇(300 mg·kg~(-1)·d~(-1),连服三日)可明显降低黄曲霉毒素B_1引起的大鼠血清转氨酶和肝脏MDA的升高,增加低毒代谢产物AFQ_1的生成.双环醇还可增加大鼠肝脏细胞色素P450总量和胞浆谷胱甘肽含量,诱导P450 CYP2B1介导的7-戊氧基香豆素脱烃酶和谷胱甘肽疏基转移酶的活性.此外,双环醇对P450 CYP3A介导的红霉素脱甲基酶和 P450 CYP1A介导的7-乙氧基香豆素脱烃酶也有诱导作用.结论:双环醇可通过增加大鼠肝脏对AFB_1代谢的解毒功能起到肝保护作用.     

联苯双酯对他克林引起的肝损伤的保护作用

目的　观察联苯双酯(DDB)对他克林(THA)诱发小鼠肝损伤的保护作用。方法　小鼠一次poTHA(56mg·kg^-1) ,观察12h内动物血清ALT ,肝脏MDA和动物体温的改变;分光光度法测定小鼠脑乙酰胆碱酯酶活性;酶动力法测定小鼠肝微粒体7-乙氧基香豆素脱乙基酶和UDP葡糖醛酸转移酶(UDPGT)的活性;荧光法测定线粒体膜电位的改变。结果　DDB 200 mg·kg^-1 可明显保护THA引起的小鼠体温下降、血清ALT和肝脏MDA的升高。DDB(100 μmol·L^-1 )可减轻THA造成的大鼠线粒体膜电位降低。DDB还可提高小鼠肝微粒体7-乙氧基香豆素脱乙基酶的活性,但对UDPGT无影响。结论　DDB似通过降低肝脏脂质过氧化反应、提高线粒体膜稳定性、调节THA代谢酶活性发挥其肝保护作用     

Bacterial lipopolysaccharide exposure alters aflatoxin B(1) hepatotoxicity: benchmark dose analysis for markers of liver injury.

Aflatoxin B(1) (AFB(1)) is a fungal toxin that causes both acute hepatotoxicity and hepatocellular carcinoma in humans and experimental animals. Previous studies demonstrated that a small, noninjurious dose of bacterial lipopolysaccharide (LPS) augments the hepatotoxicity of AFB(1) through activation of inflammatory cells and production of soluble inflammatory mediators (Barton et al., 2000b, 2001). This study was conducted to examine the effect of LPS on the dose-response relationship for AFB(1)-induced liver injury. Male Sprague-Dawley rats (250-350g) were treated with AFB(1) (0.1 mg/kg-6.3 mg/kg, ip) and 4 h later with a noninjurious dose of E. coli LPS (7.4 x 10(6) EU/kg, iv). Twenty-four h after AFB(1) administration, hepatic parenchymal cell injury was estimated from elevations in serum alanine aminotransferase and aspartate aminotransferase activities. Injury to intrahepatic bile ducts was evaluated from increased serum gamma-glutamyl transferase and alkaline phosphatase activities. Based on benchmark dose (BMD) analysis, the AFB(1) BMD for parenchymal cell injury was decreased 10-fold by LPS cotreatment, whereas AFB(1) BMDs for bile duct injury were decreased nearly 20-fold. The data suggest that concurrent inflammation renders the liver considerably more sensitive to the hepatotoxic effects of AFB(1).     

Induction of liver microsomal cytochrome P-450 2B1 by dimethyl diphenyl bicarboxylate in rats.

Dimethyl diphenyl bicarboxylate (dimethyl-4,4'-dimethyloxy-5,6,5',6'-dimethylene-dioxy-di phe nyl-2,2'- bicarboxylate, DDB), a synthetic mimic of the natural product schizandrin C, is used in China as a hepatoprotective agent to improve the liver functions of patients with hepatitis or under cancer chemotherapy. In this study, we investigated the effects of DDB on liver microsomal drug-metabolizing enzymes. When male Sprague-Dawley rats were treated with a daily intragastric dose of DDB (200 mg.kg-1) for 3 d, the microsomal pentoxyresorufin dealkylase activity and P-450 2B1 protein levels were markedly increased. The fold increase was lower than that by phenobarbital (75 mg.kg-1, ip once daily x 3 d). The level of P-450 2B1 mRNA was elevated by DDB but the magnitude of the elevation was much less than that caused by phenobarbital. DDB also increased the rates of testosterone hydroxylation at positions 16 beta, 16 alpha, 6 beta, and 2 beta as well as the rate of ethoxyresorufin dealkylation, suggesting moderate increases in the levels of P-450 3A and P-450 1A1 in addition to the huge increase in P-450 2B1. The level of glutathione S-transferase was also slightly increased, but the levels of P-450 2E1 and NAD(P)H: quinone oxidoreductase were not changed. The results indicate that DDB is an inducer of P-450 2B1.     

Fumonisin B1-induced DNA damage in rat liver and spleen: effects of pretreatment with coenzyme Q10, L-carnitine, alpha-tocopherol and selenium.

Active oxygen radical species are reported to cause organ damage. This study was designed to determine whether oxidative stress contributed to the initiation or progression of hepatic and splenic cell DNA damage induced by fumonisin B1 (FB1) in rats. Another aim was to investigate the protective effects of the antioxidants coenzyme Q10 (CoQ10), L-carnitine, vitamin E (alpha-tocopherol) and selenium against DNA damage in the liver and spleen of rats treated with FB1. Fasted rats were injected intravenously with a single dose of fumonisin B1 at 1.55 mg kg-1 body wt. into the tail vein. Treatment with FB1 led to splenic and hepatic DNA fragmentation in 85% of the test animals. DNA fragmentation was investigated as a critical event in toxic cell death by testing total Ca2+ in liver. FB1 administration caused total Ca2+ in liver to increase within 4 h (204% of control). Measurement of liver enzyme activities showed an increase in aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT). FB1 also markedly decreased splenic and hepatic glutathione (GSH) levels. Pretreatment with CoQ10 (30 mg CoQ10 kg-1 diet) together with L-carnitine (2.8 mg carnitine kg-1 diet), alpha-tocopherol (30 IU vitamin E kg-1 diet) and selenium (1 mg selenium as sodium selenite kg-1 diet), decreased DNA damage and the activities of Ca2+, ASAT and ALAT in the liver. On the other hand, the level of GSH was slightly increased. The CoQ10 alone did not significantly protect against toxic cell death and glutathione depletion caused by FB1. Oxidative damage caused by FB1 may be one of the underlining mechanisms of FB1-induced cell injury and DNA damage.     

Effects of picroliv, the active principle of Picrorhiza kurroa, on biochemical changes in rat liver poisoned by Amanita phalloides.

The efficacy of Picroliv, a standardized iridoid glycoside fraction of Picrorhiza kurroa, was studied against the Amanita phalloides-induced biochemical changes in rat liver. A phalloides (50 mg.kg-1) caused significant increases in the activities of hepatic 5'-nucleotidase, gamma-glutamyl transpeptidase, acid ribonuclease, and succinate dehydrogenase, but a decrease in glucose-6-phosphatase. The level of cytochrome P-450 in microsomal fraction and content of glycogen in liver showed significant depletions. Picroliv (25 mg.kg-1.d-1 x 10 d) provided significant restorations of all the biochemical changes poisoned by A phalloides except cytochrome P-450 and glycogen. These results demonstrated the protective effect of Picroliv against A phalloides-induced hepatotoxicity in rats.     

Lipopolysaccharide augments aflatoxin B(1)-induced liver injury through neutrophil-dependent and -independent mechanisms.

Exposure to small, noninjurious doses of the inflammagen, bacterial endotoxin (lipopolysaccharide, LPS) augments the toxicity of certain hepatotoxicants including aflatoxin B(1) (AFB(1)). Mediators of inflammation, in particular neutrophils (PMNs), are responsible for tissue injury in a variety of animal models. This study was conducted to examine the role of PMNs in the pathogenesis of hepatic injury after AFB(1)/LPS cotreatment. Male, Sprague-Dawley rats (250-350 g) were treated with either 1 mg AFB(1)/kg, ip or its vehicle (0.5% DMSO/saline), and 4 h later with either E. coli LPS (7. 4 x 10(6) EU/kg, iv) or its saline vehicle. Over a course of 6 to 96 h after AFB(1) administration, rats were killed and livers were stained immunohistochemically for PMNs. LPS resulted in an increase in PMN accumulation in the liver that preceded the onset of liver injury. To assess if PMNs contributed to the pathogenesis, an anti-PMN antibody was administered to reduce PMN numbers in blood and liver, and injury was evaluated. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5'-ND) in serum. Neutrophil depletion protected against hepatic parenchymal cell injury caused by AFB(1)/LPS cotreatment but not against markers of biliary tract injury. This suggests that LPS augments AFB(1) hepatotoxicity through two mechanisms: one of which is PMN-dependent, and another that is not.     

Effect of pregnenolone-16 alpha-carbonitrile and dexamethasone on acetaminophen-induced hepatotoxicity in mice.

Recently, we demonstrated that a microsomal enzyme inducer with a steroidal structure, pregnenolone-16 alpha-carbonitrile (PCN), markedly decreased the hepatotoxicity of acetaminophen (AA) in hamsters. Therefore, it was of interest to determine if PCN, as well as another steroid microsomal enzyme inducer, dexamethasone (DEX), would decrease the toxicity of AA in mice, another species sensitive to AA hepatotoxicity. Mice were pretreated with PCN or DEX (100 and 75 mg/kg, ip, for 4 days, respectively) and were given AA (300-500 mg/kg, ip). Twenty-four hours after AA administration, liver injury was assessed by measuring serum activities of sorbitol dehydrogenase and alanine aminotransferase and by histopathological examination. Neither PCN nor DEX protected markedly against AA hepatotoxicity in mice; PCN tended to decrease AA-induced hepatotoxicity, whereas DEX was found to enhance AA-induced hepatotoxicity and it produced some hepatotoxicity itself. DEX decreased the glutathione concentration (36%) in liver and increased the biliary excretion of AA-GSH, which reflects the activation of AA, whereas PCN produced neither effect. Thus, whereas PCN has been shown to markedly decrease the hepatotoxicity of AA in hamsters, apparently by decreasing the isoform of P450 responsible for activating AA to N-acetyl-p-benzoquinoneimine, this does not occur in mice after induction with either PCN or DEX. In contrast, DEX enhances AA hepatotoxicity apparently by decreasing liver GSH levels and increasing the activation of AA to a cytotoxic metabolite.