奥美拉唑对小鼠胸腺、脾脏免疫功能的影响

目的：研究长期使用奥美拉唑（ omeprazole,OME）是否会抑制小鼠体内溶酶体及其对小鼠免疫器官的影响。方法实验分为单纯对照组、OME低剂量组（6 mg· kg－1）、OME高剂量组（30 mg· kg－1）,每组10只小鼠。饲养24周后处死小鼠, ELISA法检测小鼠血清及脾脏中酸性磷酸酶（ acid phosphatase,ACP）、N-乙酰-β-D-氨基葡萄糖苷酶（ N-acetyL-β-D-glucosamini-dase,NAG）含量,采集小鼠胸腺、脾脏并称重计算小鼠脾脏、胸腺重量指数。结果 OME组与对照组相比血清中溶酶体酶活性下降,两者差异具有统计学意义（P＜0．05）,同时小鼠脾脏及胸腺重量指数明显下降。结论 OME可以抑制小鼠体内溶酶体及其水解酶的活性,导致系统性免疫功能受损,从而降低小鼠免疫功能。     

槲皮素对胃癌相关p53/AMPK/mTOR信号通路的影响

目的　探讨槲皮素（QE）对胃癌相关p53/AMPK/mTOR信号通路的影响。方法　将胃癌细胞分为QE组和溶剂组,QE组以DMSO为溶剂按配制QE浓度分别为0.02、0.04、0.06及0.08 mmol/L,对细胞进行干预,分别为QEA、QEB、QEC、QED组,溶剂组加入等量不含QE的溶剂。MTT实验检测槲皮素对胃癌细胞增殖的影响;MDC染色法检测槲皮素对胃癌细胞自噬的影响;双染法检测槲皮素对胃癌细胞凋亡的影响;实时荧光定量聚合酶链反应检测细胞内p53、AMPK及mTOR的mRNA相对表达水平;Western blot检测细胞内LC3Ⅱ/LC3Ⅰ、P53、AMPK、mTOR蛋白表达差异。结果　与溶剂组相比,QE各剂量组胃癌细胞的自噬程度和凋亡率均显著增加,细胞中LC3Ⅱ/Ⅰ蛋白表达量上调,p53、AMPK mRNA和蛋白水平均上调,mTOR的mRNA和蛋白表达量均下调（P＜0.05）,且呈剂量依赖性。结论　QE可以抑制胃癌细胞增殖,诱导其发生自噬、促进其凋亡,其作用机制可能与p53/AMPK/mTOR信号通路有关。     

脑苷肌肽对缺氧缺血性脑病新生大鼠SIRT1/mTOR/p70S6K通路及神经元凋亡的影响

目的探讨脑苷肌肽对缺氧缺血性脑病(HIE)新生大鼠沉默信息调节因子2相关酶1(SIRT1)/哺乳动物雷帕霉素靶蛋白(mTOR)/p70核糖体蛋白S6激酶(p70S6K)通路及神经元凋亡的影响。方法采用结扎左侧颈总动脉及缺氧玻璃仓的方法建立新生大鼠HIE模型,造模大鼠随机分为5组:模型组、脑苷肌肽低剂量组(0.8 mg/kg)、脑苷肌肽中剂量组(1.6 mg/kg)、脑苷肌肽高剂量组(3.2 mg/kg)、尼莫地平组(10 mg/kg),每组12只,另取12只设为假手术组。分组处理后,观察各组大鼠神经行为活动并进行评分;测定各组大鼠脑组织含水量;TUNEL染色检测各组大鼠脑皮质神经元凋亡情况;酶联免疫吸附法(ELISA)检测各组大鼠血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)水平;免疫印迹法检测各组大鼠脑组织SIRT1/mTOR/p70S6K通路相关蛋白表达情况。结果与假手术组相比,模型组大鼠神经功能缺损评分、脑组织含水量、脑皮质神经元凋亡率、血清TNF-α及IL-1β水平、脑组织SIRT1/mTOR/p70S6K通路相关蛋白p-mTOR/mTOR及p-p70S6K/p70S6K明显升高,脑组织SIRT1表达降低(P0.001);与模型组相比,脑苷肌肽低、中、高剂量组及尼莫地平组大鼠神经功能缺损评分、脑组织含水量、脑皮质神经元凋亡率、血清TNF-α及IL-1β水平、脑组织SIRT1/mTOR/p70S6K通路蛋白p-mTOR/mTOR及p-p70S6K/p70S6K降低,脑组织SIRT1表达升高(P0.001),且脑苷肌肽各组呈剂量依赖性(P0.001),脑苷肌肽高剂量组与尼莫地平组相比,大鼠各指标差异无统计学意义。结论脑苷肌肽可促使HIE新生大鼠脑组织SIRT1表达,降低mTOR、p70S6K磷酸化水平,抑制炎症,减轻脑水肿及神经元凋亡,修复神经功能,改善其临床症状。     

6S-5-甲基四氢叶酸钙对小鼠免疫力的增强作用研究

目的观察6S-5-甲基四氢叶酸钙对小鼠免疫力的影响。方法将小鼠分为低剂量组、中剂量组、高剂量组以及阴性对照组,每组各10只,低、中、高剂量组分别灌胃给予0.8 mg/(kg·d)、1.7 mg/(kg·d)、5.0 mg/(kg·d)6S-5-甲基四氢叶酸钙,阴性对照组给予同等容积的饮用纯净水,观察6S-5-甲基四氢叶酸钙对小鼠体重、胸腺/体重比、脾脏/体重比、小鼠脾淋巴细胞转化能力、迟发型超敏(DTH)反应、溶血空斑数、血清溶血素含量、碳廓清能力、巨噬细胞吞噬鸡红细胞能力和自然杀伤细胞(NK cells)活性的影响。结果与阴性对照组相比,受试三个剂量组小鼠体重差异无统计学意义(P 0.05),胸腺/体重比、脾脏/体重比较低(P 0.05),小鼠DTH程度增加(P 0.05);低、中、高剂量组小鼠碳廓清能力呈剂量依赖性增加(P 0.05),NK细胞活性明显增强(P 0.05);中、高剂量组小鼠淋巴细胞增殖能力、溶血空斑数、抗体积数和巨噬细胞吞噬鸡红细胞能力均增加(P 0.05)。结论 6S-5-甲基四氢叶酸钙能增强小鼠的免疫力。     

橙皮素早期干预对APPswe/PS1dE9双转基因小鼠Aβ生成的影响

目的探讨橙皮素早期干预对APPswe/PS1d E9双转基因小鼠Aβ生成、神经元脱失和学习记忆的影响。方法应用野生型C57BL/6J小鼠为对照,以APPswe/PS1d E9双转基因小鼠为模型,橙皮素高(80 mg·kg~(-1))、中(40 mg·kg~(-1))、低(20 mg·kg~(-1))3个剂量组,自3月龄开始早期干预6个月,每日灌胃1次。应用Morris水迷宫、Barens迷宫检测各组小鼠学习记忆能力;硫堇染色观察海马CA1区神经元形态;Western蛋白印迹法检测脑组织Tau蛋白表达水平;酶联免疫吸附法(ELISA)检测血清和脑组织中β分泌酶、γ分泌酶和Aβ_(42)含量。结果 (1)橙皮素早期干预对小鼠学习记忆能力的影响:实验第3天起,与对照组相比,模型组小鼠在Morris水迷宫空间探索实验中潜伏期明显延长(P<0.05);与模型组相比,橙皮素高、低剂量组潜伏期明显缩短(P<0.05);在撤台实验中,模型组小鼠穿越平台次数明显少于对照组(P<0.05),橙皮素3个剂量组小鼠穿越平台次数比模型组均明显增加(P<0.05);Barens迷宫实验中,模型组小鼠寻找目标箱错误次数高于对照组,橙皮素3个剂量组小鼠错误次数少于模型组(P<0.05);第14天Barens迷宫实验中,橙皮素高剂量组小鼠错误次数少于模型组(P<0.05)。(2)橙皮素早期干预对小鼠海马CA1区神经元的影响:对照组小鼠海马CA1区约有2～3层神经元,神经元形态完整、清晰,模型组小鼠神经元有明显缺失,神经元轮廓结构不清晰,排列紊乱,橙皮素高、中、低剂量组海马CA1区神经元结构排列整齐紧密,约有3～5层神经元,神经元形态完整清晰。(3)橙皮素早期干预对小鼠脑组织tau蛋白表达的影响:与对照组相比模型组Tau蛋白表达水平明显增加(P<0.05),橙皮素高、低剂量组Tau蛋白表达水平较模型组明显下降(P<0.05)。(4)血清与脑组织中Aβ_(42)含量与对照组相比,模型组血清与脑组织Aβ_(42)含量总和明显升高(P<0.05),与模型组相比,橙皮素高、低剂量组血清与脑组织Aβ_(42)含量总和降低(P<0.05)。脑组织中,模型组Aβ_(42)含量高于对照组(P<0.05),与模型组相比,橙皮素高、中、低3个剂量组Aβ_(42)含量均明显降低(P<0.05)。血清中,模型组Aβ_(42)含量与对照组含量差异无统计学意义,橙皮素中、低剂量组Aβ_(42)含量高于模型组(P<0.05)。脑组织与血清中Aβ_(42)含量的比值,模型组高于对照组(P<0.05);与模型组相比,橙皮素高、中、低3个剂量组均明显降低(P<0.05)。(5)脑组织中β分泌酶及γ分泌酶含量脑组织中,模型组小鼠β分泌酶含量明显高于对照组(P<0.05);与模型组相比,橙皮素高、中、低剂量组β分泌酶含量明显降低(P<0.05)。血清和脑组织中,模型组小鼠γ分泌酶含量明显高于对照组(P<0.05);与模型组相比,橙皮素高、中、低3个剂量组γ分泌酶含量明显降低(P<0.05)。结论橙皮素早期干预可保护APPswe/PS1d E9双转基因小鼠脑神经元,改善小鼠学习记忆能力,其可能的机制为降低脑组织β分泌酶和γ分泌酶活性,减少脑组织内Aβ_(42)生成,促进脑组织Aβ_(42)向外周转移,降低脑组织中Aβ_(42)含量。     

辐射对小鼠脾脏损伤及香菇多糖的保护作用

目的 研究辐射对小鼠脾脏的损伤以及香菇多糖对其保护作用。方法 建立小鼠低剂量长期辐射的损伤模型。小鼠随机分为五组,对照组、模型组、香菇多糖组(低、中、高剂量组)。测定各组小鼠的脾脏系数、MTT法测定小鼠脾脏淋巴细胞的增殖情况,法分析脾脏组织的病理变化,用投射电镜法分析脾脏细胞的超微结构。结果：与对照组相比,低剂量慢性辐射能降低小鼠的脾脏系数、抑制脾脏淋巴细胞的增殖,对小鼠脾脏造成病理损伤,破坏脾脏细胞的超微结构。香菇多糖中、高剂量组可明显抑制辐射造成的脾脏的上述损伤。结论：香菇多糖对辐射造成的脾脏损伤具有保护作用。     

二苯乙烯苷的雌激素样作用及其对性未成熟小鼠子宫ER表达的影响

目的:探讨二苯乙烯苷(TSG)的雌激素样作用,以及其对性未成熟小鼠子宫雌激素受体(ER)表达的影响。方法:将60只性未成熟雌性昆明种小鼠随机分为正常组,阳性对照组(戊酸雌二醇,0.18 mg/kg),TSG低、高剂量组(50、150 mg/kg),TSG低、高剂量+戊酸雌二醇组(剂量同单用组)。正常组小鼠灌胃等体积水,各给药组小鼠灌胃相应药物溶液0.2 mL/10 g,早晚各1次,连续5d。末次给药次日,测定并计算各组小鼠子宫指数和体质量增幅;采用酶联免疫吸附测定法检测其血清雌激素[雌二醇(E_2)、黄体生成素(LH)、卵泡雌激素(FSH)]含量;采用苏木精-伊红染色法观察其子宫组织形态学特征,并检测子宫管径和子宫内膜厚度;采用免疫组织化学染色法检测其子宫组织中ER(ER-α、ER-β)的表达水平。结果:正常组小鼠子宫肌层排列平行、紧密,子宫上皮呈单层柱状,ER-α、ER-β表达较少;各给药组小鼠子宫管径、内膜及上皮均不同程度地增大、增厚或增生,ER-α、ER-β表达有所变化。与正常组比较,各给药组小鼠子宫指数(阳性对照组、TSG高剂量组、TSG各剂量+戊酸雌二醇组)、体质量增幅(阳性对照组、TSG高剂量组、TSG低剂量+戊酸雌二醇组)、子宫管径及内膜厚度(阳性对照组、TSG低剂量组、TSG各剂量+戊酸雌二醇组)、ER-α的表达量(阳性对照组、TSG各剂量+戊酸雌二醇组)、ER-β的表达量(阳性对照组、TSG高剂量组+戊酸雌二醇联用组)均显著升高,血清LH(阳性对照组、TSG高剂量组)、FSH(TSG低剂量+戊酸雌二醇组)水平均显著降低(P<0.05或P<0.01);TSG各剂量+戊酸雌二醇组小鼠子宫指数、子宫管径及内膜厚度、ER-α及ER-β的表达量以及TSG低剂量+戊酸雌二醇组小鼠体质量增幅、血清E_2含量均显著高于TSG同剂量单用组(P<0.05或P<0.01);TSG各剂量组小鼠子宫指数、子宫管径及内膜厚度、ER-α及ER-β的表达量,TSG各剂量+戊酸雌二醇组小鼠子宫管径、ER-β的表达量以及TSG低剂量组小鼠体质量增幅均显著低于阳性对照组,而TSG各剂量+戊酸雌二醇组小鼠血清LH水平均显著高于阳性对照组(P<0.05或P<0.01)。结论:TSG可一定程度地增加性未成熟小鼠的子宫指数和体质量,并调节其体内雌激素水平,增加子宫管径及内膜厚度,上调子宫组织中ER的表达,具有一定的雌激素样作用。但这种作用弱于戊酸雌二醇,且两者联合使用可能会拮抗戊酸雌二醇的作用。     

芦荟多糖增强顺铂对肺腺癌裸鼠移植瘤生长的抑制作用

目的 观察芦荟多糖（Aloe polysaccharide,AP）和顺铂（DDP）合用对人肺腺癌A549细胞裸小鼠移植瘤生长的抑制作用,并初步探讨其作用机制。方法 采用A549细胞株建立人肺腺癌裸鼠模型,将35只,♀,成瘤裸小鼠随机分为7组：对照组（生理盐水0.2 mL）;DDP低剂量组（1.0 mg·kg^-1）;DDP高剂量组（5 mg·kg^-1）;AP低剂量组（10 mg·kg^-1）;AP高剂量组（30 mg·kg^-1）;DDP低剂量组＋AP低剂量组;DDP低剂量组＋AP高剂量组,隔天腹腔注射给药,共8次。于最后1次给药后48 h处死各组小鼠,收集瘤标本行光镜观察,免疫组化检测p53和bcl-2蛋白表达情况。结果 各实验组肿瘤的生长明显受到抑制,瘤质量明显低于对照组（P〈0.01）。低、高剂量AP联合用药组较低剂量DDP组抑瘤作用明显增强（P〈0.05）,其瘤重抑制率分别为49.34%和82.61%。高剂量AP组与对照组比较,p53和bcl-2的表达均下调,差异具有统计学意义（P〈0.05）,联合用药组该调节作用进一步增强。高剂量DDP组出现不良反应,其余各组无明显不良反应。结论 AP能够增强DDP对人肺腺癌A549细胞裸鼠移植瘤生长的抑制作用,其作用机制可能与AP抑制p53和bcl-2的表达有关。     

二氢杨梅素对小鼠葡聚糖硫酸钠结肠炎的干预作用

目的探讨二氢杨梅素(DMY)对葡聚糖硫酸钠(DSS)诱导的小鼠溃疡性结肠炎(UC)的作用效果。方法将60只Balb/C小鼠随机分为正常对照组、模型组、DMY低剂量组(50 mg·kg~(-1)·d~(-1))、DMY中剂量组(100 mg·kg~(-1)·d~(-1))、DMY高剂量组(200 mg·kg~(-1)·d~(-1))和5-氨基水杨酸组(50 mg·kg~(-1)·d~(-1)),各10只。正常对照组小鼠每日给予蒸馏水饮用,其余组小鼠给予4%DSS连续饮用7 d,诱导小鼠急性UC模型,与此同时给予对应剂量的药物灌胃治疗。7 d后处死小鼠并计算小鼠疾病活动指数(DAI)、光镜下结肠组织损伤评分(TDI),流式细胞法测定外周血中调节性T淋巴细胞(Treg)、辅助性T细胞17(Th17)占CD4+T细胞的百分比,Western blot及免疫组化法测定结肠组织中基质金属蛋白酶9(MMP 9)的表达水平。结果与正常对照组相比,模型组DAI、TDI明显升高(P<0.01),Treg/Th17比值明显降低(P<0.01),MMP 9表达升高(P<0.05)。与模型组相比,DMY低、中、高剂量组小鼠Treg/Th17比值明显升高(P<0.01),MMP 9表达降低(P<0.05),DMY中、高剂量组小鼠DAI、TDI明显降低(P<0.01),且随着治疗剂量增加,升高或降低幅度愈明显。结论 DMY可以显著缓解DSS诱导的小鼠UC炎症,且与剂量呈正相关。     

氯雷他定对小鼠鼻黏膜组织中炎症因子的影响

目的 观察氯雷他定对过敏性鼻炎小鼠鼻黏膜组织中炎症因子表达水平的影响.方法 BALB/c雄性小鼠50只,随机分为5组空白组,模型组,氯雷他定低剂量组(1 mg/kg),氯雷他定中剂量组(3mg/kg),氯雷他定高剂量组(10mg/kg)各有10只.通过小鼠打喷嚏次数和抓鼻次数评分评估小鼠鼻炎症状,通过Western blot和免疫组化检测鼻黏膜组织中IL-1、IL-6、TNF-β的表达.结果 成功建立小鼠过敏性鼻炎模型;模型组小鼠鼻黏膜组织中IL-1、IL-6和TNF-β的表达水平明显高于对照组、氯雷他定低、中、高剂量组;氯雷他定中剂量组IL-1、IL-6和TNF-β的表达水平明显高于高剂量组、低于低剂量组,呈现明显的剂量依赖性.结论 氯雷他定对过敏性鼻炎小鼠鼻黏膜组织中炎症因子的表达具有抑制作用.     

Opportunities for the replacement of animals in the study of nausea and vomiting

Nausea and vomiting are among the most common symptoms encountered in medicine as either symptoms of disease or side effects of treatments. Developing novel anti-emetics and identifying emetic liability in novel chemical entities rely on models that can recreate the complexity of these multi-system reflexes. Animal models (especially the ferret and dog) are the current gold standard; however, the selection of appropriate models is still a matter of debate, especially when studying the subjective human sensation of nausea. Furthermore, these studies are associated with animal suffering. Here, following a recent workshop held to review the utility of animal models in nausea and vomiting research, we discuss the limitations of some of the current models in the context of basic research, anti-emetic development and emetic liability detection. We provide suggestions for how these limitations may be overcome using non-animal alternatives, including greater use of human volunteers, in silico and in vitro techniques and lower organisms.     

Characteristics of histamine-induced leukocyte rolling in the undisturbed microcirculation of the rat mesentery

1. The main objective of this study was to analyse the role and mode of action of the mast cell mediator histamine in leukocyte-endothelium interactions in small venules in vivo. For this purpose, we used a histological approach (combined with intravital microscopy) that allows studies of rapid mediator-induced venular leukocyte accumulation, reflecting leukocyte rolling, in the undisturbed microcirculation of the rat mesentery where rolling is normally absent.
2. We first examined the relative importance of histamine and 5-hydroxytryptamine (5-HT) in acute mast cell-dependent leukocyte recruitment. The mast cell secretagogue compound 48/80 (i.p. for 15 min) induced a marked venular accumulation of polymorphonuclear leukocytes (PMNL) which was almost abolished by combined histamine₁ (H₁)- and histamine₂ (H₂)-receptor blockade. In contrast, the 5-HT-receptor antagonist methysergide was inactive in this regard. Moreover, exogenous 5-HT was less active than exogenous histamine in evoking venular PMNL accumulation (histamine response dose-dependent; 5-HT response bell shaped). Prostaglandin D₂ did not cause PMNL accumulation.
3. The venular PMNL response to exogenous histamine peaked between 15 min and 1 h, was still significantly elevated at 2 h, and then returned to prechallenge values after 3 h. At all time points, the histamine-induced PMNL accumulation was nearly abolished by i.v. treatment with the polysaccharide fucoidin (which blocks rolling but not firm adhesion per se), suggesting that the PMNL response to histamine was due to rolling rather than firm adhesion over the entire 3 h period. At no time point did histamine trigger accumulation of mononuclear leukocytes (MNL).
4. To examine the role of histamine-receptors in the histamine-induced PMNL accumulation (i.e. rolling), the animals were pretreated with diphenhydramine (H₁-receptor antagonist), cimetidine, or ranitidine (H₂-receptor antagonists). Diphenhydramine alone inhibited the venular PMNL response to histamine by 52%, while both H₂-receptor antagonists were completely inactive. However, the combination of cimetidine and diphenhydramine reduced the histamine-induced PMNL rolling by 82%. Furthermore, in contrast to an H₃-receptor agonist, challenge with either the H₁-receptor agonist 2-thiazolylethylamine or two different H₂-receptor agonists (impromidine, dimaprit) was sufficient to provoke significant venular PMNL accumulation.
5. Treatment with the nitric oxide-synthase inhibitor L-NAME did not affect the histamine-induced PMNL rolling. On the other hand, 3 h pretreatment with dexamethasone reduced the PMNL response to histamine by 73%, and flow cytometric analysis showed that the dexamethasone treatment almost completely inhibited binding of soluble P-selectin to rat isolated PMNLs.
6. We conclude that initial leukocyte recruitment after mast cell activation in the rat mesentery is critically dependent on histamine release. The cellular response to histamine was specifically due to PMNL rolling, involved activation of both H₁- and H₂-receptors, and lasted for 2–3 h. Moreover, the histamine-induced PMNL rolling was not dependent on nitric oxide synthesis, but was sensitive to glucocorticoid treatment, possibly via inhibition of expression or function of leukocytic P-selectin ligand(s).

     

Influence of the metabolic profile on the in vivo antioxidant activity of quercetin under a low dosage oral regimen in rats

BACKGROUND AND PURPOSE: Flavonoids are known to possess a broad set of pharmacological effects, some of which have been attributed to their antioxidant properties and, more recently, to cell signalling modulation. Nevertheless, flavonoids are extensively metabolized and their metabolites are the potential bioactive forms in vivo. Therefore, a first and crucial step to understand the mechanisms underlying potential health benefits of flavonoids is knowledge of their metabolites and their biological activities.EXPERIMENTAL APPROACH: To approximate a human dietary pattern of intake of flavonoids, regular rat chow was supplemented with 0.02% quercetin and fed to Sprague-Dawley rats over 3 weeks. Plasma samples were analysed by HPLC and electrospray tandem mass spectrometry, and plasma antioxidant capacity was measured by the 2,2'-azino-bis(3-ethylbenzothiazoline sulphonate) assay. KEY RESULTS: Major metabolites were 3'-methylquercetin (isorhamnetin) glucuronide sulphate conjugates, the most plausible conjugation positions being at the 3-, 5- and 7-hydroxyl positions. Isorhamnetin conjugates are methylated at the 3'-OH position, which decreases the high antioxidant activity of quercetin and its metabolites and their contribution to plasma antioxidant potential.CONCLUSIONS AND IMPLICATIONS: This metabolic pattern differs from that observed after a single high-dose administration, where the major metabolites were quercetin conjugates at 5- and 7-hydroxyl positions and a significantly increased plasma antioxidant activity was observed. These data show altogether that the different metabolic patterns obtained under a prolonged low-dosage regimen or after a single high dose, crucially affected the antioxidant potential of plasma in treated animals. Our data also allow for the establishment of structure-antioxidant activity relationships for quercetin metabolites.     

黄酮类化合物抗卵巢癌化疗耐药的作用进展

摘要：黄酮类化合物是广泛存在于自然界的一类多酚类物质,亦是诸多传统中草药中的有效成分之一,因其高效、低毒,且具有多种生物学活性而得到了广泛的关注。卵巢癌是病死率最高的妇科恶性肿瘤,化疗耐药是导致其预后不良的主要原因之一。研究发现,黄酮类化合物对改善卵巢癌耐药有独特的效果,或将有助于克服卵巢癌耐药。本文就近年来黄酮类化合物改善卵巢癌化疗耐药作用的相关研究进展进行综述。     

Pharmacological modulation of GABAA receptor-mediated postsynaptic potentials in the CA1 region of the rat hippocampus

1. It is unclear whether GABA_A receptor-mediated hyperpolarizing and depolarizing synaptic potentials (IPSP_As and DPSP_As, respectively) are evoked by (a) the same populations of GABAergic interneurones and (b) exhibit similar regulation by allosteric modulators of GABA_A receptor function. We have attempted to address these questions by investigating the effects of (a) known agonists for presynaptic receptors on GABAergic terminals, and (b) a range of GABA_A receptor ligands, on each response.
2. The GABA uptake inhibitor NNC 05-711 (10 μM) enhanced whereas bicuculline (10 μM) inhibited both IPSP_As and DPSP_As.
3. (−)-Baclofen (5 μM), [D-Ala²,N-Me-Phe⁴,Gly⁵-ol]-enkephalin (DAGO; 0.5 μM), and carbachol (10 μM) caused substantial depressions (up to 99%) of DPSP_As that were reversed by CGP 55845A (1 μM), naloxone (10 μM) and atropine (5 μM), respectively. In contrast, 2-chloroadenosine (CADO; 10 μM) only slightly depressed DPSP_As. Quantitatively, the effect of each agonist was similar to that reported for IPSP_As.
4. The neurosteroid ORG 21465 (1–10 μM), the anaesthetic propofol (50–500 μM), the barbiturate pentobarbitone (100–300 μM) and zinc (50 μM) all enhanced DPSP_As and IPSP_As.
5. The benzodiazepine (BZ) agonist flunitrazepam (10–50 μM) and inverse agonist DMCM (1 μM) caused a respective enhancement and inhibition of both IPSP_As and DPSP_As. The BZω₁ site agonist zolpidem (10–30 μM) produced similar effects to flunitrazepam.
6. The anticonvulsant loreclezole (1–100 μM) did not affect either response.
7. These data demonstrate that similar populations of inhibitory interneurones can generate both IPSP_As and DPSP_As by activating GABA_A receptors that are subject to similar allosteric modulation.

     

银杏叶提取物对大鼠美托洛尔药动学的影响

目的：探讨银杏叶提取物对大鼠美托洛尔药动学的影响。方法：将大鼠随机分为美托洛尔组和美托洛尔联合银杏叶提取物组,美托洛尔组口服给予美托洛尔40 mg·kg^-1,美托洛尔联合银杏叶提取物组口服给予银杏叶片28.8 mg·kg^-1（按黄酮醇苷量）和美托洛尔40 mg·kg^-1。给药后2,5,10,20,40,60,90,120,240,360,480,720 min股动脉采血,液相色谱串联质谱（LC-MS/MS）测定美托洛尔及代谢物血药浓度。结果：美托洛尔组联合灌胃给予银杏叶提取物与美托洛尔后,美托洛尔K_a和AUC_0-t显著降低（P<0.05）,t_max显著增加（P<0.05）,美托洛尔代谢产物O-去甲基美托洛尔和α-羟基化美托洛尔AUC_0-t显著增加（P<0.05）,而CL显著减小（P<0.05）。结论：银杏叶提取物能够显著降低美托洛尔的血药浓度,抑制其代谢物O-去甲基美托洛尔和α-羟基化美托洛尔的清除。     

Investigation of the role of 5-HT2 receptor subtypes in the control of the bladder and the urethra in the anaesthetized female rat

Background and purpose:

Micturition is controlled by central 5-HT-containing pathways. 5-HT₂ receptors have been implicated in this system especially in control of the urethra, which is a drug target for treating urinary incontinence. This study investigates the role of each of the three subtypes of this receptor with emphasis on sphincter regulation.

Experimental approach:

Recordings of urethral and bladder pressure, external urethral sphincter (EUS) EMG, as well as the micturition reflex induced by bladder distension along with blood pressure and heart rate were made in anaesthetized rats. The effects of agonists and antagonists for 5-HT₂ receptor subtypes were studied on these variables.

Key results:

The 5-HT_2C agonists Ro 60-0175, WAY 161503 and mCPP, i.v., activated the EUS, increased urethral pressure and inhibited the micturition reflex. The effects of Ro 60-0175 on the EUS were blocked by the 5-HT_2C antagonist SB 242084 and the 5-HT_2A antagonists, ketanserin and MDL 100907. SB 242084 also blocked the inhibitory action on the reflex, while the 5-HT_2B antagonist RS 127445 only blocked the increase in urethral pressure. The 5-HT_2A receptor agonist DOI given i.v. or i.t. but not i.c.v. activated the EUS.

Conclusions and implications:

5-HT_2A/2C receptors located in the sacral spinal cord activate the EUS, while central 5-HT_2C receptors inhibit the micturition reflex and 5-HT_2B receptors, probably at the level of the urethra, increase urethral smooth muscle tone. Furthermore, 5-HT_2B and 5-HT_2C receptors do not seem to play an important role in the physiological regulation of micturition.     

Involvement of a glibenclamide-sensitive mechanism in the nitrergic neurotransmission of the pig intravesical ureter

1. The present study was designed to investigate whether potassium (K⁺) channels are involved in the relaxations to nitric oxide (NO) of pig intravesical ureteral preparations suspended in organ baths for isometric tension recordings. In ureteral strips treated with guanethidine (10⁻⁵ M) and atropine (10⁻⁷ M) to block adrenergic neurotransmission and muscarinic receptors, respectively, NO was either released from nitrergic nerves by electrical field stimulation (EFS, 0.5–10 Hz, 1 ms duration, 20 s trains), or exogenously-applied as an acidified solution of sodium nitrite (NaNO₂, 10⁻⁶–10⁻³ M).
2. Incubation with an inhibitor of guanylate cyclase activation by NO, methylene blue (10⁻⁵ M) did not change the basal tension of intravesical ureteral strips but inhibited the relaxation induced by EFS or exogenous NO on ureteral preparations contracted with the thromboxane analogue U46619 (10⁻⁷ M).
3. Incubation with charybdotoxin (3×10⁻⁸ M) and apamin (5×10⁻⁷ M), which are inhibitors of large and small conductance calcium (Ca²⁺)-activated K⁺ channels, respectively, did not modify basal tension or the relaxations induced by EFS and exogenous NO. Treatment with charybdotoxin or apamin plus methylene blue (10⁻⁵ M) significantly reduced the relaxations to EFS and exogenous NO. However, in both cases the reductions were similar to the inhibition evoked by methylene blue alone. The combined addition of charybdotoxin plus apamin did not change the relaxations to EFS or exogenously added NO of the porcine intravesical ureter.
4. Cromakalim (10⁻⁸–3×10⁻⁶ M), an opener of ATP-sensitive K⁺ channels, evoked a dose-dependent relaxation with a pD₂ of 7.3±0.2 and maximum relaxant effect of a 71.8±4.2% of the contraction induced by U46619 in the pig intravesical ureter. The blocker of ATP-sensitive K⁺ channels, glibenclamide (10⁻⁶ M), inhibited markedly the relaxations to cromakalim.
5. Glibenclamide (10⁻⁶ M) had no effect on the basal tone of ureteral preparations but significantly reduced the relaxations induced by both EFS and exogenous NO. Combined treatment with methylene blue (10⁻⁵ M) and glibenclamide (10⁻⁶ M) did not exert an effect greater than that of methylene blue alone on either EFS- or NO-evoked relaxations of the pig ureter.
6. The present results suggest that NO acts as an inhibitory neurotransmitter in the pig intravesical ureter and relaxes smooth muscle through a guanylate cyclase-dependent mechanism which seems to favour the opening of glibenclamide-sensitive K⁺ channels.

     

The Role of the Striatum in Compulsive Behavior in Intact and Orbitofrontal-Cortex-Lesioned Rats: Possible Involvement of the Serotonergic System

In the signal attenuation rat model of obsessive-compulsive disorder (OCD), ‘compulsive'' behavior is induced by attenuating a signal indicating that a lever-press response was effective in producing food. We have recently found that lesions to the rat orbitofrontal cortex (OFC) led to an increase in compulsive lever-pressing that was prevented by systemic administration of the selective serotonin reuptake inhibitor paroxetine, and paralleled by an increase in the density of the striatal serotonin transporter. This study further explored the interaction between the OFC, the striatum, and the serotonergic system in the production of compulsive lever-pressing. Experiment 1 revealed that OFC lesions decrease the content of serotonin, dopamine, glutamate, and GABA in the striatum. Experiment 2 showed that intrastriatal administration of paroxetine blocked OFC lesion-induced increased compulsivity, but did not affect compulsive responding in intact rats. Experiments 3 and 4 found that pre-training striatal lesions had no effect on compulsive lever-pressing, whereas post-training striatal inactivation exerted an anticompulsive effect. These results strongly implicate the striatum in the expression of compulsive lever-pressing in both intact and OFC-lesioned rats. Furthermore, the results support the possibility that in a subpopulation of OCD patients a primary pathology of the OFC leads to a dysregulation of the striatal serotonergic system, which is manifested in compulsive behavior, and that antiobsessional/anticompulsive drugs exerts their effects, in these patients, by normalizing the dysfunctional striatal serotonergic system.     

Circadian variations in the effects of cyclic nucleotides on the thermoregulatory behaviour of a teleost fish

The temperatures selected by white suckers, Catostomus commersoni, placed in a thermal gradient were significantly altered by intraperitoneal injections of cAMP (1 μg/g), cGMP (1 μg/g), caffeine (15 μg/g), and imidazole (5 μg/g). There was an endogenous, circadian, rhythm in the effects of cAMP, cGMP, and caffeine on temperatures selected by individual fish held under constant illumination. Depending on injection time, there was either a significant increase or decrease in temperatures selected by fish injected with cGMP or caffeine. The preferred temperatures selected were elevated by cAMP, though there was a rhythmic variation in the amplitude of the increase. Imidazole consistently decreased the preferred temperatures selected with no apparent rhythmic variation in its actions. These results are considered in relation to the roles of cAMP and cGMP in behavioural and physiological thermoregulation.