白芍总甙对大鼠腹腔巨噬细胞产生肿瘤坏死因子的调节机制

目的：研究不同浓度白芍总甙（ＴＧＰ）调节大鼠腹腔巨噬细胞（ＭΦ）产生肿瘤坏死因子（ＴＮＦ）作用。方法：在ＭΦ培养系统中有或无环氧酶抑制剂和钙调蛋白抑制剂等工具药，测定４５Ｃａ内流、ＰＧＥ２和ＴＮＦ含量。结果：ＴＧＰ（０．５～１０ｍｇ·Ｌ－１）明显促进ＬＰＳ诱导ＭΦ的４５Ｃａ内流和ＴＮＦ产生。线性回归分析表明，４５Ｃａ内流和ＴＮＦ产生呈明显正相关。三氟拉嗪（４０μｍｏｌ·Ｌ－１）可阻断ＴＧＰ促进ＬＰＳ诱导ＭΦ产生ＴＮＦ。ＴＧＰ－ＬＰＳ的ＴＮＦ释放曲线呈钟罩形，而ＴＧＰ－ＬＰＳ的ＰＧＥ２产生曲线呈浓度依赖性升高。当ＴＧＰ在低浓度（０．５～１２．５ｍｇ·Ｌ－１）时，ＴＮＦ与ＰＧＥ２产生明显正相关，而高浓度（１２．５～２５０ｍｇ·Ｌ－１）两者呈明显负相关。吲哚美辛（１０μｍｏｌ·Ｌ－１）可使ＴＮＦ量效曲线下降支消失，而Ｎω亚硝基－Ｌ－精氨酸（１５μｍｏｌ·Ｌ－１）对此无明显影响。结论：低浓度ＴＧＰ对ＴＮＦ产生上调作用可能与促进４５Ｃａ内流，提高钙调蛋白活性从而促进ＰＧＥ２分泌等有关，而高浓度下调作用是可能与ＭΦ自身产生大量ＰＧＥ２介导有关。     

镉对人体外周血淋巴细胞内游离Ca~(2+)及钙调素影响的研究

采用体外实验方法，观察CdCl2对培养24h的人外周血淋巴细胞内游离Ga2+浓度及CaM活性的影响。结果表明：细胞内游离Ca2+浓度与镉浓度（≤100μmol／L）及染毒时间（≤60min）存在明显的剂量及时相相关，在≤50μmol／LCdCl2作用下，CaM活性随染毒剂量增加而升高，50μmol／LCdCl2使CaM活性增至0μmol／L组的190．22％（P＜0．05），但100μmol／LCaCl2则对CaM无激活作用。在一定镉浓度（0～50μmol／LCdCl2）及染毒时间（0～40min）内，细胞内游离Ca2+浓度与CaM活性呈*一致性变化，提示镉的免疫毒作用机制与Ca2+、CaM系统有关。     

Protein kinases modulate the sensitivity of hippocampal neurons to nitric oxide toxicity and anoxia

Multiple processes lead to neuronal death after ischemia, but the generation of nitric oxide (NO) is a key component in this cascade of events. The mechanisms that regulate the extent of neuronal degeneration during anoxia and NO toxicity are multifactorial. Neuronal death may be modulated by the activity of signal transduction systems that influence the toxicity of NO or its metabolic products such as cGMP. The enzyme responsible for the production of NO, nitric oxide synthase (NOS), is phosphorylated by protein kinase C (PKC), the cAMP-dependent protein kinase (PKA), and the calcium/calmodulin-dependent protein kinase II (CaM-II). We examined in primary cultured hippocampal neurons whether the protein kinases PKC, PKA, CaM-II, and cGMP-dependent protein kinase modified the toxic effects of anoxia and NO. Down-regulation of PKC activity with PMA (1μM) increased hippocampal neuronal survival during anoxia and NO exposure from approximately 22% to 88%. Inhibitors of PKC activity 9H-7, H-8, sphingosine, and staurosporine also were neuroprotective. Down-regulation of PKC activity increased survival during anoxia even in the presence of the NOS inhibitor, N^ω-methyl-L-arginine. Thus, although down-regulation of PKC activity may increase neuronal survival by decreasing NOS activity, it also is likely that PKC contributes to ischemic neuronal death by mechanisms that are independent of NOS. Inhibition of the cGMP-dependent protein kinase activity, but not the activity of the CaM-II also was neuroprotective during NO administration. In contrast to the protective effects of inhibition of PKC and the cGMP-dependent protein kinase, activation rather than inhibition of PKA increased hippocampal neuronal survival during NO exposure. These results indicate that neuronal survival during anoxia and NO exposure is linked to the modulation of PKC, PKA, and cGMP-dependent protein kinase activity but is not dependent on the CaM-II pathway. Understanding the involvement of PKC, PKA, and the cGMP-dependent protein kinase in modulating the effect of neuronal death during ischemia and NO toxicity may help in directing future therapeutic modalities for cerebrovascular disease. © 1993 Wiley-Liss, Inc.     

阿片类物质对淋巴细胞内环磷酸腺苷及游离钙的影响

文本观察了几种阿片类物质对小鼠脾脏淋巴细胞内环磷酸腺苷,游离钙及钙调蛋白的影响。结果表明:吗啡、α-CAO、MENK、DADLE及强啡肽均降低小鼠脾脏淋巴细胞内环磷酸腺苷水平,升高淋巴细胞内游离钙浓度,增加淋巴细胞内钙调蛋白活性。预先给予纳洛酮能够阻断阿片类物质的作用。说明阿片类物质的作用是通过阿片受体介导的。     

豚鼠耳蜗螺旋神经节钙调素的分布

观察正常豚鼠耳蜗螺旋神经节钙调素的分布，因为作为真核细胞中最重要的Ｃａ＾２＋受体－－钙调素在听觉径路上的分布和功能尚未见报道。     

Inhibitory effects of chlorpheniramine and astemizolum on contraction of isolated rat and rabbit uteri induced by oxytocin and PGF2α

Summary The contraction of isolated rat and rabbit uteri induced by oxytocin and PGF_2α was markedly inhibited by chlorpheniramine (Chl) and astemizolum (Ast), both of which also decreased the resting tension of uteri, and their spontaneous contraction. The inhibitory effects of both drugs were dose-dependent. At high concentrations, Chl 7.4× 10^-4 mol/L and Ast 10^-4 mol/L could counteract the contraction of the uteri induced by Oxy and PGF_2α, and their spontaneous contraction as well. They decreased the resting tension to the lower level. The mechanism of their non-special relaxed action on uteri could not be completely explained only by their H₁-receptor blocking action. Whether they act by blocking calcium channel or by inhibiting calmodulin (CaM) remains to be further explored.     

Effects of Intraventricular Injection of Calmodulin Antagonist （Trifluoperazine） on Pregnancy in Rats

Injection of TFP (a specific antagonist of CaM) into the lateral ventricles of the rat brain on the fourth day of pregnancy causes marked antifertility effect in 83% of the rats (0% in the control group). Examination with the pontamone blue reaction for the implantation elucidated that the antifertitity effect was due to the blockage of implantation of the follicle. Injection of TFP into the lateral ventricles of the brain markedly reduced the concentration of CaM in hypothalamus, ovary and uterus. Serum progesterone was also reduced. However, injection glven on day 7 was ineffective to terminate the pregnancy. Injection given on certain time of pregnancy was able to reduce the cellular CaM content and to cause antifertitity. This finding demonstrated that CaM played an important rote during the course of pregnancy.     

Melatonin reduces nitric oxide synthase activity in rat hypothalamus

Abstract: In this report, rat hypothalamic nitric oxide synthase (NOS) activity is shown to be partially inhibited by physiological concentrations of the pineal hormone melatonin. In vitro studies demonstrate that 1 nM melatonin, which approximates the physiological concentration of the hormone at night, significantly inhibited NOS activity. In vivo studies show that administering melatonin or collecting the hypothalamus from animals at night, when endogenous melatonin levels are elevated, results in a significant decrease of NOS activity. Results also show that calmodulin may be involved in this process since its presence in the incubation medium prevents the inhibitory effect of melatonin on NOS activity.     

重组人钙调素对人脐静脉内皮细胞增殖作用的影响

本文探讨外源性重组人钙调素(recombinant human calmodulin,rhCaM)对人脐静脉内皮细胞(HUVEC)增殖作用的影响。采用基因重组技术在大肠杆菌DH5α中高效表达并纯化rhCaM。将HUVEC接种于96孔培养板,加入不同浓度rhCaM,用MTT比色法检测rhCaM对HUEVC细胞增殖作用的影响。结果表明rhCaM在0.04～0.4μg/ml浓度范围内可促进HUEVC的增殖,促增殖作用随细胞培养密度的增加而减弱,也与培养基中新生小牛血清的含量密切相关。故rhCaM对HUEVC增殖具有促进作用。     

Caffeine activates preferentially α1-isoform of 5'AMP-activated protein kinase in rat skeletal muscle

Aim: Caffeine activates 5′AMP‐activated protein kinase (AMPK), a signalling intermediary implicated in the regulation of glucose, lipid and energy metabolism in skeletal muscle. Skeletal muscle expresses two catalytic α subunits of AMPK, α1 and α2, but the isoform specificity of caffeine‐induced AMPK activation is unclear. The aim of this study was to determine which α isoform is preferentially activated by caffeine in vitro and in vivo using rat skeletal muscle. Methods: Rat epitrochlearis muscle was isolated and incubated in vitro in the absence or presence of caffeine. In another experiment, the muscle was dissected after intravenous injection of caffeine. Isoform‐specific AMPK activity, the phosphorylation status of AMPKα Thr¹⁷² and acetyl‐CoA carboxylase (ACC) Ser⁷⁹, the concentrations of ATP, phosphocreatine (PCr) and glycogen, and 3‐O‐methyl‐d ‐glucose (3MG) transport activity were estimated. Results: Incubation of isolated epitrochlearis muscle with 1 mm of caffeine for 15 min increased AMPKα1 activity, but not AMPKα2 activity; concentrations of ATP, PCr and glycogen were not affected. Incubation with 3 mm of caffeine activated AMPKα2 and reduced PCr and glycogen concentrations. Incubation with 1 mm of caffeine increased the phosphorylation of AMPK and ACC and enhanced 3MG transport. Intravenous injection of caffeine (5 mg kg^?1) predominantly activated AMPKα1 and increased 3MG transport without affecting energy status. Conclusion: Our results suggest that of the two α isoforms of AMPK, AMPKα1 is predominantly activated by caffeine via an energy‐independent mechanism and that the activation of AMPKα1 increases glucose transport and ACC phosphorylation in skeletal muscle.