Polyamines in Trichomonas vaginalis

Trichomonas vaginalis was grown in a modified Bushby's medium and putrescine, spermidine and spermine levels were determined in extracts from 24- and 48-h cultures and also in the culture media. All three polyamines were present in T. vaginalis extracts; the putrescine level and putrescine/spermidine ratio were much higher than those reported for other protozoa or for mammalian tissues. There were no significant differences between 24-h and 48-h amine levels per mg protein in these extracts, but amine levels per cell were higher at 24 than at 48 h. The spent culture media had a much higher putrescine content than corresponding uninoculated media and it was concluded that T. vaginalis secreted putrescine into the culture medium.     

生物组织和细胞中多胺的高效液相色谱测定

本文对分离所得的生物样品经丹酰化反应在μ—Bondapak—C_(18)柱上,以甲醇-四氢呋喃-醋酸-水系统为流动相,采用多阶梯度反相高效液相色谱荧光检测法,测定了未成熟的大鼠前列腺、附睾、精囊等组织及生殖细胞和间质细胞中多胺的含量。其中流速为1ml/min,激发波长为370nm,发射波长为530nm,纸速为5mm/min。内标为1,10-二氨基癸烷。本法测定腐胺,精胺和精脒的精密度分别为3.63%,1.65%,2.11%;生物样品的回收率为99.6%～100.3%;三种多胺的最低检出量依次为0.2ng,0.4ng和0.8ng。     

白血病病人治疗前与缓解后红细胞多胺水平变化的观察

本文观察了20例白血病病人治疗前外周血红细胞多胺水平,发现精脒、精胺水平增高,以精胺为著(P<0.001),精脒/精胺比率显著降低(P<0.001),缓解后(7例)红细胞精脒、精胺水平均有下降(P<0.05),但仍显著高于对照组(P<0.025);精脒/精胺比率上升(P<0.025),但仍低于对照组(P<0.001).这些结果提示白血病病人的红细胞多胺水平的动态观察有助于预测病情的演变.     

Spermine interacts with cocaine binding sites on dopamine transporters

These studies were designed to assess the potential interaction of the polyamine spermine with cocaine binding to dopamine and serotonin transporters. The results of the experiments presented here indicate that spermine inhibits binding of the cocaine congener [³H] CFT to striatal synaptosomal membranes. Further, although [³H] CFT is known to interact with both dopamine and serotonin transporters, our results indicate that the observed inhibition of [³H] CFT binding is likely to reflect a specific inhibition of binding to dopamine transporters. Spermine significantly inhibited the binding of both [³H] CFT and [³H] mazindol to dopamine transporters, while it had no apparent effects on the binding of the potent serotonin uptake inhibitor [³H] paroxetine. Finally, saturation experiments show that the inhibition of ligand binding to the cocaine binding site on dopamine transporters appears not to be due to a modification of ligand affinity for the transporter, but to a decrease in the apparent density of ligand binding sites. The results of these experiments indicate that endogenously produced polyamines can alter cocaine binding to the dopamine transporter. The results are discussed in terms of possible impact on novel approaches for pharmacologically manipulating cocaine reinforcement and craving in clinical treatments for cocaine addiction, as well as for emergency treatment of cocaine overdose.     

棉酚对雄性大鼠生殖系统多胺的影响

将分离后的雄性大鼠生殖系统的组织和细胞制备成多胺的丹酰化衍生物,采用多阶梯度反相高效液相色谱荧光检测法,研究不同剂量的棉酚对大鼠前列腺、附睾精子、生殖细胞和间质细胞中多胺的影响及其时效关系。结果表明:(1)棉酚ig 30,60mg/kg,连续给药6d,与对照组相比,生殖细胞、间质细胞中精脒和精胺均显著下降,下降率分别为29.0%和54.5%,32.3%和56.3%;精囊中精脒也明显降低,下降率分别为30.2%和61.7%,精囊中精胺,低剂量无明显变化,高剂量明显降低,下降率为42.7%;附睾精子中精胺急剧升高,升高率分别为99.7%和140.2%。(2)ig 30mg/kg,分别连续给药3,6,9,12或16d,同法测定生殖系统各组织中精脒和精胺,与对照组相比,精囊在第3天、附睾精子在第6天显著增加,前列腺中在第3天也升高,但不如前两者明显。继续给药,精脒和精胺都显著降低。棉酚干扰了雄性大鼠生殖系统多胺的正常水平,这可能是棉酚抗生育作用的较为重要的生化机理之一。     

Combined stimulation of the glycine and polyamine sites of the NMDA receptor attenuates NMDA blockade-induced learning deficits of rats in a 14-unit T-maze

 The present study examined the effects of multi-site activation of the glycine and polyamine sites of the NMDA receptor on memory formation in rats learning a 14-unit T-maze task. The competitive NMDA receptor antagonist, (±)-3-(2-carboxypiperazine-4-yl)-propyl-1-phosphonic acid (CPP, 9 mg/kg), was used to impair learning. The objectives were two-fold: (1) to investigate the effects of independent stimulation of the strychnine-insensitive glycine site or the polyamine site; (2) to investigate the effects of simultaneous activation of these two sites. Male, Fischer-344 rats were pretrained to a criterion of 13 out of 15 shock avoidances in a straight runway, and 24 h later were trained in a 14-unit T-maze that also required shock avoidance. Prior to maze training, rats received intraperitoneal (IP) injections of saline, saline plus CPP, CPP plus the glycine agonist, D-cycloserine (DCS, 30 or 40 mg/kg), CPP plus the polyamine agonist, spermine (SPM, 2.5 or 5 mg/kg), or CPP plus a combination of DCS (7.5 mg/kg) and SPM (0.625 mg/kg). Individual administration of either DCS or SPM attenuated the CPP-induced maze learning impairment in a dose-dependent manner. However, the combined treatment with both DCS and SPM completely reversed the learning deficit at doses five-fold less than either drug given alone. These findings provide additional evidence that the glycine and polyamine modulatory sites of the NMDA receptor are involved in memory formation. Furthermore, the potent synergistic effect resulting from combined activation of the glycine and polyamine sites would suggest a stronger interaction between these two sites than previously considered, and might provide new therapeutic approaches for enhancing glutamatergic function. Received: 9 May 1997/Final version: 13 August 1997     

Immunocytochemical localization of polyamines in the tiger salamander retina

The polyamines spermine and spermidine are present in neural tissue, but their functions there are not well understood. Recent work suggests that the NMDA subtype of glutamate receptors, other glutamate receptor subtypes, and certain K⁺-channels, are neural targets for polyamines. To better understand the neuron-specific roles of polyamines, we have developed antibodies that interact with spermine and spermidine in aldehyde-fixed tissue and used these antibodies in immunocytochemical studies to determine the cellular localization of these polyamines in the tiger salamander retina. The affinity-purified, polyclonal antibodies were highly specific for spermine and spermidine, exhibiting < 1 % cross reactivity with putrescine, and virtually no cross-reactivity with GABA, arginine, lysine, or glutaraldehyde. Polyamine labeling was most abundant in cells in the inner half of the inner nuclear layer and in the ganglion cell layer. Some cells in the outer half of the inner nuclear layer are labeled, and there was some labeling in both synaptic layers. Double-labeling experiments indicated (1) all GABAergic amacrine cells were polyamine-positive; and (2) all ganglion cells (identified by back-filling after microinjections of rhodamine in the optic nerve) were polyamine-positive. These results are consistent with a role for polyamines as modulators of NMDA receptor function and channel function in the inner retina.     

Polyamines as a defense mechanism against lipoperoxidation in Trypanosoma cruzi

The polyamines, spermine and spermidine--organic polycations that are absolutely required for eukaryotic cell growth--are shown here to function in Trypanosoma cruzi epimastigotes, as protectors of membrane lipoperoxidation by reactive oxygen species generated either by H2O2/Fe2+ or nifurtimox. In vitro, spermine and spermidine inhibited lipoperoxidation in a dose dependent manner. Spermine was more efficient than spermidine in its inhibitory effect. Lipid peroxidation induced by H2O2 showed an IC50 of 0.55 mM for spermine and 0.9 mM for spermidine while an IC50 of 0.8 mM for spermine and 1.5 mM for spermidine were observed when lipoperoxidation was elicited by nifurtimox. Likewise in vivo, both exogenously added spermine and spermidine or endogenous increase of spermine levels induced by phorbol ester, protected against lipoperoxidation and decreased citotoxicity provoked by nifurtimox. Putrescine and cadaverine, also present in T. cruzi had no effect at all. None of the polyamines had any effect neither on the scavenging of superoxide anion nor on the regulation of antioxidant enzymes such as superoxide dismutase and peroxidases involved in H2O2 detoxification. Here we point out that spermine, by acting as a protector of membrane lipoperoxidation might contribute to survival of T. cruzi continuously exposed to oxidative stress.     

Nitric oxide donors offer protection to RBC from storage lesion

BackgroundRed blood cell (RBC), which is the most commonly transfused blood component, due to its ability to save a life in absence of any other blood components, can be stored up to maximum 6 weeks by following standard preservation procedure. During storage, RBC undergoes various biophysical and biochemical changes (commonly known as storage lesion) for which blood transfusion with “old RBC” shows a lot of clinical problems especially relevant to critically ill patients. Recent research on S-nitrosylation of haemoglobin to improve oxygen delivery of banked blood revealed the important role of nitric oxide (NO) in protecting storage lesion.Materials and methodsIn the present study, we used various “NO donating” chemicals with different NO release dynamics and chemistries in RBC storage cocktails to test the effects of NO on storage lesion. Changes in different storage markers were evaluated after 7 days storage of pre-treated RBC.ResultsAll the NO donors have shown protection against hemolysis. However, S-nitroso glutathione (GSNO) ranks first in shielding RBCs from storage lesion and additionally, it helps in elevating the value of 2, 3-di phosphoglycerate (2, 3-DPG), improving the RBC membrane fluidity and decreasing the adhesion towards endothelial monolayer.DiscussionPresent study reveals that NO released from NO donors confers protection against storage lesions of the RBC. Further, the study confirms that pre-treatment with GSNO, a NO donor and a nitrosylating agent, ensures the best protection to RBC during low temperature storage, when compared to other NO donor treatments.