聚精寡肽类似物的构效关系

依据聚精寡肽具有内皮舒张因子（EDRF）样效应的实验事实，以L－Arg-Arg-OH为先导化合物，合成了L－Arg-ArgOCH3、L－Agr-Arg-Arg-OH、（L－Arg)2(CO2)CH2以及（L-Arg)2(CO)2CH2CH2四种类似物，它们具有不同程度的舒血管效应。聚精二肽的羟端封锁，舒血管作用减弱。L－Arg的N端用丙二酸或丁二酸桥联，可减慢其代谢而呈现比聚精二肽弱的舒血管作用。聚精三肽的舒血管作用优于聚精二肽。     

一氧化氮中介雷米普利拉对氧自由基损伤兔胸主动脉内皮的保护作用

采用离体兔胸主动脉淋浴灌注方法，探讨雷米普利拉（Ｒａｍ）对氧自由基损伤血管内皮功能的保护作用及其机理．结果发现，电解Ｋｒｅｂｓ液产生的氧自由基明显抑制血管内皮依赖性舒张，降低血管壁氧化氮（ＮＯ）和ｃＧＭＰ含量，并使丙二醛含量增加；Ｒａｍ消除电解所致的上述作用，并呈现剂量依赖性；ＮＯ合成的前体物质─—Ｌ－精氨酸亦具有相似的保护作用；Ｒａｍ和Ｌ－精氨酸的保护作用均可被ＮＯ合成酶抑制剂所阻断。这些结果提示，Ｒａｍ抗氧自由基损伤血管内皮的作用可能与其促进内皮细胞合成，释放ＮＯ有关。Ｐ＜０．０１，ｃｏｍｐａｒｅｄｗｉｔｈｃｏｎｔｒｏｌ．Ｐ＜０．０５，Ｐ＜０．０１．ｃｏｍｐａｒｅｄｗｉｔｈＥｌｅ；Ｐ＜０．０１．ｃｏｍｐａｒｅｄｗｉｔｈＲａｍΔΔＰ＜０．０１．ｃｏｍｐａｒｅｄｗｉｔｈＬ－Ａｒｇ．ＳｉｍｉｌａｒｒｅｓｕｌｔｗａｓｏｂｔａｉｎｅｄｉｎｔｈｅｔｉｓｓｕｅｔｒｅａｔｅｄｗｉｔｈＬ－Ａｒｇ．Ｈｏｗｅｖｅｒ．ｔｈｅｅｆｆｅｃｔｏｆＲａｎｉｏｒＬＡｒｇｗａｓａｂｒｏｇａｔｃｄｉｎｔｈｅｐｒｅｓｅｎｃｅｏｆＮＡｒｇ．Ｒｅｄｕｃｔｉｏｎｂｙｅｌｅｃｔｒｏｌｙｓｉｓｏｆｎｉｔｒｉｔｅｖａｌｕｅｗａｓｎｏｔｉｎｆｌｕｅｎｃｅｄ?     

巴曲酶的扩血管作用及其机制探讨

目的研究巴曲酶对血管张力的影响及其可能机制。方法离体大鼠主动脉环测定张力，主动脉薄片孵育测定ＮＯ生成、血管一氧化氮合酶（ＮＯＳ）活性与Ｌ－精氨酸（Ｌ－Ａｒｇ）转运。结果巴曲酶（０．１～２０Ｂｕ·Ｌ－１）浓度依赖性扩张大鼠离体主动脉环，去内皮血管对巴曲酶的舒张反应明显低于内皮完整血管（Ｐ＜０．０１），最大舒张反应分别为４０．１％±２１．９％和８８．１％±４．２％（Ｐ＜０．０１）。巴曲酶（１０Ｂｕ·Ｌ－１）刺激孵育主动脉产生ＮＯ－２增加１２８％（Ｐ＜０．０１），固有型ＮＯＳ（ｃＮＯＳ）和总ＮＯＳ（ｔＮＯＳ）活性分别增加２．０倍和４０．０％（Ｐ值均小于０．０１），诱导型ＮＯＳ（ｉＮＯＳ）活性无显著变化（Ｐ＞０．０５）。血管壁对Ｌ－Ａｒｇ的转运呈高和低亲和两种方式，巴曲酶（１０Ｂｕ·Ｌ－１）可使其最大转运速率Ｖｍａｘ分别增加８３．８％和４７．４％（Ｐ＜０．０１）。结论巴曲酶的内皮依赖的扩血管作用通过Ｌ－Ａｒｇ／ＮＯ途径，巴曲酶增加血管壁Ｌ－Ａｒｇ的转运和激活ＮＯＳ，使ＮＯ生成增加     

Vasodilation Effects of RGD Containing Peptides and De rivatives

已经证实纤维蛋白分子内两个区域内的氨基酸序列可以介导纤维蛋白与ＧＰＩｂ／Ｉ┐Ｉａ受体的结合。除单克隆抗体外，用合成的含ＲＧＤ和ＡＰＬＲＶ的小分子多肽可以封闭ＧＰＩｂ／Ｉ┐Ｉａ的这种结合功能，我们的初步研究发现，ＲＧＤＳ除具有抑制血小板聚集和抗血栓形成的作用外，还显示舒血管作用。为了证实ＲＧＤＳ相关多肽的舒血管作用，研究了ＲＧＤＦ，ＡＰＬＲＶ，ＡＰＬＲＶＲＧＤＳ，ＡＰＬＲＶＲＧＤＦ，在体外用ＮＥ预处理大鼠的动脉肌条后观察了上述合成多肽的舒血管作用，检测了三种剂量（１０┐５ｍｏｌ／Ｌ，１０┐６ｍｏｌ／Ｌ，１０┐７ｍｏｌ／Ｌ）下收缩的肌条舒张的程度。     

NO对去甲吗啡在离体豚鼠回肠上依赖性耐受性产生的作用

目的观察 ＮＯ合酶（ ＮＯ ｓｙｎｔｈａｓｅ,ＮＯＳ）抑制剂左旋硝基精氨酸（ＮＧ－ｎｉｔｒｏ－Ｌ－ａｒｇｉｎｉｎｅ,ＮＯＡｒｇ）和 ＮＯ合成前体左旋精氨酸（Ｌ－ａｒｇｉｎｉｎｅ,Ｌ－Ａｒｇ）对去甲吗啡（ｎｏｒｍｏｒｐｈｉｎｅ,ＮＭ）在离体豚鼠回肠上依赖性耐受性产生的影响,研究ＮＯ在阿片类药物依赖性耐受性产生中的作用。方法以离休豚鼠回肠为实验对象,４℃孵育６ ｈ, ２４ ｈ后,分别测定纳洛酮（ｎａｌｏｘｏｎｅ,Ｎｘ）与氯化乙酰胆碱（ａｃｅｔｙｌｃｈｏｌｉｎｅ,Ａｃｈ）引起的收缩高度比值,作为依赖性产生的指标。在耐受性产生实验中,分别测定回肠空白组和药物组４℃孵育３ｈ后对ＮＭ抑制电刺激收缩的剂量反应曲线。结果回肠分别经ＮＭ,ＮＭ加ＮＯＡｒｇ,ＮＭ加Ｌ－Ａｒｇ中孵育６ｈ后,纳洛酮均可使其产生戒断收缩,且两组与Ａｃｈ的收缩高度比值差异无显著性（ｎ＝６）, Ｐ＞０．０５。而孵育２４ ｈ后,ＮＭ,ＮＭ加 Ｌ－Ａｒｇ组收缩高度比值分别为 ０． ８９±０． ０２, ０． ９０±０． ０２, Ｐ＞ ０． ０５,而ＮＭ加ＮＯＡｒｇ药物组对纳洛酮的戒断收缩反应明显减弱,收缩高度比值为 ０．４７± ０．０５（ｎ＝ ６, Ｐ＜ ０．０１）。可见ＮＭ加ＮＯＡ?     

Nitric oxide and soman poisoning

目的：探查索曼中毒机制是否有ＮＯ参与．方法：预先侧脑室注射Ａｒｇ、ＮＡＭＥ，观察索曼中毒小鼠惊厥潜伏期、死亡率及脑中ＮＯＳ活性变化．结果：Ａｒｇ预处理时，潜伏期从５２ｍｉｎ（对照组）缩短到４３ｍｉｎ（Ａｒｇ１６０ｎｍｏｌ），死亡率由５０％（对照组）增加至８１％（Ａｒｇ１６０ｎｍｏｌ）．ＮＡＭＥ预处理时，潜伏期从４０ｍｉｎ延长到１４５ｍｉｎ（ＮＡＭＥ２２０μｍｏｌ），死亡率由８７％（对照组）减少至５０％（ＮＡＭＥ２２０μｍｏｌ）．索曼的小鼠毒性被Ａｒｇ增强、被ＮＡＭＥ减弱，均有剂量依赖性．索曼中毒可使小鼠大脑、小脑及海马的ＮＯＳ活性分别增加４％，１５％及１１％．结论：索曼中毒小鼠的惊厥及死亡与ＮＯ信使系统有关     

脑室注射硝普钠、L-精氨酸、N~G-硝基-L-精氨酸对清醒状态大鼠心血管活动的影响

给大鼠侧脑室内注射（ｉｃｖ）硝普钠（ＳＮＰ）、ＮＯ的前体物质Ｌ精氨酸（ＬＡｒｇ）和精精二肽（ＡｒｇＡｒｇ），ＮＯ合成酶（ＮＯＳ）抑制剂ＮＧ硝基Ｌ精氨酸（ＮＮＬＡ），观察清醒状态大鼠血压和心率的变化，探讨脑内ＮＯ对清醒状态大鼠心血管活动的调节作用。实验结果表明，ｉｃｖＳＮＰ（８，１６，３２μｇ）使血压升高，并呈剂量效应关系，同时使心率加快。ｉｃｖＬＡｒｇ（２００μｇ）或不同剂量的精精二肽也使血压升高，心率加快；ｉｃｖＮＮＬＡ（１００μｇ）则使血压下降，心率减慢。以上结果提示，在一定范围内提高脑内ＮＯ，对心血管活动有正性调节作用，降低脑内ＮＯ则对心血管活动有负性调节作用。     

川芎嗪对大鼠脑梗塞的保护作用

目的　研究川芎嗪（ｌｉｇｕｓｔｒａｚｉｎｅ,Ｌｉｇ） 对脑梗塞的保护作用。方法　大鼠脑梗塞模型采用右侧颈总动脉和右侧大脑中动脉的结扎,脑梗塞重量用ＮＢＴ 染色法测定。小鼠双侧颈总动脉结扎４ ｈ 后,取脑测丙二醛（ ＭＤＡ）、一氧化氮（ＮＯ）含量。血小板聚集用Ｂｏｒｎ 法测定。结果　Ｌｉｇ １０ ,２０,４０ ｍｇ·ｋｇ－ １ｉｖ 可显著改善大鼠异常神经症状和抑制ＡＬＰ活性的下降;Ｌｉｇ 可显著降低小鼠缺血脑组织ＮＯ 和ＭＤＡ 含量;Ｌｉｇ（２００,４００ ,８００ ｍｇ·Ｌ－１） 可显著抑制ＡＤＰ致血小板的聚集。结论　Ｌｉｇ 对脑梗塞有保护作用,此作用可能与抑制血小板聚集有关     

丝裂素活化的蛋白激酶反义寡核苷酸抑制表皮生长因子诱导体外 …

目的：探讨丝裂素活化的蛋白激酶（ＮＡＰＫ）反义寡核苷（ＯＤＮ）对表皮生长因子（ＥＧＦ）诱导的培养大鼠血管平滑肌细胞增生的抑制作用。方法：用脂质体将Ｐ４２－和Ｐ４４－ＭＡＰＫ ＯＤＮ０．２μｍｏｌˉＬ＾－１转染入大鼠血管平滑肌细胞，设正义及随机ＯＤＮ为对照，用Ｗｅｓｔｅｒｎ Ｂｌｏｔ法结合Ｐ－８１滤纸法以髓磷脂碱性蛋白为底物测定ＭＡＰＫ活性。［＾３Ｈ］胸腺嘧啶核苷酸掺入测定平滑肌细胞ＤＮＡ合成。结果     

Effect of antisense mitogen-activated protein kinase oligonucleotides on rat vascular smooth muscle cell proliferation induced by EGF in vitro

目的：探讨丝裂素活化的蛋白激酶（ＭＡＰＫ）反义寡核苷酸（ＯＤＮ）对表皮生长因子（ＥＧＦ）诱导的培养大鼠血管平滑肌细胞增生的抑制作用．方法：用脂质体将ｐ４２和ｐ４４ＭＡＰＫＯＤＮ０．２μｍｏｌ·Ｌ－１转染入大鼠血管平滑肌细胞，设正义及随机ＯＤＮ为对照，用ＷｅｓｔｅｒｎＢｌｏｔ法结合Ｐ８１滤纸法以髓磷脂碱性蛋白为底物测定ＭＡＰＫ活性．［３Ｈ］胸腺嘧啶核苷酸掺入测定平滑肌细胞ＤＮＡ合成．结果：ＭＡＰＫ０ＤＮ能明显抑制ＥＧＦ诱导的ＭＡＰＫ蛋白表达及ＭＡＰＫ活性，并明显抑制血管平滑肌细胞的［３Ｈ］胸腺嘧啶核苷酸掺入．结论：针对ｐ４２和ｐ４４ＭＡＰＫ起始部位设计的１７ｍｅｒＯＤＮ能有效抑制ＥＧＦ诱导的血管平滑肌细胞的增生．     

脑室注射硝普钠,L—精氨酸,N^G—硝基—L—精氨酸对清醒状态大鼠心血管活动的

给大鼠侧脑室内注射硝普钠的前体物质Ｌ－精氨酸和精－精二肽，ＮＯ合成酶抑制剂Ｎ＾Ｇ－硝基－Ｌ－精氨酸，观察清醒状态大鼠血压和心率的变化，探讨脑内ＮＯ对清醒状态大鼠心血管活动的调节作用。     

脑室注射硝普钠、L-精氨酸、NG-硝基-L-精氨酸对清醒状态大鼠心血管活动的影响

给大鼠侧脑室内注射(icv)硝普钠(SNP)、NO的前体物质L-精氨酸(L-Arg)和精-精二肽(Arg-Arg),NO合成酶(NOS)抑制剂N^G-硝基-L-精氨酸(NNLA),观察清醒状态大鼠血压和心率的变化,探讨脑内NO对清醒状态大鼠心血管活动的调节作用。实验结果表明,icvSNP(8,16,32μg)使血压升高,并呈剂量效应关系,同时使心率加快。icvL-Arg(200μg)或不同剂量的精-精二肽也使血压升高,心率加快;icvNNLA(100μg)则使血压下降,心率减慢。以上结果提示,在一定范围内提高脑内NO,对心血管活动有正性调节作用,降低脑内NO则对心血管活动有负性调节作用。     

Structure-activity relationships of scorpion alpha-neurotoxins: contribution of arginine residues

The role of arginine residues in the structure-activity relationships of alpha-scorpion neurotoxins was studied. Toxins I and II from Androctonus australis Hector (north African scorpion), containing respectively 2 and 3 arginines, were modified by phenylglyoxal or p-hydroxyphenylglyoxal. Modified derivatives were purified by reverse-phase HPLC and/or ion exchange HPLC. Subsequent bioassays showed that toxin I (AaH I) derivatives with single modifications on Arg 2 and Arg 60 had low activity (25 and 14% of residual activity, assessed in receptor binding experiments). Doubly modified (Arg 2, Arg 60) AaH I had 7% residual activity while further derivatization of the alpha-amino group led to an almost inactive derivative. These results agree with the involvement of arginines 2 and 60, as well as the alpha-amino group, of AaH I in the toxin/receptor interaction, probably via electrostatic interactions. Consistent with the role of N-terminal residues, the selective removal of the N-terminal dipeptide Val-Arg of toxin III from the same scorpion resulted in low activity (7% residual activity). The arginine residue in position 56 of toxin II was important for bioactivity since the derivative modified by phenylglyoxal on Arg 56 exhibited low residual activity (20%). Arg 62 and Arg 18, on the other hand, can be modified without any great effect on the pharmacological activity of AaH II. These results furnish a more precise picture of those residues involved in the "toxic region", which appears to be composed of residues belonging to the conserved hydrophobic surface and to the C-terminal and N-terminal sequences.     

Endophytic fungal metabolite fumigaclavine C causes relaxation of isolated rat aortic rings

Two indole alkaloids were isolated from the culture of Aspergillus fumigatus (strain No. CY018), an endophytic fungus harboring inside the elder leaf of Cynodon dactylon. These two chemicals were identified as fumigaclavine C and fumitremorgin C. In screening the bioactivity of these two indole alkaloids, their vasorelaxant effects on isolated rat thoracic aortic rings were observed. The results showed that fumigaclavine C exhibited potent concentration-dependent vasorelaxant actions in isolated rat aortic rings pre-contracted by high K+ or phenylephrine (with EC50 values of 5.62 micromol/L and 1.58 micromol/L, respectively) whereas fumitremorgin C displayed a weaker vasorelaxation. A detailed investigation was therefore performed with fumigaclavine C. The vasorelaxing action of fumigaclavine C is independent of the presence of endothelium, suggesting its effect of vasorelaxation was not related to endothelial mediators. Blockage of L-type voltage-dependent calcium channels, activation of ATP-sensitive potassium channels and inhibition of Ca2+ release from intracellular Ca2+ stores may be involved in fumigaclavine C induced relaxation of rat isolated aortic rings. These results demonstrate that fumigaclavine C from the endophytic fungus has a potential capacity in vascular protection and thus may have therapeutic use in protection against cardiovascular disease.     

Regional differences in the vasorelaxing effects of testosterone and its 5-reduced metabolites in the canine vasculature

Although the vasorelaxing effects of testosterone (T) and various androgen metabolites have been observed in a variety of blood vessels and species, previous studies have not systematically compared the vasorelaxing effects of androgen metabolites in different vascular beds within the same species. Therefore, we studied the vasorelaxing effects of T and its 5-reduced metabolites (5α- and 5β-DHT) on KCl-induced contractions of the canine left coronary artery, femoral artery and saphenous vein, using standard isometric recordings. KCl contractions were inhibited by each androgen in a concentration-dependent manner from 1.8 to 310μM. Vascular sensitivity and efficacy were expressed as inhibitory concentration 50 (IC??) and maximal relaxation (R(max)), respectively. The coronary artery was significantly more sensitive to androgen-induced vasorelaxation than the saphenous vein or femoral artery. These vasorelaxing responses were unaffected by an antiandrogen (Flutamide) or the sulfhydryl reagent, N-ethylmaleimide, suggesting a nongenomic mechanism independent of signaling mediated by the androgen receptor or G proteins. Concentration-response curves were unchanged in endothelium-denuded preparations; thus, the endothelium appears to have no role in androgen-induced vasorelaxation. 5β-DHT was the most potent androgen in both coronary and femoral artery, but all three androgens were equipotent in the saphenous vein. It is concluded that: 1) significant regional differences exist in vasorelaxing effects of androgen metabolites in the canine vasculature; 2) structural differences in these androgens determine their vasorelaxing efficacy; and 3) regional differences in androgen-induced vasorelaxation may account for some of the conflicting findings reported on the vasorelaxing effects of the androgens.     

尼群地平对兔肺动脉的松弛作用及其与NO的关系

目的：观察尼群地平对兔离体肺动脉和腹主动脉的松弛作用及其与ＮＯ的关系。方法：采用离体血管功能实验方法，判定肺动脉环和腹主动脉环的等长张力变化。结果：尼群地平对肺动脉及腹主动脉均有浓度依赖性舒张作用，其对抗去甲肾上腺素（０．５μｍｏｌ·Ｌ－１）收缩肺动脉的最大舒张效应（Ｅｍａｘ有内皮：５２％±２１％；去内皮：４１％±１０％；加Ｌ－ＮＡＭＥ：５３％±１２％）显著强于对腹主动脉的松弛作用（Ｅｍａｘ：１９％±３％；２１％±４％；１７％±８％，Ｐ＜０．０１）。结论：尼群地平对动脉环的舒张作用不受内皮细胞及一氧化氮合成酶抑制剂Ｎ－亚硝基－Ｌ－精氨酸甲酯的影响；尼群地平也不影响乙酰胆碱对肺动脉和腹主动脉的松弛作用。     

牛磺酸对大鼠胸主动脉的舒张作用及其机制的研究

目的研究牛磺酸舒血管作用的可能机制。方法记录苯肾上腺素(PE)和KCl预收缩的离体大鼠主动脉环张力变化,观察牛磺酸的舒血管作用及不同工具药对其作用的影响。结果牛磺酸(20~80mmol.L-1)对PE(1μmol.L-1)或KCl(60mmol.L-1)预收缩的大鼠主动脉环均有非内皮依赖的、浓度依赖性的舒张作用。在内皮完整的血管环,左旋硝基精氨酸甲酯(0.1mmol.L-1)对牛磺酸的舒血管作用无明显影响;β-丙氨酸(60mmol.L-1)在PE预收缩的血管环增强牛磺酸的舒血管作用,而在KCl预收缩的血管环则降低牛磺酸的舒血管作用;在KCl预收缩基础上,钾通道阻断剂格列本脲(10μmol.L-1)和四乙胺(10mmol.L-1)明显抑制牛磺酸的舒血管作用,而4-氨基吡啶(1mmol.L-1)和BaCl2(1mmol.L-1)无影响。结论牛磺酸有浓度依赖性的血管舒张作用,此作用不依赖血管内皮,可能与其跨细胞膜转运有关,可能有钙依赖性钾通道和ATP敏感性钾通道的参与。     

Cardiovascular effects of Acanthaster planci venom in the rat: possible involvement of PAF in its hypotensive effect.

Cardiovascular effects of the crowns-of-thorns starfish (Acanthaster planci) venom were examined in rats. The crude venom extracted from the spines of A. planci caused systemic hypotension associated with an increase in heart rate and a decrease in renal cortical blood flow when given i.v. The hypotensive effect of the venom was not inhibited by pretreatment with atropine, indomethacin or aprotinin, but was significantly inhibited by SRI 63-441, a platelet activating factor (PAF) antagonist. The venom caused dose-dependent vasorelaxation of the isolated rat aortic ring preparation precontracted by noradrenaline, an effect which was significantly attenuated by pretreatment with SRI 63-441, methylene blue or parabromophenacyl bromide. Denudation of the endothelium also diminished the vasorelaxing effect of the venom. Both the vasorelaxing and the hypotensive effects showed tachyphylaxis. These results suggest the release of PAF or a PAF-like substance from the endothelium by the venom.     

N-terminal specificity of PEGylation of human bone morphogenetic protein-2 at acidic pH

Site-specific PEGylation offers the possibility to modify a therapeutic protein without interfering with its biological activity. Previously, a preferential N-terminal PEGylation has been reported for several proteins when the reaction was performed at acidic pH. In the present study it was explored if acidic pH favors N-terminal PEGylation of bone morphogenetic protein-2 (BMP-2). PEGylation by poly(ethylene glycol) aldehyde (PEG-AL) or poly(ethylene glycol) carboxymethyl succinimidyl ester (PEG-NHS) was performed at moderate acidic pH of 4. Comparing with PEG-NHS, PEG-AL converted more BMP-2 mainly to mono- or di-PEGylated derivatives at much less molar excess and shorter duration. Analysis of Tryptic fragments of the PEGylated derivatives indicated a partial N-terminal PEGylation specificity. PEG-AL exhibited higher specificity than PEG-NHS. UV spectrometry proved that PEGylation improved the solubility of BMP-2 in PBS. Surface plasmon resonance showed that PEGylation decreased the binding of BMP-2 proteins to a type II receptor. Remarkably, mono-PEGylated BMP-2 with PEG-AL showed higher cellular bioactivity than unmodified protein. Higher N-terminal PEGylation specificity correlates with higher receptor binding affinity and cellular activity. In summary, PEGylation of BMP-2 by PEG-AL and PEG-NHS at acidic pH exhibits a partial N-terminal specificity which however might be sufficient for an efficient site-specific PEGylation process.