绿臭蛙皮中与神经降压肽有关的绿臭蛙降压肽的分离及其化学和生物学特征

本文利用Sep-Pak Cu和反相HPLC从我国产绿臭蛙皮的甲醇提取物中分得一新的神经降压肽类似物:绿臭蛙降压肽。其结构为Asp-Lys-Arg-Pro-Tyr-Ile-Leu-His-Glu。此结构与神经降压肽羧端部分结构相似。但比后者多出残基His-Glu。相应的合成品与天然肽在高效液相色谱、氨基酸分析和生物测定中均表现一致。此肽对大鼠产生降血压效应,但作用比神经降压肽弱。该肽对豚鼠回肠制品有很强的和可重复的收缩活性,这一点又与两栖动物皮肤中另一神经降压肽类似物——xenopsin的相应活性有别。     

SYNTHESIS AND BIOLOGICAL ACTIVITY OF A NEW FROG SKIN PEPTIDE, RANAMARGARIN

A new frog skin peptide, ranamargarin depicted as H-Asp-Asp-Ala-Ser-Asp-Arg-Ala-Lys-Lys-Phe-Tyr-Gly-Leu-Met-NH_(2′), was synthesized by the conventionalmethod. Comparisons of chemical and biological properties of both the synthetic and natural ranamargarins indicated that they were identical, so the chemical structure of ranamargarin was confirmed. Preliminary pharmacological study showed that ranamargarin was highly selective towards the SP-P subtype receptor.     

新蛙皮活性肽-绿臭蛙激肽的合成及其活性检定

用液相片断缩合法首次合成了由中国绿臭蛙(Rana margaratae)的蛙皮中分离的速激肽类新活性肽-绿臭蛙激肽(Ranamargarin):Asp-Asp-Ala-Ser-Asp-Arg-Ala-Lys-Lys-Phe-Tyr-Gly-Leu-Met-NH_2。合成的十四肽酰胺在RP-HPLC上显示与天然肽相同的保留时间,与天然肽合并后为单一峰,从而进一步肯定了此新活性肽的结构。根据不同生物标本检定的结果,提示此肽对SP-P型速激肽受体有较高的选择性。     

我国产绿臭蛙的皮肤中一个新的速激肽——绿臭蛙激肽的分离和结构

本文利用Sep—Pak C_(13)和HPLC,从我国产绿臭蛙的皮肤甲醇提取物中分离到一个新的14肽——绿臭蛙激肽。此肽结构经分析定为:Asp—Asp—Ala—Ser—Asp—Arg—Ala—Lys—Lys—Phe—Tyr—Gly—Leu—Met—NH_2,且为化学合成所证明。此肽是两栖动物速激肽中最长的一个,其N-端氨基酸与速激肽类其它肽的相应部分有很大区别。此外,简要讨论了纯化过程中绿臭蛙激呔亚砜的形成及其色谱峰的分裂。     

ELECTRO-ACUPUNCTURE MARKEDLY INCREASES PROENKEPHALIN mRNA IN RAT STRIATUM AND PITUITARY

Electro-acupuncture (EA) has been found to increase enkephalin content in striatum, hypothalamusand cerebrospinal fluid. Further studies on rat striatum showed that the increase is accompanied by anelevation of enkephalin precursor and processed intermediate levels. In order to characterize the natureof these changes, we have measured the proenkephalin mRNA (PE-mRNA) level in rat striatum and pi-tuitary by recombinant DNA technique. The PE-mRNA was hybridized with human proenkephalincDNA using a dot-blot procedure. Rats receiving EA showed a 3-5-fold increase of PE-mRNA instriatum beginning at 1 h after the cessation of 30-min EA treatment and lasting 48 h at least. A 3-foldincrease of PE-mRNA in pituitary was found immediately after the cessation of EA and a 5-6-fold in-crease at 1 or 24 h after the termination of EA.     

ISOLATION, CHEMICAL AND BIOLOGICAL CHARACTERIZATION OF MARGARATENSIN, A NEUROTENSIN-RELATED PEPTIDE FROM THE SKIN OF Rana margaratae

A new neurotensin (NT)-related peptide, margaratensin, was obtained by Sep-Pak C_(18) and RP-HPLC from methanol extracts of the skin of Chinese frog Rana margaratae. The structure of the peptide has been determined to be Asp-Lys-Arg-Pro-Tyr-lle-Leu-His-Glu, which is found to be homologous to the COOH-terminal sequence of NT, but has an extra His-Glu at the COOH-terminus. The synthetic preparation was shown to be indistinguishable from the native peptide during HPLC, amino acid analysis and bioassay. Margaratensin exhibited a hypotensive effect in the rat but the response was weaker than NT. The peptide could induce a potent and reproducible contractile activity on GPI which was different from xenopsin, another NT-related peptide from amphibian skin.     

电针显著增加大鼠纹状体和垂体中脑啡肽原mRNA含量

电针能增加纹状体、下丘脑和脑脊液中脑啡肽的含量。进一步的研究表明大鼠纹状体内脑啡肽含量的上升伴有其前体和中间体水平的升高。为阐明这些现象,我们运用重组DNA技术测定了大鼠纹状体和垂体中脑啡肽原mRNA的水平。经点点杂交分析(Dot-blot Hybridization) 脑啡肽原 mRNA和人脑啡肽原cDNA探针专一性的结合,30min的电针后电针组大鼠纹状体中脑啡肽原mRNA升高3—5倍。这个增加发生在电针结束1h后,且可持续48h。但垂体中脑啡肽原mRNA则在电针一结束时就能观察到增加约3倍,在电针后1—24h约上升5—6倍。     

脑啡肽在针刺镇痛中的作用:放射免疫测定

脑内有数种内源性吗啡样物质,它们的分布和功能意义不尽相同.为阐明内源性吗啡样物质与针刺镇痛的关系有必要对它们分别进行研究.本文采用灵敏和专一的放射免疫分析法测定了家兔和大白鼠在针麻过程中各脑区及脑脊液中两种脑啡肽的含量变化.主要结果为:(1)针刺镇痛过程中下丘脑及纹状体两种脑啡肽均明显升高;(2)家兔侧脑室注射杆菌肽能够显著增强针效和提高脑内及脑脊液中脑啡肽的含量;(3)蛋白合成抑制剂环己亚胺可以削弱针刺升高脑啡肽含量的作用,说明加速生物合成是针刺增加脑啡肽含量的机制之一;(4)手术游离下丘脑后大白鼠电针效应削弱,提示下丘脑参与了针刺镇痛过程.     

猪脊髓中两个生物活性肽的分离与部份鉴定

从猪脊髓中分离了两个生物活性肽,并进行了部分鉴定.氨基酸分析、电泳、等电聚焦及N末端残基丹磺酰衍生物层析分析表明,这两个肽都是纯肽.氨基酸组成分析及Sephadex G50(超细)薄层层析测定的表观分子量表明SCP-1是个31肽,SCP-2是个25肽.SCP-1及SCP-2的N末端氨基酸分别为精氨酸及色氨酸。SCP-1刺激离体豚鼠迥肠收缩,SCP-2引起大鼠血压降低,两者均无吗啡样活性。SCP-I及SCP-2的化学组成和生物学性质与迄今发现的所有已知肽不同。     

针刺镇痛和吗啡镇痛过程中脑内3H-5-羟色胺释放的研究

鉴于脑内神经细胞间的信号传递是通过突触部位神经介质的释放而实现的,因此神经介质必然在针刺镇痛过程中起重要作用。本文将脑室灌流方法与同位素技术相结合,研究家兔在清醒状态下针刺时脑内5-HT释放和痛觉之间的动态关系。先后在48只家兔上观察了脑室注射³H-5-HT后,脑室灌流液中5-HT释放和痛阈变化,发现针刺组18只家兔中半数以上在针刺提高痛阈的同时5-HT释放增加,而对照组、吗啡组及手握后肢均不增加5-HT释放。这一结果表明针刺时脑内5-HT能神经原被激活。