游蛇的Duvernoy氏腺体及其分泌物

长期以来 ,人们认为毒蛇与无毒蛇的根本区别在于前者有毒腺、毒牙 ,然而 ,对后沟牙无沟牙游蛇 Duvernoy氏腺体或口腔分泌物的毒性进行研究发现 ,有些游蛇其上颌牙无沟亦无管 ,却具有毒性 [1] 。游蛇的 Duvernoy氏腺体及其分泌物一直很少受到关注 ,这种复杂的管状腺体由 1 9世纪初 ,法国著名的形态学家 George Louis Duvernoy命名 ,因而称为 Duvernoy氏腺体。　　游蛇占世界上所有蛇类的 65% ,至少包括 6个亚科 ,大约 1 56种。目前还不清楚究竟有多少种游蛇具有 Duvernoy氏腺体。在人类研究的 30 0种游蛇中 ,发现 2 50种游蛇具有 Duverno…     

我国的毒蛇

什么叫毒蛇毒蛇的类别我国的毒蛇种类我国各地的毒蛇怎样区别毒蛇与无毒蛇怎样预防毒蛇咬伤什么叫毒蛇毒蛇是指蛇类中具有毒牙和毒腺的那些种类。当它们发生咬人时,毒腺分泌的毒液经排毒导管流出来,沿着毒牙上的沟或管注入人体被咬的伤口内,能引起中毒症状。(图1)无毒蛇没有毒牙和毒腺。虽然有些无毒蛇的唾腺分泌物对人体也有一定的毒性,但是由于缺少有效的注毒工具(毒牙),所以很少可能造成人体中毒。有时发生被无毒蛇咬伤也会出现中毒的现象,多半是由于伤口发生继发性感染所致。即使被毒蛇咬伤,也不一定发生中毒现象。因为毒蛇咬·68·人时…     

毒蛇咬伤和毒虫咬（螯）伤的鉴别诊断

我院自 1 991年至今 ,诊治各类毒蛇咬伤 1 986例 ,毒虫咬 (螯 )伤 1 0 0多例。根据 1 0年来的临床工作经验 ,对毒蛇咬伤和毒虫咬 (螯 )伤的鉴别诊断体会如下。1　有毒蛇与无毒蛇的鉴别1 .1　毒腺　有毒蛇具有毒腺 ,无毒蛇不具有毒腺 ,毒腺是由唾液腺演化而来 ,位于头部两侧 ,眼的后方 ,包藏于颌肌肉中 ,能分泌出毒液 ,当毒蛇咬物时 ,包绕着毒腺的肌肉收缩 ,毒液即经毒液管和毒牙的管或沟 ,注入被咬伤对象的体内使之发生中毒。无毒蛇则无这一功能。1 .2　毒液管　毒液管是输送毒液的管道 ,连接在毒腺与毒牙之间 ,只有毒蛇才具备有毒液管。1 .…     

金花蛇

金花蛇[Chrysopelea ornata(Shaw)],又名美丽金花蛇.是我国罕见的轻毒性后沟牙毒蛇.     

赤链蛇达氏腺提取液对小白鼠致死现象的探究

对于"赤链蛇是否为毒蛇"这一问题,目前在学术界尚存争议。通过对赤链蛇的解剖观察,发现其存在一对达氏腺,进一步将达氏腺提取液稀释后,注射到小白鼠体内,发现其对小白鼠有明显的致死作用,进而证实了赤链蛇有一定的毒性,但对其上颌齿解剖观察发现其不具备后沟牙,由此,结合野外和实验室环境下对其捕食行为的观察,对其注毒的机理进行讨论。     

α-银环蛇毒素和β-银环蛇毒素的研究进展

银环蛇属动物界,脊索动物门,爬虫纲,有鳞目。眼镜蛇科,环蛇属。全身背面是黑白相间的环纹,具30～50个白色或乳黄色窄横纹。是世界十大毒蛇之一。属前沟牙类毒蛇,其一次排毒4．6mg,1mg干毒就能致人于死地。毒腺分泌的蛇毒含多种多肽成分,具有不同的生物学活性。     

蛇伤治疗与急救专题讲座

蛇伤治疗与急救专题讲座荀建宁广西中医学院二附院５３００１１卢惠萍广西南宁市第一人民医院５３００２２第二讲毒蛇与无毒蛇的区别第三节：从蛇的外观形态及毒牙毒腺来鉴别怎样才能鉴别毒蛇和无毒蛇呢？首先我们可从蛇的外观形态来鉴别,如蛇的头部、尾巴、斑纹、色泽、...     

一种有毒的游蛇——虎斑颈槽蛇

虎斑颈槽蛇是中国数量较多、分布最广的蛇类之一,但一直被当作无毒蛇而忽视。为了使人们对虎斑颈槽蛇有一个全面、正确的认识,也为以后的相关研究奠定一定的理论基础,从虎斑颈槽蛇的分布,形态,生活习性以及毒腺的研究等方面加以综述。     

我国的有毒蛇类

我国所产的有毒蛇类,约有40多种(C.H.Pope、大岛正满等,均曾研究过。Pope报告有37种,大岛正满报告有34种)。这些有毒蛇类,我们按照毒牙的构造和着生的位置,可还分为沟牙和管牙两类。沟牙类在上颌骨上着生沟牙一对到数对,各沟牙的前面,都有流通毒液的縱沟,与毒腺相接。沟牙类依其沟牙着生的位置,又可分为前沟牙类和后沟牙类。前者的沟牙,着生在前方上颌骨上,如海蛇科、     

129例五步蛇咬伤的急救与护理

五步蛇学名尖吻蝮,又称蕲蛇、五步龙、白花蛇等,属蝰蛇科类,具有管牙的毒蛇.其特点是体积较大,牙齿尖长、锋利,毒腺大,毒性强烈,以消耗性凝血障碍和纤溶症为主要病理过程,临床表现以全身广泛性内外出血为其突出症状[1],是血循毒(中医学称"火毒")类毒蛇的代表.以夏秋季节为五步蛇咬伤的高发期.五步蛇咬伤病情发展迅速,来势凶猛,病程缠绵,危险期长,致残及致死率高.现将我所2012年4~11月收治的129例五步蛇咬伤患者的急救与护理总结报告如下.     

Immunolocalization of venom metalloproteases in venom glands of adult and of newborn snakes of Bothrops jararaca

Using immunoelectronmicroscopy we analyzed qualitative and quantitatively the intracellular distribution of bothropasin, hemorrhagic factor 2 (HF2) and hemorrhagic factor 3 (HF3) in the venom secretory cells from adult snakes in the active (7 days after venom extraction) and in the resting (without venom extraction for 40 days) stages of protein synthesis. Glands from the newborn Bothrops jararaca were also studied. The results lead to the conclusion that all the secretory cells and the secretory pathway in the cells are qualitatively alike in regard to their content of the three metalloproteases. Secretory cells from the resting glands, unlike the active ones and the newborn glands, did not present immunolabeling in the narrow intracisternal spaces of the rough endoplasmic reticulum (RER). The label intensity for bothropasin was greater than that for the other proteins in the adults. HF3 and HF2 labeling densities in the newborn were higher than in the adults and HF3 labeling was not different from that of bothropasin. Co-localization of the three metalloproteases was detected in the RER cisternae of the active gland secretory cells, implying that mixing of the proteases before co-packaging into secretory vesicles occurs at the beginning of protein synthesis in the RER cisternae.     

Histology,histochemistry, and emptying mechanism of the venom glands of some elapid snakes

The venom glands of several species of elapid snakes are described. The main venom gland consists of many tubules which usually contain large amounts of secretion product. The accessory gland surrounds the entire venom duct and is usually composed of uniform mucous epithelium. The epithelium lining the tubules of the accessory gland of Naja naja is composed of two distinct types of cells. Histochemical tests indicate that the main venom gland reacts with mercury bromphenol blue and PAS but not with alcian blue. The accessory gland reacts with PAS and alcian blue, and not with mercury bromphenol blue. Treatment of sections with sialidase demonstrates the presence of a sialomucin in the accessory gland. Stimulation of the muscles associated with the venom gland offers an indication of the venom expulsion mechanism of Bungarus caeruleus. A comparison of the venom apparatus of elapid and viperid snakes emphasizes marked differences in the internal anatomy of the venom glands, muscles associated with the gland, and arrangement of glandular components. The morphological differences and dissimilar venom expulsion mechanisms support the recent view of the polyphyletic origin of venomous snakes.     

竹叶青属毒蛇的毒素研究进展

蛇毒含多种生物活性成分,其中多数为酶类和活性肽类。随着蛇毒毒理学、药物学、生物化学和分子生物学的发展,蛇毒的许多组分已得到分离纯化和序列测定,并广泛应用于理论研究和临床应用。竹叶青蛇属是中国常见的毒蛇,近年来对其应用研究的报道颇多,就竹叶青属毒蛇的种类与分布,及其蛇毒组分的分离纯化、理化性质、分子克隆表达等方面的研究资料进行了概括和综述。     

The evolution of venom-delivery systems in snakes

The Colubroidea represents approximately 2300 of the 2700 species of living snakes and includes all venomous taxa. Although many morphological studies of colubroid snakes have been carried over the last hundred years, the phylogenetic relationships within this group are poorly known. In this study, components of the venom-delivery system (VDS) were examined within the context of two conflicting phylogenetic hypotheses proposed in 1988 by Cadle and in 1998 by Kraus & Braun. The results suggest that several major morphological changes occurred early in colubroid evolution: a Duvernoy's gland evolved, the posterior maxillary teeth became specialized relative to the anterior maxillary teeth, and the attachment of the pterygoideus muscle moved forward to a position associated with the posterior maxillary teeth. These innovations may have allowed the great radiation of colubroid snakes that led to the Colubroidea representing such a large percentage of living snakes. More recently, three separate lineages of colubroids have independently evolved highly specialized front-fanged VDSs with large and complex venom glands, venom gland compressor muscles, and tubular fangs.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 137 , 337−354.     

Venom glands and some associated muscles in sea snakes

The venom glands and related muscles of sea snakes conform in their general structure to those of the terrestrial elapids. The venom gland, however, is smaller in size and the accessory gland is considerably reduced. A similar pattern is found in the Australian elapid Notechis. The musculus compressor glandulae is well developed in the sea snakes and in some species its posterior-medial portion runs uninterruptedly from the origin to the insertion of the muscle. This might be considered as a primitive condition suggesting an early divergence of the sea snakes from an ancestral elapid stock. Three species of sea snakes, Aipysurus eydouxi, Emydocephalus annulatus, and E. ijimae, feed on fish eggs and have very small, but still functioning, venom glands. The reduced accessory gland of the sea snakes is apparently connected with their aquatic environment, as a similar condition is found also in the elapine Boulengerina annulata which lives in large lakes of Central Africa. The similarity in structure of the venom gland between sea snakes and Notechis scutatus may point to a possible phylogenetic relationship between this group of Australian elapids and hydrophiine snakes.     

Immunocytochemical localization and secretion process of the toxin CSTX-1 in the venom gland of the wandering spider Cupiennius salei (Araneae: Ctenidae)

Fluorescein and horseradish peroxidase-labeled monoclonal antibodies were used to localize the predominant toxic peptide CSTX-1 in the venom gland of the spider Cupiennius salei. There was no polarity of CSTX-1 expression in repleted glands, whereas the glands of previously milked spiders showed a decreasing immunofluorescent response from the distal to the proximal portion. Detailed investigation revealed a new structure in the venom-secreting epithelium, which is postulated to be an evolutionary adaptation to increasing gland volume. CSTX-1 was found to be synthesized and stored as a fully active toxin within complex units, composed of long interdigitating cells running perpendicular to the muscular sheath and extending into the central lumen of the gland. These venom-producing units were found in all sectors of the gland, including the transitional region between the main gland and the venom duct. The venom is liberated from the venom-producing units into the glandular lumen following the contraction of the surrounding muscle layer. Free nuclei or other cellular fragments, which would have provided evidence for a holocrine secretion process, were not found in the glandular lumen or in the crude venom obtained by electrical stimulation. The fine regulation of the spider's venom injection process is postulated to be the function of the bulbous ampulla, situated in the anterior third of the venom duct.     

Comparative experimental tests of natricine antipredator displays, with special reference to the apparently unique displays in the Asian genus, Rhabdophis

Nuchal glands are unique organs known in only twelve Old World natricine species (three genera) including Rhabdophis tigrinus tigrinus. The glands of R. t. tigrinus contain a toxic secretion that may be derived from its toxic toad diet. A series of peculiar antipredator behaviors, for example neck arch, neck butt, and dorsal-facing posture, are exhibited by R. t. tigrinus, and a functional association between this behavior and the nuchal glands has been suggested. To investigate the ubiquitousness of these putatively unique displays among snakes, antipredator responses of 27 taxa of natricine snakes, both with and without nuchal glands, were studied using a common testing procedure. Three of four taxa with nuchal glands exhibited neck arch, neck butt, and dorsal-facing posture. None of the remaining 23 taxa, which do not possess the glands, showed neck arch and neck butt. Principal-components analysis indicated the association of the above three displays along with the behaviors termed neck flatten and head elevation, confirming the presence of a series of nuchal gland-related behaviors. These results support the assumption that the suite of peculiar displays is associated with the deterrent effects of the nuchal gland secretion.     

The mechanism of venom secretion from Duvernoy's gland of the snake Thamnophis sirtalis

The venom glands of snakes of the families Elapidae and Viperidae are thought to have evolved from Duvernoy's gland of colubrid ancestors. In highly venomous snakes elements of the external adductor musculature of the jaw insert fibers directly onto the capsule of the venom gland. These muscles, upon contraction, cause release of contents by increasing intraglandular pressure. In Thamnophis sirtalis, a colubrid, there is no direct connection between Duvernoy's gland and the adductor musculature. The anatomical arrangement of the gland, skull, adductor muscles, and the integument is such that contraction of the muscles may facilitate emptying of the gland. This hypothesis was tested by electrical stimulation of the muscles, which resulted in significantly greater release of secretion than elicited by controls. The results suggest a possible early step in the evolution of a more intimate association between venom glands and adductor musculature in highly venomous snakes.