Vipera Renardi Research Articles

Sexual dimorphism and allometry in the head and body size of two viperid snakes (genus Vipera)

Sexual dimorphism in the size and shape of the body and head is the result of manifold selective pressures acting on organisms. In snakes, sexual size dimorphism is common and has been well-studied. However, intersexual differences in relative head size and shape have attracted far less attention. Similarly, the allometric properties of head shape and size in snakes are poorly known. Here, we analyse sexual dimorphism in two viperid species: European adder Vipera berus (Linnaeus, 1758) and Steppe viper Vipera renardi (Christoph, 1861). We measured body length, tail length and several head characteristics: head length, head width, head height, pileus length, interorbital distance and internarial distance. Our findings were that males and females of both species did not differ in body length (SVL), but that males tended to have significantly longer tails; there were also significant differences in head characteristics – males tended to have higher heads, and larger internarial and interorbital distances. The head dimensions displayed negative allometry when compared against SVL but when scaled against head length, dimensions like head height and head width exhibited positive allometry. We argue that these differences may be related to sexual selection and that the wider heads may also serve as antipredatory signal.

Present Distribution and Numbers of the Eastern Steppe Viper (Vipera renardi (Christoph 1861), Squamata, Viperidae) in Azerbaijan

Present Distribution and Numbers of the Eastern Steppe Viper (Vipera renardi (Christoph 1861), Squamata, Viperidae) in Azerbaijan

Environmental and biological significance of the action of viper poison on the homeostasis of mammals

The article examines the ecological and biological significance of the action of animal poisons as an evolutionary adaptation that maximizes the adaptation of more than 250,000 species to the conditions of their habitat. It was found that animal poisons have a significant impact on the formation and course of various forms of connections in ecosystems, perform several ecological functions and are important biotic factors of the environment. The best-studied venomous animals have been found to be snakes, of over 3,800 different species, only a small number are highly venomous. The Viperidae family includes 101 species of poisonous snakes. In Europe, Vipera ammodytes, Vipera aspis, Vipera berus, Vipera latastei, Vipera seoanei and Vipera ursinii are the most dangerous species, their bites cause severe poisoning. In Ukraine, the genus Vipera is represented by the steppe viper (Vipera renardi (Cristoph, 1861)) and two subspecies of the common viper (Vipera berus (Linnaeus, 1758)) — Vipera berus berus and Nikolsky’s viper (Vipera berus nikolskii, Vedmederja Grubant et Rudaeva, 1986). The factors that affect the diversity of the composition of snake venom are given. It is noted that snake venoms are complex mixtures of proteins, peptides and low molecular weight substances, among which enzymes and non-enzymatic components are distinguished. The biological properties of snake venom depend significantly on the properties of its components, which have a wide range of effects on the general state of homeostasis of a living organism. A generalization of scientific data on the study of the chemical composition of the venom of Vipera renardi, Vipera berus nikolskii and Vipera berus berus and the effects of these venoms on the functioning of the mammalian body has been carried out. It was found that the venom of Vipera berus nikolskii is the most, and Vipera renardi — the least toxic for mammals (mice). The effect of Vipera berus nikolskii and Vipera berus berus venom on the proteolytic balance of individual organs of rats was evaluated. It is emphasized that viper venom toxins have a great, not yet fully developed potential in many scientific fields, therefore they deserve further practical research.

FIBRINOGEN-SPECIFIC PROTEASE IN THE Vipera renardi SNAKE VENOM

Aim. To search fibrinogenolytic enzymes among protein components of Vipera renardi snake venom. Methods. Venom of V. renardi as the lyophilized powder was supplied by Trypillia serpentarium. It was dissolved in 0.05 M Tris-HCl buffer pH 8.3 and fractionated on Superdex G-75 using FPLC system Acta Prime. Peaks were tested for their ability to directly cleave fibrinogen. Hydrolytic products were analyzed by SDS-PAGE. Enzyme-electrophoresis with fibrinogen co-polymerized in 12% polyacrylamide gel was used for the identification of protein that can cleave fibrinogen.. Results. Venom of V. renardi was fractionated on 4 fractions using size-exclusion chromatography. SDS-PAGE of fibrinogen hydrolysis products showed the presence of fibrinogen-specific protease in the 1st and 2nd fractions of venom. 2nd fraction was much more active and according to the data of enzyme electrophoresis contained protease with molecular mass 25 kDa. Conclusions. Fractionation of V. renardi snake venom allowed to detect a protease with apparent molecular mass 25 kDa that can cleave fibrinogen molecule.

Snake Conservation State in the Reserves of the Volga Basin

There are 23 nature reserves in the Volga basin, all of them in the Russian Federation. According to our data and open access literature sources, ten out of the eleven species of snakes that are reliably known to be found in the Volga basin, inhabit and, therefore, are protected in 22 reserves. No snakes have been recorded in the Vishersky Reserve. One species inhabits the nature reserves “Basegi” and “Tsentralno-Lesnoy”, two species – in the reserves “Bolshaya Kokshaga”, “Darvinsky”, “Kaluzhskie zaseki”, “Kologrivsky forest”, “Nurgush”, “Prioksko-terrasny”, in the reserves “Bashkirsky”, “Visimsky”, “Volzhsko-Kamsky”, “Kerzhensky”, “Mordovsky”, “Oksky”, “Prisursky”, “Shulgan-Tash” and “Yuzhno-Uralsky” there are 3 species each, the reserves “Zhigulevsky” and “Volga forest-steppe” – 4 species each, in the reserves “Astrakhansky” and “Bogdinsko-Baskunchaksky” – 5 species each, in the reserve “Chornye Zemli” – 7 species. Eryx jaculus was not found in the reserves of the Volga basin. Species Eryx miliaris inhabits two reserves, Natrix natrix – 20, Natrix tessellata – 2, Coronella austriaca – 11, Elaphe dione – 4, Elaphe sauromates – 2, Hierophis caspius – 3, Malpolon monspessulanus – 1, Vipera berus – 19, Vipera renardi – 2. The latter species is represented in both reserves (Volga forest-steppe and Astrakhansky) only by the nominative subspecies Vipera r. renardi, and in the Volga Basin, by the endemic subspecies V. r. bashkirovi, which has no conservation status in regional reserves. Three species of snakes are the least prosperous in terms conservation in the Volga basin: Eryx jaculus, Eryx miliaris, and Vipera renardi.

Snakes of the Volga basin in the Red Data Books of Differnt Levels

Currently, 11 species of snakes are reliably known to be found in the Volga River basin. Vipera renardi has been assigned the Vulnerable (VU) category on the IUCN Red List of Threatened Species. The authors analyze the representation of snakes in the Volga basin in the latest editions of the Red Data Book (RDB) of the Republic of Kazakhstan, the RDB of the Russian Federation and the RDBs of Russian Oblasts, which are fully or partially related to the Volga basin. The species Hierophis caspius is included in the list of protected species in the RDB of Kazakhstan in the interfluve of the Volga and the Urals. The RDB of the Russian Federation considers rare and threatened three ophidiofauna species of the Volga basin: Eryx jaculus, Eryx miliaris, and Elaphe sauromates. Coronella austriaca is the most listed species in the Red Data Books of the constituent entities of Russia in the Volga Basin (35 Red Data Books); it is widespread but rare. The RDB of the Republic of Kalmykia protects the world’s northernmost population of Eryx jaculus. The RDBs of the Republic of Bashkortostan and Samara Oblast protect the world’s northernmost populations of Natrix tessellata, the RDB of Tatarstan protects the world’s northernmost population of Vipera renardi. The RDB of Volgograd Oblast protects the world’s northernmost population of Hierophis caspius, and the RDB of Samara Oblast – the northernmost population of Elaphe dione in Europe. Anthropogenic transformation of habitats, traffic-related deaths and actual killing of snakes are the main limiting factors in the RDBs. The authors believe that an effective measure of conservation is the creation of protected areas in the habitats of species, and, first of all, the preservation of winter brumation sites.

Biodiversity of the Regional Landscape Park Samara Plavni within the first large reservoir in Europe Biodiversity of the Regional Landscape Park Samara Plavni within the first large reservoir in Europe

The creation of reservoirs in river valleys for the accumulation of fresh water has been and remains an important issue around the world. This process has both positive and negative consequences for people and nature. Significant changes in the regime of rivers and their valleys, flooding of meadows and forests, flooding of soils and changes in the composition of flora and fauna of adjacent territories are taking place. In this article, we consider the restoration of the biodiversity of a site of disturbed lands after the creation of one of the first large reservoirs in Europe – the Dnieper (Zaporozhe) on the River Dnieper, which has existed since 1933. The territory of the Samara floodplains was formed on the floodplain of the mouth of the Samara River, as a result of which the territories of various forest, meadow and bog biotopes were flooded. For almost 90 years, new biotopes have been developing, and populations of plant and animal species, especially waterfowl, have been renewed and enriched. In the conditions of climate change and anthropogenic pressure, the existence of this territory has fallen into question. To control the conservation of biodiversity, it is necessary to apply various management methods, one of which is creation of nature reserves. The article presents the results of a complex of scientific studies that were carried out during the zoning of the regional park Samara Plavni to improve the management of the protection of water areas and river banks. We have investigated: hydrological features, species diversity of the flora and coenotic diversity of the vegetation, fauna of aquatic invertebrates, and terrestrial vertebrates. Zoning of the Regional Landscape Park was based on the composition of stable components of ecosystems. When applying the protected regime in different zones, conditions will be created for the preservation of habitats of species, including those protected in Europe: higher plants (Senecio borysthenicus (DC.) Andrz. ex Czern., Tragopogon borystenicus Artemcz.), reptiles (Emys orbicularis (Linnaeus, 1758), Vipera renardi (Christoph, 1861)), birds (Aythya ferina (Linnaeus, 1758), Vanellus vanellus (Linnaeus, 1758), Haematopus ostralegus Linnaeus, 1758, Numenius arquata (Linnaeus, 1758), Alcedo atthis (Linnaeus, 1758), Lanius excubitor (Linnaeus, 1758)), mammals (Lutra lutra (Linnaeus, 1758)). Such changes would increase the implementation of the reproductive potential of all species without exception in the studied ecosystems.

Is <i>Vipera orlovi</i> a Distinct Hybrid Species?

The species status of Vipera orlovi is discussed in the context of the concept of hybrid speciation. The genome of this Caucasian viper is composed of the genomes of Vipera kaznakovi (major part) and of Vipera renardi (about 20%). V. orlovi is intermediate in ecology between its ‘parental species,’ however its habitat is not the typical habitat of neither V. kaznakovi nor V. renardi. As all three taxa are allopatric, there is no evidence of current geneflow between them. Pleistocene climatic changes may have mediated contact and hybridization between V. kaznakovi and V. renardi. The resulting hybrid flock may have had a wider ecological range than its parental species, enabling a descendant lineage to occupy a novel niche which was previously unoccupied. Similar scenarios of hybrid speciation have probably occurred in vipers throughout the Caucasus. Although the future fate of this hybrid speciation remains open unless full genetic isolation has occurred, we propose to grant species status to Vipera orlovi. This is in line with the genotypic cluster species concept and the unified species concept.

ДИНАМІКА ЧИСЕЛЬНОСТІ СТЕПОВОЇ ГАДЮКИ VIPERA RENARDI НА ПІВДНІ ЛІВОБЕРЕЖНОЇ УКРАЇНИ

The steppe viper (Vipera renardi (= ursinii) Christoph, 1861) is a background species of snakes in the steppe zone of southern left-bank Ukraine. This species is a figurant in the Red Book of Ukraine and is protected in accordance with the Bern Convention. According to the IUCN Red List, Vipera renardi has a Vulnerable species (VU) status, which is assigned to species that are under threat of becoming endangered. Anthropogenic transformation, namely, plowing, afforestation, irrigated agriculture, fires, synanthropization, etc., lead to the fact that in the Black Sea steppe, in the Lower Dnieper arenas of steppe, the viper disappears. This species has been preserved in the protected areas of the region and in the less transformed areas of the coastal and sandy steppe. The study area includes the forest-steppe areas of the Black Sea Biosphere Reserve (BSBR) and the territory of the “Svyatoslav’s Biloberezhzhya” National Nature Park (NNP BS) on the Kinburn Peninsula, the Black Sea areas and the islands of Tendrivska and Yahorlytska Bays, which are part of the Black Sea Biosphere Reserve. The dynamics of the number of steppe vipers also depends on abiotic factors too. In wetter years and the next 1-2 years, the number of vipers in the region decreases. In dry years, the number of steppe vipers increases. In the last 20 years, according to the results of long-term monitoring, the dynamics of the steppe viper population has a negative trend both in the Black Sea steppe and in the arenas of the Lower Dnieper.The cyclic dynamics of the steppe viper in our region is 3-5 years, the highest amplitude is 1.4 units, the maximum values of the relative abundance over the past 20 years have decreased from 1.5 to 0.4 ind./km, the minimum - from 0.3 to 0,1 ind./km. To preserve the population of this species in the south of the left-bank Ukraine, it is necessary to increase the areas with limited use of natural resources, namely, with the prohibition of plowing, prevention of excessive grazing and exploitation of sand deposits. In addition, it is required to strengthen environmental education and propaganda among the local population about the need to preserve the steppe viper in natural conditions and change the hypertrophied thought about the danger of this snake. The extensive network of protected areas in the region: reserves, national nature parks, regional landscape parks, protected tracts, etc., contributes to the conservation of this species. Key words: steppe viper, Black Sea steppe, Lower Dnieper arenas, population dynamics, monitoring.

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In 2020, waters and territories of the eastern part of Emerald Network object “Samarskyi Lis – UA0000212” were studied by biology specialists. The main purpose of the research was to identify rare species of plants and animals. We found species of flora and fauna protected by European Red List, Red Data Book of Ukraine, Additions to the Bern Convention and Regional Red Data Book. The list of plant species subjected to special protection contains 42 species, including Allium savranicum, Agropyron dasyanthum, and Jurinea cyanoides. It is noted that in the eastern part of the Emerald Network object “Samarskyi Lis ‒ UA0000212” the presence of other rare plant species is assumed (Senecio borysthenicus (D&c.) Andrz., Agropyron dasyanthum Ledeb, Viola lavrenkoana Klokov., Allium savranicum Besser). This matter requires monitoring in various phenological periods of the year. Concerning entomofauna in the eastern part of the Emerald Network object “Samarskyi Lis – UA0000212” it was found 7 species listed in the Red Data Book of Ukraine (2009): Lucanus cervus, Papilio machaon, Iphiclides podalirius, Zerunthia polyxena, Xylocopa valla, Scolіa maculata, Catocala sponsa, as well as 2 species of insects protected by the provisions of the Bern Convention ‒ Lucanus cervus, Lycaena dispar. The ichthyofauna of the eastern part of the Emerald Network object “Samarskyi Lis ‒ UA0000212” includes 4 species that are listed in the Bern Convention: Leucaspius delineatus, Rhodeus amarus, Cobitis taenia, Sykhorn abotter. Analysis of terrestrial vertebrates revealed the presence of 95 species to be protected. There are 5 species of amphibians (three of them are included in the International Red List – Lissotriton vulgaris, Hyla arborea, Bufo bufo), as well as 6 species of reptiles, among which one is protected by IUCN (Emys orbicularis), two species listed in the Red Data Book of Ukraine (Coronella austriaca, Vipera renardi). 74 species of birds were found in the study area. Three of them (Coracias garrulus, Ciconia nigra and Buteo rufinus) are listed in the Red Data Book of Ukraine. In the eastern part of the Emerald Network object “Samarskyi Lis ‒ UA0000212” there are 10 species of mammals, of which nine are protected by the provisions of the Bern Convention, and two species (Eptesicus serotinus, Nyctalus noctula) are listed in the Red Data Book Of Ukraine. It is proposed to conduct further monitoring studies in the eastern part of the Emerald Network “Samarskyi Lis ‒ UA00002122”

Reptiles of the Orenburgsky State Nature Reserve, Russia

Nine reptile species inhabited on the five sites in the Orenburgsky State Nature Reserve, these are Emys orbicularis, Eremias arguta, Lacerta agilis, Zootoca vivipara, Natrix natrix, N. tessellata, Coronella austriaca, Elaphe dione, and Vipera renardi. Lacerta agilis is the only abundant species. Over the last 20-25 years, the abundance of at least three species (Emys orbicularis, Zootoca vivipara, Natrix natrix) has decreased in some clusters of the reserve.

Мониторинг пресмыкающихся (Reptilia) на территории заповедника «Ростовский» c середины ХХ в. до 2020 года

To ascertain the changes in complexes of Reptilia species due to human activities on the Rostov Nature Reserve grounds in the 20th-21st centuries. Research Location and methods: There are 10 Reptilia species that habits observed territory. Starting from the middle of 20th century steppes had huge anthropological changes, which had significant impact on reptiles. The Re-serve creation had positive contribution to reptile group. In this region were preserved species included in Rostov region red book, such as Eremias arguta Pall., Coronella austriaca Laur., Hierophis caspius Gmel., Elaphe sauromates Pall., El. dione Pall. и Vipera renardi Chris. Intensification of agricultural activities in this region in last decade requires improved environmental work.

Состояние популяций и природоохранный статус степной гадюки – Vipera renardi (Christoph, 1861) (Reptilia, Serpentes) в Саратовской области

Состояние популяций и природоохранный статус степной гадюки – Vipera renardi (Christoph, 1861) (Reptilia, Serpentes) в Саратовской области

ЗНАХІДКИ ГАДЮКИ СТЕПОВОЇ В ЧЕРКАСЬКІЙ ОБЛАСТІ

Introduction. The Steppe Viper (Vipera renardi (Cristoph, 1861)) is listed in the Red Data Book of Ukraine and protected in Ukraine according to Berne Convention on the Conservation of European Wildlife and Natural Habitats. The population of the species in Ukraine had decreased during the last decades, its northern range border had shifted to the south. The Steppe Viper has been didn’t find was not recorded in Cherkasy Oblast during the last 90 years. Purpose. The aim of the present study was to present data on current distribution of the Steppe Viper on the left bank of the Dnieper in Cherkasy Oblast and to put it into context of distribution of this species in Ukraine. Methods. Materials has been collected during 2014-2019 in Cherkasy Oblast, Ukraine, in the forest-steppe zone. Results. Steppe viper has been found in two localities: in Zolotonosha Rajon near vil. Khvylovo-Sorochyn one Steppe Viper was observed 05.07.2015 and four specimens were seen 23.04.2019. In addition, two snakes were found and reported on Facebook by user Viktor Oleksenko. Snakes were observed 23.06.2014 near vil. Vilkhy (Zolotonosha Rajon, Cherkasy Oblast). In all cases snakes were observed on open places with herbaceous plants near glades or at the edge of a mixed pine-oak forest, situated on the Dnieper left bank sandy terrace at the place of its’ confluence with Zolotonoshka river. These habitats are not typical for this species in Southern Ukraine, within Steppe zone. Similar isolated populations of the Steppe Viper are existing in other regions of Ukrainian Forest Steppe: Dnipropetrovsk, Kharkiv and Kyiv. Conclusion. Our research confirms presence of small isolated populations of the Steppe Viper in the Ukrainian Forest Steppe, on the Dnieper’s left bank. Habitats along the large river valleys have an important role for conservation this species in Forest steppe.

Age differences in the properties of viperous snake venom of the Volga river basin

The Volga river basin is inhabited by two species of vipers: eastern steppe viper Vipera renardi and the common adder V. berus. Th e article provides information about the age differences of biochemical properties of viper’s snake venom. It also shows for each species that the protease activity in the snake venom of newborn vipers is significantly higher than in that of adults. All venom samples of the newborn eastern steppe vipers were colorless, with zero activity of L-amino acid oxidase. All venom samples of the newborn common adders were yellow in color, but in comparison with adults they have less active L-amino acid oxidase. Refs 11. Tables 3.

Распространение степной гадюки Vipera renardi (Reptilia, Viperidae) в Харьковской области

Изучение современного состояния популяций животных, находящихся под охраной, является неотъемлемым элементом в разработке и построении грамотной стратегии охраны видов. Vipera renardi Christoph, 1861 (Reptilia, Viperidae) включена в Красную книгу Украины, а также в Красную книгу Харьковской области и имеет статус уязвимого вида. В статье приведены обобщенные данные о распространении вида в историческом прошлом, а также о современном состояним популяций в Харьковской области, полученные в результате натурных обследований ранее известных и потенциальных местообитаний. Восемьдесят процентов известных до конца ХХ века популяций степной гадюки в области исчезли. Вероятнее всего, это связано с преобразованием биотопов и, возможно, другими не выясненными причинами, в числе которых отдаленные эффекты фрагментации популяций, загрязнение и побочные результаты применения ядохимикатов. Гадюки практически отсутствуют в северной, лесостепной части области. Северная граница вида в регионе сместилась к югу и сейчас проходит по северной границе степной зоны. На данный момент в Харьковской области достоверно подтверждено пять местообитаний этого вида. Находки в окрестностях пос. Червона Хвыля и пгт. Шевченково приводятся впервые.

Mitochondrial phylogeny shows multiple independent ecological transitions and northern dispersion despite of Pleistocene glaciations in meadow and steppe vipers (Vipera ursinii and Vipera renardi)

The phylogeny and historical demography of small Eurasian vipers of the Vipera ursinii and V. renardi complexes were studied using mitochondrial DNA sequences analysed with Bayesian inference, Maximum Likelihood and Maximum Parsimony approaches, and mismatch distributions. Diversification in the group resulted from an initial dispersion in the later Pliocene – Pleistocene in two directions: north-westwards via the Balkans (V. ursinii complex) and north-eastwards from Asia Minor via the Caucasus (V. renardi complex). An independent, comparatively recent transition occurred from montane habitats to lowland grasslands in different mitochondrial lineages during the Late Pleistocene, when representatives of the both complexes had reached lowland steppes to the north. Effective population size showed clear signs of rapid growth in eastern V. renardi, triggered by colonization of vast lowland steppes, but in western V. ursinii complex grew during the Last Glaciation and experienced stabilization in Holocene. Expansion and population growth in lowland lineages of V. renardi was not strongly affected by Pleistocene climatic oscillations, when cold, dry conditions could have favoured species living in open grasslands. The high diversity of closely related haplotypes in the Caucasus and Tien-Shan could have resulted from repetitive expansion-constriction-isolation events in montane regions during Pleistocene climate fluctuations. The mitochondrial phylogeny pattern conflicts with the current taxonomy.

A mitochondrial DNA phylogeny of the endangered vipers of the Vipera ursinii complex

The last two populations of the Hungarian meadow viper Vipera ursinii rakosiensis were thought to persist in the steppe fragments of Hungary until meadow vipers were discovered in central Romania (Transylvania), suggesting a possible existence of remnant populations elsewhere. We assessed the phylogenetic position of the Transylvanian vipers using 2030bp of mitochondrial DNA sequence. We showed that they were closely related to the Hungarian vipers, while those from northeastern Romania (Moldavia) and Danube Delta belonged to the subspecies Vipera ursinii moldavica. Montane subspecies from Europe (Vipera ursinii ursinii and Vipera ursinii macrops) formed a sister clade to the two lowland subspecies. Vipera renardi formed a sister clade to V. ursinii, with populations from the Greater Caucasus (Vipera renardi lotievi) and Tien Shan (Vipera renardi tienshanica) as the sister group to Vipera renardi renardi, and Vipera renardi eriwanensis from the Lesser Caucasus as the most basal taxon in the species. Our results illustrate that the divergence between the lowland and montane populations occurred separately in each species and several times in V. renardi. We demonstrated that the recently discovered Transylvanian population is the third surviving population of V. u. rakosiensis and the only known population outside of Hungary.

Different Forms of Melanism and Its Development with Age in the Populations of Steppe Viper <i>Vipera renardi</i> (Christoph, 1861)

Melanistic coloration has been observed in the populations of Vipera renardi in Krasnodar Region. Various forms of melanistic pattern of coloration and its development with age are analyzed.

10.1007/s11827-008-1003-x

Snake venoms contain a vast array of toxic polypeptide components interacting with a variety of cell targets. Thus, Elapidae snake venoms contain α-neurotoxins with very high affinity for nicotinic acetylcholine receptors (nAChRs) and a few toxins able to suppress the activity of Ca2+ and K+ channels. Experimental evidence for the presence of nAChR antagonists and voltage-gated ionic channel blockers in venoms of Viperidae snakes is very scarce. In this study, effects of crude venoms of seven snake species (Vipera nikolskii, Echis multisquamatus, Gloydius saxatilis, Bitis arietans, Vipera renardi, Vipera lebetina, and Naja kaouthia) on nAChRs and voltage-gated Ca2+ channels were studied for the first time. The experiments were carried out on isolated identified neurons of the fresh-water mollusc Lymnaea stagnalis using voltage-clamp and intracellular perfusion techniques. All Viperidae snake venoms under study blocked nAChRs and voltage-gated Ca2+ channels. The potency of these venoms against nAChRs was significantly lower in comparison with N. kaouthia venom which is rich of α-neurotoxins; however, the extent of Ca2+ channel block by venoms of Viperidae snakes and N. kaouthia was similar. The data obtained suggest that Viperidae snake venoms tested in this study contain peptides with affinity both for nAChRs and for voltage-gated Ca2+ channels.