Publications by authors named "Valquiria A C Dorce"

Article Synopsis
  • Scorpion venoms contain bioactive peptides primarily made up of 30 to 70 amino acids, with many being neurotoxic.
  • Research has identified 12 short linear peptides from scorpion venom, six of which are classified as cryptides, using techniques like LC-MS and MS/MS.
  • These peptides have multiple functions, including causing hemolysis, pain, and inflammation, which complicates the process of envenomation for the victim.
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Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T.

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Scorpionism is frequently accompanied by a massive release of catecholamines and acetylcholine from peripheral nerves caused by neurotoxic peptides present in these venoms, which have high specificity and affinity for ion channels. Tityus bahiensis is the second most medically important scorpion species in Brazil but, despite this, its venom remains scarcely studied, especially with regard to its pharmacology on the peripheral (somatic and autonomic) nervous system. Here, we evaluated the activity of T.

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Studies of scorpion venoms have used different venom drying methods: lyophilization, desiccation, lyophilization after mixing with 0.9% saline or purified water and centrifugation. The aim of this study was to see if these different approaches cause some alteration in the composition of the venom or interfere with its biological effects.

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Scorpion venoms are composed of several substances with different pharmacological activities. Neurotoxins exert their effects by targeting ion channels resulting in toxic effects to mammals, insects and crustaceans. Tb II-I, a fraction isolated from scorpion venom, was investigated for its ability to induce neurological and immune-inflammatory effects.

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Background: Except for the northern region, where the Amazonian black scorpion, T. obscurus, represents the predominant and most medically relevant scorpion species, Tityus serrulatus, the Brazilian yellow scorpion, is widely distributed throughout Brazil, causing most envenoming and fatalities due to scorpion sting. In order to evaluate and compare the diversity of venom components of Tityus obscurus and T.

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In Brazil, the scorpion species responsible for most severe incidents belong to the genus and, among this group, , , and are the most dangerous ones. Other species such as , , , , are also found in the country, but the incidence and severity of accidents caused by them are lower. The main effects caused by scorpion venoms - such as myocardial damage, cardiac arrhythmias, pulmonary edema and shock - are mainly due to the release of mediators from the autonomic nervous system.

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Unlabelled: Many scorpion accidents occur in the Brazilian Amazonian region and are frequently caused by Tityus obscurus. Approximately 5% of the crude venom of this species is composed of short linear, non-disulfide-bridged peptides, which have not been intensively investigated. As a consequence, only a few of these peptides have been structurally and functionally characterized to date.

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Scorpion envenomation is a public health problem, especially in tropical and subtropical countries. Considering the high incidence of scorpionism in some areas, pregnant women and nursing mothers may be possible victims. Scorpion stings alter the release of neurotransmitters and some cytokines.

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There are a great number of studies about Brazilian scorpions. However, little is known about the venom of scorpions of northern Brazil, mainly about Tityus obscurus, which is responsible for the most number of accidents in the Amazon. Thus, this study aimed to evaluate some pharmacological effects of T.

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Scorpion stings are a public health problem in Brazil and lactating women may be affected. We aimed to study the effects of Tityus bahiensis venom in the offspring of rats treated during lactation. Mothers received a subcutaneous injection of saline (1.

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TsTX-I, isolated from Tityus serrulatus scorpion venom, causes epileptic-like discharges when injected into the central nervous system. The involvement of excitatory amino acids and cytokines in this activity was investigated. Our results have demonstrated that TsTX-I increases the release of IFN-γ but does not alter the intracerebral concentration of the excitatory amino acids in rats.

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Due to the high incidence of scorpion stings in Brazil, pregnant women are among the possible victims. Cytokines are important during the pregnancy, and scorpion venoms can change their release. We evaluated the levels of some cytokines in the fetuses after the treatment of pregnant rats with the Tityus bahiensis scorpion venom.

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Scorpion venom is a mixture of peptides, including antimicrobial, bradykinin-potentiating and anionic peptides and small to medium proteins, such as ion channel toxins, metalloproteinases and phospholipases that together cause severe clinical manifestation. Tityus bahiensis is the second most medically important scorpion species in Brazil and it is widely distributed in the country with the exception of the North Region. Here we sequenced and analyzed the transcripts from the venom glands of T.

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Aims: The objective of the present study was to determine the effects of a toxin from T. bahiensis scorpion venom on the hippocampus of rats. This toxin, called Tb V-4, was chosen since it shows remarkable convulsive activity.

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The toxicity of Tityus bahiensis scorpion venom is well known, but there are little data about the damage in offspring of dams that were exposed to the venom during pregnancy. The objective of this work was to determine the toxic effects of venom in adult offspring of Wistar rats exposed to venom in utero. Dams were divided into a control group, subcutaneously injected with saline solution on the 10th (GD10) and 16th (GD16) days, and two experimental groups, subcutaneously injected with venom (2.

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A great number of studies on scorpion venoms associate their effects to the autonomic nervous system, and few data are available about their action on the central nervous system (CNS). The aim of this work was to evaluate some central effects after intraperitoneal injection of Tityus serrulatus or T. bahiensis scorpion venoms.

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Scorpion envenoming is a public health problem. In Brazil, the scorpion Tityus serrulatus is considered the most dangerous, but a large number of exposures also occur with Tityus bahiensis. There are quite a few studies in literature about the toxic effects of this venom but it is not known if the venom causes malformations or behavioral defects to the offspring of mothers exposed to the venom during pregnancy.

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Tityus serrulatus is the most venomous scorpion in Brazil. Little is known about the effect of maternal exposure to the venom on fetal development. We investigated the effect of low to moderate doses of the venom (0.

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Scorpion envenomation is a public health problem. Extensive research has been conducted to describe the systemic effects of scorpion venoms and their toxins, however, few reports are available about their effects on pre- and post-natal periods. Whole venom of the Tityus serrulatus scorpion was administered to rats on the 10th and 16th days of pregnancy to determine the effect on physical, reflexive and behavioral development of offspring.

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We examined the effects of dantrolene, an inhibitor of intracellular calcium release, on alterations associated with the intrahippocampal injection of the TsTX scorpion toxin. Male Wistar rats (230-250 g) were injected with Ringer solution (1 microl; n = 6); TsTX toxin (1 microg/microl; n = 8); and dantrolene (10.0 mg/kg) plus TsTX toxin (1 microg/microl; n = 6).

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Scorpion toxins act on ionic channels changing the release of neurotransmitters. In the present study, we investigated the glutamatergic release evoked by intrahippocampal injection of TsTX toxin isolated from Tityus serrulatus scorpion venom in male Wistar rats and the blockade of the toxin effect by glutamatergic antagonists. Microdialysis for neurotransmitter level quantification, electroencephalographic recording, and histopathological analysis were performed.

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Tityus serrulatus and Tityus bahiensis are considered to be the most venomous scorpions in Brazil and are responsible for most of the accidents that occur in our country. The main toxic agents in scorpion venoms are small basic polypeptides that act as neurotoxins. They cause a derangement of ion channels that result in abnormal release of neurotransmitters.

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