Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SCORPIONS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMed1991

[Effect of alcohol-extract from scorpion on checking externally active cysticerus cellulosae].

Putting the alcohol-extract from scorpion in the ordinary aqueous solution of 15% pork bile and having it cultured at the temperature of 37 degrees C have proved for the first time that in contrast with the chemical albendazole, Scorpion has a conspicuous effect on the external killing of the cysticercus cellulosae, The action of killing cysticercus cellulosae has almost nothing to do with the difference of processed products or of the parts used in medicine.

Animals↗
PubMedDate not supplied

Experimental chronic interstitial pancreatitis induced by scorpion toxin in rats.

Scorpion venom effects in the gastrointestinal system have been investigated both in men and experimental animals. Pancreatic flux and enzyme content are increased by TsTX, the purified venom from the scorpion Tityus serrulatus. In this study male rats received a single intravenous injection of TsTX. They were sacrificed 20 days later and their pancreas removed. Histopathological studies showed interstitial fibrosis, mononuclear infiltrate, acinar atrophy and ductal dilatation. There also appeared, although less frequently, eosinophil infiltrates, ductular hyperplasia and dense eosinophilic secretion in enlarged ducts. All lesions were multifocal. Islet hyperplasia and nesidioblastosis were also observed.

Animals↗
PubMed1977

[Action of toxins isolated from scorpion and sea anemone venoms on ileum isolated from reserpine-treated guinea pigs].

We have shown that the ileum isolated from a reserpinized guinea Pig does respond to toxin II obtained from Scorpion venom but does not react to Anemonia sulcata toxin. We conclude that if Acetylcholine is the neurotransmitter inducing pharmacological activity of Scorpion toxin it is serotonin which triggers activity of Anemonia sulcata toxin in ileum of a normal guinea Pig.

Animals↗
PubMed1988

Autoradiographic localization of voltage-dependent sodium channels on the mouse neuromuscular junction using 125I-alpha scorpion toxin. I. Preferential labeling of glial cells on the presynaptic side.

Alpha-scorpion toxins bind specifically to the voltage-sensitive sodium channel in excitable membranes, and binding is potential-dependent (Catterall, 1984). The radioiodinated toxin II from the scorpion Androctonus australis Hector (alpha ScTx) was used to localize voltage-sensitive sodium channels on the presynaptic side of mouse neuromuscular junctions (NMJ) by autoradiography using both light and electron microscopy. Silver grain localization was analyzed by the cross-fire method. At the light-microscopic level, grain density over NMJ appeared 6-8x higher than over nonjunctional muscle membrane. The specificity of labeling was verified by competition/displacement with an excess of native alpha ScTx. Labeling was also inhibited by incubation in depolarizing conditions, showing its potential-dependence. At the electron-microscopic level, analysis showed that voltage-sensitive sodium channels labeled with alpha ScTx were almost exclusively localized on membranes, as expected. Due to washout after incubation, appreciable numbers of binding sites were not found on the postsynaptic membranes. However, on the presynaptic side, alpha ScTx-labeled voltage-sensitive sodium channels were localized on the membrane of non-myelin-forming Schwann cells covering NMJ. The axonal presynaptic membrane was not labeled. These results show that voltage-sensitive sodium channels are present on glial cells in vivo, as already demonstrated in vitro (Chiu et al., 1984; Schrager et al., 1985). It is proposed that these glial channels could be indirectly involved in the ionic homeostasis of the axonal environment.

Animals↗
PubMedDate not supplied

[Space organization and structure of the scorpion population in the region of Sfax (Tunisia)].

Four species of scorpions live in Sfax area: Androctonus australis, Androctonus aeneas, Buthus occitanus and Scorpio maurus. Preliminary study of this community organization showed that: spatial segregation allow coexistence of different species, nature and texture of the soil determine biogeography distribution and populations abundances in the sector studied, populations of scorpions maintains close connections between them and with guild of insectivorous and nocturnal lizards, particularly competition and predation.

Animals↗
PubMed1989

Batrachotoxin and alpha-scorpion toxin stabilize the open state of single voltage-gated sodium channels.

The combined effects of batrachotoxin (BTX) and either scorpion (Leiurus quinquestriatus quinquestriatus) venom (LqqV) or alpha-scorpion toxin (alpha-LqqTX) purified from LqqV on single voltage-gated Na channels were studied in planar lipid bilayers. In the presence of BTX, LqqV caused the channels to remain open at membrane potentials at least 50 mV more hyperpolarized than with BTX alone. alpha-LqqTX mimicked the effect of LqqV, suggesting that this toxin is the active component of the venom. LqqV did not significantly alter single-channel conductance, voltage-dependent block by saxitoxin, or voltage-dependent block by Ca2+, indicating that the venom preferentially affects gating rather than ion permeation. The results indicate that a cooperative interaction between alpha-LqqTX and BTX strongly favors the open state of the Na channel by causing a large hyperpolarizing shift in the voltage dependence of activation. This effect on activation gating is not predicted from the individual effects of the toxins.

Animals↗
PubMedDate not supplied

Acute pancreatitis induced by scorpion toxin, tityustoxin. Histopathological study in rats.

The toxin produced by the Brazilian scorpion Tityrus serrulatus (Tityustoxin) promotes pancreatitis when injected into dogs and rats. The aim of this study is to analyse the histological picture of the rat pancreas at different time intervals after tityustoxin administration. Male adult Wistar rats, weighing 250 +/- 30 g, received i.v. injections of tityustoxin. Different groups were sacrificed after 10, 20 and 40 minutes and after 24 and 96 hours. In all groups the pancreas was removed and examined under light microscope. Results show specific lesions after TsTX administration. After 10, 20 and 40 minutes histological sections of the pancreas showed degeneration with degranulation. After 24 and 96 hours a characteristic picture of acute pancreatitis was evident. Since cellular damage to the pancreas is evident soon after TxTX injection, we suggest a direct action of the venom on this organ. Furthermore, based on these findings, it is possible to claim for a rapid onset of the management of patients offended by scorpion stings.

Acute Disease↗
PubMedDate not supplied

Increased osmotic fragility of red cells in dogs with acute myocarditis produced by scorpion (Buthus tamulus) venom.

Stings from scorpions (Buthus tamulus) produce acute myocarditis and can result in death in children and adults. Acute myocarditis was induced in anaesthetised dogs by intravenous injection of 4 mg/kg venom (Buthus tamulus). Myocarditis was confirmed by ECG. Blood was collected before and 30 minutes after venom treatment and processed for osmotic fragility. An increase in osmotic fragility of red cells in addition to initial hypertension followed by hypotension were observed in venom treated animals. These results suggest that scorpion venom causes autonomic storm and the released catecholamines were responsible for acute myocarditis, changes in the blood pressure and increased osmotic fragility of red cells.

Acute Disease↗
PubMed1986

Spontaneous electrical activity of the suboesophageal ganglion and circadian rhythms in scorpions.

The electrical activity of the suboesophageal ganglion of the scorpion Euscorpius flavicaudis was recorded. Four kinds of waves were observed: random waves, single pattern, periodic waves and perturbed periodic waves. While random waves and single pattern could be recorded at any time of the day, periodic waves were observed only during the night. We claim that periodic waves mark the activity of a suboesophageal pace-maker and we propose a system of two pace-makers to explain the visual and locomotor circadian rhythms of scorpions.

Animals↗
PubMed1984

Biochemical and electrophysiological characteristics of toxins isolated from the venom of the scorpion Centruroides sculpturatus.

Recent progress in biochemical, structural and physiological studies has revealed several interesting properties of the toxins from the American scorpion, Centruroides sculpturatus. These toxins, together with similar toxins from other species of scorpions, comprise a unique family of homologous proteins with phylogenetically related structural differences. There is now evidence from both binding and electrophysiological studies that two distinct classes of toxins are present in the venom of C. sculpturatus. One class of toxins markedly slows inactivation of the sodium permeability but has no demonstrable effect on activation, whereas the second class induces a transient shift in the voltage-dependence of activation. Both groups make inactivation incomplete.

Amino Acid Sequence↗
PubMed1984

The interaction of sea anemone and scorpion neurotoxins with tetrodotoxin-resistant Na+ channels in rat myoblasts. A comparison with Na+ channels in other excitable and non-excitable cells.

The properties of interactions of several polypeptide neurotoxins isolated from sea anemone and scorpion venom with Na+ channels of rat myoblasts, chick myotubes, neuroblastoma cells, and fibroblasts have been compared. Tetrodotoxin (TTX)-resistant Na+ channels appear to be much more sensitive to the action of sea anemone toxins than TTX-sensitive Na+ channels but have the same affinity for scorpion neurotoxins. This conclusion holds both for Na+ channels that can be activated electrically and for silent forms of Na+ channels. The sensitivity to sea anemone toxins of the different types of Na+ channels that have been studied suggests the existence of multiple forms of Na+ channels.

Animals↗
PubMed1984

Effects of several sea anemone and scorpion toxins on excitability and ionic currents in the giant axon of the cockroach.

The membrane effects of 4 sea anemone and 6 scorpion toxins have been studied under current clamp and voltage clamp conditions. Micromolar concentrations of the purified toxins were applied externally on single giant axons of the american cockroach. Periplaneta americana in a double oil-gap arrangement and the effects on the resting potential, action potential and underlying currents analysed. The 4 sea anemone toxins (Condylactis toxin, Anemonia toxin 2, Anthopleurin toxin A and Parasicyonis toxin) were found to considerably prolong the action potential. This effect is frequency dependent and long plateau spikes (100-500 ms in duration) are consistently seen for frequencies lower than 0.2 Hz. This effect is due to a considerable delay in the turning-off of the sodium current during square membrane depolarizations associated, for large concentrations, with a decrease in the potassium conductance. Toxin effects on the sodium current are not prevented by pretreatment with STX. From the 4 purified toxins extracted from the venom of the scorpion, Androctonus australis Hector, 3 (Mammal toxins 1 and 2 and crustacean toxin) were found to have sea anemone toxin like effects and to induce long duration plateau action potentials. As for sea anemone toxins, this effect is due to a lengthening of the falling phase of the sodium current associated with a small decrease in the potassium conductance. The 4th toxin (insect toxin or ITAaH) depolarizes the membrane and induces repetitive firing of short action potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1980

[Kinetics of sodium current decay during normal axon membrane repolarization and in the presence of scorpion toxin].

Decay of sodium currents in repolarization ("tail current") was studied in from axonal membrane. The decay in the membrane repolarization to -40 divided by -60 mV has two exponential components: fast and slow. The fraction of the slow component in the total "tail current" (theta M) decreases as the repolarization potential (Vp) becomes more negative; at Vp more negative than -80 mV "tail" follows practically one-exponential time course. When lengthening the test pulse (at the given Vp) the fraction of the fast component in the "tail" decreases quicker than that of the slow component, following approximately the kinetics of inactivation during the tests pulse. Scorpion toxin treatment results in slowing down "tail" kinetics mainly at the expense of increasing the fraction of the slow component. A kinetic diagram assuming two open state for the channel is suggested. A hypothesis is advanced that scorpion toxin, DDT and trinitrophenol have a common "site" to interact with the gating mechanism of the sodium channel.

Animals↗
PubMed1983

Preparation and characterization of fluorescent scorpion toxins from Leiurus quinquestriatus quinquestriatus as probes of the sodium channel of excitable cells.

Fluorescent derivatives of scorpion toxin V from Leiurus quinquestriatus quinquestriatus have been prepared so that the topographical, dynamic, and cellular properties of the neurotoxin receptor site on the voltage-dependent sodium channel could be studied. Four different modification strategies have been pursued in which acylated, amidinylated, thio-amidinylated, and reductively alkylated scorpion toxins were prepared. Acylation induces a loss of net positive charge on the toxin and these derivatives are purified by preparative isoelectric focusing and ion-exchange chromatography. Amidinylation and reductive alkylation preserve the protonation state of the toxin and maintain the native tertiary structure of the toxin. Because the native toxin does not contain cysteine, we have introduced new sulfhydryls through modification with the cyclic imidoester 2-iminothiolane which also preserves the net charge on the toxin. Novel purification methods with small amounts of toxin by immunoprecipitation using antibodies directed against the chromophores or through covalent thiol-disulfide exchange chromatography have been utilized. The biological activities, equilibrium binding, and spectroscopic properties indicate that these derivatives retain high affinity for the sodium channel and are as active or only 2-3 times less active than L. quinquestriatus V toxin itself. The spectroscopic properties of these fluorescent derivatives cover the absorption range from 290 to 470 nm, and fluorescence emissions range from 360 to 550 nm where suitable filters and spectral overlap with previously synthesized fluorescent tetrodotoxin can be found. The fluorescent properties in particular show excellent environmental sensitivity and are suitable for probing the molecular dynamics of the toxin receptor and for topographic mapping of the sodium channel by fluorescence resonance energy transfer measurements.

Action Potentials↗
PubMed1984

Structural mapping of the voltage-dependent sodium channel. Distance between the tetrodotoxin and Centruroides suffusus suffusus II beta-scorpion toxin receptors.

A 7- dimethylaminocoumarin -4-acetate fluorescent derivative of toxin II from the venom of the scorpion Centruroides suffusus suffusus (Css II) has been prepared to study the structural, conformational, and cellular properties of the beta-neurotoxin receptor site on the voltage-dependent sodium channel. The derivative retains high affinity for its receptor site on the synaptosomal sodium channel with a KD of 7 nM and site capacity of 1.5 pmol/mg of synaptosomal protein. The fluorescent toxin is very environmentally sensitive and the fluorescence emission upon binding indicates that the Css II receptor is largely hydrophobic. Binding of tetrodotoxin or batrachotoxin does not alter the spectroscopic properties of bound Css II, whereas toxin V from Leiurus quinquestriatus effects a 10-nm blue shift to a more hydrophobic environment. This is the first direct indication of conformational coupling between these separate neurotoxin receptor sites. The distance between the tetrodotoxin and Css II scorpion toxin receptors on the sodium channel was measured by fluorescence resonance energy transfer. Efficiencies were measured by both donor quenching and acceptor-sensitized emission. The distance between these two neurotoxin sites is about 34 A. The implications of these receptor locations together with other known molecular distances are discussed in terms of a molecular structure of the voltage-dependent sodium channel.

Amino Acids↗
PubMed1982

Insect toxic component from the venom of a chactoid scorpion, Scorpio maurus palmatus (Scorpionidae).

Several insect toxic components were isolated from the venom of the chactoid scorpion, Scorpio maurus palmatus (Scorpionidae), by column chromatography, with the following findings. 1) The toxicity of the crude venom to insects is due to three separate groups of substances, the so-called cytotoxins, phospholipases, and neurotoxins, which play a dominant role. 2) The neurotoxic fraction contains two factors: the fast reversibly paralytic and the slow lethal. 3) The slow lethal factor is composed of two toxins (IT1 and IT2), the purity of which was assessed by column chromatography, disc electrophoresis, isoelectrofocusing, analytical ultracentrifugation, and amino acid analyses. 4) IT1 and IT2 are two polypeptides possessing unique amino acid compositions with molecular weights of 3232 and 3963, pHi 8.8 and 9.2, and supposed to contain two and three disulfide bridges, respectively. 5) A clear cooperative interaction was demonstrated between the fast paralytic and lethal fractions as well as between the two insect toxins, resulting in an evident recovery of the original toxicity to insects of the crude venom. 6) When assayed on an isolated insect axonal preparation under current and voltage clamp conditions, the combination of IT1 and IT2 caused a reversible blockage of both the sodium and potassium currents. This may explain the specific symptomatology and the mechanism of the paralysis induced by these toxins to an insect. The above data were compared with information concerning buthoid scorpion venom insect toxins.

Amino Acids↗
PubMed1978

The sperm and its formation in the scorpion Centruroides vittatus.

The development of sperm from a spermatid in the scorpion, Centruroides vittatus (Say), is described. The mature sperm is short with helical nucleus and a peculiar structure of the sperm tail. This peculiarity consists of alternating mitochondrial derivatives and membranous or network elements wrapped about the flagellum. We note the absence both of microtubules in the sperm of Centruroides and also of the centriole adjunct, which is present in other scorpion spermatids.

Animals↗