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 1,243 records · Page 69Linked to original sources
PubMed1999

[Effect of scorpion venom on the release of GABA in hippocampus of epileptic rats induced by kainic acid].

In the present study, the effect of scorpion venom (SV) on epileptic susceptibility and its neurochemical mechanisms were investigated. After SV or normal saline (NS) administration for three weeks in epileptic rats, epileptic seizures were much more decreased in kainic acid (KA) + SV group than those of KA + NS group. GABA immunocytochemistry showed that both (gamma-aminobutyric acid immunoreactivity (GABA-IR) density and the number of GABA positive neurons were markedly decreased in the ventral hippocampus, especially in hilus of KA + NS group as compared with NS + NS group. However, in the group treated with SV for three weeks, the number of GABA positive neurons and the density of GABA-IR were greater increased than those of both KA + NS group and the NS + NS group. The number of GABA positive neurons and the density of GABA-IR were unchanged in the dorsal hippocampus of all the four groups. The above results suggest that SV may selectively prevent loss of GABAergic interneurons in the ventral hippocampus of rats susceptible to epileptic seizures and increase the release of GABA as an antiepileptic mechanism.

Animals↗
PubMedDate not supplied

[Proceedings: Interrelations between cholinergic and monoaminergic mechanisms in the determinism of spontaneous electrical activity in the central nervous system of scorpion (author's transl)].

Spontaneous electrical activity of the cerebral nervous system of Scorpion is characterized by potentials of 30 muV, and of average frequency varying between 200 et 400 impulses/min. This activity is enhanced by acetylcholine, and inhibited by adrenaline, nor-adrenaline, and serotonine, from a pharmacological study, it is assumed that spontaneous electrical activity of cerebral nervous system is due to cholinergic neurons, and antagonized by a serotoninergic system.

Acetylcholine↗
PubMedDate not supplied

[Effect of hypoxia on carbohydrate metabolism in scorpion tissues].

The levels of glycogen, glucose, lactate, as well the activities of ten enzymes of carbohydrates metabolism in brain, liver and white muscle of sea scorpion have been investigated. Metabolite concentrations didn't change in brain and the levels of glycogen and lactate were constant in the rest tissues investigated. Glucose concentration decreased in the liver and increased in muscle. In brain hypoxia decreased the activity of hexokinase and increased one of pyruvate kinase, phosphoglucoisomerase and fructoso-1,6-bisphosphatase. In liver most of the enzymes showed the tendency to decrease of their activities. In muscle the activities of phosphofructokinase and phosphoglucoisomerase decreased. Mechanisms of carbohydrates metabolism regulation under hypoxia are discussed.

Animals↗
PubMed2002

[Complements to the description of Tityus dedoslargos (Scorpiones: Buthidae)].

The female of the Costarican scorpion Tityus dedoslargos Francke and Stockwell, 1987 is described for the first time and new data on its morphological variation and natural history are given. The female differs from the male mainly in having an enlarged basal median lamellae on the pectines, and lacking modified pedipalps. The species type locality relocated. This species is recorded from only two Costarican provinces: San Jose and Puntarenas.

Animals↗
PubMed2002

[Centruroides Schmidti (scorpiones: Buthidae) in Costa Rica].

Centruroides schmidti Sissom, 1995 is the new identification designate of the scorpions previously known as C. thorelli (Kraepelin, 1891) in Northwest Costa Rica. The geographical distribution of the species in this country is established on the basis of new collected material. Its distribution includes the Pacific slope of the Guanacaste volcanic range, and the Pacific and Atlantic slopes of the Tilarán volcanic range between 50 and 775 m elevation above sea level, within the Costa Rican Guanacaste and Alajuela provinces.

Animals↗
PubMed1992

Autoradiographic localization of voltage-dependent sodium channels on the mouse neuromuscular junction using 125I-alpha scorpion toxin. II. Sodium distribution on postsynaptic membranes.

A radioiodinated alpha-scorpion toxin (toxin II from Androctonus australis Hector) (alpha ScTx) was used as a probe for EM autoradiography to study the distribution of voltage-dependent sodium channels (Na+ channel) on the postsynaptic side of the mouse neuromuscular junction. Silver grain distribution was analyzed by the cross-fire method to assess the relative Na+ channel density in each membrane domain measured by stereology. This analysis showed that the maximum Na+ channel density was located on the edge of the synaptic gutter, where it reached about twice the mean density in the postsynaptic fold membrane. Na+ channel densities have been calculated using ACh receptor (AChR) density in fold crests as reference. Sodium channel density on the edge of the synaptic gutter was estimated at about 5000/microns 2. Sodium channel distribution in the postsynaptic folds was compared to AChR distribution using density distribution analysis (Fertuck and Salpeter, 1976). The results confirmed that, as already observed by immunogold labeling (Flucher and Daniels, 1989), there are no Na+ channels on fold crests. Na+ channels are located in the rest of the fold membrane (bottom) and may be distributed according to two possible models. In the first, density would be uniformly high, although lower than on the gutter edge. In the second, density would decrease from the crest border, where the value was that of the gutter edge, to the fold end, where the value would be 50% lower. Based on the latter model, which was the "best-fit model," we propose that the postsynaptic membrane includes two domains. The first is the fold crest, which contains almost exclusively AChRs. This domain is devoted to reception-transduction of the chemical signal. The second includes both the fold bottom membrane and the perisynaptic membrane. Sodium channel density is highest along the crest border and decreases moving away. Its functions are the integration of postsynaptic potentials and generation-conduction of the muscle action potential.

Animals↗
PubMed1992

Characteristics of pancreatic exocrine secretion produced by venom from the Brazilian scorpion, Tityus serrulatus.

The influence of venom (TSV) from the Brazilian scorpion, Tityus serrulatus, on exocrine pancreatic secretion was studied in relation to known cholinergic and peptidergic secretagogue activity. Pulse-labeling followed by chase incubation in the presence of secretagogues and various pharmacological agents revealed unique physiological characteristics of TSV in guinea pig pancreatic lobules. Exocytotic discharge of newly synthesized 3H-labeled proteins during a 3-h chase incubation showed a marked increase over basal discharge levels using logarithmic TSV doses of 0.10 to 100 micrograms/ml. This stimulation was comparable to maximal values elicited by carbachol, cholecystokinin-octapeptide (CCK-8) or caerulein and discharge kinetics were similar. TSV-mediated secretion was ATP and calcium dependent and partially inhibited by atropine. Only tetrodotoxin completely blocked TSV stimulation of newly synthesized protein discharge. Both botulinum toxin and curare had no effect on venom stimulation, indicating that TSV interaction with exocrine pancreatic cells occurs postsynaptically. Verapamil, a calcium channel antagonist, produced a moderate inhibition of TSV stimulation. When antagonists to the cholecystokinin (CCK) receptor were incubated with TSV, no change in secretory activity occurred. Therefore, TSV does not bind to CCK receptors and probably operates through its own receptor which may be an ion channel. Additionally, morphological studies in vitro revealed a high level of pancreatic secretory activity as evidenced by dense secretory acinar luminal content, reduction in zymogen granule (ZG) population, and development of exocytotic images.

Amylases↗
PubMed1977

[Structure of scorpion hemocyanin: heterogeneity of its sub-units].

Six dissociation products isolated from the Androctonus australis scorpion haemocyanin are studied through analytical ultracentrifugation and acrylamide-SDS electrophoresis: the results show that one of these fractions exists as a dimer and that the five others are monomers. A genetical study shows that two subunits at least can undergo mutations.

Animals↗
PubMed2004

Pancreatic toxicity in mice elicited by Tityus zulianus and Tityus discrepans scorpion venoms.

Envenoming by Tityus discrepans (TD) scorpions in northcentral Venezuela mainly causes pancreatic and gastrointestinal complications whereas the sting by Tityus zulianus (TZ) (western Venezuela) often produces respiratory arrest and death by pulmonary oedema. Since TZ pancreatic toxicity may have been overlooked, a study was carried out to evaluate TZ venom effect on mice pancreas. BALB/c mice were injected intraperitoneally with 0.5 mg protein/kg of either TD or TZ venoms. A significant increase in serum-amylase activity (IU/mL) was obtained after 3 h (20.6 +/- 3.0, p < 0.05) and 6 h (60.4 +/- 3.0, p < 0.001) of TZ venom injection compared to saline-inoculated mice. Increased amylase levels were also elicited by TD venom, although these were significantly lower than those induced by TZ. Light microscopy of pancreas from TZ-envenomed mice revealed interstitial oedema and vacuolization of acinar cells as soon as 1 h after injection. Differences in the time course of the pancreatic oedema (wet pancreas weight/body weight ratio) elicited by TD and TZ venoms suggest the existence of species-specific mechanisms for oedema formation. Taken together, these data suggest that the TZ venom contains components highly toxic to the mammalian pancreas, which may play a role in developing TZ-related pulmonary complications.

Amylases↗
PubMed1992

Characterization of superoxide dismutase from south Indian scorpion venom.

A manganese containing superoxide dismutase was purified to homogeneity from the venom of scorpion Heterometrus fulvipes by ammonium sulfate fractionation followed by gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-cellulose. The enzyme has a molecular weight of 100,000. Optimum pH for enzyme activity was 8.5 and optimum temperature was 45 degrees C. The enzyme was not sensitive to either cyanide or hydrogen peroxide but was inhibited by chloroform-ethanol mixture and p-hydroxymercuribenzoate. Metal chelators, EDTA, o-phenanthroline and diethyldithiocarbamate inhibited the enzyme activity in decreasing order. The effect of 6 M urea, sodium dodecylsulfate, guanidinium chloride and nitroprusside on enzyme activity has been studied. An antiserum raised against H. fulvipes venom inhibited the superoxide dismutase activity.

Animals↗
PubMed2005

[Dangerous scorpions from Niger].

Two dangerous scorpion species are responsible for the severe human envenomations in Niger, Leiurus quinquestriatus (H. et E.), the most abundant, and Androctonus aeneas C.L. Koch, less frequent and described in a Sahel country for the first time. Up to now, A. aeneas was known in North Africa only. Its venom is highly toxic for humans, similar to those of the most dangerous species living in Africa, such as L. quinquestriatus and other species belonging to the genus Androctonus, A. australis (L.) and A. mauretanicus (Poc.), for the envenoming treatment of which specific antivenoms are prepared. Taking into account the absence of a specific antivenom for A. aeneas, the paraspecific neutralising effect of these antivenoms should be tested.

Animals↗
PubMed1991

Immunological studies with the venom of the scorpion Tityus serrulatus.

1. We describe a "sandwich" enzyme-linked immunosorbent assay (ELISA) sensitive to quantities of scorpion (Tityus serrulatus) venom (TsV) in the range of 1-3 ng/ml sample. 2. Cross-reactivity with the venom from the rattlesnake Crotalus durissus terrificus and with venoms from several snakes of the Bothrops genus was detected only at concentrations higher than 1 microgram/ml sample. 3. A conventional ELISA is also described for the detection of antibodies against TsV. 4. Analysis by Western Blot (WB) demonstrated a 25-kDa protein band common to TsV and to the venoms of Bothrops moojeni, B. jararacussu and B. jararaca. 5. Venom from C. d. terrificus exhibited WB cross-reactive bands of 16 and 25 kDa with TsV.

Animals↗
PubMed1991

Discharge effect on pancreatic exocrine secretion produced by toxins purified from Tityus serrulatus scorpion venom.

Three toxic polypeptides were purified from the venom of the Brazilian scorpion Tityus serrulatus by means of gel filtration in Sephadex G-50 and ion-exchange chromatography in carboxymethylcellulose. The peptides are basic molecules with molecular weights in the range of 7000 for which the amino acid compositions and sequences were determined. The effect of the purified peptides on pancreatic exocrine secretion in the guinea pig was studied. Biochemical measurements show that the cells are stimulated by these peptides to discharge their zymogen granules. Light and electron microscopic images confirm the biochemical measurements. At the light microscope level, acinar cells show dramatically fewer zymogen granules than in control pancreas with the appearance of large vacuoles and some loss of morphological integrity. Electron micrographs display apical regions devoid of zymogen granules and condensing vacuoles whereas acinar lumina contain crystalline secretory material. The secretory effect observed in vitro is comparable to that of carbamylcholine and that of the peptidergic secretagogue cholecystokinin-pancreozymin.

Amino Acid Sequence↗
PubMed1990

[Determination of the local structure of the protein insectotoxin I5A from the scorpion Buthus eupeus from 1H-NMR spectroscopy data].

The local structure (torsion angles phi, psi and chi 1 of amino acid residues) of insectotoxin I5A (35 residues) of scorpion Buthus eupeus has been determined from cross-peak integral intensities in two-dimensional nuclear Overhauser enhancement (NOESY) spectra and spin coupling constants of vicinal H--NC alpha--H and H--C alpha C beta--H protons. The local structure determination was carried out by fitting complete relaxation matrix of peptide unit protons (protons of a given residue and NH proton of the next residue in the amino acid sequence) with experimental NOESY cross-peak intensities. The obtained intervals of backbone torsional angles phi and psi consistent with NMR data were determined for all but Gly residues. The predominant C alpha--C beta rotamer of the side chain has been unambiguously determined for 42% of the insectotoxin amino acid residues whereas for another 46% residues experimental data are fitted equally well with two rotamers. Stereospecific assignments were obtained for 38% of beta-methylene groups. The determined torsional angles phi, psi and chi 1 correspond to the sterically allowed conformations of the amino acid residues and agree with the insectotoxin secondary structure established earlier by 1H NMR spectroscopy.

Amino Acids↗
PubMed1990

Purification and properties of phospholipase A2 from the venom of scorpion, (Heterometrus fulvipes).

Phospholipase A2 was purified about 78 fold from the venom of scorpion Heterometrus fulvipes. The molecular weight of the enzyme was found to be 16,000 and it was optimally active at pH 7.4 and at 50 degrees C. The Km value of the enzyme was 1.8 x 10(-3) M. Calcium, Magnesium and Zinc ions stimulated whereas Mercury ion and EDTA inhibited the enzyme activity. This enzyme exhibited fluorescence emission maximum between 310-320 nm.

Calcium↗
PubMed1990

Nesidioblastosis associated with chronic experimental pancreatitis produced by a scorpion toxin, tityustoxin, in rats.

Tityustoxin (TsTx), the purified venom of the Brazilian scorpion Tityus serrulatus, was injected intravenously (50 micrograms/kg) into rats, producing a typical picture of chronic pancreatitis after 20 days. Nesidioblastosis, a lesion characterized by hyperplasia of the islets of Langerhans, was also detected in a high percentage (40%) of animals. TsTx-induced pancreatitis may be a useful model for the study of nesidioblastosis in laboratory animals.

Animals↗
PubMed1990

Some properties of sodium channels in neuroblastoma cells modified with scorpion toxin and chloramine-T. Single channel measurements.

Currents through sodium channels of neuroblastoma cells were measured using patch technique in outside-out configuration. Scorpion toxin (ScTX) produced 3 to 4 fold prolongation of mean open time and increased number of reopenings. The mean open times showed slow fluctuations around some average values. The distribution of channel open times for ScTX-modified channels required more than one exponential to be fitted. Chloramine-T (ChT) produced qualitatively similar, though weaker, prolongation of open times.

Animals↗
PubMed1990

Isolation and characterization of hyaluronidase from scorpion (Heterometrus fulvipes) venom.

Hyaluronidase (Hyaluronate lyase, E.C. 3.2.1.35) has been isolated from Heterometrus fulvipes scorpion venom by a combination of gel filtration on Sephadex G-75 and ion exchange chromatography on DEAE-cellulose. The enzyme preparation showed a single band on polyacrylamide gel electrophoresis and a molecular weight of 82,000. The final preparation was purified 27-fold. The optimum pH for enzyme activity was 4.0. No loss of activity was observed up to 30 degrees C and showed a sharp decrease in activity at 50 degrees C. Heparin inhibited the enzyme activity.

Animals↗