Scorpion Neurotoxins
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. Estudo comparativo dos venenos de escorpiões tityus bahiensis e tityus serrulatus e serrulatus e de suas principais toxinas
T. bahiensis and T.serrulatus are the main scorpion species involved in envenomations in the Brazil, the latter being the more widely distributed. Clinically, envenomations by T. serrulatus is more serious than that by T. bahiensis. In this thesis, the lethal and neurotoxic activities of venoms from these two species were compared. Male Swiss withe mice (18-
Publicado em: 2000
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14. Cooperative activation of action potential Na+ ionophore by neurotoxins.
Four neurotoxins that activate the action potential Na+ ionophore of electrically excitable neuroblastoma cells interact with two distinct classes of sites, one specific for the alkaloids veratridine, batrachotoxin, and aconitine, and the second specific for scorpion toxin. Positive heterotropic cooperativity is observed between toxins bound at these two cla
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15. Three-dimensional structure of a protein from scorpion venom: a new structural class of neurotoxins.
The three-dimensional crystal structure of variant-3 toxin from the scorpion Centruroides sculpturatus Ewing has been determined at 3 A resolution. Phases were obtained by use of K2PtCl4 and K2IrCl6 derivatives. The most prominent secondary structural features are two and a half turns of alpha-helix and a three-strand stretch of antiparallel beta-sheet, whic
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16. Selection of variant neuroblastoma clones with missing or altered sodium channels.
Neurotoxins that cause persistent activation of voltage-sensitive sodium channels are highly cytotoxic to electrically excitable neuroblastoma cells. These toxins were used as selective agents to isolate variant neuroblastoma clones with missing or altered sodium channels. Of ten resistant clones analyzed, seven lacked functional sodium channels and one had
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17. Tetrodotoxin-sensitive sodium channels in normal human fibroblasts and normal human glia-like cells.
Tetrodotoxin-sensitive sodium channels are detectable in normal human fibroblasts and in "glia-like" cells at appreciable levels when compared to what is observed in established neuronal cell lines in culture. Two- to 3-fold stimulations of sodium influx are observed in the presence of 0.2 mM veratridine and scorpion venom at 0.1 mg/ml. Tetrodotoxin (2 micro
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18. Induction of myelination in the central nervous system by electrical activity.
The oligodendrocyte is the myelin-forming cell in the central nervous system. Despite the close interaction between axons and oligodendrocytes, there is little evidence that neurons influence myelinogenesis. On the contrary, newly differentiated oligodendrocytes, which mature in culture in the total absence of neurons, synthesize the myelin-specific constitu
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19. Centruroides toxin, a selective blocker of surface Na+ channels in skeletal muscle: voltage-clamp analysis and biochemical characterization of the receptor.
This paper describes the effects of a toxin from the scorpion Centruroides suffusus suffusus on frog skeletal muscle. The main findings are the following, (i) Centruroides toxin (CssII) blocks the early phase of the inward sodium current in the muscle that arises from influx via Na+ channels in the surface membrane, but it does not affect the late phase of t
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20. Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels.
Charybdotoxin (ChTX), a protein present in the venom of the scorpion Leiurus quinquestriatus var. hebraeus, has been purified to homogeneity by a combination of ion-exchange and reversed-phase chromatography. Polyacrylamide gel electrophoresis, amino acid analysis, and complete amino acid sequence determination of the pure protein reveal that it consists of
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21. Reconstitution of highly purified saxitoxin-sensitive Na+-channels into planar lipid bilayers.
Highly purified Na+-channels isolated from rat brain have been reconstituted into virtually solvent-free planar lipid bilayer membranes. Two different types of electrically excitable channels were detected in the absence of any neurotoxins. The activity of both channels was blocked by saxitoxin. The first channel type is highly selective for Na+ over K+ (app