EurekaMag
+ Translate
+ Most Popular
The pigeon tick (Argas reflexus): its biology, ecology, and epidemiological aspects
Prevalence of hemoglobin abnormalities in Kebili (Tunisian South)
Lipogranuloma: a preventable complication of dacryocystorhinostomy
Value of basal plasma cortisol assays in the assessment of pituitary-adrenal insufficiency
Bees from the Belgian Congo. The acraensis group of Anthophora
Placing gingival retraction cord
Total serum IgE, allergy skin testing, and the radioallergosorbent test for the diagnosis of allergy in asthmatic children
Acariens plumicoles Analgesoidea parasites des oiseaux du Maroc
Injuries of terminal phalanges of the fingers in children
Biology of flowering and nectar production in pear (Pyrus communis)
Das Reliktvorkommen der Aspisviper (Vipera aspis L.) im Schwarzwald
Hydrological modelling of drained blanket peatland
Pathologic morphology and clinical significance of the anomalous origin of the left circumflex coronary artery from the right coronary artery. General review and autopsy analysis of 30 cases
Cyto genetic analyses of lymphocyte cultures after exposure to calcium cyclamate
Axelrodia riesei, a new characoid fish from Upper Rio Meta in Colombia With remarks concerning the genus Axelrodia and description of a similar, sympatric, Hyphessobrycon-species
Favorable evolution of a case of tuberculosis of pancreas under antibiotic action
RIFM fragrance ingredient safety assessment, Valencene, CAS Registry Number 4630-07-3
Parenteral microemulsions: an overview
Temperate pasture: management for grazing and conservation
Evaluation of a new coprocessed compound based on lactose and maize starch for tablet formulation
Thermal expansion and cracking of three confined water-saturated igneous rocks to 800C
Revision of the genera of the tribe Stigmoderini (Coleoptera: Buprestidae) a discussion of phylogenetic relationships
Anal tuberculosis. Report of a case
Gastric tuberculosis in the past and present
Adaptive responses of the cardiovascular system to prolonged spaceflight conditions: assessment with Holter monitoring

TsTx toxin isolated from Tityus serrulatus scorpion venom-induced spontaneous recurrent seizures and mossy fiber sprouting


TsTx toxin isolated from Tityus serrulatus scorpion venom-induced spontaneous recurrent seizures and mossy fiber sprouting



Epilepsia 43(Suppl): 36



ISSN/ISBN: 0013-9580

PMID: 12121292

DOI: 10.1046/j.1528-1157.43.s.5.24.x

TsTx is a scorpion alpha-type toxin that binds to site 3 of the Na+ channels in a voltage-dependent mode, slowing or blocking the inactivation mechanism of these channels (Possani et al., Eur J Biochem 1999). This binding increases depolarization time of the channel and consequently induces excessive neurotransmitter release. Previously we reported that hippocampal injection of TsTx induces clonic convulsions, electrographic seizures, and hippocampal damage. This investigation was designed to characterize the long-term behavioral, electroencephalographic (EEG), and histopathologic features after a single TsTx injection into the rat hippocampus. Cannulas and electrodes were stereotaxically implanted in the CA1 dorsal hippocampus of rats. Three days after surgery, the animals were injected into the hippocampus with 1 microl of TsTx, 2 microg (n = 9) or 0.1 M phosphate buffer (n = 5). After injection, EEG records and behavioral observations were made during 10 h. For a period of 4 months, the animals were observed through direct visual observation for 8 h/day, 5 days/week for occurrence of convulsive seizures. At the end of the experiment, the animals were processed for histologic analyses. Sections 40- and 20-microm thick were stained according to neo-Timm or Nissl methods, respectively. Cell counts in the cresyl violet-stained sections were performed within the hippocampal pyramidal cell layers (CA1, CA3, and CA4) and granule cell of the dentate gyrus. Fifteen minutes after TsTx injection, facial automatisms, rearing, masticatory jaw movements, sniffing, and wet-dog shakes were observed. In approximately 1 h, limbic convulsions characterized by forelimb clonus, rearing, and falling after generalized clonic convulsion with jumping, wild running, and falling were observed. EEG showed isolated spikes and clusters of spikes that started in the hippocampus and evolved to the cortex, isolated seizures, and epileptic discharges delayed 1-2 min. These recurred repeatedly characterizing the status epilepticus (SE). SE was characterized in 77.5% of animals. Seizures were no longer observed 24 h after the injection. Spontaneous recurrent seizures (SRSs) occurred 31-49 days after TsTx injection. All animals that showed SE in the acute period developed SRSs. Facial myoclonus, generalized clonus, forelimb clonus, rearing, and falling characterized the seizures. The seizure frequency was 1-2 per animal per week. All rats injected with TsTx had significantly fewer cells in CA1, CA3, and CA4 subfield of the hippocampal formation compared with the animals of the control group (p < 0.05, analysis of variance, followed by Tukey test). Neo-Timm-positive granules, normally absent in the supragranular layer, were present in dentate gyrus of rats with TsTx-induced SRSs. Our results suggest that SRSs observed in this study may be a consequence of the TsTx-induced SE. All animals injected with the toxin showed massive neuronal loss in the hippocampal subfields CA1, CA3, and CA4, but only those that had SRSs showed mossy fiber sprouting in the supragranular layer of the dentate gyrus. This shows synaptic reorganization that also is observed in human epileptogenic tissue. These results indicate that TsTx toxin may be a useful tool for studies on neuronal lesions and/or experimental epilepsy. Studies on the mechanisms involved are under investigation.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 004373756

Download citation: RISBibTeXText

Related references

TsTx toxin isolated from Tityus serrulatus scorpion venom induces spontaneous recurrent seizures and mossy fiber sprouting. Epilepsia 44(7): 904-911, 2003

Effects induced by Tityus serrulatus scorpion venom and its toxins TsTX-I and TsTX-V on the rat isolated retractor penis muscle. Pharmacology 73(4): 190-198, 2005

The complete amino acid sequence of toxin TsTX-VI isolated from the venom of the scorpion Tityus serrulatus. Journal of Protein Chemistry 9(5): 595-601, 1990

The complete amino acid sequence of toxin TsTX-VI isolated from the venom of the scorpion Tityus serrulatus. Protein Journal 9(5): 595-601, 1990

Amino acid sequence of TsTX-V, an alpha-toxin from Tityus serrulatus scorpion venom, and its effect on K+ permeability of beta-cells from isolated rat islets of Langerhans. Biochimica et Biophysica Acta 1243(3): 309-314, 1995

Further characterization of toxin T1IV (TsTX-III) and T2IV from Tityus serrulatus scorpion venom. Toxicon (Oxford) 29(6): 663-672, 1991

Effects of Tityus serrulatus scorpion venom and its toxin TsTX-V on neurotransmitter uptake in vitro. Toxicology and Applied Pharmacology 217(2): 196-203, 2006

Isolation of toxin TsTX-VI from Tityus serrulatus scorpion venom. Effects on the release of neurotransmitters from synaptosomes. Biochemistry and Molecular Biology International 39(4): 729-740, 1996

Effect of Tityus serrulatus scorpion venom and its major toxin, TsTX-I, on the complement system in vivo. Toxicon: Official Journal of the International Society on Toxinology 41(4): 501-508, 2003

TsTX-VII, a new toxin from Tityus serrulatus scorpion venom able to induce the release of neurotransmitters from rat brain synaptosomes not blocked by tetrodotoxin. Biochemistry and Molecular Biology International 41(6): 1255-1263, 1997

Dantrolene protects hippocampal cells from damage induced by TsTX, an α-scorpion toxin from Tityus serrulatus. Toxicon (Oxford) 44(2): 179-183, 2004

Dantrolene protects hippocampal cells from damage induced by TsTX, an alpha-scorpion toxin from Tityus serrulatus. Toxicon: Official Journal of the International Society on Toxinology 44(2): 179-183, 2004

Further characterization of toxins T1IV (TsTX-III) and T2IV from Tityus serrulatus scorpion venom. Toxicon: Official Journal of the International Society on Toxinology 29(6): 663-672, 1991

The delay of the inactivation of sodium channels by TsTX-V, a new neurotoxin from Tityus serrulatus scorpion venom. Toxicon 31(2): 108-109, 1993

Isolation and characterization of TsTX-V, a new neurotoxin from Tityus serrulatus scorpion venom which delays the inactivation of Na+ channels. Biochimica et Biophysica Acta 1199(1): 69-75, 1994