- 作者：Luciene ToshieTakeishi Ossanai ; Geane Antiques Louren?o ; Ana Leonor A. Nencioni ; Ivo Lebrun ; Norma Yamanouye ; Valquiria Abr?o Coronado Dorce
- 关键词：Scorpion toxin ; Tityus bahiensis ; Neurotransmitters ; Microdialysis ; Cytosolic calcium
- 刊名：Life Sciences
- 出版年：2012
- 出版时间：17 September, 2012
- 年：2012
- 卷：91
- 期：7-8
- 页码：230-236
- 全文大小：270 K
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.Main methods
Male Wistar rats weighing 250 g were used. The toxin (1.0 ¦Ìg/¦Ìl) was injected into the hippocampus. The animals were then submitted to electroencephalographic and behavioral examinations or to microdialysis to determine the levels of neurotransmitters. The location of the implanted guide cannulae and electrodes was checked histologically. The number of cells in the CA1, CA3 and CA4 areas of the hippocampus was determined by light microscopy. Changes in the concentration of cytosolic free calcium were evaluated by confocal microscopy.
Key findings
The toxin evoked behavioral alterations such as wet dog shakes, myoclonus, yawning and orofacial automatisms. Electroencephalographic recordings exhibited alterations such as isolated or grouped spikes and epileptic-like discharges. Injection of the toxin augmented glutamate concentration in the extracellular fluid in some animals. There was also a decrease in the number of pyramidal cells, mainly in the CA1 and CA4 areas for some rats. In some slices of the hippocampus, an increase in intracellular calcium mobilization was seen.
Significance
The present results suggest that the Tb V-4 toxin may be responsible for the epileptic and behavioral effects observed with the crude venom. We suggest that the convulsive and degenerative effects induced by the toxin could be due to the enhanced release of excitatory amino acids involved in the most important pathways of the hippocampus.