Efeitos do sulfato de magnésio intracerebroventricular nas crises convulsivas induzidas pelo pentilenotetrazol em ratos
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Data
2006-04-28
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Oliveira, Luziene Dalmaschio Biasutti de
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Universidade Federal do Espírito Santo
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Almost all of antiepileptic drugs currently in use act through an influence in gabaergic neurotransmission or by means of ion channels mechanisms. There are, however, only few agents acting at glutamatergic neurotransmission. The magnesium sulfate (MgSO4) has been used for many years in the prevention of seizures in eclampsia, a specific disease of pregnancy manifested by hypertension, proteinuria and seizures or even coma. This compound probably acts through a non-competitive antagonism of Mg2+ at NMDA (N-Methyl-D-aspartate) receptors. The present study examined the effects of MgSO4 administered intracerebroventricularly (icv) at different doses (32, 100 and 320 µg) on different types of seizures induced by pentylenotetrazole (PTZ) administered intraperitoneally in rats. Behavioral responses after PTZ administration were observed and registered by two experimenters. A simultaneous brain electrical activity was measured through an adapted electroencephalographic apparatus connected to electrodes implanted bilaterally in posterior parietal-temporal region. This combined procedures allowed the characterization of different types of seizures induced by PTZ in rats such as myoclonic, tonic, clonic and tonic-clonic generalized seizures and also partial complex seizures with or without following generalization. MgSO4 icv at a dose of 100 µg increased the latency for the first seizure of any king and also reduced the total period in which animals presented seizures during the experiment as compared to control treatment (saline followed by PTZ). This dose of MgSO4 also increased the latency for the first myoclonic jerk and reduced the frequency of this type of seizure, but at nonstatistical manner. The smallest dose of MgSO4 (32 µg) increased significantly the latency for the first partial complex seizure as compared to control treatment. However, the major dose (320 µg) of MgSO4 showed no effect or it was even harmful for the most parameters observed in this study for PTZ-induced seizures. These results suggested that the magnesium sulfate can be of a clinical importance as an adjuvant agent in the treatment and prevention of epilepsy depending on its dose.
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OLIVEIRA, Luziene Dalmaschio Biasutti de. Efeitos do sulfato de magnésio intracerebroventricular nas crises convulsivas induzidas pelo pentilenotetrazol em ratos. 2006. 94 f. Dissertação (Mestrado em Ciências Fisiológicas) - Programa de Pós-Graduação em Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, 2006.