Maria Regina Lopes Sandoval

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The interaction between GABAergic and dopaminergic systems within the central nervous system was investigated in rats using the open-field apparatus and apomorphine-induced stereotypy, and in mice using haloperidol-induced catalepsy. The single intraperitoneal administration of baclofen 3.0 mg/kg, 4,5,6,7-tetrahydroisoxasolo-(5,4-c) piridin-3-ol (THIP) 10.0(More)
The effects of withdrawal from long-term treatment with increasing concentrations of sodium barbital in the drinking water were studied in rats. Animals were tested 72 hr after the removal of the drug. Withdrawal of barbital induced a significant leftward displacement of the dose-response curves obtained for the convulsive effects of strychnine, picrotoxin(More)
We have reported earlier that intrahippocampal administration of the C-pool from Tityus serrulatus scorpion venom induces convulsions in rats. Here we report the effects of seven toxins isolated from the C-pool. The strongest effects were seen after toxin 5C, which was sequenced and identified as TSII, a beta-type toxin that affects Na+ channel activation.(More)
This study was designed to investigate the effect of T. serrulatus scorpion venom on dopamine (DA) and gamma amino butyric acid (GABA) concentrations in different regions of the brain. The ratio of homovanillic acid (HVA) to DA, and the glutamic acid decarboxylase (GAD) activity were determined following intravenous or intracerebral venom injections. The(More)
Smoking crack cocaine involves the inhalation of cocaine and its pyrolysis product, anhydroecgonine methyl ester (AEME). Although there is evidence that cocaine is neurotoxic, the neurotoxicity of AEME has never been evaluated. AEME seems to have cholinergic agonist properties in the cardiovascular system; however, there are no reports on its effects in(More)
The present study evaluated four phospholipase A2 (PLA2) (Mlx-8, Mlx-9, Mlx-11 and Mlx-12) isolated from Micrurus lemniscatus snake venom (Elapidae). The effects of intrahippocampal administration of these toxins have been determined on behavior, electroencephalography, and neuronal degeneration in rats. These four PLA2 toxins induced motor and EEG(More)
The neurotoxicity of two secreted Phospholipases A2 from Brazilian coral snake venom in rat primary hippocampal cell culture was investigated. Following exposure to Mlx-8 or Mlx-9 toxins, an increase in free cytosolic Ca(2+) and a reduction in mitochondrial transmembrane potential (ΔΨm) became evident and occurred prior to the morphological changes and(More)
We apply techniques of microlocal analysis to the study of the transverse geometry of Riemannian foliations in order to analyze spectral in-variants of the basic Laplacian acting on functions on a Riemannian fo-liation with a bundle-like metric. In particular, we consider the trace of the basic wave operator when the mean curvature form is basic. We extend(More)
PURPOSE To characterize the long-term behavioral, electroencephalographic (EEG) and histopathologic features after a single TsTx microinjection into the hippocampus of rats. METHODS TsTx, 2 microg, or 1 microl of 0.1 M phosphate buffer was injected into the right dorsal hippocampus of the rat. EEG records and behavioral observations were made over a(More)
Scorpion venoms contain low molecular weight basic polypeptides, neurotoxins, that are the principal toxic agents. These toxins act on ion channels, promoting a derangement that may result in an abnormal release of neurotransmitters. In the present study we investigated some of the effects of the F, H and J fractions isolated from Tityus serrulatus scorpion(More)