Monoamines and glycogen levels in cerebral cortices of fast and slow methionine sulfoximine-inbred mice.

The experimental model of seizures which depends upon methionine sulfoximine (MSO) simulates the most striking form of human epilepsy. MSO generates epileptiform seizures in a large variety of animals, increases brain glycogen content and induces brain monoamines modifications. We selected two inbred lines of mice based upon their latency toward MSO-dependent seizures, named as MSO-Fast (sensitive), having short latency toward MSO, and MSO-Slow (resistant) with a long latency.

A fraction of neurofibromin interacts with PML bodies in the nucleus of the CCF astrocytoma cell line.

Neurofibromatosis type 1 is a common genetic disease that causes nervous system tumors, and cognitive deficits. It is due to mutations within the NF1 gene, which encodes the Nf1 protein. Nf1 has been shown to be involved in the regulation of Ras, cAMP and actin cytoskeleton dynamics.

Phenotypic differences between fast and slow methionine sulfoximine-inbred mice: seizures, anxiety, and glutamine synthetase.

Seizures induced by the convulsant methionine sulfoximine (MSO) resemble human "grand mal" epilepsy, and brain glutamine synthetase is inhibited. We recently selected two inbred lines of mice: sensitive to MSO (MSO-Fast) and resistant (MSO-Slow). In the present study, the selection pressure was increased and consanguinity established.

Brain glycogen and neurotransmitter levels in fast and slow methionine sulfoximine-selected mice.

Brain glycogen could be considered as an energy store for neuronal activity, with high relevance in epilepsies. We selected two lines of mice based upon their latency to methionine sulfoximine (MSO) dependent-seizures: MSO-Fast and MSO-Slow, and their neurochemical characterization was attempted in order to look for the mechanisms of epileptogeny. We determined the MSO effect on brain glycogen in the two selected lines and their eight parental strains, and on indolamines and catecholamines.

Uptake of functionalized mesoporous silica nanoparticles by human cancer cells.

Mesoporous silica nanoparticles (MSN) were functionalised by aminofluorescein (AMF) with diethylenetriaminepentaacetic acid spacer molecules which provide free carboxylic groups for binding cell-specific ligands such as folate. AMF allowed the exploration of cellular uptake by HeLa cells using confocal microscopy and flow cytometry. The functionalized nanoparticles (MSN-AMF) penetrated efficiently into HeLa cell cytoplasm through a clathrin dependent endocytosis mechanism.

Selection of two lines of mice based on latency to onset of methionine sulfoximine seizures.

Purpose: In various animals methionine sulfoximine (MSO) induces tonic-clonic seizures resembling the most striking form of human epilepsies. The aim of the present study was to select two lines of mice based upon differences in their latency to MSO-dependent seizures, in order to characterize them.

Methods: Random crosses involving eight inbred mice strains were used to generate the starting population in which the first MSO challenge (75 mg/kg, i.

Epilepsy, regulation of brain energy metabolism and neurotransmission.

Seizures are the result of a sudden and temporary synchronization of neuronal activity, the reason for which is not clearly understood. Astrocytes participate in the control of neurotransmitter storage and neurotransmission efficacy. They provide fuel to neurons, which need a high level of energy to sustain normal and pathological neuronal activities, such as during epilepsy.

Mesoporous silica nanoparticles enhance MTT formazan exocytosis in HeLa cells and astrocytes.

We report on the observation that mesoporous silica nanoparticles (MSNs), after being endocytosed, interfere with the MTT test in HeLa cells and astrocytes by accelerating the exocytosis of formazan crystals. The stimulation of MTT formazan exocytosis is probably related to perturbation of intracellular vesicle trafficking by MSN uptake as revealed by experiments in presence of chloroquine and genistein. Similar effect has been previously observed with a number of chemicals, especially with neurotoxic beta amyloid peptides, but not with nanoparticles.

Necrotic cell death induced by delta-aminolevulinic acid in mouse astrocytes. Protective role of melatonin and other antioxidants.

Accumulation of delta-aminolevulinic acid (ALA), as it occurs in acute intermittent porphyria (AIP), is the origin of an endogenous source of reactive oxygen species (ROS), which can exert oxidative damage to cell structures. In the present work we examined the ability of different antioxidants to revert ALA-promoted damage, by incubating mouse astrocytes with 1.0 mM ALA for different times (1-4 hr) in the presence of melatonin (2.

Stable transfection of cDNAs targeting specific steps of glycogen metabolism supports the existence of active gluconeogenesis in mouse cultured astrocytes.

In order to assess the participation of astrocytic gluconeogenesis in the synthesis of glycogen, mouse astrocytes were stably transfected with antisense cDNA of fructose-1,6-bisphosphatase (FBPase) and with sense and antisense cDNAs of glycogen synthase (GS). The antisenses of FBPase and GS have similar significant effect in decreasing astrocyte glycogen content by 60%, while sense GS significantly increased glycogen content by 100%. The FBPase activity was decreased by all three cDNAs used, while glycogen phosphorylase was not altered.

In vivo and in vitro glycogenic effects of methionine sulfoximine are different in two inbred strains of mice.

We investigated the relationship between brain glycogen anabolism and methionine sulfoximine (MSO)-induced seizures in two inbred mouse strains that presented differential susceptibility to the convulsant. CBA/J was considered a MSO-high-reactive strain and C57BL/6J a MSO-low-reactive strain. Accordingly, the dose of MSO needed to induce seizures in CBA/J mice is lower than that in C57BL/6J mice, and CBA/J mice which had seizures, died during the first convulsion.

Chronic inhibition of glutamine synthetase is not associated with impairment of learning and memory in mice.

The convulsant methionine sulfoximine (MSO) is a byproduct of the agenized flour commonly used for feeding domestic animals decades ago. MSO is a powerful glycogenic and epileptogenic agent, and it is an irreversible inhibitor of glutamine synthetase. This latter effect was hypothesized to be responsible for the increase in the incidence of some neuropathologies in humans, such as Alzheimer's disease or Parkinson's disease.