REGULATIONS PHYSIOLOGIQUES ET PATHOLOGIQUES DES FONCTIONS ASTROCYTAIRES IMPLIQUEES DANS L'HOMEOSTASIE DU GABA ET DU GLUTAMATE (DOCTORAT (NEUROSCIENCES))

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Leaf protein analysis during gibberellic and photoperiodic induction of flowering in <i>Arabidopsis thaliana</i>

Leaf proteins from Arabidopsis thaliana Landsberg erecta treated with gibberellin A₃ and different light regimes (continuous light, 16/8 h dark/light cycle and 8/16 h dark/light cycle) were analysed by two-dimensional gel electrophoresis. Qualitative differences between the controls and the treated plants were found, indicating that these treatments were responsible for the synthesis of specific proteins. A 35 kDa polypeptide is induced by gibberellin A₃ application and a 25 kDa polypeptide depends on the photoperiod

Specific alteration in the expression of glial fibrillary acidic protein, glutamate dehydrogenase, and glutamine synthetase in rats with genetic absence epilepsy

International audienceAstrocytes play a predominant role in energy metabolism and in the catabolism of gamma-aminobutyric acid (GABA) and glutamate, neurotransmitters critically involved in epileptic processes. We show specific astrocytic alterations in the genetic absence epilepsy rats from Strasbourg (GAERS). Spontaneous absence seizures appear in this strain in the cortex and thalamus after the age of 1 month. In these brain structures, we demonstrate increased GFAP expression in both adult and young GAERS, suggesting that reactive astrocytes are already present before the onset of seizures. Glutamate dehydrogenase (GDH) and glutamine synthetase (GS), which are localized mainly in astrocytes and involved in glutamate catabolism, are shown to be differentially altered. GDH expression was increased in the thalamus of both young and adult GAERS and in the cortex of young GAERS. GS expression was slightly decreased in the thalamus of young GAERS. These astrocytic modifications are not adaptive responses to seizures, as the modifications appear before the development of absence seizures. Thus, astrocytes might be involved in the neuronal processes giving rise to epileptic seizures in this strain