title: Upregulation of nucleoside triphosphate diphosphohydrolase-1 and ecto-5'-nucleotidase in rat hippocampus after repeated low-dose dexamethasone administration.
abstract: Although dexamethasone (DEX), a synthetic glucocorticoid receptor (GR) analog with profound effects on energy metabolism, immune system, and hypothalamic-pituitary-adrenal axis, is widely used therapeutically, its impact on the brain is poorly understood. The aim of the present study was to explore the effect of repeated low-dose DEX administration on the activity and expression of the ectonucleotidase enzymes which hydrolyze and therefore control extracellular ATP and adenosine concentrations in the synaptic cleft. Ectonucleotidases tested were ectonucleoside triphosphate diphosphohydrolase 1-3 (NTPDase1-3) and ecto-5'-nucleotidase (eN), whereas the effects were evaluated in two brain areas that show different sensitivity to glucocorticoid action, hippocampus, and cerebral cortex. In the hippocampus, but not in cerebral cortex, modest level of neurodegenerative changes as well as increase in ATP, ADP, and AMP hydrolysis and upregulation of NTPDase1 and eN mRNA expression ensued under the influence of DEX. The observed pattern of ectonucleotidase activation, which creates tissue volume with enhanced capacity for adenosine formation, is the hallmark of the response after different insults to the brain.
authors.affiliation: Department of Molecular Biology and Endocrinology, VINČA Institute of Nuclear Sciences, |University of Belgrade, PO Box 522, 11001, Belgrade, Serbia, drakulic@vinca.rs.
authors.forename: Dunja
authors.initials: D
authors.lastname: Drakulić
authors.forename: Miloš
authors.initials: M
authors.lastname: Stanojlović
authors.forename: Nadežda
authors.initials: N
authors.lastname: Nedeljković
authors.forename: Ivana
authors.initials: I
authors.lastname: Grković
authors.forename: Nataša
authors.initials: N
authors.lastname: Veličković
authors.forename: Ivana
authors.initials: I
authors.lastname: Guševac
authors.forename: Nataša
authors.initials: N
authors.lastname: Mitrović
authors.forename: Ivana
authors.initials: I
authors.lastname: Buzadžić
authors.forename: Anica
authors.initials: A
authors.lastname: Horvat
mesh_terms: D015720:5'-Nucleotidase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001081:Apyrase / Q000235:genetics / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation
chemical_list: D015703:Antigens, CD; D005938:Glucocorticoids; D003907:Dexamethasone; D015720:5'-Nucleotidase; D001081:Apyrase; C067869:CD39 antigen