Τίτλος:
Effects of dexamethasone on K+-evoked glutamate release from rat hippocampal slices
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Dexamethasone (DEX) at physiologically elevated (stress) concentration (1 μM) decreased K+evoked glutamate release from rat hippocampal slices under superfusion in the presence of Ca2+. On the contrary 10 μM DEX increased this K+-evoked glutamate release while 0.1 μM DEX had no effect. The glucocorticoid antagonist for the "classic" receptor, RU 486, completely reversed the effect of 1 μM DEX. Actinomycin D had no effect. Dexamethasone at 1 μM had no effect on the Ca2+-independent (10 mM Mg2+ replacing 1 mM Ca2+) K+-evoked glutamate release. Dexamethasone at 1 μM or 10 μM and no effect on the phosphate-activated glutaminase - the key enzyme for the biosynthesis of neurotransmitter glutamate. These results suggest that the effect of DEX on K+-evoked glutamate release: (i) depends on its concentration; (ii) is exerted on the Ca2+-dependent (neurotransmitter release), at least at physiological stress concentrations; and (iii) is exerted via the classical receptor but is nongenomic.
Συγγραφείς:
Ioannou, N.
Liapi, C.
Sekeris, C.E.
Palaiologos, G.
Περιοδικό:
Neurochemical Research
Λέξεις-κλειδιά:
dactinomycin; dexamethasone; glutamic acid; glutaminase; mifepristone, amino acid analysis; animal tissue; article; brain depth stimulation; brain slice; concentration response; controlled study; enzyme activation; evoked response; hippocampus; male; neurotransmission; nonhuman; priority journal; protein determination; protein secretion; rat, Animals; Calcium; Dactinomycin; Dexamethasone; Glutamic Acid; Hippocampus; Kinetics; Magnesium; Male; Mifepristone; Potassium; Rats; Rats, Wistar, Animalia; Hippocampus hippocampus
DOI:
10.1023/A:1023271325728
