Effect of corticosterone on noradrenergic nuclei in the pons-medulla and [3H]NA release from terminals in hippocampal slices

Date
1992, 1992
Authors
De Villiers A.S.
Russell V.A.
Taljaard J.J.F.
De Villiers A.S.
Russell V.A.
Taljaard J.J.F.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The aim of the present study was to investigate possible membrane and genomic effects of corticosterone on the noradrenergic system of the rat brain. Corticosterone effects were studied in vivo by treating rats s.c. with 10 mg/kg corticosterone for 7 or 14 days. In the first two experiments corticosterone significantly decreased the noradrenaline (NA) and dopamine (DA) levels in the pons-medulla, an area which contains the A1-A7 noradrenergic cell groups, while the NA and DA levels in the dorsal hippocampus remained unchanged. In a third experiment where the locus coeruleus (LC) and the A1 and A2 nuclei (A1,A2) were analysed separately, NA levels were unchanged but total MHPG levels and the total MHPG/NA ratio were decreased in the A1,A2 area. Chronic corticosterone treatment (14 days) did not alter the α2-adrenoceptor-mediated modulation of [3H]NA release from dorsal hippocampal slices. Neither the spontaneous outflow nor the electrically stimulated release of [3H]NA from dorsal hippocampal slices of untreated rats was affected by exposure of the slices to corticosterone (10-7 M - 10-4 M) in the superfusion buffer. Thus, chronic corticosterone treatment of rats altered the noradrenergic system of the pons-medulla, but did not change the α2-adrenoceptor-mediated modulation of NA release in the dorsal hippocampus, a major terminal area of the LC neurons. Corticosterone also did not appear to have a direct membrane effect on the NA terminals in the dorsal hippocampus of the rat.
The aim of the present study was to investigate possible membrane and genomic effects of corticosterone on the noradrenergic system of the rat brain. Corticosterone effects were studied in vivo by treating rats s.c. with 10 mg/kg corticosterone for 7 or 14 days. In the first two experiments corticosterone significantly decreased the noradrenaline (NA) and dopamine (DA) levels in the pons-medulla, an area which contains the A1-A7 noradrenergic cell groups, while the NA and DA levels in the dorsal hippocampus remained unchanged. In a third experiment where the locus coeruleus (LC) and the A1 and A2 nuclei (A1,A2) were analysed separately, NA levels were unchanged but total MHPG levels and the total MHPG/NA ratio were decreased in the A1,A2 area. Chronic corticosterone treatment (14 days) did not alter the α2-adrenoceptor-mediated modulation of [3H]NA release from dorsal hippocampal slices. Neither the spontaneous outflow nor the electrically stimulated release of [3H]NA from dorsal hippocampal slices of untreated rats was affected by exposure of the slices to corticosterone (10-7 M - 10-4 M) in the superfusion buffer. Thus, chronic corticosterone treatment of rats altered the noradrenergic system of the pons-medulla, but did not change the α2-adrenoceptor-mediated modulation of NA release in the dorsal hippocampus, a major terminal area of the LC neurons. Corticosterone also did not appear to have a direct membrane effect on the NA terminals in the dorsal hippocampus of the rat.
Description
Keywords
alpha 2 adrenergic receptor; corticosterone; dopamine; noradrenalin; serotonin; animal tissue; article; brain stem; controlled study; corticosterone release; dopamine release; drug blood level; drug effect; drug receptor binding; drug tissue level; electrostimulation; hippocampus; locus ceruleus; male; nonhuman; noradrenalin release; noradrenergic system; priority journal; rat; subcutaneous drug administration; Animal; Biogenic Monoamines; Corticosterone; Hippocampus; In Vitro; Male; Medulla Oblongata; Methoxyhydroxyphenylglycol; Nerve Endings; Norepinephrine; Perfusion; Pons; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't; Tritium, alpha 2 adrenergic receptor, corticosterone, dopamine, noradrenalin, serotonin, animal tissue, article, brain stem, controlled study, corticosterone release, dopamine release, drug blood level, drug effect, drug receptor binding, drug tissue level, electrostimulation, hippocampus, locus ceruleus, male, nonhuman, noradrenalin release, noradrenergic system, priority journal, rat, subcutaneous drug administration, Animal, Biogenic Monoamines, Corticosterone, Hippocampus, In Vitro, Male, Medulla Oblongata, Methoxyhydroxyphenylglycol, Nerve Endings, Norepinephrine, Perfusion, Pons, Rats, Rats, Inbred Strains, Support, Non-U.S. Gov't, Tritium
Citation
Neurochemical Research
17
3
Neurochemical Research
17
3