title: Corticosterone-induced responses in rat brain RNA are also evoked in hippocampus by acute vibratory stress.
abstract: Corticosterone (CORT) induces responses in brain cells that are mediated by glucocorticoid receptors through regulation of gene activity. We previously found rapid increases in select poly(A)-containing RNAs in rat hippocampus following treatment with CORT that are mediated by low-affinity glucocorticoid receptors. To determine if these responses are hippocampal specific, we examined RNA responses to glucocorticoids in several brain regions, myocardium, and cultured astrocytes by two-dimensional gel electrophoretic resolution of 35S-methionine labelled, in vitro translation products. RNAs coding for similar 35-, 33-, and 20-kdalton polypeptides are induced after 3 days of CORT treatment (40 mg/kg/day) in hippocampus, hypothalamus, cortex, striatum, cerebellum, and myocardium. Primary astrocyte cultures (neonatal rat), however, showed increases after hydrocortisone (1 microgram/ml) in only the 20- and 33-kdalton translation products, while the 35-kdalton polypeptide was not detected. The hippocampal responses were maintained for up to 3 months during chronic daily CORT treatment. To determine if an increase in endogenous CORT levels would also evoke the RNA responses, we subjected rats to 2 h vibratory stress and analyzed the in vitro translation products. RNAs coding for the 35- and 20-kdalton polypeptides were increased 3- to 5-fold in the hippocampus after acute stress in intact rats, but not in stressed adrenalectomized rats. These results suggest a new class of molecular stress responses in brain cells that is glucocorticoid dependent under physiological conditions.
authors: Department of Biological Sciences, University of Southern California, Los Angeles.
authors: N R
authors: NR
authors: Nichols
authors: J N
authors: JN
authors: Masters
authors: P C
authors: PC
authors: May
authors: J
authors: J
authors: de Vellis
authors: C E
authors: CE
authors: Finch
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism / Q000502:physiology; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D003345:Corticosterone / Q000502:physiology*; D015180:Electrophoresis, Gel, Two-Dimensional; D005938:Glucocorticoids / Q000378:metabolism / Q000502:physiology; D006321:Heart / Q000502:physiology; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013312:Stress, Physiological / Q000378:metabolism / Q000503:physiopathology*; D014732:Vibration / Q000009:adverse effects*
chemical_list: D005938:Glucocorticoids; D012313:RNA; D003345:Corticosterone