Down-regulation of BDNF mRNA, with no effect on trkB or glucocorticoid receptor m RNAs, in the porcine hippocampus after acute dexamethasone treatment.
Glucocorticoids bind to hippocampal mineralo-(MR) and gluco-(GR) corticoid receptors and, at high concentrations (e.g. as seen following treatment with pharmacological doses of corticosteroids or during stress), may affect hippocampal neuronal function. Such actions could involve brain-derived neurotrophic factor (BDNF), its receptor, trkB, and the excitatory neurotransmitter, glutamate. This experiment investigated the effect of a single intravenous (i.v.) injection of the synthetic glucocorticoid, dexamethasone (Dex, 5 mg kg(-1)) on gene expression for MR s, GR s, BDNF, trkB, and selected ionotropic glutamate receptor subunits (iGluRs), in the porcine hippocampus. Quantification of m RNA s in the brains of pigs (n = 4/treatment) killed 24 hours after saline or Dex administration indicated a significant Dex-induced decrease in BDNF m RNA in all hippocampal regions. However, gene expression for MR s, GR s, trkB and iGluRs was unaffected at this time-point.
Vellucci
S V
SV
MAFF Laboratory of Welfare and Behaviour, The Babraham Institute, Cambridge, UK. sandra.vellucci@bbsrc.ac.uk
Parrott
R F
RF
Mimmack
M L
ML
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis / Q000235:genetics*; D003907:Dexamethasone / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D017403:In Situ Hybridization / Q000662:veterinary; D008297:Male; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020813:Receptor, trkB / Q000096:biosynthesis / Q000235:genetics*; D018091:Receptors, AMPA / Q000096:biosynthesis / Q000235:genetics; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis / Q000235:genetics*; D018161:Receptors, Mineralocorticoid / Q000096:biosynthesis / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis / Q000235:genetics; D013552:Swine / Q000502:physiology*
D019208:Brain-Derived Neurotrophic Factor; D005938:Glucocorticoids; C409466:NR1 NMDA receptor; D012333:RNA, Messenger; D018091:Receptors, AMPA; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D016194:Receptors, N-Methyl-D-Aspartate; C104723:glutamate receptor ionotropic, AMPA 3; D003907:Dexamethasone; D020813:Receptor, trkB; C104722:glutamate receptor ionotropic, AMPA 2