title: Regulation of alpha 2A-adrenergic receptor mRNA in rat astroglial cultures: role of cyclic AMP and protein kinase C.
abstract: In this study we investigated regulation of alpha 2A-adrenergic receptor (alpha 2A-AR) mRNA in rat astroglial cultures by increases in intracellular cyclic AMP levels and by protein kinase C (PKC) activation. Treatment of astroglial cultures with forskolin (FSK), an adenylyl cyclase activator, or with the membrane-permeable cyclic AMP analogues dibutyryl cyclic AMP or Sp-adenosine 3',5'-cyclic monophosphothioate triethylamine caused time- and concentration-dependent decreases in the levels of a approximately 4.0-kb alpha 2A-AR mRNA transcript. Levels of alpha 2A-AR mRNA were reduced to approximately 10% of control levels within 4 h of 1 microM FSK treatment. PKC agonists [phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-dibutyrate, and mezerein] also decreased alpha 2A-AR mRNA levels in a time- and concentration-dependent fashion. A 90% decrease in alpha 2A-AR mRNA levels was observed with 50 nM PMA in 4 h. The decrease in alpha 2A-AR mRNA levels caused by FSK and PMA treatment appears to be the result of decreases in transcription of the alpha 2A-AR gene and is not due to decreases in alpha 2A-AR mRNA degradation rate. These observations suggest that alpha 2A-AR mRNA levels are regulated by cyclic AMP and PKC.
authors.affiliation: Department of Physiology, College of Medicine, University of Florida, Gainesville 32610, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Reutter
authors.forename: E M
authors.initials: EM
authors.lastname: Richards
authors.forename: C
authors.initials: C
authors.lastname: Sumners
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism / Q000502:physiology*; D004355:Drug Stability; D015870:Gene Expression / Q000187:drug effects; D011493:Protein Kinase C / Q000502:physiology*; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; D011942:Receptors, Adrenergic, alpha; D005576:Colforsin; D000242:Cyclic AMP; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate