BACKGROUND: We sought to study the effects of chronic exposure to fluoxetine - a selective serotonin reuptake inhibitor (SSRI) and specific 5-HT(2B) receptor agonist in astrocytes - on the expression of kainate receptors (GluK1-5) in cultured astrocytes and in intact brains in mice and on GluK2 editing by adenosine deaminase acting on RNA (ADAR), as well as the ensuing effects of fluoxetine on glutamate-mediated Ca(2+) influx and extracellular signal-regulated kinase (ERK)(1/2) phosphorylation in astrocytes. METHODS: We performed reverse transcription-polymerase chain reaction (PCR) to assess mRNA expression. We analyzed RNA editing with amplification refractory mutation system PCR and complementary DNA sequencing. Protein expression and ERK phosphorylation were assessed using Western blots. We studied gene silencing with specific small interfering RNAs (siRNA), and we studied intracellular Ca(2+) using fluorometry. RESULTS: All GluK subunits were present in the brain in vivo, and GluK2-5 subunits were present in cultured astrocytes. Fluoxetine upregulated GluK2 and ADAR2. Enhanced GluK2 editing by fluoxetine abolished glutamate-mediated increases in intra cellular Ca(2+) and ERK(1/2) phosphorylation. Enhanced editing of GluK2 was prevented by siRNA against the 5-HT(2B) receptor or ADAR2. LIMITATIONS: Limitations of our study include the use of an in vitro system, but our cultured cells in many respects behave like in vivo astrocytes. CONCLUSION: Fluoxetine alters astrocytic glutamatergic function.
BACKGROUND: We sought to study the effects of chronic exposure to fluoxetine - a selective serotonin reuptake inhibitor (SSRI) and specific 5-HT(2B) receptor agonist in astrocytes - on the expression of kainate receptors (GluK1-5) in cultured astrocytes and in intact brains in mice and on GluK2 editing by adenosine deaminase acting on RNA (ADAR), as well as the ensuing effects of fluoxetine on glutamate-mediated Ca(2+) influx and extracellular signal-regulated kinase (ERK)(1/2) phosphorylation in astrocytes. METHODS: We performed reverse transcription-polymerase chain reaction (PCR) to assess mRNA expression. We analyzed RNA editing with amplification refractory mutation system PCR and complementary DNA sequencing. Protein expression and ERK phosphorylation were assessed using Western blots. We studied gene silencing with specific small interfering RNAs (siRNA), and we studied intracellular Ca(2+) using fluorometry. RESULTS: All GluK subunits were present in the brain in vivo, and GluK2-5 subunits were present in cultured astrocytes. Fluoxetine upregulated GluK2 and ADAR2. Enhanced GluK2 editing by fluoxetine abolished glutamate-mediated increases in intra cellular Ca(2+) and ERK(1/2) phosphorylation. Enhanced editing of GluK2 was prevented by siRNA against the 5-HT(2B) receptor or ADAR2. LIMITATIONS: Limitations of our study include the use of an in vitro system, but our cultured cells in many respects behave like in vivo astrocytes. CONCLUSION:Fluoxetine alters astrocytic glutamatergic function.
Authors: Monica Beneyto; Lars V Kristiansen; Akinwunmi Oni-Orisan; Robert E McCullumsmith; James H Meador-Woodruff Journal: Neuropsychopharmacology Date: 2007-02-14 Impact factor: 7.853
Authors: P V Choudary; M Molnar; S J Evans; H Tomita; J Z Li; M P Vawter; R M Myers; W E Bunney; H Akil; S J Watson; E G Jones Journal: Proc Natl Acad Sci U S A Date: 2005-10-17 Impact factor: 11.205
Authors: Gonzalo Laje; Silvia Paddock; Husseini Manji; A John Rush; Alexander F Wilson; Dennis Charney; Francis J McMahon Journal: Am J Psychiatry Date: 2007-10 Impact factor: 18.112