Involvement of AMPA receptor phosphorylation in antidepressant actions with special reference to tianeptine.
Depression is associated with abnormal neuronal plasticity. AMPA receptors mediate transmission and plasticity at excitatory synapses in a manner which is positively regulated by phosphorylation at Ser831-GluR1, a CaMKII/PKC site, and Ser845-GluR1, a PKA site. Treatment with the selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor fluoxetine increases P-Ser845-GluR1 but not P-Ser831-GluR1. Here, it was found that treatment with another antidepressant, tianeptine, increased P-Ser831-GluR1 in the frontal cortex and the CA3 region of hippocampus and P-Ser845-GluR1 in the CA3 region of hippocampus. A receptorome profile detected no affinity for tianeptine at any monaminergic receptors or transporters, confirming an atypical profile for this compound. Behavioural analyses showed that mice bearing point mutations at both Ser831- and Ser845-GluR1, treated with saline, exhibited increased latency to enter the centre of an open field and increased immobility in the tail-suspension test compared to their wild-type counterparts. Chronic tianeptine treatment increased open-field locomotion and reduced immobility in wild-type mice but not in phosphomutant GluR1 mice. P-Ser133-CREB was reduced in the CA3 region of hippocampus in phosphomutant mice, and tianeptine decreased P-Ser133-CREB in this region in wild-type, but not in phosphomutant, mice. Tianeptine increased P-Ser133-CREB in the CA1 region in wild-type mice but not in phosphomutant GluR1 mice. There were higher basal P-Ser133-CREB and c-fos levels in frontal and cingulate cortex in phosphomutant GluR1 mice; these changes in level were counteracted by tianeptine in a GluR1-independent manner. Using phosphorylation assays and phosphomutant GluR1 mice, this study provides evidence that AMPA receptor phosphorylation mediates certain explorative and antidepressant-like actions under basal conditions and following tianeptine treatment.
Svenningsson
Per
P
Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, New York 10021, USA. per.svenningsson@ki.se
Bateup
Helen
H
Qi
Hongshi
H
Takamiya
Kogo
K
Huganir
Richard L
RL
Spedding
Michael
M
Roth
Bryan L
BL
McEwen
Bruce S
BS
Greengard
Paul
P
D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000008:administration & dosage / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004334:Drug Administration Schedule; D005625:Frontal Lobe / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D046353:Immobility Response, Tonic / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D017354:Point Mutation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D018091:Receptors, AMPA / Q000235:genetics / Q000378:metabolism*; D013841:Thiazepines / Q000008:administration & dosage / Q000494:pharmacology*; D014018:Tissue Distribution
D000929:Antidepressive Agents, Tricyclic; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017362:Cyclic AMP Response Element-Binding Protein; D016760:Proto-Oncogene Proteins c-fos; D018091:Receptors, AMPA; D013841:Thiazepines; C492004:Creb1 protein, mouse; C050504:tianeptine