LeDoux Lab 2004 SfN Abstracts

CHRONIC SSRI TREATMENT IMPAIRS THE ACQUISTION OF FEAR EXTINCTION IN RATS: A COMPARISON WITH TIANEPTINE
N.S.Burghardt1*; T.Sigurdsson1; B.S.McEwen2; J.E.LeDoux1
1. Ctr for Neural Sci, New York Univ, New York, NY, USA
2. Rockefeller Univ, New York, NY, USA
Previously, we reported that chronic treatment with the SSRI citalopram impaired the acquisition of conditioned fear memories. The purported serotonin reuptake enhancer tianeptine also impaired the acquisition of conditioned fear. To further explore the role of SSRIs in the acquisition of emotional learning, we evaluated the effects of chronic citalopram treatment on the acquisition of conditioned fear extinction by administering chronic drug treatment before extinction trials. These effects were compared to those following chronic tianeptine treatment. Fear conditioning involved 2 presentations of a tone (20s, 10kHz) that co-terminated with a footshock (0.7mA, 0.5s). Twenty-four hours after conditioning, rats were treated systemically with citalopram (10 mg/kg, ip), tianeptine (10 mg/kg, ip), or saline daily for 22 days and then given extinction trials one hour after the last injection. Chronic citalopram treatment led to an impairment in the acquisition of fear extinction, and the effect was maintained the next day when animals were tested drug-free. Rats given chronic tianeptine treatment showed a similar impairment, indicating that chronic citalopram and tianeptine treatment lead to comparable effects on behavior. Given that extinction involves new learning (learning that the tone does not predict a shock) this impairment in extinction is consistent with the impairment in acquisition previously reported with chronic treatment. These findings raise the possibility that the therapeutic effects resulting from chronic treatment with serotonin related drugs are due to an alteration in emotional learning.
Support Contributed By: P50 MH58911 and K05 MH067048
Program No. 208.6
Poster presentation:Sunday, Oct. 24, 10:00 AM - 11:00 PM
Location: NN21