Effects of chronic antidepressants in an operant conflict procedure of XXXX in the @entity35 .

@entity1 @entity20919 @entity5081 @entity5829 @entity905 @entity148 @entity2645 @entity1154 @entity35
The effects of chronic antidepressants were investigated in an animal procedure for the study of @entity148 and anxiolytics, the conditioned suppression of operant behavior in @entity35 . In daily 18-min sessions, three periods of nonpunished lever pressing for food alternated with two 4-min periods signaled by a light-on conditioned stimulus during which 50% of the responses were randomly punished by electric foot shocks. Antidepressants were administered once daily for 7-8 weeks to trained, food-restricted @entity35 . @entity5829 (dose regimen increase from 4 to 16 mg/kg/day) induced a gradual (4-5-week latency) release of response suppression during punished periods over the course of several weeks of testing. This anxiolytic-like effect was still present 3 weeks following drug discontinuation. In contrast, chronic @entity2645 (dose regimen increase from 4 to 16 mg/kg/day), @entity5081 (4 to 16 mg/kg/day), @entity20919 (2 to 4 mg/kg/day), and @entity905 (1 or 8 mg/kg/day; constant dose), resulted in no change in punished responding, suggesting that no anxiolytic-like effect developed in the course of chronic treatment with these compounds. The largest dose of all antidepressants studied (except @entity905 ) induced a moderate to marked reduction of nonpunished performance that disappeared within 1 week after the last injection. A transient release of conditioned response suppression emerged during the week that followed discontinuation of @entity2645 , @entity5081 , and @entity905 (8 mg/kg/day). This apparent anxiolytic-like activity might be due to a reduction of some adverse effect induced by the high doses used, and/or might have resulted from a new dynamic equilibrium between @entity1154 release, reuptake processes, and sensitivity of postsynaptic receptors. In conclusion, operant conflict procedures in @entity35 seem not particularly able to model @entity1 @entity148 sensitive to chronic antidepressant treatments.
