Daily fluoxetine administration impairs avoidance learning in the rat without altering sensory thresholds.
1. Male rats given daily intraperitoneal injections of fluoxetine (10 mg/kg) were slower to escape foot shock by jumping a low barrier. 2. When switched to a shuttle task requiring two crosses to terminate shock, the FLU-treated animals failed to learn in 55 trials. 3. A second experiment found FLU-treated animals could learn a one-way avoidance response, but were significantly slower to learn than control animals. 4. FLU-treated animals were no different than controls on tests of sensory thresholds for foot shock or heat. 5. Tests of motor behaviors revealed no differences in latency to traverse a narrow beam to reach a goal box, however FLU-treated animals were less active in an open field. 6. Several hypotheses can account for these data, the most promising being that a central motivational system (fear) is less active in FLU-treated animals.
Nelson
C J
CJ
Department of Psychology, St. Mary's College of Maryland, St. Mary's City, USA.
Jordan
W P
WP
Bohan
R T
RT
D000698:Analgesia; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D004597:Electroshock; D004924:Escape Reaction / Q000187:drug effects; D005473:Fluoxetine / Q000494:pharmacology*; D006358:Hot Temperature; D008297:Male; D009042:Motivation; D009043:Motor Activity / Q000187:drug effects*; D017288:Pain Threshold / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D005473:Fluoxetine