Tamoxifen and raloxifene produce conditioned taste avoidance in female rats: a microstructural analysis of licking patterns.
OBJECTIVE
Estrogen receptor activation has been shown to reduce body weight and produce conditioned taste avoidance (CTA) when estradiol administration is paired with a novel tastant. This study determined if the selective estrogen receptor modulators tamoxifen and raloxifene, which effectively prevent and treat breast cancer, can induce a CTA and alter body weight in ovariectomized (OVX)-female rats.


METHODS
During conditioning, OVX-female rats were injected with tamoxifen, raloxifene, 17beta-estradiol or vehicle, or were uninjected, prior to drinking 0.3 M sucrose in a lickometer. Immediately following sucrose access, alterations in locomotor activity and thigmotaxis (anxiety) were assessed in an open field apparatus. Conditioned drug effects on drinking, locomotor activity and anxiety were examined on a separate test day.


RESULTS
Our results suggest that both tamoxifen and raloxifene produce CTA that is similar to that produced by estradiol. Both the number and size of bursts of licking were significantly reduced, as well as body weight gain, in OVX-female rats treated with tamoxifen or raloxifene.


CONCLUSIONS
The results of the present study suggest that tamoxifen and raloxifene may have the potential to produce CTA in breast cancer patients receiving chemoprevention care.
Fudge
Melissa A
MA
Neuroscience Graduate Program, Department of Psychology, The University of Western Ontario, London, Ontario, Canada N6A 5C2. melissa.fudge@queensu.ca
Kavaliers
Martin
M
Baird
John-Paul
JP
Ossenkopp
Klaus-Peter
KP
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001835:Body Weight / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects*; D004326:Drinking / Q000187:drug effects; D005260:Female; D006801:Humans; D010052:Ovariectomy; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D013629:Tamoxifen / Q000494:pharmacology*; D013649:Taste / Q000187:drug effects*
D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; D020849:Raloxifene Hydrochloride