Dissociating the Conditioning and the Anorectic Effects of Estradiol in Female Rats

The present series of experiments challenges the ability of the hormone estradiol to act a,. an unconditioned stimulus in the conditioned taste avoidance (CTA) learning paradigm We hypothesize that reductions In sucrose consumption observed after pairing it with estradiol ire not indicative of associative learning. but due to the unconditioned expression of estradiol's anorectic effects during the time of CTA assessment Three experiments in which a sucrose solution was paired with estradiol were conducted to test this hypothesis Experiment 1 demonstrated that female rats expressed a reduction in post-pairing sucrose consumption even though the anorectic effects of estradiol had subsided. Experiment 2 showed that although a low dose of estradiol produced anorexia. it did not elicit post-pairing reductions in sucrose consumption Experiment 3 revealed that contingent pairing was a requirement for post-pairing reduction in sucrose consumption even when testing was done at a time when anorexia is expressed. These finding, demonstrate the dissociability of the conditioning and anorectic effects of estradiol, providing evidence against the hypothesis. The results are discussed in terms of independent neural mechanisms underlying the disparate behaviors