Document Type
Thesis
Date of Award
1982
Abstract
Four experiments were performed to investigate the role of the neurotransmitter serotonin in mediating LiCl-based conditioned taste aversions. Previous research has indicated that reductions in forebrain serotonin levels produce a more potent conditioned taste aversion in the rat and that pretreatment with the serotonin precursor, 5-hydroxytryptophan, will attenuate a taste aversion. However, conclusions based on studies using 5-hydroxytryptophan may be of limited value since exogenous 5-hydroxytryptophan may be converted into serotonin in catecholaminergic neurons as well as in serotonergic neurons. Use of the specific serotonin uptake inhibitor fluoxetine HCl in the present studies allowed for more controlled manipulation of serotonergic activity.Experiment 1 compared the effectiveness of fluoxetine HCl and the noradrenergic uptake inhibitor desipramine in disrupting a LiCl-based conditioned taste aversion. Although both fluoxetine HCl and desipramine were effective as disruptive agents, fluoxetine was more potent than desipramine in disrupting a LiCl-based conditioned taste aversion. Experiment 2 assessed the comparative potencies of fluoxetine HCl and desipramine as conditioning agents in the conditioned taste aversion paradigm. Fluoxetine produced a more powerful aversion than did desipramine. Experiment 3 assessed the effects of either raphe or dorsal bundle lesions on the previously observed fluoxetine HCl and desipramine pretreatment effects. Depletion of forebrain serotonin by lesions of the dorsal and median raphe nuclei or of norepinephrine by lesions of the dorsal noradrenergic bundle failed to prevent the pretreatment effect produced by either fluoxetine or desipramine. Rats with raphe lesions consumed less of the taste paired with lithium than did control animals; however, this decreased intake occurred under both drug and saline pretreatment conditions, suggesting increased sensitivity to the taste-lithium pairing rather than a diminution of the pretreatment effect. Rats with dorsal bundle lesions failed to differentiate between drug and saline pretreatment, consuming similar amounts under both conditions. Experiment 4 investigated the central mediation of pretreatment effects through intraventricular administration of fluoxetine. The observation that intraventricular administration of fluoxetine did not produce a pretreatment effect suggests a peripheral rather than a central site of action for the production of pretreatment effects of monoamine uptake inhibitors.
Recommended Citation
Nunn, William B. Jr, "Effects of Alterations in Monoamine Levels on Conditioned Taste Aversions in the Rat." (1982). All ETDs from UAB. 6935.
https://digitalcommons.library.uab.edu/etd-collection/6935
Comments
MA - Master of Arts; ProQuest publication number 31751855