| The goal of this dissertation was to develop and evaluate a paradigm for dissociating illness in rats from changes of food intake. The rationale was that many factors tend to reduce food consumption, one of them being illness. Having an easy to determine marker of illness, independent of assessing food intake, would be a major benefit for investigators interested in the study of ingestion. The specific goal of this dissertation, therefore, was to ascertain the utility of using a specific behavioral index, geophagia (operationally defined as kaolin consumption) to make inferences about the possible illness-inducing or aversive qualities of several compounds purported to be important in the normal control of food intake and energy homeostasis. My strategy was first to establish a paradigm for assessing geophagia in rats and then to validate it by use of lithium chloride, a compound which has been observed to have aversive properties in other paradigms. The next step was to administer several compounds purported to be involved in the endogenous control of food intake and to assess their ability to elicit geophagia. The compounds assessed were neuropeptide Y (NPY), which elicits food intake while also causing a conditioned taste aversion or CTA, cholecystokinin (CCK) which reduces food intake when administered at the time of meals, and glucagon-like-peptide-1 (GLP-1), which reduces food intake when administered into the brain and which also causes the formation of a CTA. |
