Behavioural evaluation of animal models of diabetes.

Abstract

Diabetes is considered as a prominent threat to the worldwide population, and if leftuntreated may result in a number of severe complications, cognitive deterioration, and death. For the most prevalent form of the disease, type 2 diabetes, the main contributing factors to the development of the disease is being overweight and obese. There are a number of mediating factors regarding the relationship between excessive weight gain and subsequent development of diabetes, the most widely supported of which is the typical eating behaviours of the individual. While the physiological characteristics of diabetes are well-known, much less is understood in relation to the behavioural consequences. Animal models may aid our understanding of a disease, but the animal model used should not only replicate the physiological symptoms but also the behavioural characteristics.

The studies discussed within this thesis encompass a thorough behavioural evaluation of two of the most commonly used diet-induced and chemically-induced animal models of diabetes; the high-fat diet model of obesity induced diabetes and Streptozotocin induced diabetes. The main focus of investigation was on the impact of the disease regarding the food preferences and motivations of mice to obtain food, using a classical method for assessing preference (T-maze) and motivation to respond for different appetitive stimuli on an operant conditioning schedule of food reinforcement (progressive ratio schedule, PR). During the latter phase of experiments, a range of behavioural processes (e.g. food deprivation alterations, prefeeding with or without satiation, and extinction) were also assessed in relation to how these may be affected by the presence of diabetes. In the final study, a new model of PR performance was applied to the results, with the intention of addressing issues relating to the accurate measurement of motivation under a PR schedule. Orderly behavioural data were obtained but neither model of diabetes showed clear effects on food motivation. Results are presented and discussed in relation to the limitations and implications of the research.

Date of Award	Mar 2017
Original language	English
Supervisor	Julian Leslie (Supervisor) & David Shaw (Supervisor)