Introduction

1. Introduction The mouse is widely used as a model organism in olfactory research. However, only a few studies, other than regarding body-borne odors, have been conducted with regard to olfaction at organismal level in the mouse. Amino acids can evoke specific taste sensations and subsequently contribute to the flavor of food. However, the knowledge about the role of amino acids as olfactory stimuli is limited. Results and discussion Among the three different L-forms of the amino acids the mice were most sensitive for cysteine and least sensitive for proline and among the three D-forms the animals displayed a lower sensitivity for D-proline, compared to D-cysteine and D-methionine. Mice also display a lower olfactory detection threshold for both cysteine and methionine compared to proline. Figure 2 Mean olfactory detection thresholds for spider monkeys (diamond), human (square) and CD-1 mice (triangle) for six amino acids. Y-axis display threshold in mM. Figure 3Molecular structure of the six amino acids used. The sulphur-containing group is marked by a red circle. Figure 1The olfactometer used in the study. A comparison between the present data and results obtained with other species showed that the CD-1 mice displayed a higher sensitivity than human subjects and spider monkeys with three of the six amino acids. Aim The aim of this project was therefore to determine olfactory detection thresholds of the mouse for six amino acids and to compare threshold data obtained here with data from other species. However, it cannot be determined whether the differences in olfactory detection depend on the presence or absence of a sulphur-containing group.

2. Olfactory sensitivity in CD-1 mice for six L- and D- amino acids Conclusion Based on the results from this study I can conclude that mice are able to detect the six amino acids tested. The mice also displayed the lowest olfactory threshold for three of the amino acids when compared to human subjects and spider monkeys. Contact informationhelwa440@student.liu.se HelenaWallén Final ThesisMaster Programme in Molecular Genetics and Physiology 2010 Acknowledgement I want to thank supervisor Matthias Laska who have helped me in the making of this report. I also want to thank the animal caretakers at the animal facility at the Universital Hospital of Linköping for their help during my time there. Supervisor: Professor Matthias Laska