The aim of the present study was to identify which genes are expressed in the amygdaloid area of rats after exposure to cat odour. A cloth containing cat odour was used to induce the ethologically relevant fear reaction in male rats. Video recording was performed so that all 12 animals belonging to each group of rats were visible. Videotaped behavioral responses were analysed by an observer who was unaware of the manipulations performed. At one-minute intervals, the videotape was paused, and the number of animals sniffing the cloth, in the proximity of the cloth, or touching the cloth was recorded. We also evaluated the number of animals grooming in each group. These behavioral measures have been shown to reflect avoidance and fear towards unpleasant objects.

The differential expression of genes was analysed using cDNA Representational Difference Analysis (cDNA RDA). The differentially expressed clones were identified by sequencing and database searching. RT-PCR (Reverse Transcription Polymerase Chain Reaction) was applied to confirm the differences found by the RDA. Exposing rats to cat odour induced avoidance behavior and suppressed the exploratory activity of these animals. During the cat odour exposure, several genes with various functions were activated in the amygdaloid area of the rats. Among these genes, we identified the activation of wolframin gene. RT-PCR confirmed quantitative elevation in the levels of wolframin transcripts in the amygdaloid area. Thus, this study supports the role of wolframin in the regulation of emotional behavior.

Paper presented at Measuring Behavior 2002 , 4^th International Conference on Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, The Netherlands

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