Thesis defense Lourens Nonkes (Donders Series 87)

15 May 2012

Promotors: Prof.dr. C.C.A.M. Gielen, Prof. dr. J.H.L.M. van Bokhoven

Copromotor: Dr. J.R. Homberg

Serotonin transporter gene variance causes individual differences in rat behaviour: for better and for worse

Some people are more sensitive to environmental conditions than others. This makes them more vulnerable to developing emotional disorders, including depression and anxiety-related disorders. Genetic variation in the serotonin transporter gene plays an important role herein: people carrying the low expression variant of the so called ‘5-HTTLPR polymorphism’ are more vulnerable compared to carriers of the high expression variant. During his PhD study, Lourens Nonkes investigated serotonin transporter gene variance by means of a translational animal model: the serotonin transporter knockout rat. In his thesis he reveals that, like humans carrying the 5-HTTLPR low expression variant, these animals show an increased sensitivity for environmental conditions. However, next to an increased vulnerability to develop negative emotional behaviour, they also showed an increased flexibility to adapt to changing environmental stimulus conditions. Interestingly, this flexibility could be used to offset negative emotional behaviour. These insights may facilitate the development of better person-specific therapies and show that a specific genetic makeup is not only good or bad.