Present address: Department of Anatomy and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
An mTph2 SNP gives rise to alterations in extracellular 5-HT levels, but not in performance on a delayed-reinforcement task
Article first published online: 20 AUG 2005
European Journal of Neuroscience
Volume 22, Issue 4, pages 997–1000, August 2005
How to Cite
Isles, A. R., Hathway, G. J., Humby, T., De La Riva, C., Kendrick, K. M. and Wilkinson, L. S. (2005), An mTph2 SNP gives rise to alterations in extracellular 5-HT levels, but not in performance on a delayed-reinforcement task. European Journal of Neuroscience, 22: 997–1000. doi: 10.1111/j.1460-9568.2005.04265.x
- Issue published online: 20 AUG 2005
- Article first published online: 20 AUG 2005
- Received 25 January 2005, revised 7 June 2005, accepted 13 June 2005
- delayed gratification;
- tryptophan hydroxylase
5-Hydroxytryptamine (5-HT) is an important neurotransmitter mediating many aspects of cognition and behaviour. One psychology in which 5-HT plays an important role is impulsive responding. Recently, we have demonstrated that variation in an aspect of impulsive behaviour, namely delayed gratification, has a clear genetic contribution. Here, we examined the neurobiological relevance of a recently discovered single nucleotide polymorphism (SNP) in the murine gene tryptophan hydroxylase (mTph2) by analysing extracellular levels of 5-HT in medial prefrontal cortex (mPFC) and ventral striatum (VS), key brain regions for impulsive behaviours. The allelic variants were associated with systematic effects on baseline 5-HT efflux in the mPFC and VS. We then went on to examine whether the mTph2 allelic variants gave rise to differences in impulsive behaviour. However, the mTph2 genotype, and therefore presumably baseline brain levels of 5-HT, did not predict impulsive choice, as indexed by sensitivity to delayed reinforcement. Consequently, the data do not support a role for the mTph2 C1473G polymorphism on this aspect of impulsive behaviour. Instead, they indicate that perturbations of the 5-HT system via heritable traits may have differential consequences for qualitatively distinct aspects of impulsive behaviour.