Cerebral 5-HT2A receptor and serotonin transporter binding in humans are not affected by the val66met BDNF polymorphism status or blood BDNF levels

Abstract

Recent studies have proposed an interrelation between the brain-derived neurotrophic factor (BDNF) val66met polymorphism and the serotonin system. In this study, we investigated whether the BDNF val66met polymorphism or blood BDNF levels are associated with cerebral 5-hydroxytryptamine 2A (5-HT(2A)) receptor or serotonin transporter (SERT) binding in healthy subjects. No statistically significant differences in 5-HT(2A) receptor or SERT binding were found between the val/val and met carriers, nor were blood BDNF values associated with SERT binding or 5-HT(2A) receptor binding. In conclusion, val66met BDNF polymorphism status is not associated with changes in the serotonergic system. Moreover, BDNF levels in blood do not correlate with either 5-HT(2A) or SERT binding.

Figure 1

Neocortical 5-HT_2A binding in the val/val and met groups. (A) There were no significant differences between the two groups (mean: 1.41±0.43 versus 1.35±0.43). (B) Correlation between BDNF levels in blood and neocortical 5-HT_2A binding. Although there was a modest significant positive correlation (P=0.03), this was no longer present after adjustments for age and BMI. BDNF, brain-derived neurotrophic factor; BMI, body mass index; 5-HT_2A, 5-hydroxytryptamine 2A.

Figure 2

Mean SERT binding in the subcortical high-binding region in val/val and met carriers. (A) There were no significant differences in SERT binding between val/val and met carriers (1.66±0.20 versus 1.62±0.16, respectively, P=0.61). (B) Correlations between blood BDNF levels and SERT binding. There were no significant associations between these parameters (r=−0.09, P=0.59). BDNF, brain-derived neurotrophic factor; SERT, serotonin transporter.