Quadri-pulse stimulation (QPS) induced LTP/LTD was not affected by Val66Met polymorphism in the brain-derived...

It has been reported that the brain derived neurotrophic factor (BDNF) has some functional roles in inducing plasticity in the adult human brain and the Val66Met BDNF polymorphism affects the plasticity induction. In contrast, some long lasting effects were not fully induced in subjects with non-Val-Val polymorphism. In this communication, we retrospectively investigated whether this polymorphism affects the plastic changes induced by a newly developed stimulation method (quadripulse stimulation (QPS)) in 12 subjects. Both long-term potentiation (LTP) and long-term depression (LTD) like effects were induced by QPS for 30min in any types of BDNF Val66Met polymorphisms. This finding presents a striking contrast to the previous results, which showed reduced long-term effects elicited by some other induction methods in subjects with non-Val-Val polymorphism. Although we are not able to make a final conclusion about the effect of Val66Met BDNF polymorphism on QPS because of the small number of subjects studied, QPS may be less affected by the BDNF polymorphism than several other protocols for inducing LTP/LTD-like effects in humans. Several possibilities may explain this difference. One candidate possibility is that QPS may be long enough for inducing the late LTP/LTD like effect whereas the other stimulation methods may be long enough for early but not enough for late LTP/LTD like effect. It is conspicuous that the QPS for 30min does elicit stable bidirectional long-term effects even in subjects with non-Val-Val polymorphism of BDNF.