Altered dopamine modulation of LTD-like plasticity in Alzheimer's disease patients

作者：Koch Giacomo^*; Esposito Zaira; Codeca Claudia; Mori Francesco; Kusayanagi Hajime; Monteleone Fabrizia; Di Lorenzo Francesco; Bernardi Giorgio; Martorana Alessandro

来源：Clinical Neurophysiology, 2011, 122(4): 703-707.

DOI：10.1016/j.clinph.2010.10.033

• Transcranial magnetic stimulation
• Cortical plasticity
• Alzheimer's disease
• LTD
• Dopamine
• rTMS

Objective: Mechanisms of synaptic plasticity like long term depression (LTD) are altered in experimental models of Alzheimer's disease (AD). LTD-like plasticity mechanisms has not been yet fully investigated in AD patients.
Methods: Here we studied the effects of low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex in a group of patients with a diagnosis of probable AD, compared to healthy age-matched controls (HS). Moreover, we tested the effects of a single dose of orally administered L-dopa, one of the key neurotransmitters in modulating synaptic plasticity mechanisms, on rTMS induced plasticity.
Results: We found that in AD patients the 1 Hz rTMS protocol did not induce the expected inhibitory effect, while a long lasting inhibition of MEP was observed in HS. In addition, L-dopa induced a clear form of reversal of the direction of plasticity in HS that was not evident in AD.
Conclusions: Dopamine modulation of LTD-like plasticity is impaired when tested in AD patients.
Significance: These findings provide evidence of possible dysfunction of dopaminergic transmission in AD patients.

• 出版日期2011-4