Experimental Brain Research

, Volume 234, Issue 12, pp 3659–3667

Paradoxical facilitation after depotentiation protocol can precede dyskinesia onset in early Parkinson’s disease

  • Angel Lago-Rodriguez
  • Viviana Ponzo
  • Ned Jenkinson
  • Sonia Benitez-Rivero
  • Miguel Fernandez Del-Olmo
  • Michele Hu
  • Giacomo Koch
  • Binith Cheeran
Research Article

DOI: 10.1007/s00221-016-4759-5

Cite this article as:
Lago-Rodriguez, A., Ponzo, V., Jenkinson, N. et al. Exp Brain Res (2016) 234: 3659. doi:10.1007/s00221-016-4759-5
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Abstract

Loss of dopamine, a key modulator of synaptic signalling, and subsequent pulsatile non-physiological levodopa replacement is believed to underlie altered neuroplasticity in Parkinson’s disease (PD). Animal models suggest that maladaptive plasticity (e.g. deficient depotentiation at corticostriatal synapses) is key in the development of levodopa-induced dyskinesia (LID), a common complication following levodopa replacement in PD. Human studies using transcranial magnetic stimulation protocols have shown similar depotentiation deficit in patients with LID. We hypothesized that subtle depotentiation deficits should precede LID if these deficits are mechanistically linked to LID onset. Moreover, patients on pulsatile levodopa-based therapy may show these changes earlier than those treated with levodopa-sparing strategies. We recruited 22 early non-dyskinetic PD patients (<5 years since diagnosis) and 12 age-matched healthy controls. We grouped patients into those on Levodopa-Based (n = 11) and Levodopa-Sparing therapies (n = 11). Patients were selected to obtain groups matched for age and disease severity. We used a theta-burst stimulation protocol to investigate potentiation and depotentiation in a single session. We report significant depotentiation deficits in the Levodopa-Based group, compared to both Levodopa-Sparing and Healthy Control groups. Potentiation and Depotentiation responses were similar between Levodopa-Sparing and Healthy Control groups. Although differences persist after accounting for potential confounds (e.g. levodopa-equivalent dose), these results may yet be caused by differences in disease severity and cumulative levodopa-equivalent dose as discussed in the text. In conclusion, we show for the first time that paradoxical facilitation in response to depotentiation protocols can occur in PD even prior to LID onset.

Keywords

Synaptic plasticity Potentiation Depotentiation Levodopa-induced dyskinesia Parkinson’s disease 

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
  2. 2.School of PsychologyUniversity of BirminghamBirminghamUK
  3. 3.Laboratorio di Neurologia Clinica e ComportamentaleFondazione Santa Lucia IRCCSRomeItaly
  4. 4.Department of Physical Education, Faculty of Sciences of Sport and Physical EducationUniversity of A CoruñaA CoruñaSpain
  5. 5.Stroke Unit, Dipartimento di NeuroscienzeUniversità di Roma Tor VergataRomeItaly