Suppression of LTP-like plasticity in human motor cortex by the GABAB receptor agonist baclofen

Exp Brain Res. 2007 Jun;180(1):181-6. doi: 10.1007/s00221-006-0849-0. Epub 2007 Mar 10.


Previous experiments in slice preparations revealed that pharmacological activation of GABAB receptors down- or up-regulates long-term potentiation (LTP), depending on whether increase of GABAB receptor mediated inhibitory postsynaptic potentials or decrease of presynaptic auto-inhibition of GABAA receptor mediated inhibition predominates. The effects of GABAB receptor activation on LTP in humans in vivo are unknown. Here we show, by using transcranial magnetic stimulation, that the GABAB receptor agonist baclofen decreases paired associative stimulation induced LTP-like plasticity in human motor cortex. This suggests that increased GABAB mediated inhibitory postsynaptic potentials drive this effect, and that baclofen may have a negative impact on LTP-dependent behavioural processes such as motor learning.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Baclofen / pharmacology*
  • Cross-Over Studies
  • Double-Blind Method
  • Electric Stimulation / methods
  • Electromyography
  • Evoked Potentials, Motor / drug effects
  • Evoked Potentials, Motor / radiation effects
  • Female
  • GABA Agonists / pharmacology*
  • Humans
  • Linear Models
  • Long-Term Potentiation / drug effects*
  • Long-Term Potentiation / radiation effects
  • Male
  • Median Nerve / physiology
  • Median Nerve / radiation effects
  • Motor Cortex / drug effects*
  • Motor Cortex / radiation effects
  • Pyramidal Tracts / drug effects
  • Pyramidal Tracts / physiology
  • Pyramidal Tracts / radiation effects
  • Transcranial Magnetic Stimulation / methods


  • GABA Agonists
  • Baclofen