Effects of L-DOPA on neuronal activity of the globus pallidus externalis (GPe) and globus pallidus internalis (GPi) in the MPTP-treated monkey

Brain Res. 1998 Mar 16;787(1):157-60. doi: 10.1016/s0006-8993(97)01563-1.


We studied the effects of L-DOPA on the firing patterns of pallidal neurons in experimental parkinsonism. After a unilateral injection of MPTP, we observed a decrease in the firing rate of GPe neurons, and a slight increase in their bursting activity. In the GPi, there was a considerable augmentation of both neuronal firing frequency and the number of bursting cells. During l-DOPA treatment (10 mg/kg), GPe neurons.pattern is almost unmodified. The firing frequency of GPi neurons, on the contrary, decreased even lower than the control level. A slight reduction was observed in bursting activity. These unexpected results would show that the normalizing effect of L-DOPA on GPi output is limited.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dopamine Agents / toxicity*
  • Female
  • Globus Pallidus / cytology
  • Globus Pallidus / drug effects*
  • Immunohistochemistry
  • Levodopa / pharmacology*
  • MPTP Poisoning*
  • Macaca mulatta
  • Neurons / drug effects*
  • Parkinson Disease, Secondary / chemically induced
  • Parkinson Disease, Secondary / drug therapy*
  • Parkinson Disease, Secondary / pathology


  • Dopamine Agents
  • Levodopa