High frequency stimulation of the subthalamic nucleus improves speed of locomotion but impairs forelimb movement in Parkinsonian rats

Neuroscience. 2007 Sep 7;148(3):815-23. doi: 10.1016/j.neuroscience.2007.06.043. Epub 2007 Jul 17.

Abstract

The subthalamic nucleus (STN) plays an important role in motor and non-motor behavior in Parkinson's disease, but its involvement in gait functions is largely unknown. In this study, we investigated the role of the STN on gait in a rat model of PD using the CatWalk method. Parkinsonian rats received bilateral high frequency stimulation (HFS) with different stimulation amplitudes of the STN. Rats were rendered parkinsonian by bilateral injections of 6-hydroxydopamine (6-OHDA) into the striatum. One group of 6-OHDA animals was implanted bilaterally with stimulation electrodes at the level of the STN. Stimulations were performed at 130 Hz (frequency), 60 micros (pulse width) and varying amplitudes of 0, 3, 30 and 150 microA. Rats were evaluated in an automated quantitative gait analysis method (CatWalk method). After behavioral evaluations, rats were killed and the brains processed for histological stainings to determine the impact of the dopaminergic lesion (tyrosine hydroxylase immunohistochemistry) and the localization of the electrode tip (hematoxylin-eosin histochemistry). Results show that bilateral 6-OHDA infusion significantly decreased (70%) the number of dopaminergic cells in the substantia nigra pars compacta (SNc). Due to 6-OHDA treatment, the gait parameters changed considerably. There was a general slowness. The most pronounced effects were seen at the level of the hind paws. Due to implantation of STN electrodes the step pattern changed. STN electrical stimulation improved the general slowness but induced slowing of the forelimb movement. Furthermore, we found that HFS with a medium amplitude significantly changed speed, the so-called dynamic aspect of gait. The static features of gait were only significantly influenced with low amplitude. Remarkably, STN stimulation affected predominantly the forepaws/limbs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Corpus Striatum / drug effects
  • Corpus Striatum / physiopathology
  • Denervation
  • Disease Models, Animal
  • Dopamine / metabolism
  • Electric Stimulation Therapy / adverse effects*
  • Electric Stimulation Therapy / instrumentation
  • Electric Stimulation Therapy / methods
  • Electrodes, Implanted / adverse effects
  • Forelimb / innervation
  • Forelimb / physiopathology
  • Gait / physiology
  • Gait Disorders, Neurologic / physiopathology*
  • Gait Disorders, Neurologic / therapy*
  • Locomotion / physiology
  • Male
  • Nerve Degeneration / chemically induced
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / physiopathology
  • Neurotoxins
  • Oxidopamine
  • Parkinsonian Disorders / physiopathology*
  • Parkinsonian Disorders / therapy*
  • Rats
  • Rats, Inbred Lew
  • Substantia Nigra / metabolism
  • Substantia Nigra / pathology
  • Substantia Nigra / physiopathology
  • Subthalamic Nucleus / physiopathology*
  • Treatment Outcome
  • Tyrosine 3-Monooxygenase / metabolism

Substances

  • Neurotoxins
  • Oxidopamine
  • Tyrosine 3-Monooxygenase
  • Dopamine