Time-course of changes in firing rates and firing patterns of subthalamic nucleus neuronal activity after 6-OHDA-induced dopamine depletion in rats
Brain Research. 2001-04-01; 899(1-2): 142-147
DOI: 10.1016/S0006-8993(01)02219-3
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1. Brain Res. 2001 Apr 27;899(1-2):142-7. doi: 10.1016/s0006-8993(01)02219-3.
Time-course of changes in firing rates and firing patterns of subthalamic
nucleus neuronal activity after 6-OHDA-induced dopamine depletion in rats.
Ni ZG(1), Bouali-Benazzouz R, Gao DM, Benabid AL, Benazzouz A.
Author information:
(1)Laboratoire de Neuroscience Préclinique, INSERM U. 318, CHU – Pavillon B,
B.P. 217, 38043 Cedex 09, Grenoble, France.
The subthalamic nucleus (STN) plays a key role in motor control. Disorganization
of its neuronal activity is implicated in the manifestation of parkinsonian
motor symptoms. The aim of the present work was to study the time-course of
changes in the firing activity of STN neurons in a rat model of parkinsonism.
Electrophysiological recordings were done in normal rats and four groups of rats
at different time points after 6-hydroxydopamine (6-OHDA) microinjection into
the pars compacta of substantia nigra (SNc). Results showed a significant
decrease in firing rate during the first and second weeks post lesion
(5.53+/-0.56 and 7.66+/-0.73 spikes/s, respectively) compared to normal rats
(11.13+/-0.59 spikes/s). From the 3rd week after 6-OHDA injection the firing
rates returned toward baseline, with an average of 9.71+/-0.51 spikes/s during
the 3rd week and 11.13+/-0.71 spikes/s during the 4th week. With regard to
firing pattern, the majority of STN cells (90%) discharged regularly or slightly
irregularly in normal animals. Only 4% exhibited burst activity and 6% had mixed
firing patterns. After SNc-lesion, the percentage of cells exhibiting burst and
mixed patterns increased progressively from 35% during the first week to 56% at
week 4 post-lesion. In sum, these experiments revealed that the firing rate of
STN neurons was altered only transiently following nigral lesions, whereas a
progressive and stable change in the firing pattern was observed up to 4 weeks
post lesion, suggesting that the persistence of bursts firing more closely
relates to the motor pathologies of this rat model of parkinsonism.
DOI: 10.1016/s0006-8993(01)02219-3
PMID: 11311875 [Indexed for MEDLINE]