Time-course of changes in firing rates and firing patterns of subthalamic nucleus neuronal activity after 6-OHDA-induced dopamine depletion in rats.
Brain Res
; 899(1-2): 142-7, 2001 Apr 27.
Article
em En
| MEDLINE
| ID: mdl-11311875
ABSTRACT
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potenciais de Ação
/
Dopamina
/
Oxidopamina
/
Núcleo Subtalâmico
/
Transtornos Parkinsonianos
/
Neurônios
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article