Artículo
Consequences of partial and severe dopaminergic lesion on basal ganglia oscillatory activity and akinesia
Fecha de publicación:
11/2005
Editorial:
Wiley Blackwell Publishing, Inc
Revista:
European Journal of Neuroscience
ISSN:
0953-816X
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Severe chronic dopamine (DA) depletion increases the proportion of neurons in the basal ganglia that fire rhythmic bursts of action potential (LFO units) synchronously with the cortical oscillations. Here we report on how different levels of mesencephalic DA denervation affect substantia nigra pars reticulata (SNpr) neuronal activity in the rat and its relationship to akinesia (stepping test). Chronic nigrostriatal lesion induced with 0 (control group), 4, 6 or 8 microg of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle resulted in a dose-dependent decrease of tyrosine hydroxylase positive (TH+) neurons in the SN and ventral tegmental area (VTA). Although 4 microg of 6-OHDA reduced the number of TH+ neurons in the SN by approximately 60%, both stepping test performance and SNpr neuronal activity remained indistinguishable from control animals. By contrast, animals that received 6 microg of 6-OHDA showed a marked reduction of TH+ cells in the SN ( approximately 75%) and VTA ( approximately 55%), a significant stepping test deficit and an increased proportion of LFO units. These changes were not dramatically enhanced with 8 microg 6-OHDA, a dose that induced an extensive DA lesion (> 95%) in the SN and approximately 70% reduction of DA neurons in the VTA. These results suggest a threshold level of DA denervation for both the appearance of motor deficits and LFO units. Thus, the presence of LFO activity in the SNpr is not related to a complete nigrostriatal DA neuron depletion (ultimate stage parkinsonism); instead, it may reflect a functional disruption of cortico-basal ganglia dynamics associated with clinically relevant stages of the disease.
Palabras clave:
BASAL GANGLIA
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Colecciones
Articulos(OCA HOUSSAY)
Articulos de OFICINA DE COORDINACION ADMINISTRATIVA HOUSSAY
Articulos de OFICINA DE COORDINACION ADMINISTRATIVA HOUSSAY
Citación
Tseng, Kuei Y.; Kargieman, Lucila; Gacio, Sebastian; Riquelme, Luis Alberto; Murer, Mario Gustavo; Consequences of partial and severe dopaminergic lesion on basal ganglia oscillatory activity and akinesia; Wiley Blackwell Publishing, Inc; European Journal of Neuroscience; 22; 10; 11-2005; 2579-2586
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