Effects of L-DOPA on neuronal activity of the globus pallidus externalis (GPe) and globus pallidus internalis (GPi) in the MPTP-treated monkey.
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.
Boraud
T
T
Basal Gang, Lab. Neurophysiologie, CNRS UMR 5543, Université Victor Segalen Bordeaux 2, 146, rue Léo Saignat, 33076 Bordeaux Cedex, France. thomas.boraud@umr5543.u-bordeaux2.fr
Bezard
E
E
Guehl
D
D
Bioulac
B
B
Gross
C
C
D000818:Animals; D015259:Dopamine Agents / Q000633:toxicity*; D005260:Female; D005917:Globus Pallidus / Q000166:cytology / Q000187:drug effects*; D007150:Immunohistochemistry; D007980:Levodopa / Q000494:pharmacology*; D020267:MPTP Poisoning; D008253:Macaca mulatta; D009474:Neurons / Q000187:drug effects*; D010302:Parkinson Disease, Secondary / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology
D015259:Dopamine Agents; D007980:Levodopa