The Journal of Neuroscience, July 1, 2000, 20(13):5170-5178
Nigrostriatal Lesions Alter Oral Dyskinesia and c-Fos Expression
Induced by the Serotonin Agonist
1-(m-Chlorophenyl)piperazine in Adult Rats
Philippe
De Deurwaerdère and
Marie-Françoise
Chesselet
Department of Neurology, University of California, Los Angeles
School of Medicine, Los Angeles, California 90095
The loss of dopaminergic innervation of the basal ganglia, a group
of subcortical regions involved in motor control, is the hallmark of
Parkinson's disease. The resulting molecular and cellular alterations
mediate behavioral deficits and may modify neuronal responses to other
neurotransmitters. In the present study, we sought to determine the
effects of chronic dopamine (DA) depletion on responses mediated by
stimulation of serotonergic 2C (5-HT2C) receptors, a
serotonergic receptor subtype present in discrete regions of the basal
ganglia. Specifically, the effects of unilateral lesions of
nigrostriatal DA neurons on oral dyskinesia and Fos protein expression
induced by the non-selective 5-HT2C agonist 1-(m-chlorophenyl)piperazine (m-CPP) were examined.
Confirming previous findings, both peripheral and local injections of
m-CPP into the subthalamic nucleus elicited oral
dyskinesia. Nigrostriatal lesions markedly enhanced oral bouts induced
by peripheral but not intrasubthalamic administration of
m-CPP. In intact rats, Fos expression was increased by
m-CPP (1 mg/kg, i.p.) in the striatum and the
subthalamic nucleus. After nigrostriatal lesions,
m-CPP-induced Fos expression remained unchanged in the subthalamic nucleus but was reduced in the medial quadrants of the
striatum and was markedly enhanced in the entopeduncular nucleus. These
data demonstrate regionally specific alterations in behavioral and
cellular responses to a serotonergic agonist in an animal model of
Parkinson's disease.
Key words:
Parkinson's disease; dyskinesia; dopamine; serotonin; basal ganglia; serotonin 2C receptors; c-Fos; m-CPP
Copyright © 2000 Society for Neuroscience 0270-6474/00/20135170-09$05.00/0