Effect of dopaminergic substances on sleep/wakefulness in saline- and MPTP-treated mice
Sleep/wakefulness (S/W) disorders are frequent in Parkinson’s disease (PD). The underlying causes have yet to be elucidated but dopaminergic neurodegenerative lesions seem to contribute to appearance of the disorders and anti-Parkinsonian medication is known to accentuate S/W problems. Hence, we reasoned that studying the acute effect of dopaminergic compounds on S/W in an animal model of PD might improve our knowledge of S/W regulation in the context of partial dopaminergic depletion. To this end, we tested the effect of levodopa (l-dopa), pergolide (a mixed D2/D1 agonist) and lisuride (a D2 agonist) on S/W recordings in MPTP-treated mice, in comparison with controls. Our results showed that dopaminergic compounds modify S/W amounts in both control and MPTP mice. Wakefulness amounts are greater in MPTP mice afterl-dopa (50 mg kg−1) and lisuride (1 mg kg−1) injections compared with control mice. Moreover, the paradoxical sleep latency was significantly longer in MPTP mice after high-dosel-dopa administration. Our observations suggest that the actions of bothl-dopa and lisuride on S/W differ slightly in MPTP mice relative to controls. Hence, MPTP-induced partial DA depletion may modulate the effect of dopaminergic compounds on S/W regulation.
Document Type: Research Article
Affiliations: 1: Laboratoire de Physiologie 2: Laboratoire de Pharmacologie, Institut Fédératif de Recherche, Faculté de Médecine, Pôle recherche 3: Clinique Neurologique, Hôpital R. Salengro, CHRU de Lille, Lille cedex, France
Publication date: 2008-03-01