Central Nervous System Agents in Medicinal Chemistry

(Formerly Current Medicinal Chemistry - Central Nervous System Agents)

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L-DOPA and Serotonergic Neurons: Functional Implication and Therapeutic Perspectives in Parkinson's Disease

Author(s): Sylvia Navailles, Manolo Carta, Martin Guthrie, Philippe De Deurwaerdere.

Abstract:

L-DOPA is the gold standard medication of Parkinson's disease, a neurological disorder consequent upon the degeneration of mesencephalic dopaminergic neurons. The therapeutic efficacy of L-DOPA has been related to its ability to restore dopamine (DA) extracellular levels in the Parkinsonian brain. The origin of the L-DOPA-induced rise in DA has been the object of numerous studies and controversies but the data collectively point to serotonergic (5-HT) neurons as being most significant in the release. Here, we review biochemical and behavioral evidence supporting serotonergic neurons as playing the main role in the actions of L-DOPA, considered from two points of view. The main aspect concerns the biochemical demonstration that 5-HT neurons are almost solely implicated in the release of DA induced by L-DOPA. The mechanism of action of L-DOPA inside 5-HT neurons will be thoroughly dissected on the basis of L-DOPA effects on extracellular versus tissue DA levels. The unique contribution of 5-HT neurons in mediating the release of newly synthesised DA from L-DOPA will be discussed in parallel with DA-dependent behaviors induced by L-DOPA. The other, and neglected, aspect concerns the possible deleterious impact of the presence of L-DOPA inside 5-HT neurons on 5-HT neuronal function. Overall, the fact that 5-HT neurons release the newly synthesised DA from L-DOPA in multiple brain regions beyond the striatum gives new insight into the large impact of L-DOPA in the Parkinsonian brain and strengthens therapeutic perspectives targeting the 5-HT system to reduce both motor and non-motor complications of L-DOPA medication.

Keywords: 6-Hydroxydopamine, receptors, dopamine release, L-DOPA, motor complications, serotonin neurons, non-serotonin, serotonin release, dopaminergic neurons, dyskinesia, non-motor complications, serotonin receptors

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Article Details

VOLUME: 11
ISSUE: 4
Year: 2011
Page: [305 - 320]
Pages: 16
DOI: 10.2174/1871524911106040305
Price: $58