Dopaminergic control of the globus pallidus through activation of D2 receptors and its impact on the electrical activity of subthalamic nucleus and substantia nigra reticulata neurons
PLoS ONE. 2015-03-05; 10(3): e0119152
DOI: 10.1371/journal.pone.0119152
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1. PLoS One. 2015 Mar 5;10(3):e0119152. doi: 10.1371/journal.pone.0119152.
eCollection 2015.
Dopaminergic control of the globus pallidus through activation of D2 receptors
and its impact on the electrical activity of subthalamic nucleus and substantia
nigra reticulata neurons.
Mamad O(1), Delaville C(2), Benjelloun W(3), Benazzouz A(2).
Author information:
(1)Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293,
F-33000, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR
5293, F-33000, Bordeaux, France; Université Mohamed V-Agdal, Faculté des
Sciences, Equipe Rythmes Biologiques, Neurosciences et Environnement, 10000,
Rabat, Morocco.
(2)Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293,
F-33000, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR
5293, F-33000, Bordeaux, France.
(3)Université Mohamed V-Agdal, Faculté des Sciences, Equipe Rythmes Biologiques,
Neurosciences et Environnement, 10000, Rabat, Morocco.
The globus pallidus (GP) receives dopaminergic afferents from the pars compacta
of substantia nigra and several studies suggested that dopamine exerts its
action in the GP through presynaptic D2 receptors (D2Rs). However, the impact of
dopamine in GP on the pallido-subthalamic and pallido-nigral neurotransmission
is not known. Here, we investigated the role of dopamine, through activation of
D2Rs, in the modulation of GP neuronal activity and its impact on the electrical
activity of subthalamic nucleus (STN) and substantia nigra reticulata (SNr)
neurons. Extracellular recordings combined with local intracerebral
microinjection of drugs were done in male Sprague-Dawley rats under urethane
anesthesia. We showed that dopamine, when injected locally, increased the firing
rate of the majority of neurons in the GP. This increase of the firing rate was
mimicked by quinpirole, a D2R agonist, and prevented by sulpiride, a D2R
antagonist. In parallel, the injection of dopamine, as well as quinpirole, in
the GP reduced the firing rate of majority of STN and SNr neurons. However,
neither dopamine nor quinpirole changed the tonic discharge pattern of GP, STN
and SNr neurons. Our results are the first to demonstrate that dopamine through
activation of D2Rs located in the GP plays an important role in the modulation
of GP-STN and GP-SNr neurotransmission and consequently controls STN and SNr
neuronal firing. Moreover, we provide evidence that dopamine modulate the firing
rate but not the pattern of GP neurons, which in turn control the firing rate,
but not the pattern of STN and SNr neurons.
DOI: 10.1371/journal.pone.0119152
PMCID: PMC4350999
PMID: 25742005 [Indexed for MEDLINE]
Conflict of interest statement: Competing Interests: The authors have declared
that no competing interests exist.