 |
The Journal of Neuroscience, April 5, 2006, 26(14):3875-3884; doi:10.1523/JNEUROSCI.4439-05.2006
Previous Article
Neurobiology of Disease
Cortical Inputs and GABA Interneurons Imbalance Projection Neurons in the Striatum of Parkinsonian Rats
Nicolas Mallet,
Bérangère Ballion,
Catherine Le Moine, and
François Gonon
Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5541, Université Victor Segalen Bordeaux 2, 33076 Bordeaux, France
Correspondence should be addressed to François Gonon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5541, Boîte postale 28, Université Victor Segalen Bordeaux 2, 33076 Bordeaux, France. Email: francois.gonon{at}umr5541.u-bordeaux2.fr
The striatum receives massive cortical excitatory inputs and is densely innervated by dopamine. Striatal projection neurons form either the direct or indirect pathways. Models of Parkinson's disease propose that dopaminergic degeneration imbalances both pathways, although direct electrophysiological evidence is lacking. Here, striatal neurons were identified by electrophysiological criteria and Neurobiotin labeling combined with either immunohistochemistry or in situ hybridization. Their spontaneous discharge activity and spike response to cortical stimulation were recorded in vivo in anesthetized rats rendered hemi-parkinsonian by 6-hydroxydopamine. We showed that striatonigral neurons (direct pathway) were inhibited whereas striatopallidal neurons (indirect pathway) were activated by dopaminergic lesion. We also identified, with antidromic stimulations, corticostriatal neurons that preferentially innervate striatonigral or striatopallidal neurons and showed that dopaminergic depletion selectively decreased the spontaneous activity of the former. Therefore, dopamine degeneration induces a cascade of imbalances that spread out of the basal ganglia and affect the whole basal ganglia-thalamo-cortical circuits.
Fast-spiking GABA interneurons provide potent feedforward inhibition of striatal projection neurons. We showed here that these interneurons narrowed the time window of the responses of projection neurons to cortical stimulation. In the dopamine-depleted striatum, because the intrinsic activity of these interneurons was not altered, their feedforward inhibition worsened the striatal imbalance. Indeed, the time window of the evoked responses was narrower for striatonigral neurons and wider for striatopallidal neurons. Therefore, after dopaminergic depletion, cortical inputs and GABA interneurons might imbalance striatal projection neurons and represent two novel nondopaminergic mechanisms that might secondarily contribute to the pathophysiology of Parkinson's disease.
Key words: basal ganglia; striatum; GABAergic; interneuron; dopamine; Parkinson's disease
Received Oct. 18, 2005;
revised Jan. 31, 2006;
accepted Feb. 24, 2006.
Correspondence should be addressed to François Gonon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5541, Boîte postale 28, Université Victor Segalen Bordeaux 2, 33076 Bordeaux, France. Email: francois.gonon{at}umr5541.u-bordeaux2.fr
This article has been cited by other articles:

|
 |

|
 |
 
S. Taverna, E. Ilijic, and D. J. Surmeier
Recurrent Collateral Connections of Striatal Medium Spiny Neurons Are Disrupted in Models of Parkinson's Disease
J. Neurosci.,
May 21, 2008;
28(21):
5504 - 5512.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
O. Darbin and T. Wichmann
Effects of Striatal GABAA-Receptor Blockade on Striatal and Cortical Activity in Monkeys
J Neurophysiol,
March 1, 2008;
99(3):
1294 - 1305.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. K. Ade, M. J. Janssen, P. I. Ortinski, and S. Vicini
Differential Tonic GABA Conductances in Striatal Medium Spiny Neurons
J. Neurosci.,
January 30, 2008;
28(5):
1185 - 1197.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
O. Ibanez-Sandoval, L. Carrillo-Reid, E. Galarraga, D. Tapia, E. Mendoza, J. C. Gomora, J. Aceves, and J. Bargas
Bursting in Substantia Nigra Pars Reticulata Neurons In Vitro: Possible Relevance for Parkinson Disease
J Neurophysiol,
October 1, 2007;
98(4):
2311 - 2323.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. R. Sadek, P. J. Magill, and J. P. Bolam
A Single-Cell Analysis of Intrinsic Connectivity in the Rat Globus Pallidus
J. Neurosci.,
June 13, 2007;
27(24):
6352 - 6362.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. M. COSTA
Plastic Corticostriatal Circuits for Action Learning: What's Dopamine Got to Do with It?
Ann. N.Y. Acad. Sci.,
May 1, 2007;
1104(1):
172 - 191.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|