Unilateral lesion of the nigrostriatal pathway induces an increase of neuronal activity of the pedunculopontine nucleus, which is reversed by the lesion of the subthalamic nucleus in the rat
European Journal of Neuroscience. 2001-12-01; 14(11): 1833-1842
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1. Eur J Neurosci. 2001 Dec;14(11):1833-42. doi:
Unilateral lesion of the nigrostriatal pathway induces an increase of neuronal
activity of the pedunculopontine nucleus, which is reversed by the lesion of the
subthalamic nucleus in the rat.
Breit S(1), Bouali-Benazzouz R, Benabid AL, Benazzouz A.
(1)INSERM U318, Laboratoire de Neuroscience Preclinique, CHU-Pavillon B, BP 217,
38043 Grenoble cedex 09, France.
The role of the pedunculopontine nucleus (PPN) in the pathophysiology of
Parkinson’s disease is still unclear. Using microrecordings, we investigated the
changes occurring in PPN neurons after lesions of the substantia nigra compacta
(SNc) and the role of the subthalamic nucleus (STN) in these changes. In normal
rats the firing rate of PPN neurons was 10.6 +/- 1.4 spikes/s, the majority of
neurons (91%) having a regular firing pattern, 6% irregular and 3% in bursts. In
rats with 6-hydroxydopamine lesions of the SNc, the firing rate increased
significantly to 18.3 +/- 3.0 spikes/s compared with normal rats. In addition,
the firing pattern changed significantly: 70% of the neurons discharged
regularly, 27% irregularly and 3% in bursts. In rats with ibotenic acid lesions
of the STN, the firing rate decreased significantly to 7.2 +/- 0.9 spikes/s and
the firing pattern changed significantly: 50% of the neurons discharged
regularly, 43% irregularly and 7% in bursts. The rats with combined SNc and STN
lesions showed no change in the firing rate (8.5 +/- 1.0 spikes/s) compared to
normal rats. The firing pattern changed significantly: 69% of the cells
discharged regularly, 26% irregularly and 5% in bursts. These findings
demonstrate that PPN neurons are overactive and more irregular in the
6-hydroxydopamine-lesioned rats, suggesting the implication of this nucleus in
the pathophysiology of parkinsonism. Moreover, the fact that STN lesions induced
a reduction in the firing rate of the PPN in normal rats and a normalization of
the firing rate in rats with 6-hydroxydopamine lesions suggests that this
nucleus is under major control of the STN.
PMID: 11860479 [Indexed for MEDLINE]