Subthalamic nucleus lesions alter basal and dopamine agonist stimulated electrophysiological output from the rat basal ganglia
Abstract
The subthalamic nucleus (STN) is an important link in the "indirect" striatal efferent pathway. To assess its role on basal ganglia output via the substantia nigra pars reticulata (SNr), we monitored the single unit activities of SNr neurons in chloral hydrate-anesthetized rats 5-8 days after bilateral kainic acid lesions (0.75 microg/0.3 microl/side) of the STN. Consistent with loss of an excitatory input, the average basal firing rate of SNr neurons was significantly reduced in STN-lesioned animals. Moreover, the lesions modified the responses of SNr neurons to individual and concurrent stimulation of striatal D1 and D2 receptors. Bilateral striatal infusions of the D1/D2 agonist apomorphine (10 microg/microl/side) into the ventral-lateral striatum (VLS) were previously shown to cause significant increases in SNr cell firing (to 133% of baseline) in normal rats. However, in STN-lesioned rats, identical infusions caused no overall change in SNr activity (mean, 103% of basal rates). Conversely, selective stimulation of striatal D2 receptors by bilateral co-infusion of the D2 agonist quinpirole and the D1 antagonist SCH 23390 that previously caused little change in SNr firing in normal rats significantly inhibited their firing i...Continue Reading
References
Bilateral lesions of the subthalamic nucleus induce multiple deficits in an attentional task in rats
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Basal Ganglia
Basal Ganglia are a group of subcortical nuclei in the brain associated with control of voluntary motor movements, procedural and habit learning, emotion, and cognition. Here is the latest research.