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Induction of c‐fos in specific thalamic nuclei following stimulation of the pedunculopontine tegmental nucleus
Author(s) -
Ainge James A.,
Jenkins Trisha A.,
Winn Philip
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2004.03647.x
Subject(s) - pedunculopontine tegmental nucleus , neuroscience , thalamus , pedunculopontine nucleus , nucleus accumbens , cholinergic , ventral tegmental area , deep brain stimulation , acetylcholine , chemistry , dopamine , psychology , biology , medicine , parkinson's disease , endocrinology , dopaminergic , disease
The pedunculopontine tegmental nucleus (PPTg) is a major source of cholinergic input to the thalamus. Tracing studies have established that the PPTg has projections to many thalamic nuclei and electrophysiological studies have shown acetylcholine (ACh) to have characteristic effects on thalamic neurons. Behavioural studies point to a role for the PPTg in attention and it is possible that a key substrate for this is the ability of the PPTg to modify sensorimotor gating through the thalamus. However, it is not clear how altered PPTg activity effects neuronal activity across the thalamus en masse . We have attempted to examine this by stimulating the PPTg in freely moving rats and measuring thalamic activation with c‐fos immunohistochemistry. The PPTg was stimulated by unilateral microinjection of the l ‐glutamate uptake inhibitor l ‐ trans ‐pyrrolidine‐2,4‐dicarboxylic acid (PDC) with the rationale that reuptake blockade increases locally the availability of endogenous neurotransmitter. It was shown that PDC microinjection into PPTg produced clear and consistent changes in Fos immunoreactivity in several thalamic nuclei, but most markedly in the centrolateral, ventrolateral and reticular nuclei. A second study was carried out to determine the gross behavioural effects of intra‐PPTg l ‐glutamate blockade. No changes in locomotion or other general behaviours were observed, indicating that observed changes in thalamic Fos expression were not the result of increased behavioural output but rather a direct consequence of increased neuronal activity from PPTg input. The present data extend previous work establishing pedunculopontine–thalamic connections by specifying which particular nuclei are most affected by PPTg activation.