Jun, Fos and Krox in the thalamus after C-fiber stimulation: coincident-input-dependent expression, expression across somatotopic boundaries, and nucleolar translocation.

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Title Jun, Fos and Krox in the thalamus after C-fiber stimulation: coincident-input-dependent expression, expression across somatotopic boundaries, and nucleolar translocation.
Author Pearse, Damien; Bushell, Gillian Robin; Leah, John David
Journal Name Neuroscience
Year Published 2001
Place of publication UK
Publisher Pergamon
Abstract Expression of the inducible transcription factors Jun, Fos and Krox is commonly used to map neurons in the brain that are activated by sensory inputs. However, some neurons known to be electrically excited by such inputs do not always express these factors. In particular, stimulation of hindlimb sensory nerve C-fibers induces expression of c-Fos in the medial thalamus (the mediodorsal, intermediodorsal, centrolateral and centromedial), but not in the lateral thalamus (the ventroposterolateral, ventroposteromedial and posterior group). We hypothesized that c-Fos expression might only occur in these lateral areas after more complex stimulation patterns, or that only other transcription factors can be induced in these areas by such stimuli. Thus we examined the effects of single, repeated and coincident C-fiber inputs on expression of six inducible transcription factors in the medial, lateral and reticular thalamus of the rat. A weak C-fiber input caused by noxious mechanical stimulation of the skin of one hindpaw did not induce expression of c-Fos, FosB, Krox-20 or Krox-24; but it did reduce the basal expressions of c-Jun and JunD in both the medial and lateral areas. An intense input produced by electrical stimulation of all the C-fibers in one sciatic nerve also failed to induce expression of c-Fos, FosB, Krox-20 or Krox-24 in the medial or lateral areas. However, in the medial thalamus it increased c-Jun and reduced the basal expression of JunD, whereas in the lateral thalamus it had no effect on c-Jun but again reduced the basal expression of JunD. With repeated stimulation, i.e. when the noxious stimulus was applied to the contralateral hindpaw 6 h after the sciatic stimulation, there was again no induction of c-Fos, FosB or Krox-20 in the medial thalamus; but there was an increase in c-Jun and Krox-24, and a decrease in JunD levels. In the lateral thalamus the repeated stimulation again failed to induce c-Fos, but the expressions of FosB, c-Jun and Krox-24 were increased, and that of JunD was again reduced. With coincident stimulation, i.e. when a stimulus was applied to each hindpaw simultaneously, c-Fos and Krox-24 remained absent; but there was a marked induction of FosB and Krox-20, a strong repression of c-Jun, and no effect or a reduction of the basal levels of JunD. This coincident stimulation also caused FosB to appear in the nucleolus of many thalamic neurons. MK-801, but not L-NAME, blocked all these changes. In summary, noxious stimulation affects the expression of all transcription factors in the medial, lateral and reticular thalamus in a complex manner depending upon the inducible transcription factor considered, the thalamic nucleus, and the stimulation paradigm. The expression of some transcription factors uniquely after simultaneous inputs suggests they act as coincidence detectors at the gene level.
Peer Reviewed Yes
Published Yes
Publisher URI http://www.elsevier.com/wps/find/journaldescription.cws_home/468/description#description
Copyright Statement Copyright 2001 Elsevier : Reproduced in accordance with the copyright policy of the publisher : This journal is available online - use hypertext links.
Volume 107
Issue Number 1
Page from 143
Page to 159
ISSN 0306-4522
Date Accessioned 2002-04-05
Date Available 2007-03-14T02:26:20Z
Language en_AU
Research Centre Griffith Medical Research College
Subject Central Nervous System
URI http://hdl.handle.net/10072/4020
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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