Journal of Neuroscience, Vol 13, 4130-4145, Copyright © 1993 by Society for Neuroscience
Long-lasting expression of JUN and KROX transcription factors and nitric oxide synthase in intrinsic neurons of the rat brain following axotomy
T Herdegen, S Brecht, B Mayer, J Leah, W Kummer, R Bravo and M Zimmermann
II. Physiologisches Institut, Universitat Heidelberg, Germany.
In adult rats, the medial forebrain bundle (MFB) and mammillothalamic tract
(MT) were unilaterally transected, resulting in axotomy of neurons in
numerous areas such as the substantia nigra (SN), ventral tegmental area
(VTA), nucleus (ncl.) mammillaris (MnM), and ncl. parafascicularis of the
thalamus (PF). In these areas, expression of the transcription factor
proteins c-JUN, JUN B, JUN D, c-FOS, FOS B, KROX-20, KROX-24, and CREB was
investigated by immunocytochemistry up to 150 d. In parallel, the
expression of nitric oxide synthase (NOS) was investigated both
immunocytochemically and by the NADPH-diaphorase reaction (NDP), and the
antibody against NOS was further characterized. The colocalization of c-JUN
with NDP or NOS was also studied in the axotomized neurons. c-JUN and JUN D
became visible in nuclei of many neurons of the ipsilateral MnM, PF, VTA,
and SN (predominantly in the pars compacta and those double labeled by
tyrosine hydroxylase, TH) after 36 hr, not after 24 hr, following
transection of MFB and MT. In MnM, c-JUN and JUN D persisted at a nearly
maximal level for up to 150 d. In PF, these proteins returned to control
levels after 75 d. Expression of c-JUN and JUN D declined in the VTA after
30 d, but in the SN, it already declined after only 10 d. KROX-24 had a
later onset of expression, being visible after 3 d in all investigated
areas, and its pattern was similar to that of JUN proteins, although
labeling was visible in fewer nuclei and declined earlier. JUN B, c-FOS,
FOS B, and KROX-20 were not expressed in these areas, and substantial
alterations of CREB immunoreactivity (CREB-IR) could not be detected. A
subset of SN neurons (predominantly in the pars reticularis and negative
for TH) presented an early and transient expression of all studied JUN,
FOS, and KROX-24 proteins within 3 hr of transection that declined between
24 hr and 48 hr to basal levels. This expression pattern is typical of that
caused by transynaptic stimulation (probably due to excitation of
descending striatal neurons running within the MFB) and was clearly
distinct from that evoked by c-JUN, JUN D, and KROX-24 IRs after 36 hr
(predominantly in the pars compacta). An ipsilateral increase in NOS and
NDP became visible in many neurons of the MnM after 10 d, but not after 5
d, and this persisted up to 150 d. The temporospatial pattern of NDP was
similar to the pattern of NOS-IR.(ABSTRACT TRUNCATED AT 400 WORDS)
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