EXPRESSION OF NERVE GROWTH-FACTOR AND NEUROTROPHIN-3 MESSENGER-RNAS IN HIPPOCAMPAL INTERNEURONS - MORPHOLOGICAL CHARACTERIZATION, LEVELS OFEXPRESSION, AND COLOCALIZATION OF NERVE GROWTH-FACTOR AND NEUROTROPHIN-3
M. Pascual et al., EXPRESSION OF NERVE GROWTH-FACTOR AND NEUROTROPHIN-3 MESSENGER-RNAS IN HIPPOCAMPAL INTERNEURONS - MORPHOLOGICAL CHARACTERIZATION, LEVELS OFEXPRESSION, AND COLOCALIZATION OF NERVE GROWTH-FACTOR AND NEUROTROPHIN-3, Journal of comparative neurology, 395(1), 1998, pp. 73-90
We have investigated the distribution and morphology of hippocampal in
terneurons that express the neurotrophins nerve growth factor (NGF) an
d neurotrophin-3 (NT-3) in the rat. For this study, we combined in sit
u hybridization for the detection of NGF and NT-3 mRNAs and immunocyto
chemistry against the calcium-binding proteins parvalbumin (PARV), cal
retinin (CALR), and calbindin (CALB). Whereas the majority of PARV(+)
interneurons expressed NGF mRNA, only subsets of CALR- and CALB-immuno
reactive interneurons (23% and 24%, respectively) displayed NGF hybrid
ization. Most CALB/NGF(+) cells were located in the stratum oriens/alv
eus of the CA3-CA1 regions, suggesting that they may include the popul
ation of CALB(+), hippocamposeptal, nonpyramidal neurons. Most of the
nonspiny CALR/NGF(+) neurons were located within or in the vicinity of
the pyramidal layer and had faint CALR immunostaining and stellate, t
hin dendrites. Regarding the spiny CALR-immunoreactive cells, we found
that most of these neurons in the hilus were NGF(+), whereas only 59%
of displayed NGF hybridization in the stratum lucidum of the CA3 regi
on. A small subset of PARV- and CALR-immunoreactive cells expressed NT
-3 mRNA (16% and 13%, respectively). NT-3 message was not found in the
large basket cells of the dentate gyrus, whereas the distribution and
morphology of CALR/NT-3(+) cells were similar to those of nonspiny CA
LR/NGF(+) cells. In fact, double in situ hybridization analysis confir
med that most NT-3(+) neurons also expressed NGF mRNA, indicating coex
pression of both neurotrophins in subpopulations of PARV(+) and CALR() neurons. Moreover, the level of NGF mRNA expression was higher in PA
RV(+) neurons than in CALR- and CALB-immunoreactive interneurons, wher
eas NT-3 message was expressed similarly in PARV(+) and CALR(+) neuron
s. The present findings show a differential expression of NGF and NT-3
mRNAs in subsets of hippocampal interneurons and suggest that the exp
ression of these transcripts depends on factors intrinsic to particula
r cell types. (C) 1998 Wiley-Liss, Inc.