Y. Liu et al., DISTRIBUTION OF CALRETININ IMMUNOREACTIVITY IN THE MOUSE DENTATE GYRUS .1. GENERAL DESCRIPTION, Experimental Brain Research, 108(3), 1996, pp. 389-403
Calretinin-containing elements were visualized with immunocytochemistr
y in the adult mouse dentate gyrus (DG). In the ventral DG calretinin
immunoreactive (CR-LR) large multipolar cells were clustered; they ext
ended between two and four thick cylindrical dendrites which further b
ranched into several thinner processes. Characteristic grape-like spin
y appendages were occasionally observed on these thick and thinner den
dritic processes. On the basis of these structural features these larg
e CR-IR cells were identified as hilar messy cells. At the supragranul
ar zone a dense CR-IR band was seen, where numerous CR-IR punctae and
fibers were packed tightly among putative granule cell dendrites. In t
he granule cell layer, especially at the dorsal DG, numerous faintly C
R-IR cells were located at the interface with the hilus. They were tri
angular in shape and neither calbindin D28k nor GABA positive, but wer
e immunoreactive for highly polysialylated neural cell adhesion molecu
le (NCAM-H) and thus considered as newly generated neurons. In the mol
ecular layer CR-LR cells were also scattered; they were mainly located
near the pial surface and the hippocampal fissure, small in size, ovo
id in shape and usually gave rise to one very thin axon-like and one t
hin cylindrical dendritic process. These cells were assumed to be Caja
l-Retzius cells. Throughout the layers, that is, the molecular layer,
the granule cell layer and the hilus, CR-IR multipolar and/or fusiform
cells were encountered. They resembled those reported in the rat DG i
n their structural features and usually extended smooth or varicose or
sparsely spiny dendritic processes; some of them were confirmed to be
GABA-like immunoreactive and/or glutamic acid decarboxylase immunorea
ctive. The present study showed that CR immunoreactivity in the mouse
DG differed significantly from that in the rat and monkey dentate gyri
reported previously.