Effects of monosodium glutamate treatment on calretinin-immunoreactive neurons in hippocampus of postnatal rats.
BACKGROUND
Calretinin (CR) is a protein, which is present in GABAergic neurons and belongs to the calcium-binding proteins family. It may reduce the excitotoxicity phenomenon through its Ca2+ buffering properties. This phenomenon is due to the increase of calcium ions levels caused by the excess of glutamate—the main excitatory neurotransmitter. The aim of the study was to investigate alterations of calretinin-immunoreactivity in neurons of hippocampal CA1 region and dentate gyrus with hilus in 10 day-old rats treated with monosodium glutamate (MSG).


METHODS
Ten 7 day-old Wistar rats were used. The MSG-group consisted of 5 MSG-treated rats at a dose of 4 g/kg b.w. for 3 consecutive days and the second group consisted of 5 control animals. After euthanasia the brains containing hippocampus were dissected and embedded in paraffin blocks. The immunohistochemical peroxidase-antiperoxydase reaction was performed on tissue sections. The morphometric analyses of CR-immunopositive neurons: density, percentage ratio to the density of all cells and an assessment of digital immunostaining intensity were performed.


RESULTS
The distribution of the CR-immunoreactive neurons in the hippocampus was irregular. In the MSG-group there were single cells, which were more intensely stained than in control animals. Some of cells contained processes of different length. The density of CR-immunopositive cells and their percentage ratio to the density of all cells did not change significantly after MSG treatment. However, there was a statistically significant increase in the staining intensity of CR-immunopositive cells.


CONCLUSIONS
The obtained results indicate that CR-positive cells in P7-P10 rats are only slightly affected by MSG in CA1 region and dentate gyrus with hilus of the hippocampus.
Department of Animal Anatomy and Histology, University of Life Sciences, Lublin, Poland. karol.rycerz@up.lublin.pl.
Karol
K
Rycerz
Aleksandra
A
Krawczyk
Jadwiga
J
Jaworska-Adamu
Izabela
I
Krawczyk-Marc
D000818:Animals; D002452:Cell Count; D002478:Cells, Cultured; D006624:Hippocampus / Q000187:drug effects* / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D012970:Sodium Glutamate / Q000494:pharmacology*
D012970:Sodium Glutamate