| Abstract No.: | C-B3028 |
| Country: | Canada |
| | |
| Title: | CHANGES IN GLIAL MARKERS WITHIN THE CINGULATE CORTEX OF POSTPARTUM RATS. |
| | |
| Authors/Affiliations: | 1 Natalina Salmaso*; 1 Barbara Woodside;
1 Concordia University, Montreal, QC, Canada
|
| | |
| Content: | Objectives: Recent work from our laboratory has demonstrated a much greater number of astrocytes labeled with glial fibrillary acidic protein (GFAP) in cingulate cortex area 2 (Cg2) of post-partum animals than in cycling females. To investigate further the nature of these changes, in the current study we compared immunoreactivity for two other glial markers: vimentin and glutamine synthetase between cycling and postpartum rats. Vimentin, like GFAP, is a marker of intermediate filaments and glutamine synthetase is commonly used as a marker for mature astrocytes.
Materials and Methods: 20 female Wistar rats were assigned to either a cycling group perfused on metestrus or one of four lactating groups: perfused at 3 hours, 24 hours, 4 days or 16 days postpartum. All brains were collected, sliced and processed for GS and vimentin immunohistochemistry. The average number of immunoreactive cells per section throughout Cg2 was calculated for each animal and data analyzed using ANOVA for independent groups.
Results: There were no differences in Vimentin-ir across groups. The number of GS-ir cells were lowest in cycling animals and highest in the 24h postpartum rats.
Conclusion: These data suggest that the upregulation of GFAP-ir that we have observed in CG2 of lactating rats does not represent an increase in all intermediate filament proteins in astrocytes in this area. There were changes in GS-ir across groups, although, the pattern of change varied from that observed in GFAP-ir. Whereas typically levels of GFAP-ir do not change across lactation, there was a clear peak in GS-ir 24h postpartum. GS has been used as a specific marker for a glutamatergic enzymatic activity, and thus its expression indicates glutamate metabolic activity within astrocytes. Interestingly, we have also shown that peri-parturition changes in glia are accompanied with a transient upregulation in dendritic spines on neurons in this area. Many studies have shown that increased glutamatergic activity can lead to increases in dendritic spines. Whether there are indeed changes in glutamatergic activity in Cg2 of lactating rats and whether these may play a role in the changes observed in glia and neurons within Cg2 during this period remains to be determined.
|
| | |
| Back |
|
