ACUTE CHANGES IN GENE EXPRESSION OF GABA RECEPTOR SUBUNITS IN DENTATE GYRUS AFTER PROLONGED SEIZURES ARE AGE-DEPENDENT
Abstract number :
3.003
Submission category :
Year :
2004
Submission ID :
4946
Source :
www.aesnet.org
Presentation date :
12/2/2004 12:00:00 AM
Published date :
Dec 1, 2004, 06:00 AM
Authors :
1Guojun Zhang, 1YogendraSinh H. Raol, and 1,2Amy R. Brooks-Kayal
GABAA receptors are the most abundant inhibitory neurotransmitter receptors in forebrain, and many studies indicated that alterations in these receptor may play a important role in epileptogenesis. Previous studies from our laboratory suggest that long-term alterations in GABA receptor function and gene expression in hippocampal dentate granule neurons (DGNs) during epileptogenesis differ between immature and mature rats. For example, a decrease in a1-mRNA levels were found in the rats that had experienced SE in adulthood, whereas, adult rats that had experienced SE at 20 days postnatal age (P20) had higher a1 levels in single DGNs. In the present study we determined the acute effect of SE at P20 and adult on GABAR expression in the whole dentate gyrus. P20 and adult rats were subjected to pilocarpine induced status epilepticus (SE). The antisense RNA amplification (aRNA) technique was used to examine the expression of 16 GABAAR and two GABABR subunits mRNA in acutely dissected dentate gyrus 24 hours and 7 days after SE. 24 hours after SE, total GABAAR subunit mRNA expression was decreased in both P20 and adult rats; Both [alpha]1 and [alpha]2 subunit mRNA expression were decreased significantly in adult rats; whereas, there were no changes after SE in P20 rats. 7 days after SE, total GABAAR subunits mRNA expression was decreased 1.5 fold in adult rats and increased 3 fold in P20 rats; [alpha]1 subunit mRNA expression was decreased 2 fold in adult rats and increased 3 fold in P20 rats; [alpha]2 subunit mRNA expression was decreased 1.5 fold in adult rats and increased 2.5 fold in P20 rats; and [alpha]5 subunit mRNA expression was decreased 1.5 fold in adult rats and increased 3 fold in P20 rats. GABAB receptor subunits R1 mRNA expression was decreased 2 fold in adult rats and increased 2.5 fold in P20 rats at 7 days after SE. Prolonged seizures at P20 and in adulthood lead to differential alterations in GABAAR and GABABR subunits mRNA expression. These findings suggest that GABA receptor subunit mRNA changes after SE are dependent on the age at which SE occurs. (Supported by NIH NS38595 to ABK)