The altered expression of GABA shunt enzymes in the gerbil hippocampus before and after seizure generation.
In the present study, the distribution of succinic semialdehyde dehydrogenase (SSADH) and succinic semialdehyde reductase (SSAR) in the hippocampus of the Mongolian gerbil and its association with various sequelae of spontaneous seizure were investigated in order to identify the roles of GABA shunt in the epileptogenesis and the recovery mechanisms in these animals. Both SSADH and SSAR immunoreactivities in the GABAergic neurons were significantly higher in the pre-seizure groups of seizure sensitive (SS) gerbil as compared to those seen in the seizure resistant (SR) gerbils. The distributions of both SSADH and SSAR immunoreactivities in the hippocampus showed significant differences after the on-set of seizure. At 3 h postictal, when compared to the pre-seizure group of SS gerbils, a decline in the immunoreactivities in the perikarya was observed. At 12 h after seizure on-set, the densities of both SSADH and SSAR immunoreactivities were begun to recover to the pre-seizure level of SS gerbils. These results suggest that the GABAergic neurons in the hippocampal complex of the SS gerbil may be highly activated. In addition, the imbalance of GABA shunt expressions in the GABAergic neurons may imply a malfunction of the metabolism of GABAergic neurons in the SS gerbils, and this defect may trigger seizure on-set. Therefore, the initiation of seizure, at least in gerbils, may be the result of a malfunction in GABA shunt in the GABAergic neurons.
Kang
Tae-Cheon
TC
Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, Kangwon-Do, South Korea. tckang@hally.ac.kr
Park
Seung-Kook
SK
Hwang
In Koo
IK
An
Sung-Jin
SJ
Choi
Soo Young
SY
Kwon
Oh-Shin
OS
Baek
Nam-In
NI
Lee
Hyeon Yong
HY
Won
Moo Ho
MH
D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D000818:Animals; D005849:Gerbillinae; D006624:Hippocampus / Q000201:enzymology*; D006884:Hydroxybutyrate Dehydrogenase / Q000378:metabolism*; D007150:Immunohistochemistry; D012640:Seizures / Q000201:enzymology*; D050644:Succinate-Semialdehyde Dehydrogenase; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid; D006884:Hydroxybutyrate Dehydrogenase; C019416:4-hydroxybutyrate dehydrogenase; D000445:Aldehyde Oxidoreductases; D050644:Succinate-Semialdehyde Dehydrogenase