Altered expression of K+ -Cl- cotransporters affects fast paired-pulse inhibition during GABA receptor activation in the gerbil hippocampus.
K+ -Cl- cotransporter (KCC) plays an important role in maintaining neuronal activity. However, the effect of seizure activity or pharmacological manipulation of GABAergic transmission on KCC expression remains to be clarified. Therefore, the present study was performed to investigate whether seizure activity or GABA receptor agonist treatment changes KCC expression in the gerbil hippocampus. Furthermore, the effect of blockade of KCC on inhibitory transmission in the dentate gyrus was identified following applications of GABA receptor agonists. The distribution of KCC immunoreactivity in the hippocampus was similarly detected between seizure-resistant (SR) and seizure-sensitive (SS) gerbils. Baclofen (a GABAB receptor agonist) treatment markedly increased KCC expression in the gerbil hippocampus. Baclofen treatment significantly reduced paired-pulse inhibition in the dentate gyrus. Furosemide (a KCC inhibitor) treatment amplified the effect of baclofen on paired-pulse responses. In contrast, muscimol (a GABAA receptor agonist) treatment reduced KCC expression. Enhanced paired-pulse inhibition by muscimol treatment was not affected by furosemide treatment. These findings suggest that seizure activity in the gerbil may not affect KCC expression in the hippocampus. In addition, altered KCC immunoreactivity induced by baclofen or muscimol may play an important role in maintaining or regulating inhibitory transmission during GABA receptor activation.
Kang
Tae-Cheon
TC
Department of Anatomy, College of Medicine, Hallym University, Chunchon, Kangwon-Do, 200-702, South Korea. tckang@hallym.ac.kr
Kim
Duk-Soo
DS
Kim
Ji-Eun
JE
Kwak
Sung-Eun
SE
Yoo
Ki-Yeon
KY
Hwang
In-Koo
IK
Jung
Ju-Young
JY
Won
Moo Ho
MH
Kwon
Oh-Shin
OS
Choi
Soo-Young
SY
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D005071:Evoked Potentials; D018755:GABA Agonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005849:Gerbillinae; D006624:Hippocampus / Q000502:physiology*; D007150:Immunohistochemistry; D009118:Muscimol / Q000494:pharmacology; D018079:Receptors, GABA / Q000502:physiology*; D027981:Symporters / Q000235:genetics*; D000096922:K Cl- Cotransporters
D001418:Baclofen; D018755:GABA Agonists; D009118:Muscimol; D018079:Receptors, GABA; D027981:Symporters; D000096922:K Cl- Cotransporters