Opposite changes in GABAA receptor function in the CA1-3 area and fascia dentata of kindled rat hippocampus.
Muscimol-stimulated radiotracer 36CI- uptake in synaptoneurosomes was used to investigate the function of the GABAA receptor complex in the CA1-3 area and fascia dentata (granular and molecular layers and hilus) of rats kindled by stimulation, twice a day, of the Schaffer collateral fibers. Two kindled groups were studied: (a) 24 h after the last generalized tonic-clonic seizure [fully kindled (FK) stage] and (b) 28 days after the last generalized seizure (long-term stage). Synaptoneurosomes were prepared in parallel from subslices of the CA1-3 area and fascia dentata. In FK animals, the muscimol-stimulated 36CI- uptake was significantly reduced by 21% in the CA1-3 area in comparison with nonstimulated controls, whereas a significant increase of 29% was found in the fascia dentata. Significant changes were no longer present at 4 weeks after the last generalized seizure. The observed changes in muscimol-stimulated 36CI- uptake at the FK stage closely parallel the recently observed changes in [3H]muscimol binding in the CA1 area and fascia dentata. These results indicate that kindling causes a transiently decreased GABAA receptor-mediated function in the CA1-3, in contrast to an increased GABAA receptor-mediated function in the fascia dentata.
Titulaer
M N
MN
Graduate School for the Neurosciences, Faculty of Biology, University of Amsterdam, The Netherlands.
Ghijsen
W E
WE
Kamphuis
W
W
De Rijk
T C
TC
Lopes da Silva
F H
FH
D000818:Animals; D002712:Chlorides / Q000493:pharmacokinetics; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D007696:Kindling, Neurologic; D008297:Male; D008854:Microscopy, Electron; D009118:Muscimol / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D017208:Rats, Wistar; D018079:Receptors, GABA / Q000378:metabolism*; D012640:Seizures / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution
D002712:Chlorides; D018079:Receptors, GABA; D009118:Muscimol