Dendritic but not somatic GABAergic inhibition is decreased in experimental epilepsy.
Impaired inhibition is thought to be important in temporal lobe epilepsy (TLE), the most common form of epilepsy in adult patients. We report that, in experimental TLE, spontaneous GABAergic inhibition was increased in the soma but reduced in the dendrites of pyramidal neurons. The former resulted from the hyperactivity of somatic projecting interneurons, whereas the latter was probably due to the degeneration of a subpopulation of dendritic projecting interneurons. A deficit in dendritic inhibition could reduce seizure threshold, whereas enhanced somatic inhibition would prevent the continuous occurrence of epileptiform activity.
Cossart
R
R
INMED, INSERM Unité 29, Avenue de Luminy, B.P. 13, 13 273 Marseille Cedex 09, France.
Dinocourt
C
C
Hirsch
J C
JC
Merchan-Perez
A
A
De Felipe
J
J
Ben-Ari
Y
Y
Esclapez
M
M
Bernard
C
C
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D064026:Calbindins; D003712:Dendrites / Q000378:metabolism* / Q000648:ultrastructure; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000378:metabolism*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007395:Interneurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007608:Kainic Acid; D018721:Muscarinic Agonists / Q000494:pharmacology; D009433:Neural Inhibition; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D064026:Calbindins; D018691:Excitatory Amino Acid Antagonists; D007527:Isoenzymes; D018721:Muscarinic Agonists; D012333:RNA, Messenger; D064030:S100 Calcium Binding Protein G; D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D007608:Kainic Acid