Paradoxical GABAergic facilitation on seizure development observed from bicuculline-induced effects on visual cortical kindling at short interstimulus intervals in chronically prepared rabbits.
To investigate the influence of GABAergic function on seizure development, the effects of bicuculline, a GABAa receptor antagonist, on visual cortical and hippocampal kindling were examined in chronically prepared rabbits. Kindling-inducing stimulations were repeated at 5-min intervals. The changes in afterdischarge (AD) durations were compared before and 30 min after a low (2 mg/kg) and high dose (5 mg/kg) i.p. injection of bicuculline solution. In the visual cortical kindling group, the AD durations were markedly shortened after the low dose bicuculline injection, while bicuculline produced a prolongation of the AD durations in the visual cortical with the high dose injection and hippocampal kindling groups. The low dose bicuculline-induced inhibition of visual cortical kindling suggests facilitative GABAergic action on seizure development, while the drug-induced enhancement in the other groups reflects the well-known inhibitory GABAergic action.
Kurokawa
K
K
Department of Neuropsychiatry, Kanazawa University School of Medicine, Japan.
Jibiki
I
I
Kubota
T
T
Fukushima
T
T
Fujimoto
K
K
Wakita
S
S
Yamaguchi
N
N
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004569:Electroencephalography / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects; D058787:GABA-A Receptor Antagonists; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D007696:Kindling, Neurologic / Q000187:drug effects* / Q000502:physiology; D008297:Male; D011817:Rabbits; D011963:Receptors, GABA-A / Q000502:physiology; D014793:Visual Cortex / Q000187:drug effects* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline