Generalization of seizures parallels the formation of "dark" neurons in the hippocampus and pontine reticular formation after focal-cortical application of 4-aminopyridine (4-AP) in the rat.
Distribution and time course of the occurrence of "dark" neurons were compared with the EEG activity and behavior of rats during 4-aminopyridine (4-AP) induced epileptic seizures. A crystal of the K(+) channel blocker 4-AP (0.5 mg/kg) was placed onto the exposed parieto-occipital cortex of Halothane-anesthetized rats for 40 min. Thereafter, the anesthesia was discontinued and the behavioral signs of the epileptic seizure activity were observed. The presence of "dark" neurons was demonstrated by the sensitive silver method of Gallyas in rats sacrificed at 0, 3 and 6 h after the end of the 4-AP crystal application. The EEG activity was recorded in the rats with longer survival times. The EEG analysis revealed the generalization of the epileptic seizures. We found that the formation of "dark" neurons in the hippocampus and the pontine reticular formation paralleled the generalization of the seizures.
Baracskay
Péter
P
Institute of Biology, Faculty of Natural Sciences, Eötvös Loránd University, H-1117 Budapest, Hungary.
Szepesi
Zsuzsanna
Z
Orbán
Gergely
G
Juhász
Gábor
G
Czurkó
András
A
D015761:4-Aminopyridine / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004569:Electroencephalography; D006624:Hippocampus / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008845:Microinjections; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000473:pathology; D011149:Pons / Q000166:cytology / Q000187:drug effects* / Q000473:pathology*; D026902:Potassium Channel Blockers / Q000008:administration & dosage / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012154:Reticular Formation / Q000187:drug effects* / Q000473:pathology; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology*
D026902:Potassium Channel Blockers; D015761:4-Aminopyridine