Status epilepticus affects the gigantocellular network of the pontine reticular formation.
BACKGROUND
The impairment of the pontine reticular formation (PRF) has recently been revealed to be histopathologically connected with focal-cortical seizure induced generalized convulsive status epilepticus. To elucidate whether the impairment of the PRF is a general phenomenon during status epilepticus, the focal-cortical 4-aminopyridine (4-AP) application was compared with other epilepsy models. The presence of "dark" neurons in the PRF was investigated by the sensitive silver method of Gallyas in rats sacrificed at 3 h after focal 4-AP crystal or systemic 4-AP, pilocarpine, or kainic acid application. The behavioral signs of the developing epileptic seizures were scored in all rats. The EEG activity was recorded in eight rats.


RESULTS
Regardless of the initiating drug or method of administration, "dark" neurons were consistently found in the PRF of animals entered the later phases of status epilepticus. EEG recordings demonstrated the presence of slow oscillations (1.5-2.5 Hz) simultaneously with the appearance of giant "dark" neurons in the PRF.


CONCLUSIONS
We argue that the observed slow oscillation corresponds to the late periodic epileptiform discharge phase of status epilepticus, and that the PRF may be involved in the progression of status epilepticus.
Baracskay
Péter
P
Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary. baracskay@freemail.hu
Kiglics
Viola
V
Kékesi
Katalin A
KA
Juhász
Gábor
G
Czurkó
András
A
D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D048430:Cell Shape; D004567:Electrodes, Implanted; D004569:Electroencephalography; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D009415:Nerve Net / Q000187:drug effects / Q000503:physiopathology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010862:Pilocarpine / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012154:Reticular Formation / Q000187:drug effects / Q000503:physiopathology*; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D016622:Silver Staining; D013226:Status Epilepticus / Q000139:chemically induced / Q000503:physiopathology*
D018690:Excitatory Amino Acid Agonists; D018721:Muscarinic Agonists; D026902:Potassium Channel Blockers; D010862:Pilocarpine; D015761:4-Aminopyridine; D007608:Kainic Acid