Effect of Diazoxide in Conunterating on Hyperexcitability by 4-Aminopyridine-induced Epileptiform Discharge Followed by Hypoxia in Young Rats

Choi, Byung Joon

Abstract

PURPOSE
The goal of the present study was to investigate the effects of diazoxide on 4-aminopyridine(4-AP)-induced hyperexcitability followed by normal oxygenation or an anoxia state in young rats. Also, we investigated the effects of carbamazepine(CBZP) on 4-AP-induced hyperexcitability followed by normal oxygenation or an anoxia state in young rats.
METHODS
The visual cortex slices in this study were obtained from 13 to 18-days-old Sprague-Dawley rats. Extracellular recordings were performed to observe the induction of the epileptiform discharges perfused by artificial CSF containing 100 micrometer 4-AP with 7.5 mM K and the effects of 1 mM diazoxide and 50 micrometer CBZP followed by normal oxygenation or an anoxia state.
RESULTS
Spontaneous epileptiform activities were observed in artificial CSF containing 100 micrometer 4-AP. The addition of diazoxide decreased the frequency of 4-AP- induced epileptiform activities followed by anoxia, but didnt block the 4-AP-induced epileptiform activities followed by anoxia. The addition of CBZP blocked the 4-AP-induced epileptiform activities followed by normal oxygenation.
CONCLUSION
We observed that diazoxide did not counteract the epileptiform activities induced by 4-AP. Diazoxide inhibited the increased excitability followed an anoxia state in young rats. CBZP counteracted the epileptiform activities induced by 4-AP. Diazoxide may have limited utilities in the seizure therapy. Nevertheless, this could be of benefit during prolonged seizures where hypoxia becomes a significant factor.