- 作者: Lei Chen; Ying-Shing Chan; Wing-Ho Yung
- 作者服務機構: Department of Physiology, Chinese University of Hong Kong, and Department of Physiology, Univesity of Hong Kong , Hong Kong, China
- 中文摘要: --
- 英文摘要: To determine the involvement of the globus pallidus inmediating epilepsy, the effects of microinjection of aGABA uptake blocker (tiagabine), a benzodiazepine ago-nist (zolpidem) and a GABA-B receptor agonist(baclo-fen) on pentylenetetrazol (PTZ)-induced tonic seizurewere examined in adult rats. Administration of PTZinduced tonic seizures in all control animals, accompa-nied with a 100% mortality rate. Pretreatment with bilat-eral intrapallidal microinjection of tiagabine(1mM)sup-pressed the incidence of tonic seizures to 67.7% andreduced the mortality rate to 16.7%. Furthermore, thelatency to tonic seizures was 1,275±277 s, which wassignificantly longer than that of the corresponding con-trol animals (319±225 s). On the other hand, adminis-tration of zolpidem (1 mM) was without significanteffects on the mortality rate, the incidence and latency ofthe tonic seizure. In sharp contrast, microinjection ofbaclofen (1mM) completely suppressed PTZ-inducedtonic seizures and reduced the mortality rate to 0%. Thiseffect was largely abolished by co-injection of the GABA-B receptor antagonist CGP55845. To elucidate the directcellular action of baclofen, the excitability and mem-brane potential of globus pallidus neurons were studiedby cell-attached and whole-cell patch-clamp recordingsin the brain slice. Bath application of baclofen (50 μM)significantly reduced the firing of these neurons, andwas often accompanied by a clear membrane hyperpo-larization, in a CGP55845-sensitive manner. These datasuggest that activation of GABA-B receptors in globuspallidus could significantly modulate PTZ-induced tonicseizures.
- 中文關鍵字: --
- 英文關鍵字: --