Status epilepticus （SE） is a life-threatening neurological emergency associated with a high mortality rate. The serotonin 1A （5-HTIA） receptor is a possible target for the treatment of SE, but its role in animal models and the precise area of brain involved remain controversial. The hippocampus is a candidate site due to its key role in the development of SE and the existence of a high density of 5-HT1A receptors. Therefore, we investigated the effects of subcutaneous and intrahippocampal activation of 5-HT1A receptors in lithium-pilocarpine-induced SE, and tested whether the hippocampus is a true effector site. We developed SE in male Sprague-Dawley rats by giving lithium chloride （LiCI; 3 meq/kg, i.p.） 22-24 h prior to pilocarpine （25 mg/kg, i.p.）, and found that 8-OH-DPAT, a 5-HT1A receptor agonist administered subcutaneously （s.c.） at 0.5 or 1.0 mg/kg 1 h before pilocarpine injection increased the latency to the first epileptiform spikes, the electrographic SE, and the behavioral generalized seizures （GS）, while reducing the total EEG seizure time （P 〈0.01）. The duration of GS was shortened only by 1.0 mg/kg 8-OH-DPAT s.c. （P 〈0.05）. All these effects were inhibited by combined administration of WAY-100635 （1.0 mg/kg, s.c.） （P 〈0.05）, an antagonist of the 5-HT1A receptor, but WAY-100635 alone and low doses of 8-OH- DPAT （0.01 and 0.1 mg/kg） did not alter seizure activity. Furthermore, intrahippocampal 8-OH-DPAT only shortened the GS duration （P 〈0.05）. These findings imply that the 5-HT1A receptor is a promising therapeutic target against the generation and propagation of SE, and hippocampal receptors are involved in reducing the seizure severity.
Yi YangYi GuoYifang KuangShan WangYan JiangYao DingShuang WangMeiping Ding
