Abstracts

To evaluate the changes induced by 5-HT[sub]1A[/sub] agonists, 8-hydroxi-2-(di-n-propylamino) tetralin (8-0H-DPAT) and indorenate, in the electrographic activity during the kainic acid (KA)- induced status epilepticus (SE) in rats. Male Wistar rats (250-300 g) were estereotactically implanted with a bipolar electrode in CA1 field from ventral hippocampus (HIP) and two stainless steel screws on the frontal cortex (FCX). Electrodes were attached to a connector and fixed to the skull with dental acrylic. One week after surgery, rats received KA administration (10 mg/kg, i.p.) after one of the following treatments: 90 min after indorenate (10 mg/Kg, i.p.; KA+INDO group); 20 min after 8-OH-DPAT (1 mg/kg, s.c.; KA+8-OH-DPAT group); 30 min after diazepam (10 mg/kg, i.p.; KA+DZP group). The following electrographic parameters were evaluated after KA administration for 3 h: latencies to the first epileptiform spike, the first ictus and synchronization of HIP and FCX; the spike frequency at different intervals. Values were compared with those obtained from a control group pretreated with saline sol. (KA+SS). DZP increased the latency to the first epileptiform spike (128%) and to the first ictus (160%) and diminished the frequency of the spikes at 30 (79%), 45 (55%) and 90 (41%) min after KA administration in FCX. DZP also augmented the latency to the synchronization of both HIP and FCX (158%) and to the electrographic status epilepticus (p[lt]0.05) when compared with the KA+SS group. 8-OH-DPAT enhanced the latency to the synchronization (125%) and diminished the frequency of the spikes in FCX at 120 and 180 min (38% in both) after the application of KA. INDO decreased the frequency of the spikes in HIP during the first wet dog shake (37%) and at 90 min (40%) after KA, and diminished the frequency of the spikes in FCX at 180 min (44%) of recordings. Additionally, DZP, 8-OH-DPAT and INDO diminished the frequency of the spikes during all the recording in FCX, whereas INDO decreased also this parameter in HIP. The present results indicate that 8-OH-DPAT and indorenate diminish the severity of SE induced by KA, an effect that is different with that produced by DZP. It is suggested that the serotonergic 5HT[sub]1A[/sub] agonists reduce the intensity of the KA-induced status epilepticus.