Effect of the allopregnanolone and allotetrahydrodeoxycorticosteron on spike-wave discharges in the EEG of absence epilepsy rat models.

Absence epilepsy is a generalized nonconvulsive type of epilepsy that is characterized by spike-wave discharges (SWD) with a frequency of 2.5-4 Hz in the EEG. The activation of the GABAergic system in central nervous system suppresses convulsive seizures but exacerbates absence seizures. Endogenous neuroactive steroids such as 3α-hydroxy-5α-pregnan-20-one (3α,5α-THPROG; allopregnanolone) and 3α,21-dihydroxy-5α-pregnan-20-one (3α,5α-THDOC, allotetrahydrodeoxycorticosteron) are GABA-A receptor-positive allosteric modulators. Finasteride which is a 5α-reductase inhibitor can selectively block the synthesis of endogenous steroids. In this study, we compared the effects of endogenous steroids (THPROG and THDOC) on SWD by using finasteride-treated Wistar Albino Glaxo from Rijswijk (WAG/Rij) rats as a model of absence epilepsy. Wistar (WIS-THPROG and WIS-THDOC) and WAG/Rij (WAG-THPROG and WAG-THDOC) rats were divided into 4 groups (n = 8). After stereotactic surgical procedures, all rats were prepared for direct cortical EEG measurement. Following finasteride administration to each group, THPROG was administered to WIS-THPROG and WAG-THPROG groups, and THDOC to WIS-THDOC and WAG-THDOC groups intraperitoneally. While there was no any SWD activity detected in WIS-THPROG and WIS-THDOC groups, a significant increase in SWD count in WAG-THPROG (p = 0.012) and in WAG-THDOC (p = 0.012), and in SWD total duration in WAG-THPROG (p = 0.012) and WAG-THDOC groups (p = 0.011) were observed after steroid injection. No difference between the efficacy of THPROG and THDOC on absence seizures in WAG/Rij rats was observed.

Effects of extremely low frequency electromagnetic fields on morphine analgesia and tolerance in rats.

Several studies have demonstrated that the electromagnetic fields produce analgesic activity. The aim of this study was to investigate the effects of extremely low frequency (ELF) electromagnetic fields (EMF) on morphine analgesia and tolerance in rats. In the study, 78 adult male Wistar albino rats (approximately 240 ± 12 g) were used. The application of 50 Hz magnetic field, each day the same times for 30 minutes for 15 days, and a total of four times every 15 minute intervals. To constitute morphine tolerance, high dose of morphine (50 mg/kg) were administered for 3 days in rats and tolerance was evaluated on day 4. Prior to analgesia tests, the effective dose (5 mg/kg) of morphine was injected into rats. In the statistical analyzes of the data, analysis of variance (two-way ANOVA) was used and the multiple comparison determined by Tukey tests. The maximum analgesic effect of the 5 mT magnetic field was determined on 7 days. Administration of morphine (5 mg/kg) in rats exposed to a magnetic field, the analgesic effect was significantly higher compared to the morphine group (p < 0.05). Morphine tolerant animals exposed to a magnetic field, the analgesic effect was found significantly higher than morphine tolerant group rats (p < 0.05). Analgesia test data demonstrated that application of ELF-EMFs to rats increases the morphine analgesia and reduces morphine tolerance.