Ersin Beyazçiçek

Effects of thymoquinone, the major constituent of Nigella sativa seeds, on penicillin-induced epileptiform activity in rats

Objective: To investigate the effects of thymoquinone (TQ) in a penicillin-induced epilepsy model in rats. Methods: This experimental study included 56 adult male Wistar rats. Experiments were performed in the Research Laboratory of the Department of Physiology, Medical School, Duzce University, Duzce, Turkey, between October 2013 and December 2014. Animals were divided into the following 7 groups: sham, control, only thymoquinone, vehicle (Dimethylsulfoxide), and doses of 10, 50, and 100 mg/kg of TQ. After rats were anesthetized, the left part of the skull was removed. A pair of silver/silver chloride electrodes was placed on the somatomotor area, and electrocorticographic recording was started. After 5 minutes basal activity was recorded, and TQ was applied intraperitoneally. At the thirtieth minute after TQ, epileptiform activity was induced by intracortical penicillin. The first spike latency, spike frequency, and the amplitude of epileptiform activity were analyzed statistically. Results: The different doses of TQ significantly increased the latency time to onset of first spike wave, and decreased the frequency, and amplitude of epileptiform activity in the first 20 minutes compared with the control group. Conclusion: Thymoquinone shows potential as an antiepileptic drug resulting from its effects of prolonged latency time, and reduced spike wave frequency and amplitude of epileptiform activity.

Effects of an Extract of Salvia Miltiorrhiza on a Penicillin-Induced Epilepsy Model in Rats

In a penciling-induced epilepsy model, Wistar rats (16 males, 16 females) were i.p. administered with an extract of Salvia miltiorrhiza (SmE; total dose 50 mg/kg) once a day for 15 days. The rats were divided into four equal groups, control and SmE-treated for each sex. After the treatment period, an epilepsy model was produced by penicillin G injection (500 IU) into the motor cortex; the electrocorticogram (EcoG) was recorded for 120 min, and statistical analysis was performed. In the male control group with penicillin-induced epilepsy, the spike frequency was significantly (P < 0.05) higher than that in the female control group. The frequency values have been significantly (P < 0.01) increased within the observation period in the female SmE-treated group, while the respective values significantly (P < 0.05) decreased in the analogous male group. There were insignificant differences in the amplitude values and latency to onset of the spike/wave events between female/male SmE and female/male control groups (P > 0.05). Thus, the SmE exerts anticonvulsant effects in the male rat group, while its effect should be characterized as proconvulsant in the female group in the penicillin-induced epilepsy model. The difference (related to the presence of estrogen analogs in the SmE) is determined by dissimilar hormonal backgrounds in males and females. The SmE may be considered as the base for development of anticonvulsant drugs for clinical therapy of epilepsy in the future.

Gender Specificity of Genistein Treatment in Penicillin-Induced Epileptiform Activity in Rats

We investigated gender-dependent differences of genistein (isoflavone phytoestrogen) treatment in a penicillin-induced experimental epilepsy rat model. Twenty-eight adult Wistar Albino rats (14 females and 14 males) were devided into four groups, control and genistein-treatmed males and females. Genistein (100 μg/kg, i.p) or saline was given during 15 days before the electrocorticography (ECoG) recordings. The epileptiform activity was induced by penicillin G potassium salt (500 IU) injections into the left somatomotor cortex. Significant differences among the groups were found in the latency to onset of epileptiform activity. This value in the female control group was significantly longer than the latencies in the male control, male genistein, and female genistein groups (respectively, P = 0.002, 0.015, and 0.032). There were no significant differences regarding the spike/wave frequencies and amplitudes in epileptiform activity between female/male genistein and control groups within all observation intervals (P > 0.05). Thus, genistein exerts a proconvulsant effect in the penicillin-induced epilepsy model, and the effect demonstrates the clear gender specificity related to the specificity of hormonal backgrounds in males and females.

Penicillin-Induced Epileptiform ECoG Activity in Gerbils: Effects of Physical Exercise and a Diospyros kaki Extract

Mongolian gerbils (28 males) were divided into four groups, control (C), treadmill-exercised (Ex), treated with the extract of Diospyros kaki (Dk), and exercised plus treated with the Dk extract (Ex+Dk). Animals of the respective groups were running-exercised for 30 min per day during 8 weeks, and the Dk extract (dose 20 mg/kg) was given by gavage during five days per week within the same period. After the treatment and exercise period, an epilepsy model was produced by penicillin G injection (500 IU) into the left somatomotor cortex, and the electrocorticogram (ECoG) was recorded during 120 min. The mean frequency of spike/wave complexes was significantly smaller in the Ex and Ex+Dk groups from the 65th min of the observation period and, in the Dk group, from the 75th min than the respective value in the C group (P < 0.01, P < 0.05, and P < 0.01, respectively). The differences in the amplitude values and latency to onset of the spike/wave events among all groups did not reach the significance level (P > 0.05). Thus, both the running exercise and Dk extract applications inhibit penicillin-induced epileptiform activity by altering the spike/wave frequency or severity of seizures observed in ECoG recordings. Further studies are needed to determine the effects of physical activity of different intensities and forms and to analyze the active compounds in the Dk extract.