The Antiepileptic Effect of Ghrelin During Different Phases of the Estrous Cycle in PTZ-Induced Seizures in Rat

Catamenial epilepsy is a special form of epilepsy in women whom seizure aggravation is arranged with menstrual cycle that may affect up to 70 % of epileptic women. Antiepileptic effect of Ghrelin hormone has been proved recently. Due to effects of Ghrelin on GABA and LH concentration and periodic variation in the level of estrogen (E 2 ) and progesterone (P 4 ) during menstrual cycle, it seems that antiepileptic effect of Ghrelin can be different during various phases of estrous cycle. So this study was conducted to survey antiepileptic effect of Ghrelin during various phases of estrous cycle in rats. 72 adult female Wistar rats in three groups (control, 40 and 80 μg/kg of Ghrelin), each with four subgroups (proestrus, estrus, metestrus and diestrus) were used ( n = 6). Then, intracerebroventricular (ICV) injection of Ghrelin (40 and 80 μg/kg) followed by intraperitoneal injection of 80 μg/kg pentylenetetrazole in control and treatment groups were done. Initiation time of myoclonic seizures (ITMS), initiation time of tonic–clonic seizures (ITTS), seizures duration and mortality rate were monitored and recorded for 30 min. Results showed that, ICV injection of Ghrelin significantly increased ITMS and ITTS during luteal phase than follicular phase compared to control group ( P < 0.05). Also, seizure duration significantly decreased after ICV injection of Ghrelin during luteal phase and follicular phase compared to control group ( P < 0.05). Furthermore, there was no mortality after ICV injection of Ghrelin (40 and 80 μg/kg) during luteal and follicular phases compared to control group ( P < 0.05). These results suggest that Ghrelin has antiepileptic effects which are more prominent during luteal phase than follicular phase.