Original articleIntra-hippocampal microinjection of oxytocin produced antiepileptic effect on the pentylenetetrazol-induced epilepsy in rats

- Intra-hippocampal microinjections of oxytocin and diazepam produced antiepileptic effect.
- Oxytocin increased the antiepileptic effect of diazepam.
- Flumazenil and atosiban both prevented antiepileptic effects of oxytocin and diazepam.

BackgroundIn addition to its role as a circulating hormone, oxytocin can also act as a neurotransmitter and a neuromodulator within the brain. In this study, we investigated the intra-hippocampal effect of oxytocin on an experimental seizure model induced by pentylenetetrazole (PTZ) in rats. We also used atosiban (oxytocin antagonist), diazepam and flumazenil (gamma-aminobutyric acid or GABA-benzodiazepine receptor agonist and antagonist, respectively) to clarify the involved mechanism.MethodIn ketamine-xylazine anesthetized rats, the right and left sides of the dorsal hippocampus (CA1) were implanted with two guide cannulas. Epileptic behaviors were induced by intraperitoneal (ip) injection of PTZ (60 mg/kg), and the latency time to onset of first myoclonic jerk, and the duration of epileptic seizures were determined for 30 min.ResultsIntra-hippocampal microinjections of oxytocin at doses of 10 and 20 ng/site, diazepam (100 and 200 ng/site) and co-administration of their ineffective doses significantly (p < 0.01) increased the onset of first myoclonic jerk and decreased duration of epileptic seizure. Antiepileptic effects of oxytocin (20 ng/site) were inhibited by atosiban (20 and 40 ng/site) and flumazenil (100 and 200 ng/site) pretreatments. On the other hand, prior administration of flumazenil (100 and 200 ng/site) and atosiban (20 and 40 ng/site) prevented the antiepileptic effects induced by diazepam (100 and 200 ng/site).ConclusionsThe results of the present study showed that at the level of the hippocampus oxytocin suppressed the severity of epileptic behaviors. A hippocampal GABA-benzodiazepine receptor mechanism may be involved in antiepileptic effect of oxytocin.