Effects of melatonin and theanine administration on pentylenetetrazole-induced seizures and brain tissue oxidative damage in ovariectomized rats

Background/aim: The effects of coadministration of melatonin and theanine (Mel/Thea) on pentylenetetrazole (PTZ)-induced seizures and brain tissue oxidative damage were investigated in ovariectomized (OVX) and sham-operated rats. Materials and methods: The rats were divided into the following groups: 1) sham, 2) ovariectomized (OVX), 3) sham-PTZ, 4) OVX-PTZ, 5) sham-Mel/Thea-PTZ, and 6) OVX-Mel/Thea-PTZ. Groups 1-4 received saline, while groups 5 and 6 received a combination of Mel/Thea for 6 weeks. All animals except for those in groups 1 and 2 received a single injection of PTZ. Results: The OVX-PTZ group had higher generalized tonic-clonic seizure (GTCS) latency compared to the sham-PTZ group. Administration of Mel/Thea increased minimal clonic seizure and GTCS latencies in both the sham-Mel/Thea-PTZ and OVX-Mel/Thea-PTZ groups compared to the controls. Additionally, PTZ exposure increased malondialdehyde levels and reduced thiol concentrations in brain tissues of both the sham-PTZ and OVX-PTZ groups. Mel/Thea pretreatment resulted in MDA reduction and thiol increase in brain tissues. Conclusion: The results of this study demonstrated the antioxidant and anticonvulsant activities of Mel/Thea despite the presence or absence of ovarian hormones.