Indexed on: 07 Nov '12Published on: 07 Nov '12Published in: Molecular Biology Reports
Ghrelin has two major molecular forms, acylated ghrelin (AG) and unacylated ghrelin (UAG). Only AG to bind growth hormone secretagogue receptor 1a (GHSR-1a) has central endocrine activities. An antiapoptotic effect of AG in cortical neuronal cells has recently been reported. However, whether there is a neuroprotective effect of AG in hippocampal neurons of pilocarpine-induced seizures in rats, is still unknown. Therefore, in the present study, the underlying mechanism of AG on lithium-pilocarpine-induced excitotoxicity was examined in the hippocampus of rat. The results showed that AG inhibited pilocarpine-induced apoptosis. Exposure of rats to the receptor-specific antagonist D-Lys-3-GHRH-6 abolished the protective effects of AG against epilepsy. Administration of AG resulted in increased expression of phosphor-Akt in status epilepticus model in rats, which was accompanied with the attenuation of hippocampal cell death. Furthermore, administration of AG resulted in decreased expression of phosphor-JNK in pyramidal neurons of hippocampus after status epilepsy, which was also accompanied with the attenuation of hippocampal cell death, too. In addition, AG increased the Bcl-2/Bax ratio and inhibited caspase-3 activation. The data indicate that AG can function as a neuroprotective agent that inhibits apoptotic pathways. These effects may be mediated via activation of the PI3K/Akt pathway.