An immunohistochemical study of the effects of orexin receptor blockade on phospholipase C-β3 level in rat hippocampal dentate gyrus neurons.

Orexin-A (hypocretin-1) is a neuropeptide that is produced in the lateral hypothalamic area (LHA) and promotes widespread cortical activation. We investigated the effect of SB-334867, a selective orexin receptor 1 (OXR1) antagonist, on phospholipase C-β3 (PLCβ3) level using slices of rat hippocampus preparations and immunohistochemistry. We used three Wistar rats in each of three groups. The control group was untreated rats and SB vehicle and SB groups received SB vehicle and 10 mg/kg SB-334867 daily from postnatal day (PND) 12 to PND30, respectively. We found that the orexin receptor antagonist decreased the PLCβ3 level in the inner and outer blades of dentate gyrus (DG) compared to SB vehicle treated rats. Orexin may increase the PLCβ3 level in most regions of the rat hippocampus.