Although the phospholipase C (PLC)${eta}$-1 isoform is associated with spontaneous seizure and distinctively expressed in the telencephalon, the distribution of PLC${eta}$-1 expression in the epileptic gerbil hippocampus remains controversial. Therefore, we determined whether PLC${eta}$-1 is associated with spontaneous seizure in an animal model of genetic epilepsy. In the present study, PLC${eta}$-1 immunoreactivity was down-regulated in seizure-sensitive (SS) gerbils more than in seizure-resistant (SR) gerbils. The expression of PLC${eta}$-1 within calretinin (CR)-positive neurons was rarely detected within the dentate hilar region of SS gerbils. PLC${eta}$-1 immunoreactivity in the hippocampus was significantly elevated as compared to that in pre-seizure SS gerbil 3 h post-ictal. These findings suggest that alterations in PLC${eta}$-1 immunoreactivity in the SS gerbil hippocampus may be closely related to the epileptic state of the gerbil brain and transiently elevated PLC${eta}$-1 protein levels following seizure episodes. Such alterations may be compensatory responses in the SS gerbil hippocampus.