In the present study, we investigated the
neuroprotective effect of post-ischemic treatment with
oxcarbazepine (OXC; an
anticonvulsant compound) against ischemic injury induced by transient forebrain
ischemia and its mechanisms in gerbils. Transient
ischemia was induced in the forebrain by occlusion of both common carotid arteries for 5 min under normothermic conditions (37 ± 0.2 °C). The ischemic gerbils were treated with vehicle,
hypothermia (whole-body cooling; 33.0 ± 0.2 °C), or 200 mg/kg OXC. Post-ischemic treatments with vehicle and
hypothermia failed to attenuate and improve, respectively,
ischemia-induced hyperactivity and
cognitive impairment (decline in spatial and short-term memory). However, post-ischemic treatment with OXC significantly attenuated the hyperactivity and the
cognitive impairment, showing that OXC treatment significantly reduced body temperature (to about 33 °C). When the hippocampus was histopathologically examined, pyramidal cells (principal neurons) were dead (lost) in the subfield Cornu Ammonis 1 (CA1) of the gerbils treated with vehicle and
hypothermia on Day 4 after
ischemia, but these cells were saved in the gerbils treated with OXC. In the gerbils treated with OXC after
ischemia, the expression of transient receptor potential vanilloid type 1 (TRPV1; one of the
transient receptor potential cation channels) was significantly increased in the CA1 region compared with that in the gerbils treated with vehicle and
hypothermia. In brief, our results showed that OXC-
induced hypothermia after transient forebrain
ischemia effectively protected against
ischemia-reperfusion injury through an increase in TRPV1 expression in the gerbil hippocampal CA1 region, indicating that TRPV1 is involved in OXC-
induced hypothermia.