Abstract: AimTo determine the protective effect of ONO-1078, a leukotriene receptor antagonist, on focal cerebral ischemia induced by endothelin-1 in rats. MethodsSlow microinjection of endothelin-1 (120 pmol in 6 μL, for >6 min) into the region near the middle cerebral artery was used to induce focal cerebral ischemia. ONO-1078 (0.1 mg·kg^-1) was ip injected 1 h before endothelin-1 injection. Neurological symptoms, brain edema, brain infarction size, and the survival neurons in cortex and striatum were observed 24 h after ischemia. ResultsIntracerebral microinjection of endothelin-1 induced remarkable neurological symptoms, brain infarction, brain edema, and decrease of survival neurons in the cortex and striatum. In rats pretreated with ONO-1078, endothelin-1-induced brain edema and brain infarction size were decreased. The numbers of survival neurons in striatum and cortex were increased significantly. The neurological symptoms were improved but not significantly. ConclusionONO-1078 possesses neuroprotective effect against cerebral ischemic injury induced by endothelin-1, therefore, leukotrienes may play a role in the injury of cerebral ischemia.