Losartan suppresses the kainate-induced changes of angiotensin AT^sub 1^ receptor expression in a model of comorbid hypertension and epilepsy

Aims: Experimental and clinical studies have demonstrated that components of renin-angiotensin system are elevated in the hippocampus in epileptogenic conditions. In the present work, we explored the changes in the expression of angiotensin II receptor, type 1 (AT1 receptor) in limbic structures, as well as the effect of the AT1 receptor antagonist losartan in a model of comorbid hypertension and epilepsy. Main methods: The expression of AT1 receptors was compared between spontaneously hypertensive rats (SHRs) and Wistar rats by using immunohistochemistry in the kainate (1(A) model of temporal lobe epilepsy (TLE). The effect of losartan was studied on AT1 receptor expression in epileptic rats that were treated for a period of 4 weeks after status epilepticus. Key findings: The naive and epileptic SHRs were characterized by stronger protein expression of AT1 receptor than normotensive Wistar rats in the CA1, CA3a, CA3b, CA3c field and the hilus of the dentate gyrus of the dorsal hippocainpus but fewer cells were immunostained in the piriform cortex. Increased AT1 immunostaining was observed in the basolateral amygdala of epileptic SHRs but not of epileptic Wistar rats. Losartan exerted stronger and structure-dependent suppression of AT1 receptor expression in SHRs compared to Wistar rats.