Angiotensin II is responsible for vasoconstriction in the renin-angiotensin system. In addition to its direct effect on blood vessels it stimulates the synthesis and release of aldosterone and also promotes renal tubular reabsorption of sodium, resulting in water retention¹.

Losartan potassium (Cozaar, Loszaar, Losaprex) is a synthetic antagonist of the Angiotensin II type 1 receptor with an effective concentration of 1-100 nM and an IC₅₀ of 5 nM². Losartan is used for the treatment of hypertension and heart failure, especially with patients who suffer from severe cough due to ACE inhibitor intake. It also improves the prognosis of diabetic nephropathy and reduces the risk of CVA in patients with left ventricle hypertrophy. Maximum effect is reached 3-6 weeks after beginning of treatment. Interestingly, long term treatment with Losartan in a model of hypertensive and epileptic mice yielded neuroprotective results. These mice are characterized by elevated activity of the renin-angiotensin system and a higher level of Angiotensin receptors than other mouse models. Losartan delayed the onset of epileptic seizures and reduced their amount and duration. Neuroprotection was mostly demonstrated in the CA3 area of the hippocampus and the septo-temporal hilus of the dentate gyrus³.