Cerebral ischemia is one of the most common cardiovascular diseases and requires continuous improvement of medical prevention and therapy. The renin angiotensin aldosterone system (RAAS) might function as a potential therapeutic target, since angiotensin mediated processes such as fibrosis, necrosis and the development of reactive oxygen species contribute to cardiovascular and neurological diseases. The results of my dissertation suggest a potential relevance of intracellular RAAS as well as the alternative renin transcript Ren[1a-9] for further understanding of cerebral ischemia and resulting optimization of medical treatment and prevention.