REN and Hypertension: SHRSP were obtained by selective breeding from spontaneously hypertensive rats (SHR) for the development of spontaneous infarcts[11-13] and exhibit an overactivity of the renin-angiotensin-system[14], a detectability of renin within the vascular walls[15], an altered endothelin system[16] and an increased sympathetic nerve activity[17] potentiated by elevated levels of prostaglandins[18] in their sum leading to an early development of chronic severe arterial hypertension[12].