Pathomorphological reactions of myocardium and intramural vessels of rats in the course of hypertension induced by depot angiotensin. Autoradiographic, light and electron microscopic investigations

Autoradiographic, light and electron microscopic investigations on the effect of depot angiotensin on the hearts of rats suggested that the myocardium and the intramural vessels reacted with an activation of the mesenchymal and DNA metabolism already 3 hrs, after the injection of depot angiotensin. The reactions in the capillaries and small arterioles were dominating. Degenerative alterations could be found in the cardiac muscle cells only 9 hrs. after inj ection and culminated in infarction-like necroses and intensive mesenchymal proliferation after the 4th A II injection. Despite further daily applications of A II the degenerative and necrotic myocardial alterations will extensively diminish until the 14th day of experiment, while the mesenchymal activation and the enhanced DNA synthesis in the vessels remained unchanged. Thus an initial stage with the development of disseminated muscle fibre necroses and infarction-like alterations and a stage of compensatory adaptation may be distinguished in the heart after depot angiotensin injections.