Neurohistochemical and electron microscopic investigations of pathological and age-related changes in the cardiovascular system.

Neurohistochemical and electron microscopic investigations of the autonomic nervous system (ANS) of man and animals suggest that its ontogenesis can be divided into the premediatory, mediatory and postmediatory periods of development. The postmediatory period begins heterochronically in various ganglia of the ANS. A normal process of early cardiac desympathization usually occurs at the age of 35 to 60 years. Specific changes of preceding sudden cardiac death are elicited in different parts of the ANS and adrenal glands. This is accompanied by focal myocardial desympathization. Coronary vessels and conducting system which may influence myocardial hypersensitivity zones to catecholamines are involved in the process of destabilization of the cardiac function. Moreover, relationships are demonstrated which exist between the atherosclerotic lesions of the aortic wall and the status of its nerve plexuses.