Abstract: | The intramural nervous apparatus of rabbit lymphoid organs was examined after 15 and 30 sessions of electric stimulation of the posterior hypothalamus. The function of nerve cells was evaluated by cytophotometry according to the content of catecholamines and acetylcholinesterase (ACE) activity. In the mesenteric lymph nodes, stimulation led to a decrease in the activity of both adrenergic and ACE-containing nerve cells. The spleen demonstrated a reduction in the catecholamine content in the perivascular nerve plexuses, with a simultaneous rise of the catecholamine content in the fibers located in the parenchyma, which evidences inhibition of the neurogenous mechanisms of vasomotor control and possible selective activation of the sympathetic mechanisms involved in the regulation of the immunogenesis. Thymic preparations impregnated with silver salts manifested high argyrophilia of the nerve cells, characteristic of the reactive phase of the destructive process. The problems of the hypothalamic effects on the blood supply and functions of the immune system organs are discussed. |