The Specifics of Adrenergic Innervation of Lymph Nodes from Different Body Regions in Young, Mature, and Old Animals.

Adrenergic innervation in the tissue of the cervical, mesenteric, and popliteal lymph nodes in rats of different age groups (from 2-45 days to 24 months) was studied using the specific fluorescence-microscopic imaging of catecholamines. Adrenergic innervation in the lymph nodes of rats is present from the first days of life, but it develops and complicates during postnatal ontogeny and is fully formed by thedays 20-30 of life. By the age of one month, adrenergic innervation represents a well-formed apparatus in all parts of the node, i.e. in the capsule, trabeculae, and cortical and medullary substance. These are brightly fluorescent nerve fibers that form plexuses with regularly located multiple varicosities. In senile animals, the density and number of plexuses in all parts of the lymph node are preserved, but the brightness of plexuses decreases, plexus fibers become discontinuous, varicosities become less frequent or disappear. These changes are seen in lymph nodes from different body regions.

[Transport function of lymph nodes in body antiorthostatic posture].

The spontaneous contractile activity of isolated lymph nodes and the lymph flow from intestine lymphatic vessel in antiorthostatic posture of rats with an inclination angle of 30 degrees during 7-14 days, was decreased. Contractions of the rat lymph nodes in response to actions of adrenaline, acetylcholine and histamine were diminished. There are changes of biochemical components of lymph and blood plasma with simultaneous decrease of the blood plasma volume. It is concluded that the lymphatic system on antiorthostatic posture plays the compensatory role with the purpose of stabilization of homeostasis in the brain.