[Axons of sympathetic neurocytes and their relation to lemmocytes during postnatal ontogeny in the rat].
The external carotid nerves have been studied electronmicroscopically in rats at the age of 1, 6, 13, 30 days and 5 months. The growth dynamic of diameter of the axons composing the nerve has been followed, as well as formation of glial membranes around them and quantitative changes of microtubules in the axons. During the first month of life, the average axonal diameter increases more than twice, the content of organells rises in them. Concentration of the microtubules is higher in thin axons (0.1--0.2 mcm), with increasing of their diameter it becomes lower. No correlation between concentration of the microtubules and age of the animal is noted. In newborn rats the glial membranes around the axons are nearly completely absent, by the end of the second week of life, most of the axons already have them. Sometimes, in one groove of the lemmocyte there can be seen several of them. By the first month of life, the axons are situated in individual grooves, this is specific for mature animals. In a 2-week-old rat one lemmocyte surrounds several dozens of axons, in a mature one--about 5--13.
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D001369:Axons / Q000648:ultrastructure; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D009441:Neurilemma; D051381:Rats; D013564:Sympathetic Nervous System / Q000166:cytology / Q000254:growth & development*
Aksony simpaticheskikh neĭrotsitov i ikh vzaimootnoshenie s lemmotsitami v postnatal'nom ontogeneze krysy.