[Rate of axoplasmic transport in the ventral roots of the spinal cord of the rat in old age and its relation to the level of energy metabolism].

Aqueous solution of L-leucine-14C (specific activity 339 mCi/mmol) was introduced in a dose of 7-8 microliter to the ventral horn (L5,6) of the spinal cord of adult (8-12 month) and old (26-28 month) rats. The radioactivity of various parts of the corresponding ventral roots was measured after 1-2.5 hrs. Labelled substances (including protein) were found to migrate with fast flow in adult rats with the rate of 408 +/- 10.9 and 380 +/- 22 mm/24 hrs, respectively, as compared with 217 +/- 11.3 and 200 +/- 40 mm/24 hrs in old rats. The axoplasmic flow slows down in old rats with the increase of distance from the neuronal body. Uncoupling of oxidation and phosphorylation due to intraperitoneal administration of 2.4-dinitrophenol, NaF inhibition of glycolysis, hypoxic hypoxia produce more marked deceleration of axoplasmatic flow in old rats, while small doses of NaF accelerate the flow, which correlates with the rise of cAMP level in the ventral roots.