Frolkis V V, Tanin S A, Marcinko V I, Kulchitsky O K, Yasechko A V
Mech Ageing Dev. 1985 Jan;29(1):19-28. doi: 10.1016/0047-6374(85)90043-0.
Seven to eight microliters of aqueous solution of L-[14C]Leucine (spec. act. 339 mCi/mmol) were introduced in the zone of ventral horn (L5-L6) of the spinal cord of adult (8-12 months) and old (26-28 months) rats. The radioactivity of various parts of the corresponding ventral roots was measured 1-2.5 h thereafter. Labelled substances (including protein) were found to migrate with fast flow in adult rats at the rate of 408 +/- 10.9 and 380 +/- 22 mm/24 h, respectively, as compared with 217 +/- 11.3 and 200 +/- 40 mm/24 h 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 by the administration of 2,4-dinitrophenol, inhibition of glycolysis with NaF, hypoxemia produce more marked deceleration of axoplasmic flow in old rats, while small doses of NaF accelerate the flow, which correlates with the rise of cAMP in ventral roots. Sex steroids accelerate significantly the rate of axoplasmic flow. There is a marked increase in the rate due to the administration of estradiol dipropionate in old rats and due to testosterone propionate in adult animals. Changes in resting membrane potential and direct excitability thresholds of some muscles following colchicine blockade of axoplasmic transport are less marked in old rats that evidences for the weakening of neurotrophic control in old age.
将7至8微升L-[14C]亮氨酸水溶液（比活度为339 mCi/mmol）注入成年（8至12个月）和老年（26至28个月）大鼠脊髓腹角（L5-L6）区域。此后1至2.5小时测量相应腹根各部分的放射性。结果发现，标记物质（包括蛋白质）在成年大鼠中以快速流动迁移，速率分别为408±10.9和380±22毫米/24小时，而在老年大鼠中为217±11.3和200±40毫米/24小时。在老年大鼠中，轴浆流随着与神经元体距离的增加而减慢。通过给予2,4-二硝基苯酚使氧化与磷酸化解偶联、用氟化钠抑制糖酵解、低氧血症在老年大鼠中使轴浆流减速更明显，而小剂量的氟化钠则加速轴浆流，这与腹根中cAMP的升高相关。性类固醇显著加速轴浆流速率。在老年大鼠中，由于给予二丙酸雌二醇，在成年动物中由于给予丙酸睾酮，速率有显著增加。秋水仙碱阻断轴浆运输后，一些肌肉的静息膜电位和直接兴奋性阈值的变化在老年大鼠中不太明显，这证明了老年时神经营养控制的减弱。
