Politis M J, Ingoglia N A
Brain Res. 1979 Jun 22;169(2):343-56. doi: 10.1016/0006-8993(79)91035-7.
The axonal migration of RNA, the nucleoside uridine and its nucleotide derivates (NS/NT) were compared in neonatal and young adult rat optic axons. Tritiated uridine was injected into right eyes of developing (1- or 4-day-old) and young adult (40-day-old) rats which were sacrificed at times after injection ranging from 6 h to 20 days. Right and left lateral geniculates were removed and assayed for trichloroacetic acid soluble (NS/NT) and RNA radioactivity. Left minus right geniculate (L-RLG) radioactivity was used as an index of axonally migrating radioactivity. Results showed that uridine and its phosphorylated derivatives were transported along both neonatal and young adult rat optic axons. Greater than 90% of right geniculate (blood-borne) TCA soluble radioactivity was metabolized to volatile substances (probably 3H2O) by three days after injection, leaving approximately 3% of the neonatal and approximately 10% of the adult activity as [3H]NS/NT. In left geniculate fractions (containing transported material) approximately 15% and 40% of total TCA soluble radioactivity was present as [3H]NS/NT in neonates and adults, respectively. Thus, axonal NS/NT appears to be relatively protected from degradation when compared with blood-borne NS/NT. The amount of L-RLG [3H]RNA in the neonates was 10 times higher than in young adults. Peaks of neonatal [3H]RNA occurred at 5 and 10 days after birth, whether injections were made at 1 or 4 days of age indicating that this [3H]RNA may be linked to developmental events. Gel electrophoretic analysis of neonatal geniculate RNA indicated that a small portion of the [3H]RNA in the first peak represented axonally transported 4S RNA. The remainder of the L-RLG [3H]RNA in the neonates was probably due to a rapid and efficient incorporation of axonally transported [3H]NS/NT into extraaxonal geniculate RNA. In contrast, little or no axonal RNA transport could be demonstrated in the young adults.
在新生大鼠和成年幼龄大鼠的视神经轴突中，对RNA、核苷尿苷及其核苷酸衍生物（NS/NT）的轴突运输进行了比较。将氚标记的尿苷注入发育中的（1日龄或4日龄）和成年幼龄（40日龄）大鼠的右眼，在注射后6小时至20天的不同时间点将大鼠处死。取出左右外侧膝状体，检测三氯乙酸可溶性（NS/NT）和RNA放射性。用左外侧膝状体减去右外侧膝状体（L-RLG）的放射性作为轴突运输放射性的指标。结果表明，尿苷及其磷酸化衍生物沿新生大鼠和成年幼龄大鼠的视神经轴突运输。注射后三天内，右外侧膝状体（血源性）三氯乙酸可溶性放射性的90%以上代谢为挥发性物质（可能是3H2O），新生大鼠约3%、成年大鼠约10%的活性以[3H]NS/NT形式留存。在左外侧膝状体组分（含运输物质）中，新生大鼠和成年大鼠三氯乙酸可溶性总放射性中分别约15%和40%以[3H]NS/NT形式存在。因此，与血源性NS/NT相比，轴突NS/NT似乎相对不易降解。新生大鼠L-RLG [3H]RNA的量比成年幼龄大鼠高10倍。无论在出生1天还是4天进行注射，新生大鼠[3H]RNA的峰值均出现在出生后5天和10天，这表明这种[3H]RNA可能与发育事件有关。新生外侧膝状体RNA的凝胶电泳分析表明，第一个峰值中一小部分[3H]RNA代表轴突运输的4S RNA。新生大鼠L-RLG [3H]RNA的其余部分可能是由于轴突运输的[3H]NS/NT快速高效地掺入轴突外外侧膝状体RNA。相比之下，成年幼龄大鼠几乎没有或无法证明有轴突RNA运输。
