Hietanen E, Kilpiö J, Närhi M, Savolainen H, Vainio H
Arch Environ Contam Toxicol. 1980;9(3):337-47. doi: 10.1007/BF01057413.
Lead was administered to adult male rabbits in drinking water at a 0.1% concentration for four and five week periods. The lead contents were determined in the central and peripheral nervous tissues and in the liver, kidney, and intestinal mucosa. The conduction velocity of sciatic nerve and the activities of drug metabolizing enzymes in other tissues were determined. The lead concentration in the blood was at a steady state at four to five weeks of exposure. Lead accumulated in all tissues except the brain. The brain lead concentration was 40 to 50% of that in the blood, indicating the existence of a blood-brain barrier. However, the lead concentration in the sciatic nerve increased significantly from four to five weeks of exposure and exceeded that in the blood. This indicates the lack of a blood-nervous tissue barrier in the sciatic nerve allowing a continuous accumulation of lead. This accumulation affected the function of the sciatic nerve; motor nerve conduction velocity decreased from the control level (58.3 +/- 7.4 m/sec) to 43.8 +/- 6.3 m/sec after the four-week exposure and to 35.0 +/- 1.3 m/sec at 5 weeks of exposure. After five weeks of exposure, no changes in the hepatic, intestinal, or renal drug metabolizing enzyme activities were found. These results suggest that motor nerve conduction velocity is affected by lead exposure prior to any influence on biotransformation enzymes.
以0.1%的浓度将铅添加到成年雄性家兔的饮用水中，持续四到五周。测定中枢和外周神经组织以及肝脏、肾脏和肠黏膜中的铅含量。测定坐骨神经的传导速度以及其他组织中药物代谢酶的活性。在接触铅四到五周时，血液中的铅浓度处于稳定状态。铅在除大脑以外的所有组织中蓄积。大脑中的铅浓度为血液中的40%至50%，表明存在血脑屏障。然而，从接触铅四周到五周，坐骨神经中的铅浓度显著增加，并超过了血液中的铅浓度。这表明坐骨神经中缺乏血神经组织屏障，使得铅能够持续蓄积。这种蓄积影响了坐骨神经的功能；运动神经传导速度从对照水平（58.3±7.4米/秒）在接触四周后降至43.8±6.3米/秒，在接触五周时降至35.0±1.3米/秒。接触五周后，未发现肝脏、肠道或肾脏的药物代谢酶活性有变化。这些结果表明，在对生物转化酶产生任何影响之前，运动神经传导速度就受到铅暴露的影响。
