Levin E D, Schneider M L, Ferguson S A, Schantz S L, Bowman R E
Psychiatric Research Center, Ulleråker Hospital, University of Uppsala, Sweden.
Dev Psychobiol. 1988 May;21(4):371-82. doi: 10.1002/dev.420210408.
Postnatal lead exposure has been found to cause long-term learning and memory deficits in monkeys. Pulse-chronic exposure, consisting of acute high-level exposure followed by chronic lower-level exposure, has been particularly effective in causing these impairments. We investigated possible antecedents of lead-induced cognitive dysfunction by evaluating the behavioral effects of pulse-chronic lead exposure in rhesus monkeys during the first 6 months of postnatal life. Blood lead concentrations in the monkeys reached a peak of 55.8 +/- 7.8 ug/dl during week 5 after birth and then averaged between 33.1 and 42.9 ug/dl during the rest of the first 6 months after birth. Zinc protoporphyrin levels were increased by lead exposure, but hematocrits were unaffected. Significant lead-related effects were detected on a visual exploration test and a neonatal behavioral assessment battery. Lead-treated monkeys exhibited decreased looking behavior on the visual exploration test and decreased muscle tonus and increased arousal or agitation on the behavioral assessment battery. No effects were seen on a Piagetian object permanence task and no toxic effects on health or growth were detected. In addition to providing indices of behavioral dysfunction during postnatal lead exposure, performance on these early behavioral tests may predict later lead-induced cognitive dysfunction.
已发现出生后铅暴露会导致猴子出现长期的学习和记忆缺陷。脉冲式慢性暴露，即先进行急性高水平暴露，随后是慢性低水平暴露，在引发这些损伤方面尤为有效。我们通过评估出生后前6个月恒河猴脉冲式慢性铅暴露的行为影响，来研究铅诱导的认知功能障碍可能的先兆。猴子的血铅浓度在出生后第5周达到峰值，为55.8 +/- 7.8微克/分升，然后在出生后的前6个月剩余时间里平均在33.1至42.9微克/分升之间。铅暴露使锌原卟啉水平升高，但血细胞比容未受影响。在视觉探索测试和新生儿行为评估量表上检测到了与铅相关的显著影响。接受铅处理的猴子在视觉探索测试中表现出注视行为减少，在行为评估量表上表现出肌肉张力降低、觉醒或激动增加。在皮亚杰客体永久性任务中未观察到影响，也未检测到对健康或生长的毒性作用。除了提供出生后铅暴露期间行为功能障碍的指标外，这些早期行为测试的表现可能预测后期铅诱导的认知功能障碍。
