Nation J R, Bourgeois A E, Clark D E, Hare M F
Neurobehav Toxicol Teratol. 1983 Jan-Feb;5(1):9-15.
Adult rats fed daily rations of laboratory chow laced with cobalt chloride were tested for operant (schedule-controlled) responding and conditioned suppression (CER). Animals exposed to 20 mg/kg Co, but not animals exposed to 5 mg/kg Co, lever pressed at a significantly slower rate than nontreated control subjects over the last 8 sessions of a 35 session operant training phase (1 session/day). Control and treatment subjects did not show significantly different CER performances. Nor were significant differences found on a test of mixed VI-2, DRO responding where subjects were required to lever press for reward during the first 15 min component and not lever press during the last 15 min component of the schedule. Testicular atrophy was evident among subjects exposed to 20 mg/kg Co. Atomic absorption spectrophotometric analyses revealed a dose-response effect regarding tissue accumulations of Co in blood, bone, brain, hair, small intestine, kidney, liver, and testes. Contrary to the biochemical pattern shown by some other heavy metals, prolonged Co exposure did not induce significant increases in metallothionein concentrations in the liver, kidney, or small intestine.
给成年大鼠每日喂食掺有氯化钴的实验室饲料，然后对其进行操作性（按时间表控制）反应和条件性抑制（CER）测试。在为期35节的操作性训练阶段（每天1节）的最后8节中，接触20mg/kg钴的动物，而非接触5mg/kg钴的动物，其杠杆按压速度明显慢于未处理的对照动物。对照和处理组动物的CER表现没有显著差异。在混合VI-2、DRO反应测试中也未发现显著差异，在该测试中，要求动物在时间表的前15分钟内按压杠杆以获取奖励，在最后15分钟内不按压杠杆。在接触20mg/kg钴的动物中明显出现了睾丸萎缩。原子吸收光谱分析显示，钴在血液、骨骼、大脑、毛发、小肠、肾脏、肝脏和睾丸中的组织蓄积存在剂量反应效应。与其他一些重金属所显示的生化模式相反，长期接触钴并未导致肝脏、肾脏或小肠中金属硫蛋白浓度显著增加。
