Nation J R, Bourgeois A E, Clark D E
Pharmacol Biochem Behav. 1983 Jun;18(6):833-40. doi: 10.1016/s0091-3057(83)80001-x.
Adult rats fed daily rations of laboratory chow laced with lead acetate, were tested for operant (schedule-controlled) responding and conditioned suppression. In Experiment 1, animals receiving 10 mg/kg lead showed significantly lower operant response rates (lever pressing) than controls. Conditioned suppression performance was not different between the two groups. During retraining that followed a 42 day no-training period, lead-treated subjects showed greater percent of prior baseline responding than controls. The groups were not different on a test for stimulus control or an appetitive resistance to extinction test. In Experiment 2, separate lead-treated groups were chronically exposed to either 10 mg/kg, 5 mg/kg, or 1 mg/kg lead daily. Behavioral tests showed that while the lowest lead level (1 mg/kg) occasioned higher rates of operant lever pressing relative to controls, the highest level (10 mg/kg) again produced lower rates. On a retraining task administered after an interpolated 90 day no-training period, the two highest exposure groups were significantly above controls regarding percent of baseline responding and there was evidence that the 5 mg/kg group was significantly superior to controls in terms of absolute response rate. No differences in conditioned suppression or resistance to extinction were observed in the second experiment.
给成年大鼠每日喂食添加醋酸铅的实验室饲料，对其进行操作性（按计划控制）反应和条件性抑制测试。在实验1中，接受10毫克/千克铅的动物表现出的操作性反应率（杠杆按压）明显低于对照组。两组之间的条件性抑制表现没有差异。在为期42天的无训练期后的再训练期间，接受铅处理的受试者表现出的先前基线反应百分比高于对照组。在刺激控制测试或消退测试中的食欲抵抗方面，两组没有差异。在实验2中，将接受铅处理的不同组分别长期每日暴露于10毫克/千克、5毫克/千克或1毫克/千克的铅中。行为测试表明，虽然最低铅水平（1毫克/千克）相对于对照组导致更高的操作性杠杆按压率，但最高水平（10毫克/千克）再次产生较低的率。在经过90天的无训练期后的再训练任务中，两个最高暴露组在基线反应百分比方面明显高于对照组，并且有证据表明5毫克/千克组在绝对反应率方面明显优于对照组。在第二个实验中，未观察到条件性抑制或消退抵抗方面的差异。
