Geller I, Hartmann R J, Randle S R, Gause E M
Pharmacol Biochem Behav. 1979 Oct;11(4):395-9. doi: 10.1016/0091-3057(79)90114-x.
Six rats were trained to press a lever for a liquid food reward on a multiple fixed ratio--fixed interval (FR--FI) schedule of reinforcement. When lever-pressing rates became relatively stable, the animals were exposed to 150 ppm of either acetone or toluene for duration times of 1/2, 1, 2 and 4 hr. Exposures were conducted at least three weeks apart. Acetone produced minimal changes on the FR--FI responding during the 1/2 hr exposure. During the 1 hr exposure period, both FR and FI rates increased while during the 2 hr exposure, both FR and FI responses decreased below control levels. During the 4 hr exposure FI responses approximated control levels for 2 rats and were above the control level for the third animal while FR rates were below controls for 2 of the 3 subjects. Rate changes under toluene were generally qualitatively similar to those produced by acetone. An initial enhancement of FR and FI rates occurred during the shorter exposure periods followed by a decrease in rates during the longer exposure periods.
六只大鼠被训练在多重固定比率——固定间隔（FR——FI）强化程序下按压杠杆以获取液体食物奖励。当杠杆按压率变得相对稳定时，将动物暴露于150 ppm的丙酮或甲苯中，持续时间分别为半小时、1小时、2小时和4小时。暴露至少相隔三周进行。在半小时暴露期间，丙酮对FR——FI反应产生的变化极小。在1小时暴露期内，FR和FI率均增加，而在2小时暴露期间，FR和FI反应均降至对照水平以下。在4小时暴露期间，两只大鼠的FI反应接近对照水平，第三只动物的FI反应高于对照水平，而三只受试动物中有两只的FR率低于对照水平。甲苯作用下的率变化在性质上通常与丙酮产生的变化相似。在较短暴露期内，FR和FI率最初增强，随后在较长暴露期内率下降。
