Ksir C, Nelson S
Pharmacol Biochem Behav. 1977 Mar;6(3):269-72. doi: 10.1016/0091-3057(77)90025-9.
Food-deprived rats were trained to press a key which produced a food pellet for the first press after 3 min had elapsed (FI 3 min). Daily sessions consisted of 10 such intervals. Graded doses of LSD (0.04 - 1.28 mg/kg) and a d-amphetamine (0.5 - 2.0 mg/kg) were given 30 min before sessions. LSD produced a decrease in response rate at doses of 0.32 mg/kg and above, but did not disrupt the typical FI pattern of responding except at the highest dose (1.28 mg/kg). Amphetamine did not significantly alter the overall response rate, but caused a dose-related disruption of the FI response pattern, with previously low response rates increased more than higher rates, and occasional decreases in the previously highest rates. The experiment was repeated using the same rats responding on a multiple FIFR schedule. The presence of a 2000 Hz tone signalled FR periods; the tone was absent during FI periods. During the FR components, a pellet was produced after 30 responses had been emitted. The FI components were unchanged. LSD (0.08 - 0.32 mg/kg) again produced decreases in FI rate without altering the pattern, and amphetamine again altered the FI pattern without significantly changing overall rate.
对食物匮乏的大鼠进行训练，使其按压一个按键，在3分钟过去后首次按压按键会产生一粒食物颗粒（固定间隔3分钟）。每日训练包含10个这样的间隔时段。在训练前30分钟给予不同剂量的麦角酸二乙酰胺（LSD，0.04 - 1.28毫克/千克）和右旋苯丙胺（0.5 - 2.0毫克/千克）。LSD在剂量为0.32毫克/千克及以上时会使反应率降低，但除了最高剂量（1.28毫克/千克）外，并未扰乱典型的固定间隔反应模式。苯丙胺并未显著改变总体反应率，但导致了与剂量相关的固定间隔反应模式紊乱，之前较低的反应率增加幅度大于较高的反应率，并且之前最高的反应率偶尔会下降。使用相同的大鼠在多重固定间隔/固定比率时间表上进行反应，重复该实验。2000赫兹的音调出现表示固定比率时段；在固定间隔时段则没有音调。在固定比率部分，发出30次反应后会产生一粒食物颗粒。固定间隔部分保持不变。LSD（0.08 - 0.32毫克/千克）再次使固定间隔率降低而不改变模式，苯丙胺再次改变固定间隔模式但未显著改变总体率。
