Predy P A, Kokkindis L
Behav Brain Res. 1984 Sep;13(3):251-9. doi: 10.1016/0166-4328(84)90167-0.
The effects of daily administration of 1.0 mg/kg of D-amphetamine for 20 consecutive days on self-stimulation responding from the substantia nigra, and nucleus accumbens were evaluated at several current intensities. Raising current intensity increased rates of responding when electrodes were situated in these areas, and amphetamine significantly enhanced rates of responding from both brain regions. Moreover, the drug-induced response enhancements were facilitated further after repeated drug/test pairings. Although response sensitization was observed at several current intensities, it developed sooner at the lower current levels indicating that the sensitizing effect of repeated drug administration on self stimulation responding was not due to variations in locomotor activity or arousal levels induced by amphetamine treatment. Furthermore, sensitization was observed at current levels that engendered both high and low levels of responding, suggesting that the sensitization was unrelated to the rate dependent effects of the drug. Rather, it was argued that repeated amphetamine treatment sensitized animals to the rewarding properties of electrical brain stimulation. Possible neurochemical and behavioral mechanisms that may be involved in the development of reverse tolerance after repeated amphetamine treatment were discussed.
连续20天每天给予1.0毫克/千克的右旋苯丙胺，在几种电流强度下评估其对来自黑质和伏隔核的自我刺激反应的影响。当电极位于这些区域时，提高电流强度会增加反应速率，并且苯丙胺显著提高了来自这两个脑区的反应速率。此外，在重复药物/测试配对后，药物诱导的反应增强进一步得到促进。虽然在几种电流强度下都观察到了反应敏化，但在较低电流水平下反应敏化出现得更快，这表明重复给药对自我刺激反应的敏化作用不是由于苯丙胺治疗引起的运动活动或唤醒水平的变化。此外，在产生高反应水平和低反应水平的电流水平下都观察到了敏化现象，这表明敏化与药物的速率依赖性效应无关。相反，有人认为重复给予苯丙胺会使动物对脑电刺激的奖赏特性产生敏化。讨论了重复给予苯丙胺治疗后可能参与反向耐受发展的神经化学和行为机制。
