Trusk T C, Stein E A
Department of Biology, Marquette University, Milwaukee, WI 53233.
Pharmacol Biochem Behav. 1988 Aug;30(4):983-93. doi: 10.1016/0091-3057(88)90130-x.
Cerebral functional activity was measured as changes in distribution of the free fatty acid [1-14C]octanoate in autoradiograms obtained from rats during brief presentation of a tone previously paired to infusions of heroin or saline. Rats were trained in groups of three consisting of one heroin self-administering animal and two animals receiving yoked infusions of heroin or saline. Behavioral experiments in separate groups of rats demonstrated that these training parameters imparts secondary reinforcing properties to the tone for animals self-administering heroin while the tone remains behaviorally neutral in yoked-infusion animals. The optical densities of thirty-seven brain regions were normalized to a relative index for comparisons between groups. Previous pairing of the tone to heroin infusions irrespective of behavior (yoked-heroin vs. yoked-saline groups) produced functional activity changes in fifteen brain areas. In addition, nineteen regional differences in octanoate labeling density were evident when comparison was made between animals previously trained to self-administer heroin to those receiving yoked-heroin infusions, while twelve differences were noted when comparisons were made between the yoked vehicle and self administration group. These functional activity changes are presumed related to the secondary reinforcing capacity of the tone acquired by association with heroin, and may identify neural substrates involved in auditory signalled conditioning of positive reinforcement to opiates.
在短暂呈现先前与海洛因或生理盐水注射配对的音调期间，通过测量从大鼠获得的放射自显影片中游离脂肪酸[1-14C]辛酸酯分布的变化来测定大脑功能活动。大鼠以每组三只进行训练，每组包括一只自我注射海洛因的动物和两只接受与海洛因或生理盐水配对注射的动物。在单独的大鼠组中进行的行为实验表明，这些训练参数赋予了自我注射海洛因的动物的音调以二级强化特性，而在配对注射动物中音调在行为上保持中性。对37个脑区的光密度进行归一化处理，以获得用于组间比较的相对指数。无论行为如何（配对海洛因组与配对生理盐水组），先前将音调与海洛因注射配对都会在15个脑区产生功能活动变化。此外，当比较先前训练自我注射海洛因的动物与接受配对海洛因注射的动物时，辛酸酯标记密度有19个区域差异明显，而在配对生理盐水组和自我给药组之间进行比较时，有12个差异。这些功能活动变化被认为与通过与海洛因关联而获得的音调的二级强化能力有关，并且可能识别参与阿片类药物正强化听觉信号条件作用的神经底物。
