Blake M J, Stein E A
Biology Department, Marquette University, Milwaukee, WI 53233.
Brain Res. 1987 Dec 1;435(1-2):181-94. doi: 10.1016/0006-8993(87)91600-3.
An in vivo autoradiographic technique was employed to visualize discrete neuroanatomical changes in opiate receptor binding as a result of aversive footshock (FS) and rewarding electrical brain stimulation (ICS). Footshock-induced escape responding was shown to be attenuated by the simultaneous presentation of non-contingent ICS. Rats were divided into 4 groups (n = 6) receiving ICS, FS, ICS + FS or neither stimulus in an escape paradigm. During the final behavioral test session, rats were injected with 0.002 mg/kg [3H]diprenorphine ( [3H]Dpr) and subsequently prepared for autoradiography. Results indicated two groups of brain areas distinguishable by their treatment-induced changes in [3H]Dpr binding. One group of areas included the nucleus accumbens, claustrum, claustrocortex, perirhinal cortex and ventral tegmental area. These structures showed increased binding due to both FS and ICS. The other group consisted of the diagonal band of Broca, bed nucleus of the stria terminalis, lateral hypothalamus-medial forebrain bundle and amygdala. In these regions, an increase in binding ipsilateral to the electrode was observed in animals receiving ICS with no apparent effect of FS. These results demonstrate that non-contingent ICS may not be strictly aversive and suggest an anatomic, opioid-sensitive basis for both a rewarding and aversive component of this stimulus. It appears, further, that ICS can inhibit the release of endogenous opioid peptides in areas along the mesotelencephalic dopamine pathways, possibly to regulate the activity of neurons conveying reward information. Finally, the observed changes in opiate receptor binding may indicate a mechanism for ICS to produce both drive and reward.
采用体内放射自显影技术来观察因厌恶性足部电击（FS）和奖赏性脑电刺激（ICS）导致的阿片受体结合的离散神经解剖学变化。结果表明，同时给予非条件性ICS会减弱足部电击诱发的逃避反应。在逃避范式中，将大鼠分为4组（每组n = 6），分别接受ICS、FS、ICS + FS或不接受任何刺激。在最后的行为测试阶段，给大鼠注射0.002 mg/kg的[3H]二丙诺啡（[3H]Dpr），随后准备进行放射自显影。结果显示，两组脑区可根据其治疗引起的[3H]Dpr结合变化加以区分。一组脑区包括伏隔核、屏状核、屏状皮质、梨状周皮质和腹侧被盖区。这些结构因FS和ICS均表现出结合增加。另一组包括布罗卡斜带、终纹床核、外侧下丘脑 - 内侧前脑束和杏仁核。在这些区域，接受ICS的动物在电极同侧观察到结合增加，而FS无明显影响。这些结果表明，非条件性ICS可能并非严格意义上的厌恶性，并提示了这种刺激的奖赏性和厌恶性成分的解剖学、阿片类敏感基础。此外，ICS似乎可以抑制中脑边缘多巴胺通路沿线区域内源性阿片肽的释放，可能是为了调节传递奖赏信息的神经元的活动。最后，观察到的阿片受体结合变化可能表明了ICS产生驱力和奖赏的一种机制。
