Ballesteros-Yanez Inmaculada, Ambrosio Emilio, Pérez Jacqueline, Torres Isabel, Miguéns Miguel, García-Lecumberri Carmen, DeFelipe Javier
Cajal Institute (CSIC), Avda Doctor Arce 37, 28002 Madrid, Spain.
Brain Res. 2008 Sep 16;1230:61-72. doi: 10.1016/j.brainres.2008.06.128. Epub 2008 Jul 15.
Repeated administration of drugs of abuse is thought to induce a variety of persistent changes in both behavior and brain morphology, including modifications of neurons from the brain regions involved in addiction. We have studied the morphology of the basal dendritic arbor of cortical pyramidal neurons in addiction-resistant Fischer 344 strain rats that self-administered morphine. Pyramidal neurons in the prelimbic and motor cortex were intracellularly injected with Lucifer Yellow in fixed tissue and they were reconstructed in three dimensions using Neurolucida software. Morphine self-administration did not produce significant changes in the structure of the dendritic arbors or in the spine density of pyramidal neurons in either the prelimbic or motor cortex of F344 rats. Moreover, pyramidal cell morphology did not differ in these two cortical areas in saline self-administered animals. However, when the structure of these cortical pyramidal cells from Fischer 344 rats was compared with that previously reported in addiction-prone Lewis rats in the same cortical areas, significant morphological differences were found between both strains. Indeed, these differences were not only observed following morphine self-administration but also in saline self-administered control animals. We suggest that strain differences in the structure of pyramidal cells in certain cortical areas might represent an anatomical substrate for the distinct vulnerability to the reinforcing effects of morphine exhibited by Fischer 344 and Lewis rats in operant self-administration paradigms.
反复使用成瘾药物被认为会在行为和脑形态学上引发多种持续性变化，包括对参与成瘾的脑区神经元的改变。我们研究了自行注射吗啡的抗成瘾Fischer 344品系大鼠皮质锥体细胞基底树突分支的形态。在固定组织中，对前边缘皮质和运动皮质中的锥体细胞进行细胞内注射路西法黄，并使用Neurolucida软件对其进行三维重建。在F344大鼠的前边缘皮质或运动皮质中，自行注射吗啡并未使锥体细胞树突分支结构或棘密度产生显著变化。此外，在自行注射生理盐水的动物中，这两个皮质区域的锥体细胞形态并无差异。然而，当将Fischer 344大鼠这些皮质锥体细胞的结构与之前报道的同一皮质区域中易成瘾的Lewis大鼠的结构进行比较时，发现两个品系之间存在显著的形态学差异。事实上，这些差异不仅在自行注射吗啡后观察到，在自行注射生理盐水的对照动物中也存在。我们认为，某些皮质区域锥体细胞结构的品系差异可能是Fischer 344大鼠和Lewis大鼠在操作性自行给药范式中对吗啡强化作用表现出不同易感性的解剖学基础。
