Study on neural subtrates involved in taste-aversion learning by means of molecular biology.

学习的形成包括增加蛋白质、mRNAs等对刺激的反应。Yamamoto等人。(1993)报道了大鼠臂旁核(PBN)对不同味觉溶液的反应，以及动物学会条件性味觉厌恶(CTA)后的条件性味觉反应。在本项目中，我们研究了在CTA形成时，小鼠岛叶皮质包括味觉皮质区的FOS蛋白的产生，并参照PBN中的FOS蛋白的产生。当小鼠饮用基本味觉溶液时，不同的味道在PBN的不同亚核中诱导出FOS蛋白：氯化钠、蔗糖和盐酸在中央外侧亚核诱导了大量FOS阳性神经元，在腹侧亚核也产生了FOS阳性神经元。奎宁在外侧外侧亚核可见少量FOS阳性神经元。在已有味觉传递神经元定位的区域未发现FOS阳性神经元。在大鼠，Fos阳性神经元被诱导为…在其他一些亚核中也有更多。在岛叶皮质，蔗糖在初级躯体感觉区和颗粒岛叶皮质诱导了大量的FOS阳性神经元，而其他味觉刺激(包括氯化钠)在无粒岛叶皮质诱导了较少数量的FOS阳性神经元。小鼠饮用氯化锂引起咸味和内脏病变后，在外侧中央亚核和外侧外侧亚核可见FOS阳性细胞。腹膜内注射氯化锂仅引起内脏病变，仅在外侧外侧亚核产生FOS阳性神经元。在这两个病例中，在颗粒障碍的岛叶皮质均可见到FOS阳性细胞。当小鼠通过与内脏疾病相关的方式学会CTA后，条件刺激在PBN中央外侧亚核、腹侧亚核和颗粒障碍皮质均可诱导FOS阳性细胞，但仅在PBN外侧外核诱导。这一结果通过原位杂交观察c-FOS mRNA的诱导得到了证实。较少

Formation of learning involves increase in production of protein, mRNAs and so forth in response to stimuli. Yamamoto et al. (1993) reported about FOS-protein in the parabrachial nucleus (PBN) of rats in reponse to various taste solution in normal rats, and to conditoned taste after the animal learned conditioned taste-aversion (CTA). In the present project, we studied the production of FOS protein in insular cortex including the gustatory cortical area in mice at CTA formation, in reference to that in the PBN.When mice drunk basic taste solution, different taste induced FOS protein in different subnucleus of the PBN : NaCl, sucrose snd HCl induced many FOS-positive neurons at the lateral central subnucleus, and HCl produced them at the ventral subnucleus, as well. Quinine yielded a few FOS-postive neurons at the lateral external subnucleus. No FOS-positive neuron was found at the region where taste relay neurons have been located previously. In rats, FOS-positive neurons were induced … More in some other subnucleus, as well. In the insular cortex, sucrose induced many FOS-positive neurons at primary somatosensory area and granular insular cortex, while other taste stimuli including NaCl a fewer number of such neurons in the dysgranular insular cortex. After mice received salty taste and visceral illness by drinking LiCl, FOS-posiitive cells were seen at the lateral central and lateral external subnucleus of the PBN.Intraperitoneral injection of LiCl which induces only visceral illness produced FOS-positive neurons only at the lateral external subnucleus. In both cases, FOS-positive cells were noted at the dysgranular insular cortex. After mice learned CTA to NaCl or sucrose by associating it with visceral illness, either conditioned stimulus induced FOS-positive cells at the lateral central and ventral subnucleus of the PBN,and at the dysgranular cortex, though such a stimulus induced them only at the lateral external nucleus of the PBN.These findings were confirmed by observing induction of c-fos mRNA by in situ hybridization.The present results indicate that neural circuits involved in CTA differ in some degree between mice and rats. Less