Lénárd László, Ollmann Tamás, László Kristóf, Kovács Anita, Gálosi Rita, Kállai Veronika, Attila Tóth, Kertes Erika, Zagoracz Olga, Karádi Zoltán, Péczely László
Institute of Physiology, Pécs University, Medical School, Pécs, Hungary; Molecular Neuroendocrinology and Neurophysiology Research Group, Pécs University, Szentágothai Research Center, Pécs, Hungary.
Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
Behav Brain Res. 2017 Mar 15;321:99-105. doi: 10.1016/j.bbr.2017.01.005. Epub 2017 Jan 3.
In our present experiments, the role of D2 dopamine (DA) receptors of the ventral pallidum (VP) was investigated in one trial step-through inhibitory avoidance paradigm. Animals were shocked 3 times in the conditioning trial, with 0.5mA current for 1s. Subsequently bilateral microinjection of the D2 DA receptor agonist quinpirole was administered into the VP in three doses (0.1μg, 1.0μg or 5.0μg in 0.4μl saline). We also applied the D2 DA receptor antagonist sulpiride (0.4μg in 0.4μl saline) alone or 15min prior to the agonist treatment to elucidate whether the agonist effect was specific for the D2 DA receptors. Control animals received saline. In a supplementary experiment, it was also investigated whether application of the same conditioning method leads to the formation of short-term memory in the experimental animals. In the experiment with the D2 DA receptor agonist, only the 0.1μg quinpirole increased significantly the step-through latency during the test trials: retention was significant compared to the controls even 2 weeks after conditioning. The D2 DA receptor antagonist sulpiride pretreatment proved that the effect was due to the agonist induced activation of the D2 DA receptors of the VP. The supplementary experiment demonstrated that short-term memory is formed after conditioning in the experimental animals, supporting that the agonist enhanced memory consolidation in the first two experiments. Our results show that the activation of the D2 DA receptors in the VP facilitates memory consolidation as well as memory-retention in inhibitory avoidance paradigm.
在我们目前的实验中，运用一次性步入式抑制性回避范式研究了腹侧苍白球（VP）中D2多巴胺（DA）受体的作用。在条件性试验中，动物接受3次电击，电流为0.5mA，持续1秒。随后，将D2 DA受体激动剂喹吡罗以三种剂量（0.1μg、1.0μg或5.0μg溶于0.4μl生理盐水中）双侧微量注射到VP中。我们还单独应用D2 DA受体拮抗剂舒必利（0.4μg溶于0.4μl生理盐水中），或在激动剂治疗前15分钟应用，以阐明激动剂的作用是否对D2 DA受体具有特异性。对照动物接受生理盐水注射。在一项补充实验中，还研究了采用相同的条件性方法是否会导致实验动物形成短期记忆。在D2 DA受体激动剂实验中，只有0.1μg喹吡罗显著增加了测试试验中的步入潜伏期：即使在条件化后2周，与对照组相比，记忆保持情况仍很显著。D2 DA受体拮抗剂舒必利预处理证明，该效应是由于激动剂诱导激活了VP中的D2 DA受体。补充实验表明，实验动物在条件化后形成了短期记忆，这支持了激动剂在前两个实验中增强了记忆巩固。我们的结果表明，VP中D2 DA受体的激活促进了抑制性回避范式中的记忆巩固和记忆保持。
