Department of Animal Physiology, University of Gdansk, 24Kładki Str, 80-822 Gdansk, Poland.
Behav Brain Res. 2013 Mar 15;241:161-72. doi: 10.1016/j.bbr.2012.12.012. Epub 2012 Dec 17.
The pedunculopontine tegmental nucleus (PPN) is anatomically connected with dopaminergic cells in the ventral tegmental area (VTA). In the present study, VTA-stimulation induced feeding or locomotor response was tested after temporary inactivation (procaine injection) or activation (bicuculline injection) of the PPN in the ipsi- or contralateral hemisphere. Motor and motivation aspects of appetitive behavior were analyzed on the basis of the latency/stimulation frequency curve shift paradigm, in male Wistar rats (n=48). Procaine injections into the PPN had more significant effects on both types of behavioral response during VTA stimulation than bicuculline. On the day of injection (day 0) procaine increased reaction threshold of the observed responses: a rise by 22% after contra- and 17% after ipsilateral injection in the case of feeding, and an inverse result side-wise for locomotor response, i.e. around 12% and 20% respectively. Bicuculline injected into the PPN did not cause significant effects on day 0 and the values of reaction threshold oscillated around ±10% for both behaviors, except in rats with locomotor reaction after contralateral injection. The observed reactions stabilized within on consecutive days (days 1-3) after procaine/bicuculline injection in both behavioral groups. The results indicate that the PPN and VTA belong to the same central circuitry involved in the regulation of psychomotor activation. However, the influence of PPN-VTA inter-hemispheric connections on reward and addiction function of the VTA is still unexplained.
被盖腹侧网状核（PPN）在解剖学上与腹侧被盖区（VTA）中的多巴胺能细胞相连。在本研究中，在同侧或对侧半球内暂时失活（可卡因注射）或激活（毒蕈碱注射）PPN 后，测试了 VTA 刺激引起的进食或运动反应。根据潜伏期/刺激频率曲线移位范式，在雄性 Wistar 大鼠（n=48）中分析了食欲行为的运动和动机方面。与毒蕈碱相比，可卡因注射到 PPN 对 VTA 刺激期间的这两种行为反应都有更显著的影响。在注射日（第 0 天），可卡因增加了观察到的反应的反应阈值：在对侧注射时增加了 22%，在同侧注射时增加了 17%，而在运动反应中则相反，即分别增加了约 12%和 20%。在第 0 天，注入到 PPN 的毒蕈碱没有引起明显的效果，并且对于两种行为，反应阈值的数值都在±10%左右波动，除了在对侧注射后有运动反应的大鼠之外。在可卡因/毒蕈碱注射后的连续几天（第 1-3 天），在两个行为组中，观察到的反应都稳定下来。结果表明，PPN 和 VTA 属于同一中枢回路，参与调节精神运动激活。然而，PPN-VTA 半球间连接对 VTA 的奖励和成瘾功能的影响仍未得到解释。
