Takahashi H, Takada Y, Nagai N, Urano T, Takada A
Department of Physiology, Hamamatsu University, School of Medicine, Shizuoka-ken, Japan.
Brain Res Bull. 1998;45(2):157-62. doi: 10.1016/s0361-9230(97)00332-8.
We have used a microdialysis technique to analyze the effects of nicotine administration on the release of dopamine in the striatum and the nucleus accumbens (NAC) in rats under footshock stress. In the striatum, neither chronic systemic nicotine administration alone nor stress alone changed the extent of dopamine release. During stress application, however, chronic nicotine administration significantly increased dopamine release. In the NAC, stress did not induce increase in dopamine release in rats given nicotine chronically. However, in rats subjected to stress alone, dopamine release in the NAC was significantly increased after stress. In the striatum, the local infusion of 1.0 mM nicotine increased dopamine release. Furthermore, stress significantly increased nicotine-induced dopamine release. The local infusion of 1.0 mM nicotine into the NAC significantly increased dopamine release, but the levels returned to the baseline 30 min later. On the other hand, stress alone induced the release of dopamine 30 min later and the combination of stress and nicotine induced the release of dopamine during the stress and the effects lasted for 30 min. These results suggest that the responses of nicotine-induced dopamine release were different in the striatum and in the NAC under the stress. Stress and nicotine (systematically or locally administered) induced an immediate effect on dopamine release in the striatum, but in the nucleus accumbens stress alone and the combination of stress and nicotine induced a lasting release of dopamine (DA).
我们采用微透析技术分析了尼古丁给药对足部电击应激下大鼠纹状体和伏隔核（NAC）中多巴胺释放的影响。在纹状体中，单独长期全身性给予尼古丁或单独应激均未改变多巴胺释放程度。然而，在施加应激期间，长期给予尼古丁显著增加了多巴胺释放。在伏隔核中，应激并未诱导长期给予尼古丁的大鼠多巴胺释放增加。然而，在仅接受应激的大鼠中，应激后伏隔核中的多巴胺释放显著增加。在纹状体中，局部注入1.0 mM尼古丁增加了多巴胺释放。此外，应激显著增加了尼古丁诱导的多巴胺释放。向伏隔核局部注入1.0 mM尼古丁显著增加了多巴胺释放，但30分钟后水平恢复至基线。另一方面，单独应激在30分钟后诱导多巴胺释放，应激与尼古丁联合作用在应激期间诱导多巴胺释放，且作用持续30分钟。这些结果表明，在应激状态下，尼古丁诱导的多巴胺释放在纹状体和伏隔核中的反应不同。应激和尼古丁（全身或局部给药）对纹状体中的多巴胺释放产生即时影响，但在伏隔核中，单独应激以及应激与尼古丁联合作用诱导了多巴胺（DA）的持续释放。
