Wanat M J, Bonci A
Neuroscience Graduate Program at University of California, San Francisco, California 94143, USA.
Synapse. 2008 Oct;62(10):790-5. doi: 10.1002/syn.20546.
Changes in synaptic strength on ventral tegmental area (VTA) dopamine neurons are thought to play a critical role in the development of addiction-related behaviors. However, it is unknown how a single injection of cocaine at different doses affects locomotor activity, behavioral sensitization, and glutamatergic synaptic strength on VTA dopamine neurons in mice. We observed that behavioral sensitization to a challenge cocaine injection scaled with the dose of cocaine received 1 day prior. Interestingly, the locomotor activity after the initial exposure to different doses of cocaine corresponded to the changes in glutamatergic strength on VTA dopamine neurons. These results in mice suggest that a single exposure to cocaine dose-dependently affects excitatory synapses on VTA dopamine neurons, and that this acute synaptic alteration is directly associated with the locomotor responses to cocaine and not to behavioral sensitization.
腹侧被盖区（VTA）多巴胺能神经元的突触强度变化被认为在成瘾相关行为的发展中起关键作用。然而，单次注射不同剂量可卡因如何影响小鼠的运动活动、行为敏化以及VTA多巴胺能神经元上的谷氨酸能突触强度尚不清楚。我们观察到，对可卡因激发注射的行为敏化与前一天接受的可卡因剂量成比例。有趣的是，初次接触不同剂量可卡因后的运动活动与VTA多巴胺能神经元上谷氨酸能强度的变化相对应。小鼠的这些结果表明，单次接触可卡因会剂量依赖性地影响VTA多巴胺能神经元上的兴奋性突触，并且这种急性突触改变与对可卡因的运动反应直接相关，而非与行为敏化相关。
