Zheng Yingjun, Sudou Kousuke, Nawa Hiroyuki, Namba Hisaaki
Department of Molecular Neurobiology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Niigata 951-8585, Japan.
Neurosci Res. 2006 Aug;55(4):426-33. doi: 10.1016/j.neures.2006.04.013. Epub 2006 Jun 5.
Addictive drugs and psychologic stress influence the input strength of ventral tegmental area (VTA) neurons, which implies the involvement of synaptic plasticity in dopaminergic neurons. Properties of excitatory synaptic transmission to the dopaminergic neurons have been analyzed using intracellular and patch-clamp recording methods. In the present study, we attempted to establish the field recording procedure in VTA slice preparations to monitor excitatory synaptic transmission. We evaluated this procedure using slice preparations from 6-hydroxydopamine (6-OHDA)-treated animals. In horizontal slices containing the VTA, electrical stimulation of anterior afferent fibers produced two distinct negative field potentials, presumably a fiber volley component and a transsynaptic component. Pharmacological analysis revealed that the transsynaptic component was composed of bicuculline-sensitive and CNQX-sensitive components. Neonatal 6-OHDA administration reduced approximately 90% of tyrosine hydroxylase expression in the VTA and eliminated more than 50% of the transsynaptic components. This result suggests that at least 50% of the observed transsynaptic component reflected the postsynaptic responses of the dopaminergic neurons.
成瘾性药物和心理压力会影响腹侧被盖区（VTA）神经元的输入强度，这意味着突触可塑性参与了多巴胺能神经元的活动。已使用细胞内和膜片钳记录方法分析了向多巴胺能神经元的兴奋性突触传递特性。在本研究中，我们试图建立VTA脑片制备中的场记录程序，以监测兴奋性突触传递。我们使用来自6-羟基多巴胺（6-OHDA）处理动物的脑片制备物评估了该程序。在包含VTA的水平脑片中，对前传入纤维进行电刺激产生了两个不同的负场电位，推测为纤维群峰成分和跨突触成分。药理学分析表明，跨突触成分由荷包牡丹碱敏感成分和CNQX敏感成分组成。新生期给予6-OHDA可使VTA中酪氨酸羟化酶表达降低约90%，并消除超过50%的跨突触成分。该结果表明，至少50%观察到的跨突触成分反映了多巴胺能神经元的突触后反应。
