Ishii K, Kato T
Brain Res. 1985 Dec 16;359(1-2):260-6. doi: 10.1016/0006-8993(85)91436-2.
In order to investigate self-regulation of dopamine (DA) neurons, the effects of intranigrally administered haloperidol (Hal), a DA receptor antagonist, on nigrostriatal DA systems were examined using differential pulse voltammetry with carbon fiber electrode. The measurements were achieved in the bilateral caudate-putamen (CP) of behaving rats, in the region of which DA or 3,4-dihydroxyphenylacetic acid made an oxidative current peak (P2) spontaneously. Unilateral injection of Hal (5 micrograms in 1 microliter) into the substantia nigra of rat increased P2 in a time-dependent manner. This phenomenon was observed in both CP, but a more significant increase was in the ipsilateral side (156 +/- 2% of spontaneous height 2.75 h after injection) than in the contralateral side (129 +/- 7%). These effects enlarged in a dose-dependent manner. The same results were found in tissue homogenates determined by high-performance liquid chromatography with electrochemical detection. In the latter case, however, no significant difference was observed between the left and right sides. The present results suggest that Hal, attaching nigral autoreceptors on the cell bodies and dendrites, blocks inhibitory influence of endogenous DA and then activates the nigrostriatal DA neurons, while the contribution of non-dopaminergic neurons is also possible.
为了研究多巴胺（DA）神经元的自我调节，使用碳纤维电极微分脉冲伏安法，检测了DA受体拮抗剂氟哌啶醇（Hal）脑内注射对黑质纹状体DA系统的影响。测量在行为学实验大鼠双侧尾状核-壳核（CP）中进行，在该区域DA或3,4-二羟基苯乙酸可自发产生氧化电流峰（P2）。向大鼠黑质单侧注射Hal（1微升含5微克）可使P2呈时间依赖性增加。两侧CP均观察到该现象，但同侧增加更显著（注射后2.75小时为自发高度的156±2%），对侧增加相对较小（129±7%）。这些效应呈剂量依赖性增强。高效液相色谱电化学检测法测定组织匀浆时也得到相同结果。不过在后一种情况下，两侧之间未观察到显著差异。目前的结果表明，Hal作用于细胞体和树突上的黑质自身受体，阻断内源性DA的抑制性影响，进而激活黑质纹状体DA神经元，同时非多巴胺能神经元也可能起作用。
