Stamford J A, Kruk Z L, Miller J
Eur J Pharmacol. 1986 Aug 7;127(1-2):57-65. doi: 10.1016/0014-2999(86)90206-2.
Carbon fibre microelectrodes were implanted acutely into the striatum of chloral hydrate-anaesthetised rats to measure the dopamine released by electrical stimulation of the ipsilateral nigrostriatal pathway. High speed cyclic voltammetry was used throughout. The effects of metoclopramide and of different stimulation parameters (frequency and duration) were investigated. Using a 10 s stimulus train, it was found that frequencies less than 25 Hz evoked little measurable dopamine release. Maximum release occurred at 50-62.5 Hz. Metoclopramide (2.5-20 mg/kg i.p.) increased stimulated dopamine release in a dose-dependent fashion. The effect of metoclopramide (10 mg/kg) was investigated in detail at 25, 37.5 and 50 Hz stimulation frequency and at 2.5, 5.0 and 10.0 s after the onset of stimulation. Metoclopramide, at all stimulation frequencies, caused the largest percentage elevation of release at 2.5 s of stimulation. The results indicate that prolonged stimulation can deplete the releasable pool of dopamine and mask the effects of dopamine receptor blockade.
将碳纤维微电极急性植入水合氯醛麻醉大鼠的纹状体，以测量电刺激同侧黑质纹状体通路释放的多巴胺。全程使用高速循环伏安法。研究了甲氧氯普胺以及不同刺激参数（频率和持续时间）的影响。使用10秒的刺激序列，发现频率低于25赫兹时几乎检测不到多巴胺释放。最大释放量出现在50 - 62.5赫兹。甲氧氯普胺（腹腔注射2.5 - 20毫克/千克）以剂量依赖方式增加刺激诱导的多巴胺释放。在25、37.5和50赫兹刺激频率以及刺激开始后2.5、5.0和10.0秒时，详细研究了甲氧氯普胺（10毫克/千克）的作用。在所有刺激频率下，甲氧氯普胺在刺激2.5秒时引起的释放增加百分比最大。结果表明，长时间刺激会耗尽可释放的多巴胺池，并掩盖多巴胺受体阻断的作用。
