Gerhardt G A, Ksir C, Pivik C, Dickinson S D, Sabeti J, Zahniser N R
Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262, USA.
J Neurosci Methods. 1999 Feb 1;87(1):67-76. doi: 10.1016/s0165-0270(98)00158-7.
Methodology is presented for constructing and using an electrode/microcannulae assembly that allows in vivo electrochemical measurements coupled with local application of dopamine (DA) and other chemicals in the unanesthetized freely-moving rat. Rats were implanted with a voltammetric electrode constructed of a carbon fiber sealed in fused silica tubing attached to a pair of stainless steel guide cannulae, into which fused silica injection cannulae were inserted for local application of DA and other chemicals. Precise delivery of nanoliter volumes was accomplished using a syringe drive combined with a fluid swivel to deliver the solutions to the injection cannulae. A newly-designed miniature potentiostat connected to a commutator via a modular telephone jack assembly allowed for high-speed chronoamperometric electrochemical recordings in freely-moving rats. Initial experiments characterized the in vitro electrochemical recording characteristics of the voltammetric electrode. In vivo studies were also carried out to study clearance of locally-applied DA and of potassium-evoked endogenous DA in the striatum and nucleus accumbens of freely-moving rats. In addition, the effects of chloral hydrate anesthesia on DA clearance signals in the nucleus accumbens were investigated. Moreover, the stability and reproducibility of this recording technique for measuring exogenous DA clearance was verified over a period of 5 days. Finally, the concurrent effects of systemic cocaine injection on DA uptake in nucleus accumbens and locomotor activity were examined. These studies support the conclusion that the methodology described herein allows for rapid chronoamperometric electrochemical recordings in freely-moving rats with precise microapplications of DA and other chemicals combined with concurrent measures of animal behavior.
本文介绍了一种构建和使用电极/微插管组件的方法，该组件可在未麻醉的自由活动大鼠体内进行电化学测量，并同时局部应用多巴胺（DA）和其他化学物质。将由密封在熔融石英管中的碳纤维构成的伏安电极植入大鼠体内，该管连接到一对不锈钢引导插管，将熔融石英注射插管插入其中以局部应用DA和其他化学物质。使用与流体旋转接头相结合的注射器驱动器将溶液输送到注射插管，从而精确输送纳升体积的溶液。通过模块化电话插孔组件连接到换向器的新设计的微型恒电位仪允许在自由活动的大鼠中进行高速计时电流电化学记录。初步实验表征了伏安电极的体外电化学记录特性。还进行了体内研究，以研究自由活动大鼠纹状体和伏隔核中局部应用的DA以及钾诱发的内源性DA的清除情况。此外，研究了水合氯醛麻醉对伏隔核中DA清除信号的影响。此外，在5天的时间内验证了这种测量外源性DA清除的记录技术的稳定性和可重复性。最后，研究了全身注射可卡因对伏隔核中DA摄取和运动活动的同时影响。这些研究支持以下结论：本文所述的方法允许在自由活动的大鼠中进行快速计时电流电化学记录，同时精确微应用DA和其他化学物质，并同时测量动物行为。
