Cook C J
Animal Stress and Welfare Programme, Meat Industry Research Institute of New Zealand, Hamilton.
J Neurosci Methods. 1997 Apr 4;72(2):161-6. doi: 10.1016/s0165-0270(96)02175-9.
Measurements of neurotransmitters in conscious animals have been restrictive in real-time. The use of specific enzymes within an amperometric probe, based upon a microdialysis membrane, may overcome some of these problems. I report the use of such a probe, with different perfusions of enzymes, to allow real-time measurement of glutamate, catecholamines and indoleamines, in conscious animals. At an adjacent site microdialysis sample collections were made concurrently and neurotransmitters measured in the dialysate. Both probes were positioned within the somatosensory cortex. Values obtained by amperometric probes were similar to those in dialysate samples for glutamate, catecholamines and indoleamines during basal and stimuli related collections. Amperometric measurements showed higher peak concentrations and better time resolution than dialysate sampling. This reflects sampling differences. Application of external stimuli increased extracellular concentrations of glutamate, catecholamines and indoleamines, in both forms of sampling. Dopamine measurements did not correlate well between the two forms of sampling. This may reflect the non-specificity of the enzyme (dopamine-beta-hydroxylase) used in the amperometric probe. This combination, of microdialysis and amperometry, offers a useful tool for real-time neurotransmitter studies in vivo.
对清醒动物神经递质的测量一直局限于实时测量。基于微透析膜在电流型探针中使用特定酶，可能会克服其中一些问题。我报告了使用这种带有不同酶灌注的探针，在清醒动物中实时测量谷氨酸、儿茶酚胺和吲哚胺。在相邻部位同时进行微透析样本采集，并测量透析液中的神经递质。两个探针都置于体感皮层内。在基础状态和与刺激相关的采集过程中，电流型探针获得的谷氨酸、儿茶酚胺和吲哚胺的值与透析液样本中的值相似。电流型测量显示出比透析液采样更高的峰值浓度和更好的时间分辨率。这反映了采样差异。外部刺激的应用在两种采样形式中均增加了谷氨酸、儿茶酚胺和吲哚胺的细胞外浓度。两种采样形式之间多巴胺的测量结果相关性不佳。这可能反映了电流型探针中使用的酶（多巴胺-β-羟化酶）的非特异性。微透析和电流测定法的这种结合为体内实时神经递质研究提供了一种有用的工具。
