Alexander N, Nakahara D, Ozaki N, Kaneda N, Sasaoka T, Iwata N, Nagatsu T
Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033.
Am J Physiol. 1988 Feb;254(2 Pt 2):R396-9. doi: 10.1152/ajpregu.1988.254.2.R396.
The purpose of this study was to provide new evidence favoring the hypothesis that cardiovascular information from arterial baroreceptors is integrated with the nigrostriatal system that contributes to regulation of motor activity. Samples of extracellular striatal dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were collected by the technique of in vivo microdialysis and analyzed by high-performance liquid chromatography-electron capture detection. Rats were prepared with a guide tube placed in the caudate-putamen for subsequent insertion of microdialysis probes. During the 1st wk after sinoaortic denervation (SAD) or sham operation (SO), a microdialysis probe was inserted and perfused with Ringer solution at the rate of 2 microliter/min in the freely moving rats. Samples were collected every 20 min before and after injection of pargyline, 100 mg/kg ip. The results showed that SAD rats have approximately 50% less extracellular striatal DA, DOPAC, and HVA than SO rats (P less than 0.01). After blockade of monoamine oxidase activity with pargyline, striatal DA accumulated three times faster in SO than SAD rats suggesting DA synthesis is reduced in SAD rats. These data provide further evidence that the arterial baroreceptor system affects dopaminergic metabolism in the nigrostriatal system possibly as a means for integration of cardiovascular and motor activity.
本研究的目的是提供新的证据，支持以下假说：来自动脉压力感受器的心血管信息与黑质纹状体系统整合，该系统有助于调节运动活动。通过体内微透析技术收集细胞外纹状体多巴胺（DA）及其代谢产物二羟基苯乙酸（DOPAC）和高香草酸（HVA）的样本，并通过高效液相色谱-电子捕获检测进行分析。给大鼠制备一根导管，置于尾状核-壳核中，以便随后插入微透析探针。在进行去主动脉窦神经支配（SAD）或假手术（SO）后的第1周，将微透析探针插入自由活动的大鼠体内，并用林格氏液以2微升/分钟的速度灌注。在腹腔注射100毫克/千克优降宁前后，每20分钟收集一次样本。结果显示，与SO大鼠相比，SAD大鼠的细胞外纹状体DA、DOPAC和HVA减少了约50%（P<0.01）。在用优降宁阻断单胺氧化酶活性后，SO大鼠纹状体DA的积累速度比SAD大鼠快三倍，这表明SAD大鼠的DA合成减少。这些数据进一步证明，动脉压力感受器系统可能通过影响黑质纹状体系统中的多巴胺能代谢，来整合心血管和运动活动。
