Endogenous Release of Neuronal Serotonin and 5‐Hydroxyindoleacetic Acid in the Caudate‐Putamen of the Rat as Revealed by Intracerebral Dialysis Coupled to High‐Performance Liquid Chromatography with Fluorimetric Detection

作者：Peter Kalén, Robert E. Strecker, Evald Rosengren, Anders Björklund · 发表于：Journal of Neurochemistry · 年份：1988 · DOI：10.1111/j.1471-4159.1988.tb01107.x · 被引用次数：236 · 研究领域：Neurotransmitter Receptor Influence on Behavior、Pain Mechanisms and Treatments、Ion channel regulation and function

Abstract: Extracellular levels of endogenous serotonin (5‐HT) and its major metabolite, 5‐hydroxyindoleacetic acid (5‐HIAA), were measured in the caudate‐putamen of anesthetized and awake rats using intracerebral microdialysis coupled to HPLC with fluorimetric detection. A dialysis probe (of the loop type) was perfused with Ringer solution at 2 μl/min, and samples collected every 30 or 60 min. Basal indole levels were followed for up to 4 days in both intact and 5,7‐dihydroxytryptamine (5,7‐DHT) lesioned animals. Immediately after the probe implantation, the striatal 5‐HT levels were about 10 times higher than the steady‐state levels that were reached after 7‐8 h of perfusion. The steady‐state baseline levels, which amounted to 22.5 fmol/30 min sampling time, remained stable for 4 days. In 5,7‐DHT‐denervated animals, the steady‐state levels of 5‐HT, measured during the second day after probe implantation, were below the limit of detection (<10 fmol/60 min). However, during the first 6h post‐implantation, the 5‐HT output was as high as in intact animals, which suggests that the high 5‐HT levels recovered in association with probe implantation were blood‐derived. As a consequence, all other experiments were started after a delay of at least 12 h after implantation of the dialysis probe. In awake, freely moving animals, the steady‐state 5‐HT levels were about 60% higher than in halothane‐anesthetized animals, whereas 5‐HIAA was unaffected by anesthesia. KCI (60 and 100 mM) added...