Carboni E, Cadoni C, Tanda G L, Di Chiara G
Institute of Experimental Pharmacology and Toxicology, University of Cagliari, Italy.
J Neurochem. 1989 Sep;53(3):976-8. doi: 10.1111/j.1471-4159.1989.tb11802.x.
The effect of intraperitoneal administration of tryptophan (50, 100, or 200 mg/kg) on extracellular concentrations of tryptophan, serotonin (5-hydroxytryptamine, 5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) was studied in the cortex of freely moving rats by transcerebral dialysis. Rats were implanted with dialysis probes in the frontal cortex, and experiments were performed 24 h later. Tryptophan, 5-HT, and 5-HIAA were quantified in 20-min samples of dialysate by HPLC with electrochemical detection after separation on reverse-phase columns. Tryptophan administration resulted in a significant increase of tryptophan, 5-HT, and 5-HIAA levels in dialysates. The maximal increase of 5-HT and 5-HIAA output was approximately 150% over basal values. Perfusion with Ringer's solution containing tetrodotoxin (1 microM) reduced 5-HT output by 90% and prevented the increase of 5-HT and 5-HIAA content after 100 mg/kg of tryptophan. Similar results were obtained after perfusion with Ringer's solution without Ca2+. The results indicate that a tryptophan load stimulates the physiological release of 5-HT.
通过脑透析研究了腹腔注射色氨酸（50、100或200毫克/千克）对自由活动大鼠皮层中色氨酸、5-羟色胺（5-羟色胺，5-HT）和5-羟吲哚乙酸（5-HIAA）细胞外浓度的影响。在大鼠额叶皮层植入透析探针，24小时后进行实验。通过高效液相色谱法结合电化学检测，在反相柱上分离后，对20分钟透析液样本中的色氨酸、5-HT和5-HIAA进行定量分析。注射色氨酸导致透析液中色氨酸、5-HT和5-HIAA水平显著升高。5-HT和5-HIAA输出的最大增幅比基础值高出约150%。用含河豚毒素（1微摩尔）的林格氏液灌注使5-HT输出降低了90%，并阻止了100毫克/千克色氨酸注射后5-HT和5-HIAA含量的增加。在无Ca2+的林格氏液灌注后也获得了类似结果。结果表明，色氨酸负荷刺激了5-HT的生理性释放。
