Masiello P, Balestreri E, Bacciola D, Bergamini E
Acta Diabetol Lat. 1987 Jan-Mar;24(1):43-50. doi: 10.1007/BF02732052.
The variations in serum and brain concentrations of the large neutral amino acids and the simultaneous changes in brain levels of monoamine neurotransmitters have been studied in normal and streptozotocin-diabetic rats after tryptophan loading. An impaired acute accumulation of tryptophan and serotonin in the brain of diabetic rats was observed, concomitantly with a much faster disappearance of the administered tryptophan from the bloodstream in these animals than in controls. Following the tryptophan load, transient differences in the brain levels of catecholamine neurotransmitters became also apparent between the two groups of rats in correlation with differences in the brain uptake and levels of tyrosine. In diabetic animals, the basal brain concentrations of serotonin and dopamine were normal and those of norepinephrine were increased. Since uptake of the precursors tryptophan and tyrosine from the blood is chronically reduced, it is likely that long-term adjustments of neurotransmitter metabolism occur in the diabetic brain.
在正常大鼠和链脲佐菌素诱导的糖尿病大鼠中，经色氨酸负荷后，研究了血清和脑中大型中性氨基酸浓度的变化以及脑内单胺类神经递质水平的同步变化。观察到糖尿病大鼠脑内色氨酸和血清素的急性蓄积受损，与此同时，与对照组相比，这些动物血液中注入的色氨酸消失得更快。色氨酸负荷后，两组大鼠脑内儿茶酚胺类神经递质水平的短暂差异也变得明显，这与脑内酪氨酸摄取和水平的差异相关。在糖尿病动物中，脑内血清素和多巴胺的基础浓度正常，去甲肾上腺素的基础浓度升高。由于血液中前体色氨酸和酪氨酸的摄取长期减少，糖尿病脑内可能发生神经递质代谢的长期调节。
