Hegstrand L R, Simon J R
J Neurochem. 1985 Aug;45(2):407-14. doi: 10.1111/j.1471-4159.1985.tb04002.x.
Histidine transport and metabolism in rat brain synaptosomes were investigated to study the possible role of histidine uptake in the synthesis of the putative neurotransmitter histamine (HA). Histidine uptake was found to be regionally distributed and temperature sensitive, and was not totally independent of sodium or potassium ions. Transport was inhibited by metabolic inhibitors, as well as by promethazine and quinacrine. A number of other HA-related agents and several histidine metabolites had no effect. Kinetic analyses of histidine transport revealed the presence of both high- and low-affinity systems in cerebral cortex. Histidine uptake increased following preexposure of synaptosomes to depolarizing concentrations of potassium. This effect was dependent on the presence of calcium ions during the preincubation. No newly formed [3H]HA was detectable in rat brain synaptosomes following [3H]histidine transport. Lesions of the medial forebrain bundle did not alter histidine uptake in the hippocampus or cerebral cortex. Ontogenic studies indicated that the histidine uptake system developed rapidly and reached a peak during postnatal days 12-17. Overall, the present findings do not support a role for histidine transport in the regulation or maintenance of neurotransmitter pools of HA in rat brain.
为了研究组氨酸摄取在假定神经递质组胺（HA）合成中的可能作用，对大鼠脑突触体中的组氨酸转运和代谢进行了研究。发现组氨酸摄取具有区域分布且对温度敏感，并且并非完全独立于钠离子或钾离子。转运受到代谢抑制剂以及异丙嗪和奎纳克林的抑制。许多其他与HA相关的试剂和几种组氨酸代谢物没有作用。组氨酸转运的动力学分析表明，大脑皮层中同时存在高亲和力和低亲和力系统。突触体预先暴露于去极化浓度的钾后，组氨酸摄取增加。这种效应取决于预孵育期间钙离子的存在。在[3H]组氨酸转运后，大鼠脑突触体中未检测到新形成的[3H]HA。内侧前脑束损伤并未改变海马体或大脑皮层中的组氨酸摄取。个体发育研究表明，组氨酸摄取系统发育迅速，并在出生后第12 - 17天达到峰值。总体而言，目前的研究结果不支持组氨酸转运在大鼠脑中HA神经递质池的调节或维持中起作用。
