Dougan D F, Duffield A M, Duffield P H, Wade D N
Br J Pharmacol. 1983 Oct;80(2):309-14. doi: 10.1111/j.1476-5381.1983.tb10035.x.
The concentration in rat striatum of the meta and para isomers of tyramine and alpha-methyltyramine, after the administration of (+)-amphetamine, alpha-methyl-p-tyrosine (AMPT) and alpha-methylphenylalanine (AMPA) has been determined using chemical ionization gas chromatography mass spectrometry (c.i.g.c.m.s.). Twenty hours after the last of 7 daily injections of (+)-amphetamine (5 mg kg-1 i.p.) the concentration of alpha-methyl-p-tyramine in striatal tissue increased twofold compared to the concentration 20 h after a single injection. In contrast the concentration of alpha-methyl-m-tyramine did not change. alpha-Methyl-m-tyramine and alpha-methyldopamine were found in the striatum at concentrations of 42 ng g-1 and 13.5 ng g-1 respectively after treatment of rats 20 h before with AMPA (100 mg kg-1 i.p.). After treatment with AMPT (100 mg kg-1, 20 h before decapitation) only the para isomer of alpha-methyltyramine could be detected (13.7 ng g-1) although the striatal concentration of alpha-methyldopamine was 274 ng g-1, a level 20 times greater than that observed after AMPA treatment. The combined administration of both AMPT and AMPA (100 mg kg-1 each, 20 h) resulted in a reduction of the striatal concentration of alpha-methyl-m-tyramine but not alpha-methyl-p-tyramine. These data suggest that alpha-methyl-m-tyramine in rat striatum is formed by the enzyme tyrosine hydroxylase on substrate AMPA, rather than by ring dehydroxylation of alpha-methyldopa and alpha-methyldopamine. Significant reductions in the striatal concentrations of m-tyramine 2 h after the administration of AMPT, suggest that tyrosine hydroxylase is involved similarly in the production of m-tyramine.
运用化学电离气相色谱质谱联用仪（c.i.g.c.m.s.）测定了给予（+）-苯丙胺、α-甲基对酪氨酸（AMPT）和α-甲基苯丙氨酸（AMPA）后，大鼠纹状体中酪胺和α-甲基酪胺的间位和对位异构体的浓度。在每日7次注射（+）-苯丙胺（5mg/kg，腹腔注射）的最后一次注射20小时后，纹状体组织中α-甲基对酪胺的浓度相较于单次注射20小时后的浓度增加了两倍。相比之下，α-甲基间酪胺的浓度没有变化。在用AMPA（100mg/kg，腹腔注射）处理大鼠20小时后，在纹状体中发现α-甲基间酪胺和α-甲基多巴胺的浓度分别为42ng/g和13.5ng/g。在用AMPT（100mg/kg，断头前20小时）处理后，虽然纹状体中α-甲基多巴胺的浓度为274ng/g，是AMPA处理后观察到水平的20倍，但仅能检测到α-甲基酪胺的对位异构体（13.7ng/g）。同时给予AMPT和AMPA（各100mg/kg，20小时）导致纹状体中α-甲基间酪胺的浓度降低，但α-甲基对酪胺的浓度未降低。这些数据表明，大鼠纹状体中的α-甲基间酪胺是由酪氨酸羟化酶作用于底物AMPA形成的，而不是由α-甲基多巴和α-甲基多巴胺的环脱羟基作用形成的。给予AMPT 2小时后，纹状体中间酪胺的浓度显著降低，这表明酪氨酸羟化酶同样参与了间酪胺的生成。
