ANALYSIS OF β-PHENYLETHYLAMINE AND CHANGES OF ITS LEVEL IN THE BRAIN AFTER ADMINISTRATION OF METHAMPHETAMINE

β-苯乙胺（PEA）是一种内源性化合物，其结构与多巴胺和兴奋剂药物相似。脑B区PEA浓度的变化可能与智力低下的表现有关，而PEA作为一种多巴胺能神经毒素对其产生影响，兴奋剂药物对PEA的影响对于评价神经细胞的变化、行为效应等也显得非常重要。本研究采用微透析法结合气相色谱/质谱联用技术测定了大鼠纹状体细胞外液中PEA浓度的基础值。1）以3-苯基-1-丙胺为内标，五氟苯甲醛为衍生试剂，建立了灵敏、可靠的分析方法。大鼠纹状体细胞外液中PEA的基础水平约为260.54pg/ml。2）MA给药后，大鼠纹状体细胞外液中PEA水平逐渐升高，至24天时略有下降。这一发现表明，在检查过程中，MA的强代谢产物安非他明会竞争性地使单胺氧化酶B脱乙酰化或抑制PEA的再摄取。纹状体和下丘脑细胞内液中PEA的基础水平略高于脑的其他部分。MA给药后，纹状体、海马、下丘脑、中脑和脑桥等脑区PEA浓度逐渐降低，导致神经细胞发生微变性。另一方面，在10 mg/kg MA给药后6或12小时，在脑的各个部位未观察到组织病理学检查的显著变化。

The structure is similar to dopamine and stimulant drug on β-phenyl-ethylamine (PEA) which is an endogenous chemical compound. The change of the PEA concentration in the b rain may be concerned in the mental retardation expression, while PEA affects it as a dopaminergic neurotoxin, and influence of stimulant drugs on PEA also seems to be very important in order to evaluate nerve cell change behavioral effects, etc..In this study, we measured the basic value of PEA concentration in extracellular fluid obtained from rat striatum by using microdialysis method combined with gas chromatography/mass spectrometry. Simultaneously, the changes of PEA concentration in various parts of the brain after methamphetamine (MA) administration was also examined.1) A sensitive and reliable analytical method was established by means of 3-phenyl-1-propylamine as an internal standard and pentafluorobenzaldehyde as a derivative agent. The basal level of PEA in extracellular fluid of rat striatum was around 260.54 pg/ml.2) Extracellular PEA level in rat striatum gradually increased with a slight decrease at the time of 24th after administration of 20 mg/kg of MA. This finding indicated that the competitive antagonization of monoamine oxydase B by amphetamine which is a potent metabolite of MA or inhibition of reup take of PEA would occur during the examination. The basal levels of PEA in intracellular fluid were slightly higher in the striatum and hypothalamus than the other parts of the brain. The PEA concentrations in the striatum, hippocampus, hypothalamus, mesencephalon and pons, etc. were gradually decreased after administration of MA, so that the micro-degeneration of neural cells would generate by MA administration. On the other hand, no remarkable changes In histo-pathological examinations were observed in the various parts of the brains at the time of 6 or 12hr after 10 mg/kg of MA administration.