Studies of plasma PEA and platelet MAO in affective disorders

β-苯乙胺（PEA）是一种内源性单胺，其化学结构类似于安非他明，已在人类和其他哺乳动物的大脑中鉴定出。虽然PEA的存在量比儿茶酚胺少得多，但PEA作为神经调节剂的作用模式特别令人感兴趣。最近，有越来越多的临床证据表明，PEA在情感障碍中发挥作用。本文采用气相色谱-质谱联用技术，建立了一种灵敏的测定人血浆中PEA浓度的方法，并对抑郁症患者的血浆PEA浓度进行了测定。将抑郁症患者分为高、低PEA水平组。PEA低者，给予去甲丙咪嗪后生长激素反应低，血浆3-甲氧基-4-羟基苯乙二醇（MHPG）浓度高。另一组抑郁症患者去甲丙咪嗪试验生长激素反应正常，血浆MHPG水平低。血小板单胺氧化酶（MAO）活性也在这些患者中进行了测定。部分患者血小板单胺氧化酶活性增高。抑郁症患者血浆PEA水平与正常对照组相比无显著性差异，提示抑郁症患者PEA水平的差异可能与抑郁症的临床表现有关，PEA可能是抑郁症患者的生物学标志之一。

beta-phenylethylamine(PEA), an endogenous monoamine that resembles amphetamine in its chemical structure, has been identified in human and other mammalian brains. Although PEA exists in much smaller amounts than catecholamines, the mode of action of PEA as a neuromodulator is of special interest. Recently, there has been growing clinical evidence suggesting that PEA plays a role in affective disorders. The authors investigated a sensitive method for the assay of PEA in human plasma, using a gas-chromatography mass spectrometry.The plasma levels of PEA was measured in depressive patients by this new method. The depressive patients were divided into those with high and low PEA levels. The low response of growth hormone after the desmethylimipramine administration and higher 3methoxy 4hydroxy phenylethyleneglycol(MHPG) in plasma were shown in the patients with low plasma levels of PEA. The normal response of growth hormone by desmethylimipramine test and low plasma levels of MHPG were found in the other group of depressive patients. Platelet monoamine oxidase(MAO) activity was also determined in those patients. The higher platelet MAO additivity was found in some patients. But, platelet MAO activity in the depressive patients was not significantly increased, compared with the healthy subjects.These results suggest that the distinction of PEA levels between two subgroups in depressive patients raise the possibility of clinical differences between the groups, and that PEA in plasma might be one of biological markers in the depressive patients.These results will be reported in the symposium of CINP,1990.