重性抑郁症首发未用药患者的枕叶GABA波谱研究

在中枢神经系统中,γ-氨基丁酸(GABA)是主要的抑制性神经递质。由于GABA在普通磁共振波谱(MRS)上为低谱峰信号,且与其他物质的波峰重叠,因此难以准确得出其在脑内感兴趣区的含量。为观察抑制性神经递质GABA在首发未用药重性抑郁症(MDD)患者枕叶的含量改变,本研究采用了J-耦合编辑点分辨波谱(MEGA-PRESS)技术检测18例首发未用药重性MDD(17项HAMD评分>18分)患者和23名健康对照被试枕叶皮层的GABA含量。采用双样本t检验及相关分析进行统计学处理。结果表明,病例组枕叶GABA含量(11.35±3.26)显著低于对照组(27.30±8.87),P<0.001。病例组枕叶GABA含量与汉密尔顿抑郁量表及贝克抑郁自评量表相关性均不显著。首发未用药重性MDD患者的枕叶GABA含量降低,可能导致其视觉功能下降。

Decreased occipital GABA concentrations in patients with first-episode major depressive disorder: a magnetic resonance spectroscopy study

Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. Alterations in GABAergic function are associated with a variety of neurological and psychiatric disorders. However, noninvasive in vivo measurement of GABA is difficult because of its low concentration and the presence of overlapping resonances. To study GABA concentration in the occipital cortex in major depressive disorder (MDD), a group of medication-naive, first episode depressed patients (n = 18, HAMD > 17), and a group of healthy controls (n = 23) were investigated using a Point Resolved Spectroscopy (MEGA-PRESS) on a 3.0 T MR scanner. The results showed that occipital GABA levels were significantly lower (P < 0.001) in the patient group than those in the healthy controls, yet the correlations between the severity of MDD (HAMD, BDI) and the GABA concentration is insignificant. Therefore, our data suggest that patients with first episode, unmedicated MDD have changes in cortical concentrations of GABA. This biochemical abnormality may be a marker of a trait vulnerability to mood disorder, and may explain the visual problem of severe MDD patients.