Wang Po W, Sailasuta Napapon, Chandler Rebecca A, Ketter Terence A
1Department of Psychiatry and Behavioral Sciences, Bipolar Disorders Clinic, Stanford University School of Medicine, Stanford, CA, USA.
2Department of Medicine, University of Hawaii, Honolulu, HI ,USA.
Acta Neuropsychiatr. 2006 Apr;18(2):120-6. doi: 10.1111/j.1601-5215.2006.00132.x.
Animal models of depression and psychopharmacological mechanisms of action suggest the importance of the gamma-amino butyric acid (GABA) system in the pathophysiology of mood disorders. Mood stabilizers have overlapping effects on GABAergic neurotransmission, and antidepressant use has been associated with alterations in GABAB receptor function. Magnetic resonance spectroscopy (MRS) provides an opportunity to noninvasively assess cerebral GABA concentrations in anterior paralimbic circuits that have been implicated in mood disorders.
In bipolar disorder patients and healthy control subjects, we used MRS with a modified GABA-edited point resolved spectroscopy sequence (TE 68 ms, TR 1500 ms, 512 averages, total scan time 26 min) to assess GABA in an 18-cm3 occipital voxel. In addition, in another cohort of bipolar disorder patients and healthy control subjects, we similarly assessed GABA in a 12.5-cm3 medial prefrontal/anterior cingulate (MPF/AC) voxel. The concentration of GABA was referenced to creatine (Cr) from unedited spectra.
In bipolar patients and controls, we consistently detected 3.0 p.p.m. GABA peaks in occipital lobe and MPF/AC. In 16 bipolar (nine bipolar I and seven bipolar II) disorder patients, compared with six healthy control subjects, mean occipital GABA/Cr concentration was 61% higher. In addition, in 15 bipolar (five bipolar I, nine bipolar II, and one bipolar not otherwise specified) disorder patients, compared with six healthy control subjects, mean MPF/AC GABA/Cr concentration tended to be 41% higher.
Patients with bipolar disorders may have increased cerebral GABA concentrations. Although this was more evident in the occipital lobe, MPC/AC GABA disturbance may be of greater potential interest in view the more established role of MPF/AC in affective processing. Additional studies are warranted to assess changes in GABAergic neurotransmission and the influences of diagnosis, mood state, and medication status in bipolar disorder patients.
抑郁症动物模型和精神药理学作用机制表明，γ-氨基丁酸（GABA）系统在情绪障碍的病理生理学中具有重要意义。心境稳定剂对GABA能神经传递具有重叠效应，并且抗抑郁药的使用与GABAB受体功能的改变有关。磁共振波谱（MRS）为无创评估与情绪障碍相关的前边缘旁回路中的脑GABA浓度提供了机会。
在双相情感障碍患者和健康对照受试者中，我们使用具有改良的GABA编辑点分辨波谱序列（TE 68 ms，TR 1500 ms，512次平均，总扫描时间26分钟）的MRS来评估18立方厘米枕叶体素中的GABA。此外，在另一组双相情感障碍患者和健康对照受试者中，我们同样评估了12.5立方厘米内侧前额叶/前扣带回（MPF/AC）体素中的GABA。GABA浓度以未编辑波谱中的肌酸（Cr）为参照。
在双相情感障碍患者和对照组中，我们在枕叶和MPF/AC中一致检测到3.0 ppm的GABA峰。在16例双相情感障碍（9例双相I型和7例双相II型）患者中，与6例健康对照受试者相比，枕叶GABA/Cr平均浓度高61%。此外，在15例双相情感障碍（5例双相I型、9例双相II型和1例未另行指定的双相型）患者中，与6例健康对照受试者相比，MPF/AC GABA/Cr平均浓度倾向于高41%。
双相情感障碍患者的脑GABA浓度可能升高。虽然这在枕叶中更为明显，但鉴于MPF/AC在情感加工中已确立的作用，MPC/AC GABA紊乱可能更具潜在研究价值。有必要进行更多研究来评估双相情感障碍患者中GABA能神经传递的变化以及诊断、情绪状态和用药状态的影响。
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