Inhibitory and excitatory neurotransmitter systems in depressed and healthy: A positron emission tomography and magnetic resonance spectroscopy study

The Gamma-aminobutyric acid (GABA) and glutamate (Glu) neurotransmitter systems are implicated in depression. While previous studies found reduced GABA levels, a tendency towards Glu, using proton (1H) magnetic resonance spectroscopy (1H-MRS), little is known about GABAA receptor availability Here, the aim was to characterize Glu-levels dorsal anterior cingulate cortex (dACC), whole-brain availability, their relationship patients with depression compared healthy controls. Forty-two 45 controls underwent 1H-MRS MEGA-PRESS sequence quantify dACC GABA+ Glu (contrasted against creatine [Cr]). Immediately preceding 1H-MRS, subsample of 28 15 positron emission tomography (PET) [11C]Flumazenil assess availability. There were no differences GABA+/Cr or Glu/Cr ratios between same true for However, there significant negative ratio ACC, voxel-wise analysis across controls, controlling group depressive symptoms. This relatively large study did not support GABA-deficit hypothesis depression, but shed light on GABA-system functioning, suggesting balance concentration dACC.