Elevated glutamine levels and activation of astrocytes involved in excessive excitatory neurotransmissions in autism spectrum disorder

We conducted MRS and PET to examine if enhanced excitatory tones occur and correlate with astroglial activations and/or diminished dopaminergic suppression of astrocytic functions in autism spectrum disorder (ASD) cases. MRS revealed elevated glutamate and glutamine levels associated with astroglial activation in ASD versus control anterior cingulate cortex, while there were also inverse correlations between glutamine levels and dopamine D1 receptor availability in this area of both ASD cases and controls. Hence, dopamine transmissions may repress astroglial glutamine synthesis independently of the ASD etiology, while astroglial activation in ASD could elicit augmented glutamate synthesis and consequent excitation of neuronal tones.