Development of amino acid receptors in frontal cortex from girls with Rett syndrome.

To determine whether a disorder of excitatory neurotransmission plays a role in the pathophysiology of Rett syndrome (RS), N-methyl-D-aspartate (NMDA), adenosine monophosphate acid (AMPA), kainate, and metabotropic types of glutamate receptors were labeled autoradiographically in the superior frontal gyrus (SFG) from 9 RS patients and 10 female controls. The results showed a trend for the densities of NMDA, AMPA, gamma-aminobutyric acid, and metabotropic glutamate receptors to be higher in younger patients than in controls and for densities in older patients to fall below those of controls. The age-related changes in SFG NMDA receptor density may be correlated with the shift from psychomotor regression and seizures in younger stage II/III RS girls to the less epileptic plateau stage in older girls.