Our aim has been to study the effect of gestational and early postnatal hypothyroidism on the distribution, ratio and size of vesicular glutamate transporter type 1 (VGluT1; labeling glutamatergic) and that of vesicular inhibitory amino acid transporter (VGAT; labeling GABAergic) immunoreactive (ir) boutons in the hippocampal formation and somatosensory cortex of rats. This evidence concerns the gene SLC32A1 and hypothyroidism.