Postnatal development of the GABA system in the rat spinal cord.

Abstract
To assess the postnatal development of the GABA system in the rat spinal cord, GABA levels, GAD [glutamic acid decarboxylase] activity and specific [3H]-muscimol binding were determined in the dorsal and ventral areas. GABA levels and GAD activities did not vary in parallel from 1-8 postnatal days since the former decreased and the latter increased. After 8 days increases in GABA levels and GAD activities were observed in tissues from the dorsal area and decreases were observed in tissues from the ventral area. Specific [3H]muscimol binding was unexpectedly high in both areas at 1 and 8 days but decreased linearly up to 22 days. There were apparently distinct differences in the development of the GABA system in the rat spinal cord and brain.