GABA metabolism controls inhibition efficacy in the mammalian CNS.

The effects of changes in gamma-aminobutyric acid (GABA) metabolism or inhibitory processes was studied in the perforant path-dentate gyrus synapses in rat cortico-hippocampal slices, and in the monosynaptic-reflex circuit in isolated newborn, rat spinal cord. GABA metabolism was modulated by pharmacological block of either the anabolic enzyme glutamate decarboxylase (GAD) or the catabolic enzyme GABA transaminase (GABA-T). The results support the notion that GABA concentration determines the efficacy of inhibition in these regions of the central nervous system (CNS).