both substances inhibited the activity of glutamic acid decarboxylase [ ec 4.1.1.15 ] ( gad ) in the synaptosomal fraction ( nerve ending particles ) and reduced the concentration of gaba in the same fraction at the onset of convulsions , though changes in the total gaba concentration in the brain did not correlate with the onset of convulsions .
C0086045
concentration
C0006104
brain