Binding of gamma-aminobutyric acid and taurine to synaptosomal fractions of regions of the feline CNS.

The "binding" of 3H-gamma-aminobutyric acid (3H-GABA) and 14C-taurine (7 X 10(-5) M) to synaptosomal fractions of the feline CNS was studied using differential centrifugation and double-isotope methods. Of the regions examined, the "binding" of GABA (in nmole/mg protein) occurred to the greatest extent, in cerebral cortex, olfactory bulb, and colliculi and, to a lesser extent, in caudate nucleus, corona radiata, and fornix. Distribution ratios revealed that GABA binding was greater in the cerebral cortex than in caudate nucleus, brain stem, spinal cord, and white matter regions. The binding of taurine (in nmole/mg protein) was lowest in cerebral cortex and highest in brain stem and spinal gray regions. Distribution ratios for taurine indicated that its accumulation was similar in all CNS regions studied, except for slightly higher values for cerebellar cortex and fornix. These results indicated that preferential binding of both GABA and taurine exists among regions of the feline CNS.