Complex sentence: Upon release, GABA is taken up by glial cells via GABA transporters, metabolized into succinate, then in a series of steps to alpha-ketoglutarate and then back to glutamine via glutamate.
Split into simpler sentences: Upon release, GABA is taken up into astrocytes via GABA transporters and then catabolized into succinate, a TCA cycle intermediate. Then in a series of steps to alpha-ketoglutarate and then back to glutamine via glutamate.