GABA AS METABOLIC REGULATOR. “Consider g-aminobutyric acid (GABA), an amino acid present in plant and animals alike. In plants, unlike in the animal literature where its role in neurotransmission is the focus of attention, GABA has been studied primarily for its metabolic role (protection against oxidative stress, cytosolic pH regulation, etc.”
http://link.springer.com/article/10.1007/s11229-016-1040-1