GABA, the main inhibitory neurotransmitter in the adult brain, hyperpolarizes the membrane and inhibits neuronal firing by activating two different classes of receptors: GABA SB A sb and GABA SB B sb . Unlike GABA SB A sb receptors, which form integral ion channels, GABA SB B sb receptors are coupled to ion channels via guanine nucleotide-binding proteins and second messengers. This Special Issue, "GABA Signaling: Therapeutic Targets for Neurodegenerative and Neurodevelopmental Disorders", focuses on a fundamental property of the neurotransmitter -aminobutyric acid (GABA), namely its capacity to shift, in particular conditions, from the hyperpolarizing to the depolarizing direction. [Extracted from the article]