Extrasynaptic δ-subunit containing GABAA receptors

Abstract

γ-Aminobutyric acid type A receptors (GABA_ARs) are GABA gated heteropentameric chloride channels responsible for the adult brain's primary inhibition. In specific brain cells, such as in the hippocampus, one of the subtypes of GABA_ARs, the δ subunit containing GABA_ARs (δ-GABA_ARs), is predominantly expressed and located in extrasynaptic or perisynaptic positions. δ-GABA_ARs mediate a slow constant inhibitory current called tonic inhibition. While δ-GABA_ARs and tonic inhibition is critical for the excitability of single neurons, accumulating data suggest that the function of δ-GABA_ARs are broader and includes an integrative role in the network oscillations. While these open new horizons on the neurobiology of δ-GABA_ARs, the complexity continues to challenge the analysis of GABA_ARs and their subtypes. This review will summarize the current knowledge of molecular, cellular and physiological characteristics of δ-GABA_ARs during health and disease.

Keywords: Anxiety; Cys-loop receptors; Dentate gyrus; Depression; Epilepsy; Extrasynaptic; GABA; GABA receptor; GABA(A) receptor; GABAergic interneurons; GABRD; Granule cells; Hippocampus; Inhibition; Ion channel; Phasic; Postpartum; Synaptic; Tonic; δ-subunit.