Gamma-aminobutyric acid (GABA) promotes recovery from spinal cord injury in lampreys: role of GABA receptors and perspective on the translation to mammals

In mammals, spinal cord injury (SCI) is a devastating event that can lead to a permanent loss of motor, sensory and autonomic functions below the site of injury. In the last years, the role of different neurotransmitter systems on regeneration and recovery from SCI has been deciphered. For example, studies in lampreys have shown that neurotransmitters play a key role in modulating the survival and regeneration of brainstem descending neurons after SCI (Romaus-Sanjurjo et al., 2018; Sobrido-Cameán et al., 2018). Glutamate is known to play a prominent role after SCI since it causes excitotoxicity to non-injured neurons during the secondary phase after a traumatic injury both in mammals and lampreys (Fernández-López et al., 2014). In contrast, recent work in lampreys has shown that γ-aminobutyric acid (GABA) can play a neuroprotective and pro-regenerative role after SCI (Romaus-Sanjurjo et al., 2018). GABA is the main inhibitory neurotransmitter in the central nervous system (CNS) of vertebrates, and acts through both metabotropic G-protein-coupled GABAB receptors, and ionotropic ligand-gated chloride channel GABAA receptors. Here, we discuss recent work from our group and others on the possible role of different GABA receptors in neuronal survival and regeneration after SCI and provide a perspective on future work in this field.