GABAergic signalling in a neurogenic niche of the turtle spinal cord

Non-technical summary Neurogenesis is tightly regulated by epigenetic factors that assure the correct assembly of neural circuits. Neurotransmitters play a fundamental role in this type of control. We show that GABA signals on progenitors and immature neurones within a neurogenic niche around the central canal (CC) of the turtle spinal cord. GABA depolarized progenitors whereas the effect on immature neurones varied from excitation to inhibition. In both cell types GABAA receptor activation induced an increase in intracellular calcium. Our findings imply that GABAergic signalling around the CC shares fundamental properties with those in the embryo and adult neurogenic niches in the brain, suggesting that GABA is part of the mechanisms regulating the production and integration of neurones to already operational spinal circuits. Understanding the GABAergic modulation of progenitors and neuroblasts may provide useful clues about key mechanisms needed for functional neurogenesis in the spinal cord.