TY - JOUR
T1 - Spinal dorsal horn astrocytes release GABA in response to synaptic activation
AU - Christensen, Rasmus Kordt
AU - Delgado-Lezama, Rodolfo
AU - Russo, Raúl E
AU - Lind, Barbara Lykke
AU - Alcocer, Emanuel Loeza
AU - Rath, Martin Fredensborg
AU - Fabbiani, Gabriela
AU - Schmitt, Nicole
AU - Lauritzen, Martin
AU - Petersen, Anders Victor
AU - Carlsen, Eva Meier
AU - Perrier, Jean-François
N1 - This article is protected by copyright. All rights reserved.
PY - 2018
Y1 - 2018
N2 - KEY POINTS SUMMARY: GABA is an essential molecule for sensory information processing. It is usually assumed to be released by neurons. Here we show that in the dorsal horn of the spinal cord, astrocytes respond to glutamate by releasing GABA. Our findings suggest a novel role for astrocytes in somatosensory information processing.ABSTRACT: Astrocytes participate in neuronal signalling by releasing gliotransmitters in response to neurotransmitters. We investigated if astrocytes from the dorsal horn of the spinal cord of adult red-eared turtles (Trachemys scripta elegans) release GABA in response to glutamatergic receptor activation. For this, we developed a GABA sensor consisting of HEK cells expressing GABAA receptors. By positioning the sensor recorded in the whole-cell patch-clamp configuration within the dorsal horn of a spinal cord slice, we could detect GABA in the extracellular space. Puff application of glutamate induced GABA release events with time courses that exceeded the duration of inhibitory postsynaptic currents by one order of magnitude. Because the events were neither affected by extracellular addition of nickel, cadmium and tetrodotoxin nor by removal of Ca2+ , we concluded that they originated from non-neuronal cells. Immunohistochemical staining allowed the detection of GABA in a fraction of dorsal horn astrocytes. The selective stimulation of A∂ and C fibres in a dorsal root filament induced a Ca2+ increase in astrocytes loaded with Oregon Green BAPTA. Finally, chelating Ca2+ in a single astrocyte was sufficient to prevent the GABA release evoked by glutamate. Our results indicate that glutamate triggers the release of GABA from dorsal horn astrocytes with a time course compatible with the integration of sensory inputs. This article is protected by copyright. All rights reserved.
AB - KEY POINTS SUMMARY: GABA is an essential molecule for sensory information processing. It is usually assumed to be released by neurons. Here we show that in the dorsal horn of the spinal cord, astrocytes respond to glutamate by releasing GABA. Our findings suggest a novel role for astrocytes in somatosensory information processing.ABSTRACT: Astrocytes participate in neuronal signalling by releasing gliotransmitters in response to neurotransmitters. We investigated if astrocytes from the dorsal horn of the spinal cord of adult red-eared turtles (Trachemys scripta elegans) release GABA in response to glutamatergic receptor activation. For this, we developed a GABA sensor consisting of HEK cells expressing GABAA receptors. By positioning the sensor recorded in the whole-cell patch-clamp configuration within the dorsal horn of a spinal cord slice, we could detect GABA in the extracellular space. Puff application of glutamate induced GABA release events with time courses that exceeded the duration of inhibitory postsynaptic currents by one order of magnitude. Because the events were neither affected by extracellular addition of nickel, cadmium and tetrodotoxin nor by removal of Ca2+ , we concluded that they originated from non-neuronal cells. Immunohistochemical staining allowed the detection of GABA in a fraction of dorsal horn astrocytes. The selective stimulation of A∂ and C fibres in a dorsal root filament induced a Ca2+ increase in astrocytes loaded with Oregon Green BAPTA. Finally, chelating Ca2+ in a single astrocyte was sufficient to prevent the GABA release evoked by glutamate. Our results indicate that glutamate triggers the release of GABA from dorsal horn astrocytes with a time course compatible with the integration of sensory inputs. This article is protected by copyright. All rights reserved.
KW - astrocyte
KW - GABA
KW - spinal cord
UR - http://www.scopus.com/inward/record.url?scp=85052822596&partnerID=8YFLogxK
U2 - 10.1113/jp276562
DO - 10.1113/jp276562
M3 - Journal article
C2 - 30079574
SN - 0022-3751
VL - 596
SP - 4983
EP - 4994
JO - The Journal of Physiology
JF - The Journal of Physiology
IS - 20
ER -