title: Role of Astrocytes in Central Respiratory Chemoreception.
abstract: Astrocytes perform various homeostatic functions in the nervous system beyond that of a supportive or metabolic role for neurons. A growing body of evidence indicates that astrocytes are crucial for central respiratory chemoreception. This review presents a classical overview of respiratory central chemoreception and the new evidence for astrocytes as brainstem sensors in the respiratory response to hypercapnia. We review properties of astrocytes for chemosensory function and for modulation of the respiratory network. We propose that astrocytes not only mediate between CO2/H+levels and motor responses, but they also allow for two emergent functions: (1) Amplifying the responses of intrinsic chemosensitive neurons through feedforward signaling via gliotransmitters and; (2) Recruiting non-intrinsically chemosensitive cells thanks to volume spreading of signals (calcium waves and gliotransmitters) to regions distant from the CO2/H+sensitive domains. Thus, astrocytes may both increase the intensity of the neuron responses at the chemosensitive sites and recruit of a greater number of respiratory neurons to participate in the response to hypercapnia.
authors.affiliation: Departamento de Biología, Universidad de Santiago de Chile (USACH), PO 9170022, Santiago, Chile. jaime.eugenin@usach.cl.
authors.forename: Jaime
authors.initials: J
authors.lastname: Eugenín León
authors.affiliation: Departamento de Biología, Universidad de Santiago de Chile (USACH), PO 9170022, Santiago, Chile.
authors.forename: María José
authors.initials: MJ
authors.lastname: Olivares
authors.affiliation: Departamento de Biología, Universidad de Santiago de Chile (USACH), PO 9170022, Santiago, Chile.
authors.forename: Sebastián
authors.initials: S
authors.lastname: Beltrán-Castillo
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000502:physiology*; D020013:Calcium Signaling; D002245:Carbon Dioxide / Q000378:metabolism*; D002628:Chemoreceptor Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D006935:Hypercapnia / Q000378:metabolism* / Q000503:physiopathology; D008125:Locus Coeruleus / Q000166:cytology / Q000502:physiology; D066267:Midbrain Raphe Nuclei / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism; D011522:Protons; D012125:Respiratory Center / Q000166:cytology / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism; D009435:Synaptic Transmission
chemical_list: D000596:Amino Acids; D018377:Neurotransmitter Agents; D011522:Protons; D002245:Carbon Dioxide; D012701:Serotonin
keywords: Astrocytes; Brainstem; Central chemoreception; Glia; Gliotransmitters; Locus coeruleus nuclei; Raphe nuclei; Respiratory rhythm; Retrotrapezoid nuclei