title: Determinants of functional coupling between astrocytes and respiratory neurons in the pre-Bötzinger complex.
abstract: Respiratory neuronal network activity is thought to require efficient functioning of astrocytes. Here, we analyzed neuron-astrocyte communication in the pre-Bötzinger Complex (preBötC) of rhythmic slice preparations from neonatal mice. In astrocytes that exhibited rhythmic potassium fluxes and glutamate transporter currents, we did not find a translation of respiratory neuronal activity into phase-locked astroglial calcium signals. In up to 20% of astrocytes, 2-photon calcium imaging revealed spontaneous calcium fluctuations, although with no correlation to neuronal activity. Calcium signals could be elicited in preBötC astrocytes by metabotropic glutamate receptor activation or after inhibition of glial glutamate uptake. In the latter case, astrocyte calcium elevation preceded a surge of respiratory neuron discharge activity followed by network failure. We conclude that astrocytes do not exhibit respiratory-rhythmic calcium fluctuations when they are able to prevent synaptic glutamate accumulation. Calcium signaling is, however, observed when glutamate transport processes in astrocytes are suppressed or neuronal discharge activity is excessive.
authors: Abt. Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany.
authors: Christian
authors: C
authors: Schnell
authors: Jens
authors: J
authors: Fresemann
authors: Swen
authors: S
authors: Hülsmann
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D001464:Barium / Q000494:pharmacology; D066298:In Vitro Techniques; D008564:Membrane Potentials; D051379:Mice; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D018408:Patch-Clamp Techniques; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D012137:Respiratory System / Q000166:cytology* / Q000378:metabolism
chemical_list: D027322:Amino Acid Transport System X-AG; D018094:Receptors, Metabotropic Glutamate; D001464:Barium