Spontaneous and multifaceted ATP release from astrocytes at the scale of hundreds of synapses

Glia. 2023 Sep;71(9):2250-2265. doi: 10.1002/glia.24392. Epub 2023 Jun 1.

Abstract

Astrocytes participate in information processing by releasing neuroactive substances termed gliotransmitters, including ATP. Individual astrocytes come into contact with thousands of synapses with their ramified structure, but the spatiotemporal dynamics of ATP gliotransmission remains unclear, especially in physiological brain tissue. Using a genetically encoded fluorescent sensor, GRABATP1.0 , we discovered that extracellular ATP increased locally and transiently in absence of stimuli in neuron-glia co-cultures, cortical slices, and the anesthetized mouse brain. Spontaneous ATP release events were tetrodotoxin-insensitive but suppressed by gliotoxin, fluorocitrate, and typically spread over 50-250 μm2 area at concentrations capable of activating purinergic receptors. Besides, most ATP events did not coincide with Ca2+ transients, and intracellular Ca2+ buffering with BAPTA-AM did not affect ATP event frequency. Clustering analysis revealed that these events followed multiple distinct kinetics, and blockade of exocytosis only decreased a minor group of slow events. Overall, astrocytes spontaneously release ATP through multiple mechanisms, mainly in non-vesicular and Ca2+ -independent manners, thus potentially regulating hundreds of synapses all together.

Keywords: astrocytes; calcium imaging; channel-mediated ATP release; exocytosis; extracellular ATP imaging; gliotransmission; neuron-glia interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Astrocytes* / metabolism
  • Calcium / metabolism
  • Calcium Signaling / physiology
  • Mice
  • Neuroglia / metabolism
  • Neurons / metabolism
  • Synapses* / metabolism

Substances

  • Adenosine Triphosphate
  • Calcium