Exocytosis of gliotransmitters from cortical astrocytes: implications for synaptic plasticity and aging

Biochem Soc Trans. 2014 Oct;42(5):1275-81. doi: 10.1042/BST20140163.

Abstract

Maintaining brain function during aging is very important for mental and physical health. Recent studies showed a crucial importance of communication between two major types of brain cells: neurons transmitting electrical signals, and glial cells, which maintain the well-being and function of neurons. Still, the study of age-related changes in neuron-glia signalling is far from complete. We have shown previously that cortical astrocytes are capable of releasing ATP by a quantal soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) complex-dependent mechanism. Release of ATP from cortical astrocytes can be activated via various pathways, including direct UV-uncaging of intracellular Ca²⁺ or G-protein-coupled receptors. Importantly, release of both ATP and glutamate from neocortical astrocytes was not observed in brain slices of dominant-negative SNARE (dnSNARE) mice, expressing dnSNARE domain selectively in astrocytes. We also discovered that astrocyte-driven ATP can cause significant attenuation of synaptic inhibition in the pyramidal neurons via Ca²⁺-interaction between the neuronal ATP and γ-aminobutyric acid (GABA) receptors. Furthermore, we showed that astrocyte-derived ATP can facilitate the induction of long-term potentiation of synaptic plasticity in the neocortex. Our recent data have shown that an age-related decrease in the astroglial Ca²⁺ signalling can cause a substantial decrease in the exocytosis of gliotransmitters, in particular ATP. Age-related impairment of ATP release from cortical astrocytes can cause a decrease in the extent of astroglial modulation of synaptic transmission in the neocortex and can therefore contribute to the age-related impairment of synaptic plasticity and cognitive decline. Combined, our results strongly support the physiological relevance of glial exocytosis for glia-neuron communications and brain function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Aging*
  • Animals
  • Astrocytes / cytology
  • Astrocytes / metabolism*
  • Astrocytes / pathology
  • Calcium Signaling
  • Cell Communication
  • Exocytosis*
  • Glutamic Acid / metabolism*
  • Humans
  • Neocortex / cytology
  • Neocortex / growth & development
  • Neocortex / metabolism*
  • Neocortex / pathology
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neuronal Plasticity*
  • SNARE Proteins / genetics
  • SNARE Proteins / metabolism
  • Synaptic Transmission

Substances

  • Nerve Tissue Proteins
  • SNARE Proteins
  • Glutamic Acid
  • Adenosine Triphosphate