Neuronal activity-induced, equilibrative nucleoside transporter-dependent, somatodendritic adenosine release revealed by a GRAB sensor

Proc Natl Acad Sci U S A. 2023 Apr 4;120(14):e2212387120. doi: 10.1073/pnas.2212387120. Epub 2023 Mar 30.


The purinergic signaling molecule adenosine (Ado) modulates many physiological and pathological functions in the brain. However, the exact source of extracellular Ado remains controversial. Here, utilizing a newly optimized genetically encoded GPCR-Activation-Based Ado fluorescent sensor (GRABAdo), we discovered that the neuronal activity-induced extracellular Ado elevation is due to direct Ado release from somatodendritic compartments of neurons, rather than from the axonal terminals, in the hippocampus. Pharmacological and genetic manipulations reveal that the Ado release depends on equilibrative nucleoside transporters but not the conventional vesicular release mechanisms. Compared with the fast-vesicular glutamate release, the Ado release is slow (~40 s) and requires calcium influx through L-type calcium channels. Thus, this study reveals an activity-dependent second-to-minute local Ado release from the somatodendritic compartments of neurons, potentially serving modulatory functions as a retrograde signal.

Keywords: ENT transporter; adenosine; neuronal activity; somatodendrite.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine* / pharmacology
  • Guanine Nucleotide Exchange Factors / metabolism
  • Neurons*
  • Nucleoside Transport Proteins / genetics
  • Signal Transduction / physiology


  • Adenosine
  • Nucleoside Transport Proteins
  • Guanine Nucleotide Exchange Factors