Letter | Published:

Neuromodulators signal through astrocytes to alter neural circuit activity and behaviour

Nature volume 539, pages 428432 (17 November 2016) | Download Citation


Astrocytes associate with synapses throughout the brain and express receptors for neurotransmitters that can increase intracellular calcium (Ca2+)1,2,3. Astrocytic Ca2+ signalling has been proposed to modulate neural circuit activity4, but the pathways that regulate these events are poorly defined and in vivo evidence linking changes in astrocyte Ca2+ levels to alterations in neurotransmission or behaviour is limited. Here we show that Drosophila astrocytes exhibit activity-regulated Ca2+ signalling in vivo. Tyramine and octopamine released from neurons expressing tyrosine decarboxylase 2 (Tdc2) signal directly to astrocytes to stimulate Ca2+ increases through the octopamine/tyramine receptor (Oct-TyrR) and the transient receptor potential (TRP) channel Water witch (Wtrw), and astrocytes in turn modulate downstream dopaminergic neurons. Application of tyramine or octopamine to live preparations silenced dopaminergic neurons and this inhibition required astrocytic Oct-TyrR and Wtrw. Increasing astrocyte Ca2+ signalling was sufficient to silence dopaminergic neuron activity, which was mediated by astrocyte endocytic function and adenosine receptors. Selective disruption of Oct-TyrR or Wtrw expression in astrocytes blocked astrocytic Ca2+ signalling and profoundly altered olfactory-driven chemotaxis and touch-induced startle responses. Our work identifies Oct-TyrR and Wtrw as key components of the astrocytic Ca2+ signalling machinery, provides direct evidence that octopamine- and tyramine-based neuromodulation can be mediated by astrocytes, and demonstrates that astrocytes are essential for multiple sensory-driven behaviours in Drosophila.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    , , & Glutamate induces calcium waves in cultured astrocytes: long-range glial signaling. Science 247, 470–473 (1990)

  2. 2.

    , , & Intercellular signaling in glial cells: calcium waves and oscillations in response to mechanical stimulation and glutamate. Neuron 6, 983–992 (1991)

  3. 3.

    , & Neuronal activity triggers calcium waves in hippocampal astrocyte networks. Neuron 8, 429–440 (1992)

  4. 4.

    Do astrocytes process neural information? Prog. Brain Res. 94, 119–136 (1992)

  5. 5.

    & Astrocyte calcium signaling: from observations to functions and the challenges therein. Cold Spring Harb. Perspect. Biol. 7, a020404 (2015)

  6. 6.

    et al. Gliotransmitters travel in time and space. Neuron 81, 728–739 (2014)

  7. 7.

    & Diversity of astrocyte functions and phenotypes in neural circuits. Nat. Neurosci. 18, 942–952 (2015)

  8. 8.

    & Spontaneous changes in intracellular calcium concentration in type I astrocytes from rat cerebral cortex in primary culture. Glia 5, 95–104 (1992)

  9. 9.

    , & Hippocampal astrocytes in situ exhibit calcium oscillations that occur independent of neuronal activity. J. Neurophysiol. 87, 528–537 (2002)

  10. 10.

    & Hippocampal astrocytes in situ respond to glutamate released from synaptic terminals. J. Neurosci. 16, 5073–5081 (1996)

  11. 11.

    , & Motor behavior activates Bergmann glial networks. Neuron 62, 400–412 (2009)

  12. 12.

    , , & Ensheathing glia function as phagocytes in the adult Drosophila brain. J. Neurosci. 29, 4768–4781 (2009)

  13. 13.

    et al. Drosophila hygrosensation requires the TRP channels water witch and nanchung. Nature 450, 294–298 (2007)

  14. 14.

    et al. α1-Adrenergic receptors mediate coordinated Ca2+ signaling of cortical astrocytes in awake, behaving mice. Cell Calcium 54, 387–394 (2013)

  15. 15.

    et al. Norepinephrine controls astroglial responsiveness to local circuit activity. Neuron 82, 1263–1270 (2014)

  16. 16.

    et al. Ca2+ signaling in astrocytes from Ip3r2-/- mice in brain slices and during startle responses in vivo. Nat. Neurosci. 18, 708–717 (2015)

  17. 17.

    , , & Control of directional change after mechanical stimulation in Drosophila. Mol. Brain 5, 39–52 (2012)

  18. 18.

    , , , & TRPA1 channels are regulators of astrocyte basal calcium levels and long-term potentiation via constitutive D-serine release. J. Neurosci. 33, 10143–10153 (2013)

  19. 19.

    & Adrenergic calcium signaling in astrocyte networks within the hippocampal slice. J. Neurosci. 15, 5535–5550 (1995)

  20. 20.

    & Norepinephrine-evoked calcium transients in cultured cerebral type 1 astroglia. Glia 3, 529–538 (1990)

  21. 21.

    & Neuroarchitecture of aminergic systems in the larval ventral ganglion of Drosophila melanogaster. PLoS One 3, e1848 (2008)

  22. 22.

    , , , & Membrane electrical excitability is necessary for the free-running larval Drosophila circadian clock. J. Neurobiol. 62, 1–13 (2005)

  23. 23.

    , , , & Cloning and characterization of a Drosophila tyramine receptor. EMBO J. 9, 3611–3617 (1990)

  24. 24.

    et al. Agonist-specific coupling of a cloned Drosophila octopamine/tyramine receptor to multiple second messenger systems. EMBO J. 13, 1325–1330 (1994)

  25. 25.

    , , & A tyramine receptor gene mutation causes a defective olfactory behavior in Drosophila melanogaster. Gene 245, 31–42 (2000)

  26. 26.

    et al. Layered reward signalling through octopamine and dopamine in Drosophila. Nature 492, 433–437 (2012)

  27. 27.

    Glial cell inhibition of neurons by release of ATP. J. Neurosci. 23, 1659–1666 (2003)

  28. 28.

    , & Exocytosis of gliotransmitters from cortical astrocytes: implications for synaptic plasticity and aging. Biochem. Soc. Trans. 42, 1275–1281 (2014)

  29. 29.

    & Drosophila melanogaster G protein-coupled receptors. J. Cell Biol. 150, F83–F88 (2000)

  30. 30.

    et al. Drosophila TRPA1 channel mediates chemical avoidance in gustatory receptor neurons. Proc. Natl Acad. Sci. USA 107, 8440–8445 (2010)

  31. 31.

    , & Characterization of Drosophila tyramine β-hydroxylase gene and isolation of mutant flies lacking octopamine. J. Neurosci. 16, 3900–3911 (1996)

  32. 32.

    et al. Two functional but noncomplementing Drosophila tyrosine decarboxylase genes: distinct roles for neural tyramine and octopamine in female fertility. J. Biol. Chem. 280, 14948–14955 (2005)

  33. 33.

    et al. Converging circuits mediate temperature and shock aversive olfactory conditioning in Drosophila. Curr. Biol. 24, 1712–1722 (2014)

  34. 34.

    & Sex-specific control and tuning of the pattern generator for courtship song in Drosophila. Cell 133, 354–363 (2008)

  35. 35.

    & smellblind: a gene required for Drosophila olfaction. Genetics 124, 293–302 (1990)

Download references


We thank our colleagues, the Vienna Drosophila RNAi Center and the Bloomington Stock Center for providing fly stocks, members of the Freeman laboratory for comments on the manuscript and A. Sheehan for generating the wtrw::gfp construct. This work was supported by NINDS grant R01 NS053538 (to M.R.F.). During the period of this study M.R.F. was an Investigator with the Howard Hughes Medical Institute.

Author information

Author notes

    • Marc R. Freeman

    Present address: Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97239, USA.


  1. Department of Neurobiology and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA

    • Zhiguo Ma
    • , Tobias Stork
    •  & Marc R. Freeman
  2. Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA

    • Dwight E. Bergles


  1. Search for Zhiguo Ma in:

  2. Search for Tobias Stork in:

  3. Search for Dwight E. Bergles in:

  4. Search for Marc R. Freeman in:


Z.M. and M.R.F. designed experiments. Z.M. performed all experiments. T.S. provided alrm-LexA::GAD transgenic flies. D.E.B. provided unpublished data on norepinephrine-mediated activation of mammalian astrocytes and input that helped guide the course of the study. Z.M. and M.R.F. wrote the manuscript with editing by T.S.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Marc R. Freeman.

Reviewer Information

Nature thanks L. Luo, B. MacVicar, L. Vosshall and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Extended data

Supplementary information


  1. 1.

    Synchronous somatic calcium transients in Drosophila astrocytes

    Top left: mCherry. Top right: GCaMP6s. Bottom left: merge. Video was sped up X100.

  2. 2.

    Concomitant activity of Tdc2+ neurons and astrocytes

    Top left: GCaMP6s labeled astrocytes. Top right: R-GECO1 labeled Tdc2+ neurites. Bottom left: merge. Video was sped up X50.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.