Standard Article

Using pHluorins to Investigate Synaptic Function

  1. Matthew S Grubb,
  2. Juan Burrone

Published Online: 15 MAR 2009

DOI: 10.1002/9780470015902.a0021387



How to Cite

Grubb, M. S. and Burrone, J. 2009. Using pHluorins to Investigate Synaptic Function. eLS. .

Author Information

  1. King's College London, MRC Centre for Developmental Neurobiology, London, UK

Publication History

  1. Published Online: 15 MAR 2009


Genetically encoded probes are becoming increasingly powerful for measuring neuronal activity in vitro and in vivo. pHluorins, such as synaptopHluorin (spH), are genetically encoded reporters whose fluorescence depends on the pH of their biological environment. Because there are large differences in pH between synaptic vesicles and the extracellular medium, spH can be used to monitor presynaptic vesicle cycling, with various experimental manipulations allowing the study of specific exo- or endocytosis dynamics. pHluorins can also be used to study the turnover of neurotransmitter receptors on the postsynaptic membrane, and are being used with great effect to study the activity of neurons in a variety of in vivo systems.

Key concepts

  • pH-sensitive probes can be used to measure important aspects of synaptic function, including presynaptic vesicle cycling and postsynaptic receptor turnover.

  • SynaptopHluorin (spH) can be co mbined with other experimental manipulations to provide detailed information about specific presynaptic vesicle cycling processes.

  • Whereas synaptopHluorin possesses many advantages as an indicator of presynaptic vesicle cycling, it also possesses numerous drawbacks. These must be considered when interpreting spH studies.

  • The sensitivity of spH is not particularly good. However, presynaptic vesicle cycling can be followed with greater sensitivity using different pHluorin-based probes.

  • pHluorins can provide useful information about neuronal activity in vivo.


  • synaptopHluorin;
  • vesicle cycling;
  • neurotransmitter release;
  • presynaptic;
  • functional imaging