Fluorescence lifetime imaging tracks voltage patterns across frog embryonic tissue for more than 17 hours
Using fluorescence lifetime imaging to estimate membrane potential in spreading Xenopus neural crest explants, Tufts researchers saw voltage dynamics on timescales of seconds, minutes and hours that often spanned several cells.
What happened
The authors applied quantitative fluorescence lifetime imaging (FLIM) to optically estimate membrane potential in explants of Xenopus laevis neural crest as the tissue spread, recording for more than 17 hours.
They identified a slow component of bioelectric change over hours, and distinct faster components over minutes and over seconds. These dynamics often spanned multiple cells, consistent with a role in the tissue's collective behaviour. Using information theory, they found that the minutes-scale voltage dynamics were largely distinct from calcium dynamics. They also catalogue a range of bioelectric events, and suggest that tunnelling nanotubes are likely to be involved in transmitting them.
Why it matters
A recurring difficulty in developmental bioelectricity is measuring voltage quantitatively, across many non-neural cells, for long enough to relate it to what the tissue does. A lifetime-based readout that works at this scale is a methodological step towards mapping what the authors call the bioelectric code.
Caveats
This entry is based on the abstract. The measurements are optical estimates of membrane potential in explanted tissue, not in intact embryos. The abstract reports no test of what the observed patterns do, and the involvement of tunnelling nanotubes is put forward as likely, not shown.
Lifetime imaging reveals long-distance non-neural bioelectric patterns on timescales from seconds to hours
Read at Developmental Biology ↗