posted on 2022-01-25, 21:31authored byYuanyu Chang, B. Jill Venton
Rapid
adenosine signaling has been detected spontaneously or after
mechanical stimulation in the brain, providing rapid neuromodulation
in a local area. To measure rapid adenosine signaling, a single carbon-fiber
microelectrode has traditionally been used, which limits spatial resolution
and an understanding of regional coordination. In this study, we utilized
dual-channel fast-scan cyclic voltammetry to measure the spontaneous
or mechanically stimulated adenosine release at two electrodes placed
at different spacings in hippocampal CA1 mouse brain slices. For mechanically
stimulated adenosine release, adenosine can be detected up to 150
μm away from where it was stimulated, although the signal is
smaller and delayed. While spontaneous adenosine transients were detected
at both electrodes, only 10 percent of the events were detected concurrently,
and that number was similar at 50 and 200 μm electrode spacings.
Thus, most adenosine transients were not caused by the widespread
coordination of release. There was no evidence of diffusion of spontaneous
transients to a second electrode 50–200 μm away. This
study shows that spontaneous adenosine events are very localized and
thus provide only local neuromodulation. Injury, such as mechanical
stimulation, allows adenosine to diffuse farther, but the neuroprotective
effects are still regional. These results provide a better understanding
of the spatial and temporal profiles of adenosine available to act
at receptors, which is crucial for future studies that design neuroprotective
treatments based on rapid adenosine signaling.