Methods used in the lab
Improved fluorescent (calcium indicator) dye uptake in acute slice preparations by blocking multidrug resistance transporters
Fluorescence changes upon transporter blocking.
ATP-binding cassette (ABC) transporters are a family of transmembrane proteins that, also known as multidrug resistance proteins, transport a wide variety of substrates across biological membranes in an energy-dependent manner. We have found out that members of this protein family interfere with fluorescent (calcium indicator) dye uptake in cells in the OE of larval Xenopus laevis, including olfactory receptor neurons as well as in cells of the OB of larval Xenopus laevis. This shows that this effect not only serves to extrude xenobiotics in sensory cells of the OE, but that it is a more general feature occurring also in central nervous system neurons.
Effect of MK571 on dye uptake.
Therefore, blocking these transporters could improve fluorescent dye uptake in general. In practical terms this means that in many fluorescent (calcium) dye imaging studies the recording conditions may be improved. Note that this is particularly true in cases where the experimenter has not considered this possibility because the results so far obtained appeared satisfactory and did not openly call for improvement. Nonetheless, in these cases, applying a MRP transporter blocker during dye-ester loading would have the advantage of shorter slice incubation duration (and thus a fresher preparation) and of a better observability of fine cellular processes such as dendrites and spines.
For more information:
Manzini et al. (2008)