Fluorescent tracers (sodium fluorescein and Dextrans) are usually injected into the lateral tail vein of the mouse. The tracers are allowed to circulate for 30 minutes before trans cardiac perfusion.

If one wants to check permeability of two tracers (for example sodium fluorescein- mol. wt 376 Da and Rhodamine B dextran- mol. wt. 10000 Da), can one inject both tracers at the same time? One has to prepare a mixture of these tracers and adjust the concentrations so that the maximum volume of IV injection is 125 ul for a 25 gm mouse.

Are these tracers compatible with each other in solution in PBS?

Alternatively, one can inject tracers intraperitoneally. How long one should wait before cardiac perfusion when tracers are injected intraperitoneally? Is it possible to assess BBB function when tracers are injected in this manner?